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New Mexico Bureau of Geology Editorial Style Guide

Last updated July 26, 2023

This style guide is designed for you, our valued collaborators. You are the contributors who create content for the New Mexico Bureau of Geology and Mineral Resources’ (NMBGMR) technical and general audience publications. This editorial style guide is meant to support you in developing your important and valuable written work and to ensure consistency and excellence across all Bureau of Geology communications.

This style guide is a living document that will be updated continually with your input. The publications team welcomes your insight into the best style practices in your particular field, and we want to know of any content and style issues not currently addressed by this guide. Please send questions and suggestions to and help us keep our guidelines current.

The style presented here combines several sources:

The number one rule of style is simply be consistent.
First and foremost, be internally consistent within a single document. Then, be consistent among documents.

Standalone entries with no definition/style guidance represent preferred bureau capitalization or spelling.

Use Control+F (PC) or Command+F (Mac) to search the guide.


AA – see academic degrees

abbreviations and acronyms

General rules

  • Be consistent in the use of abbreviations and acronyms throughout the document.
  • Common abbreviations and acronyms don’t need to be defined when used (for example, radar for radio detecting and ranging, GIF for graphics interchange format).
  • For less well-known abbreviations or acronyms, or those that are unique to a publication, spell out the full name or term, followed by the abbreviation/acronym in parentheses (for example, net vertical tectonic displacement (NVTD)) at the first mention of the term in the abstract and in the text and at the first mention in chapters with different authors. After that, use the abbreviation/acronym.
  • Don’t use abbreviations or acronyms to start a sentence. Instead, write out the abbreviation/acronym, or consider rewriting the sentence; for acronyms, the can be used to start the sentence (for example, The New Mexico Bureau of Geology and Mineral Resources is the state geological survey).
  • Abbreviations and acronyms may start a figure caption to save space.
  • Don’t use abbreviations or acronyms in headings.
  • Don’t abbreviate the names of months and days in the main text; abbreviations are acceptable in figures and tables to save space (see time).
  • Don’t abbreviate geographic names in the text (for example, Elephant Butte Lake, not EBL; San Juan Basin, not SJB). However, cumbersome geologic names that appear numerous times throughout the text can be abbreviated (for example, FSLC for Farmington Siding landslide complex, WVFZ for West Valley fault zone).
  • Don’t use two-letter postal service abbreviations (for example, NM) in the text to abbreviate state names; instead, write out state names in the text (see state). Postal service abbreviations should be used in mailing/physical addresses, and are acceptable in figures and maps to save space.
  • When in doubt, spell it out. This especially applies to reports written for a nontechnical audience who may be unfamiliar with certain abbreviations and acronyms.

Chemical terminology

The names of chemical elements and molecules are written out rather than abbreviated, with the following exceptions:

  • When referring to geochronology methods (for example, 40Ar/39Ar, U-Pb).
  • When listing more than five elements (for example, descriptions of samples accompany analytical data for Au, Ag, Cu, Pb, Zn, and As).
  • In a complex term (for example, Ca-Mg-SO3-NO solution).
  • When describing ions (for example, Ca+ and Mg+).

Elements and molecules are abbreviated in figures.

Lithologic and time-stratigraphic terms

Don’t abbreviate lithologic and time-stratigraphic terms in the text. Abbreviations are acceptable in figures and tables to save space.

Capitalize lithologic abbreviations when they follow a formal rock unit name (for example, Navajo Ss.). When used informally to refer to a general rock type, the lithologic abbreviation is lowercase (sandstone, ss.). Always capitalize time-stratigraphic abbreviations. Table 1 summarizes abbreviations used for lithologic and time-stratigraphic terms.


Time as a unit of measure Use a numeral to express lengths of time (for example, 2 years, 4 months, 8 weeks, 13 days).

Calendar dates – Common Era (CE) and Before the Common Era (BCE) are the preferred notations for the Gregorian calendar; they are equivalent to Anno Domini (A.D.) and Before Christ (B.C.) but are religiously neutral. The abbreviations don’t take periods and are placed after the year. No abbreviations are needed if the time period is defined in the text (for example, a discussion of 20th century land-use policy would not need CE after dates). There is no year 0; the year 1 CE comes after the year 1 BCE. For ranges of years, start with the oldest year:

  • 350–335 BCE
  • 2000–2019

Use numerals for all dates (note comma usage in the examples below):

  • January 1994
  • May 18, 1980
  • April 17, 1983, to August 26, 1995

January, February, August, September, October, November, and December may be abbreviated to save space in figures and captions:

  • Oct. 13, 1956

Dates may be abbreviated with only numerals in tables to save space; use the format mm/dd/yyyy.

When naming computer files, the format yyyymmdd used at the beginning of the file name is preferred so the files will sort chronologically (for example, 20230711_file.docx).

Spell out months when used alone or with only a year:

  • The convention is usually in September.
  • She was born in October 1956.

Don’t use the ordinal form of the number (adding st, th, rd, etc.) with dates:

  • The deadline for entries is May 31 (not May 31st)

Geologic time – ka for kilo-annum (thousand years), Ma for mega-annum (million years), and Ga for giga-annum (billion years) are reserved for reporting geologic ages. Time measured from the present is implicit in ka, Ma, and Ga, and neither before present nor ago is added to these abbreviations.

Durations and intervals of time (for example, for geologic processes) may be abbreviated as kyr (thousands of years), Myr (millions of years), and Gyr (billions of years).

Use 14C yr BP for uncalibrated radiocarbon ages (radiocarbon years before present, with present fixed as 1950 CE). Use cal yr BP (calendar years before present) for calendar-calibrated radiocarbon ages.

When listing ranges of geologic ages, list the oldest date first (for example, radiometric ages range between 24 and 22 Ma). Otherwise, time ranges are given with the youngest date first (as with ranges of other values; for example, 10–20 years ago, 22–25 Myr).


  • An 40Ar/39Ar age of 986 ka and a K/Ar age of 1.22 Ma identify the age of the tuff as middle Pleistocene.
  • The radiocarbon age of 3,650 ± 70 14C yr BP (4,400–3,600 cal yr BP) obtained from the buried A horizon corresponds well with the thermoluminescence age of 4,200 ± 400 yr BP obtained from the loess unit.
  • The beginning and the end of the Cretaceous Period are calibrated at 145.0 ± 4.0 Ma and 66.0  Ma, respectively; the interval of time represented by the Cretaceous is 79 Myr.

academic degrees – no periods in abbreviations; not capitalized when used as general terms
Associate of Arts (AA), Associate of Science (AS), associate’s degree (for example, Pat Jones was awarded an Associate of Science degree in biology; Pat Jones has an associate’s degree)
Bachelor of Arts (BA), Bachelor of Science (BS), bachelor’s degree
Master of Arts (MA), Master of Science (MS), master’s degree
Doctor of Philosophy (PhD), doctoral degree or doctorate
Name, degree (for example, Pat Jones, PhD)

acequia – refers both to the canal and other irrigation infrastructure and the political organization/community that manages and uses the community-operated irrigation system

acequia parciante

acid mine drainage – used to refer to the outflow of acidic water from mining operations

acid rock drainage – used to refer to the outflow of acidic water that can occur naturally as part of weathering processes

acknowledgments – not acknowledgements

A.D. – see time

adjective – a word or phrase that describes a noun (for example, large, grainy, oblong); see parts of speech

adverb – a word or phrase that modifies an adjective, verb, or other adverb or a group of words, usually describing a relation of place, time, circumstance, manner, cause, degree, etc. (for example, loudly, here, often); see parts of speech

affect/effectaffect as a verb means to influence (for example, may affect flow patterns), effect as a verb means to cause (for example, to effect change) and as a noun means a result (for example, the effect was quite positive)

aftereffect – not after-effect or after effect

Albuquerque Basin – see capitalization

Albuquerque Bernalillo County Water Utility Authority – referred to as the Water Authority (not ABCWUA, as of March 2023)

American Indian – acceptable for general use (for example, American Indian cultures); when referring to a specific tribe, nation, or pueblo, use that group’s preferred name (for example, Jicarilla Apache Nation, Pueblo of Acoma); if possible, verify the usage with the tribe, nation, or pueblo

among/betweenbetween is used with two items, among is used for more than two

Ancestral Rocky Mountains

anti – see prefixes and suffixes

approximately – The ≈ symbol means approximately with evidence, the ~ symbol means approximately without the context of evidence. Over the years, ~ has become the de facto symbol, but neither should be used for scientific publications; write out approximately instead.

apostrophe – see punctuation

40Ar/39Ar – argon-argon dating, a method of radioisotopic dating

ArcGIS – a family of client, server, and online GIS software developed and maintained by Esri

archaeology (n), archaeological (adj) – for example, the science of archaeology, an archaeological dig

areal extent – used in technical publications; for general audiences, use size instead

A research and service division of New Mexico Tech – lowercase, not A Research and Service Division of, not A research division of  

aridity indexes – not indices

artifact (n), artifactual (adj) – not artefact; for example, an artifact was discovered, the dig produced a lot of artifactual material

AS – see academic degrees

ash fall – preferred over Plinian deposits; don’t use air fall or airfall

azimuth – for compass directions using azimuth angles (0–360°), no directional symbol (N, NE, NNW, etc.) is needed (for example, 210°); note that azimuth measurements are preferred for reporting strike in reports, and dip direction is required in GIS


BA – see academic degrees

back end (n), back-end (adj) – for example, the application’s back end, a back-end developer

backcountry – spelled as one word, unless used in a formal title and spelled as two words (for example, Black Hills Back Country Byway)


back slope

backup (n, adj), back up (v) – for example, make a backup of the files, a backup copy, they will back up the files

bankfull capacity

base flow

base map – not basemap

basin – see capitalization

B.C. – see time



between/amongbetween is used with two items, among is used for more than two

bi/bio – see prefixes and suffixes

billion – equals 1,000 million (109)

blueline/digital dylux – types of printers’ proofs

bootheel – for example, the bootheel of New Mexico


bosque – not Bosque, except as part of a formal name (for example, Bosque del Apache)

BP – see time

brackets – see punctuation

BS – see academic degrees

BTU – see units of measurement

buildup (n), build up (v) – for example, a buildup of sediments, the sediments build up over time

buy-in (n), buy in (v) – for example, we had buy-in from the stakeholders, you must buy in to join the poker game




ca. – abbreviation for circa, Latin for about or approximately

caldera – see capitalization



Rules governing capitalization are numerous and subject to many exceptions. The goal is to avoid random acts of capitalization! Be consistent throughout a publication.

Biological classification

Capitalize the name of a biological phylum, class, order, family, or genus, but not species, subspecies, or variety (for example, Foraminifera, Arecaceae, Tyrannosaurus rex, Homo sapiens, Prunus virginiana var. demissa).

Callouts to figures, tables, appendices, and chapters

Capitalize the words figure, table, appendix, and chapter when they’re given in the text to refer readers to a subsequent item (for example, the features in Figure 1 illustrate, refer to Chapter 2).

When calling out to another chapter in the same publication, use the same numbering convention as the chapter itself; that is, if the chapters are numbered in Roman numerals, use Roman numerals in the callouts.

If another author’s figure, table, appendix, or chapter is being called out, use lowercase (for example, At its reference section in the Rio Salado Valley (Hook et al., 1983, table 3), the formation is divided into three members.).

See figure callouts.

Chemical elements and molecules

The names of elements and molecules are not capitalized in text. When using chemical symbols (see abbreviations and acronyms), use the capitalization style in the periodic table.

Compass directions

Use lowercase for compass directions when written out (for example, north, south, northwest, north-northwest) and for descriptive terms that denote direction or position (for example, southeastern New Mexico). Abbreviations for compass directions should be capitalized (for example, N, S, E, W, NE, SW, NNE).

Capitalize directions only when they designate regions:

  • Farmington is northwest of Albuquerque.
  • Earthquakes are more common on the West Coast.
  • Southerners eat more fried foods than Northerners.
  • The climate is wet in the Northwest.

See directionals.


Proper geographic names are capitalized (for example, Monument Valley, Organ Mountains, El Vado Lake). Names that are not recognized as formal may be capitalized in some cases, for example, if they are the subject of a publication. This guide contains individual entries for some geographic names whose capitalizations differs from these rules due to common usage. For terms not listed here, authors should refer to the U.S. Geological Survey Geographic Names Information System (GNIS) to determine if a geographic name is formal and should be capitalized.

More specifics:

  • Areas of indefinite extent are lowercase (for example, Albuquerque area, Bonneville basin).
  • Mining districts, oil fields, gas fields, fields, mines, smelters, and other terms related to mineral or hydrocarbon extraction and processing are not capitalized when included as part of a proper name (for example, Luis Lopez mining district, Hobbs oil field, Raton coalfield, Kelley mine, Cuba smelter).
  • Structural geologic terms are not capitalized when included as part of a geologic name (for example, San Ysidro anticline, Embudo fault zone). Even when used with a proper name, lowercase is preferred for anticline, arch, area, basalt flow, batholith, claim, coal bed, coalfield, coal seam, cone, cyclothem, deposit, dome, embayment, escarpment, facies, fault, fault zone, homocline, mill, mine, mining district, monocline, oil field, pluton, principal meridian, prospect, quadrangle, region, rift, sag, syncline, uplift, well, and zone.

See geographic names.

Geologic time/stratigraphy

Capitalize the names of eons, eras, periods, epochs, ages, eonothems, erathems, systems, series, and stages.

The geochronologic terms early, middle, and late and the chronostratigraphic terms lower, middle, and upper are capitalized only as part of a formal geologic time or rock series name (for example, Early Jurassic, Upper Devonian). They are lowercase for informal designations (for example, early Holocene, middle Eocene). For geochronologic use, authors are encouraged to follow the Geological Society of America’s Geologic Time Scale. For chronostratigraphic use, authors are encouraged to follow the International Commission on Stratigraphy’s International Chronostratigraphic Chart.

Geochronologic (time)

  • Capitalize the names of geologic eons, eras, periods, epochs, and ages.
  • All subdivisions of ages are informal (for example, early Maastrichtian, late Albian).
  • Capitalize early, middle, and late when used with Jurassic, Triassic, Pennsylvanian, Mississippian, Devonian, and Ordovician. Capitalize early and late with Cretaceous (no middle).
  • Lowercase early, middle, and late when used with Quaternary, Neogene, Paleogene, Permian, and Silurian.

Chronostratigraphic (position)

  • Capitalize the names of geologic eonothems, erathems, systems, series, and stages.
  • All subdivisions of stages are informal (for example, lower Maastrichtian, upper Albian).
  • Capitalize lower, middle, and upper when used with Jurassic, Triassic, Pennsylvanian, Mississippian, Devonian, and Ordovician. Capitalize lower and upper with Cretaceous (no middle).
  • Lowercase lower, middle, and upper when used with Quaternary, Neogene, Paleogene, Permian, and Silurian.

Geologic units

The names of formal geologic units are proper nouns and are capitalized (for example, Chinle Formation, Navajo Draw Member of Arroyo Ojito Formation of Santa Fe Group). Authors should consult the U.S. Geological Society National Geologic Map Database (aka Geolex) to determine if a unit is formally recognized.

In the names of informal geologic units, don’t capitalize unit terms for lithology or formation (for example, Huckleberry Ridge ash bed, Left Creek quartzite, formation of Aurora).

See geologic names/geologic units.


Use title case capitalization for headings.

Legislative, administrative, and judicial bodies

The full names of legislative, administrative, and judicial bodies, departments, bureaus, and offices are capitalized (for example, U.S. Department of Energy). Abbreviated names are not (for example, the energy department [in relation to the U.S. Department of Energy]).

Mineral names

Mineral names are not capitalized unless they begin a sentence; see minerals.

Professional titles

Capitalize professional titles only when they come before a person’s name (for example, Pat Jones is the state geologist, State Geologist Pat Jones).

Proper nouns

Always capitalize proper nouns, including hyphenated words in titles and headings (for example, Pat Jones, Open-File Report 618).

Don’t capitalize conjunctions, short prepositions (for example, of, for, from), or articles (for example, the, a, an) in long proper names (for example, New Mexico Bureau of Geology and Mineral Resources).

In the report text, capitalize all important words in the titles of books, journal articles, and reports (for example, Geologic History of Utah by Lehi F. Hintze; see title case); for capitalization of reference entries, see references.

Singular nouns used to replace proper nouns are not capitalized (for example, Rio Grande del Norte National Monument, but the monument; White Sands National Park, but the park).


Don’t capitalize spring, summer, fall, autumn, or winter unless part of a formal name (for example, sampling was carried out in spring and winter, the program was held in the fall, the New Mexico Geological Society Fall Field Conference was in October).


Use title case capitalization for titles of works (books, journals, articles, etc.) in the main text of a publication.


For all visuals (figures, maps, charts, and photos), captions have an end period and are not italicized. If a credit is included, it immediately follows the main caption text, and the credit is written in italics with no end period (for example, View of the Albuquerque volcanoes from the South Valley. Photo by Pat Jones). If the contributor is not a Bureau of Geology employee, include their organizational affiliation (for example, Photo by Pat Jones, USGS).

A photo credit may also read Photo courtesy of Name and follow the same format; this is used when the identity of the original photographer is not known and the photo has been provided to the Bureau of Geology by a contributing author or editor.

Permissions statements in captions are italicized and have a period (for example, The clinker formation sequence. Reproduced with permission from Pendant Publishing.).

carbon-14 – also symbol 14C

cattle guard


Celsius – not centigrade; see units of measurement and temperature


cfs – see units of measurement

chemistry – see abbreviations and acronyms and capitalization

Chihuahuan Desert – see capitalization

circa – abbreviated as ca.; Latin for approximately; do not use ca. in the main text of a publication; instead, write out around or approximately


Citations are parenthetical source attributions in the body of text. Each citation must have a corresponding entry in the reference list at the end of the publication. In-text citations within a separate parenthetical statement should be enclosed in brackets (see brackets). For guidance on formatting reference entries, see references.

  • Give the author’s name and year of publication, separated by a comma:
    • The outcrop had eroded (Jones, 2016).
  • If there are two authors, give both, separated by and:
    • The outcrop had eroded (Jones and Doe, 2016).
  • If there are three or more authors, give the first author, then et al.:
    • The formation consists of three members (Jones et al., 2016).
  • If the citation is part of the sentence, include only the date in parentheses:
    • According to Jones et al. (2016), the outcrop is accessible only by helicopter.
  • If there are multiple publications by the same author, separate them with commas and list them in ascending chronological order:
    • (Jones, 2010, 2012, 2016)
  • To list multiple sources in the same citation, separate them with semicolons and list them in ascending chronological order. If two sources have the same date, alphabetize them:
    • (Jones et al., 2010; Doe, 2012; Miller, 2012; Baker and Jones, 2020)
  • If you are citing a direct quote (see quotations), paraphrasing material, or citing data/measurements without quotation marks, include the page number:
    • The outcrop “was dangerous to access” (Jones, 2016, p. 47).
  • Cite unpublished information relayed personally by a source in written or verbal form as “personal communication” or “unpublished data,” and include at least the year (include a more precise date if possible):
    • (P. Jones, personal communication, June 2019)
    Personal communications/unpublished data are not listed in the references section because readers cannot access such unpublished information.
  • For information on citing legal sources, consult the U.S. legal profession’s primary style guide, The Bluebook Online (

cleanup (n), clean up (v) – for example, the spill cleanup is finished, we must clean up the spill

cliff former (n), cliff-forming (adj) – for example, the cliff former is more resistant to erosion, a cliff-forming outcrop


co – see prefixes and suffixes

coal bed

coalbed methane


coal-fired power plant


collective nouns – in American English, these (for example, class, company, family, group, staff, etc.) take a singular verb (for example, the class is working, the staff was seated)

colon – see punctuation

Colorado Mineral Belt

comma – see punctuation

compared to/withto indicates similarity (for example, we compared the seismicity of the central United States to the seismicity of Gansu Province in China); with indicates juxtaposition (for example, the formation contains few fossils compared with the type section)

compass directions – unhyphenated unless two directions are combined (for example, northeast, southwest, east-northeast); see capitalization and punctuation

compliment/complementcompliment is polite praise or congratulations (for example, please send my compliments to the chef); complement is something that completes something else (for example, their tie is a nice complement to their suit)

compose, comprise, constitutecompose means to put together (for example, the United States is composed of 50 states); comprise means to contain (for example, the United States comprises 50 states); a whole comprises its parts, not the other way around (incorrect: 50 states comprise the United States); constitute means to form or make up (for example, 50 states constitute the United States); comprised of is never correct, use comprises or composed of instead

Congress – capitalize when referring to the United States Congress; don’t capitalize congressional; don’t capitalize congress when used with its other meanings (that is, a formal meeting, a society/organization, or the act of coming together)

continual/continuouscontinual indicates steady repetition over time (for example, we continually argue about stratigraphic boundaries); continuous means uninterrupted (for example, the wind blew continuously)

copyrighted material

If you use photographs, illustrations, or long quotations from someone else, you must cite the source and, in most cases (see government agencies exception below), obtain permission to use the material. Don’t assume that because you copied a figure from the internet that you can use it without permission. Modifying a figure doesn’t negate the copyright; it’s still the intellectual property of the original source. The copyright holder is often not the author but instead the author’s employer or publisher.

The major exception is works published by U.S. government agencies; these are automatically in the public domain. You don’t need to get permission to use anything published by government agencies or departments (for example, U.S. Geological Survey [USGS], U.S. Environmental Protection Agency [EPA]); however, you must still include an appropriate citation.

Many publishers have statements on their websites automatically granting permission to use their materials. Others may ask you to fill out a form, but most will grant permission for free. Sometimes the publisher asks for specific language to be used in the credit. Occasionally, permission carries a fee; in these cases, you might reconsider using the figure. Keep a record of any permissions you secure and forward them to the publications group in case there is a question of usage in the future.


credits – for any visuals that require a credit (including figures, maps, charts, and photos), use italics and no end period (for example, Photo by Pat Jones); see captions

Cretaceous – the K–T boundary is now known as the K–Pg boundary; see Tertiary

critical mineral deposits – not critical-mineral deposits

cross – Many compound words are formed with cross. For geologic terms, refer to the Glossary of Geology; for general terms, refer to Merriam-Webster Dictionary. If a word is unlisted and is a noun, don’t hyphenate; hyphenate only adjective, adverb, and verb forms.

cross-bedding (n), cross-bed (n), cross-bedded (adj) – for example, the sandstone exhibits extensive cross-bedding, cross-beds can indicate prior conditions, a cross-bedded sandstone

crosscut (n), crosscutting (adj) – for example, the crosscut intersects a vein, a crosscutting passageway


cross section (n), cross-sectional (adj) – for example, Figure 1 shows a cross section of the structure, a cross-sectional diagram


cuesta – not questa, except for the village of Questa, New Mexico



damage/damagesdamage means destruction (for example, the earthquake caused great damage); damages are monies awarded as compensation (for example, they received $1 million in damages)

dash – see punctuation

data – takes a plural verb in scientific writing (for example, the data show, data were collected)



datum – singular of data

DCMI – domestic, commercial, municipal, industrial (water use)

de – see prefixes and suffixes

decimal degrees (DD) – use a degree mark after the last number in each measurement, with no space, but do include a space between the degree mark and cardinal direction (for example, 34.068377° N, 106.904071° W NAD83); see degree mark

decision maker – unhyphenated (for example, that is a question for the decision makers) unless used as an adjective (for example, Decision-Makers Field Conference)

degree – see academic degrees and degree mark

degrees – for temperatures and latitude/longitude, use the degree mark; don’t spell out the word degrees; no space between the numeral and degree mark (for example, 20°C, 34.758333° N, 34°45′30″ N NAD83); see degree mark

degrees minutes seconds (DMS) – Use a degree mark after the first number in each measurement, a prime symbol (′) after the second number (minutes), and a double prime (″) after the third number (seconds), with no spaces; include the cardinal direction (for example, 34°4′6.16″ N, 106°54′14.66″ W NAD83); see degree mark and prime symbol.

depression – lowercase as a landform or economic term; capitalize in the Great Depression

description of map units

Geologic maps typically require a stratigraphically ordered list of descriptions of bedrock units and unconsolidated deposits; geologic reports may include similar information in an appendix. A few general guidelines and examples are given below to help format these descriptions uniformly. Note that this discussion applies to geologic quadrangle maps and similar maps where the geologic mapping itself is the focus of the document, as opposed to geologic maps used as figures in a report.

Every unit shown on a geologic map and cross section must include a written description. The description should include sufficient information on the essential attributes of the unit to allow recognition in the field. The essential attributes may vary depending on the nature of the unit and the quality and accessibility of exposures. Generally, they will include age, lithologic characteristics, mineral content, color, texture, cementation, bedding and outcrop characteristics, fossil content, thickness, and relationships to other units. Since internal consistency is important, and providing clear descriptions aids readers’ comprehension, unit-description attributes should be described in approximately the same order for each unit.

Sentence structure

If the unit description includes comments on the geologic history of the unit, or if it consists of two or more subunits described separately, write it as a complete sentence.

Even if the description consists of incomplete phrases, separating phrases that differ significantly in content with periods is preferred:

  • Lower red member—Slope-forming, red siltstone, and fine-grained arkosic sandstone, commonly cross-bedded, coarsening upward; upper contact unconformable. About 50–75 m thick, thickening westward. Depositional environment: very shallow, low-energy marine to deltaic.

Conversely, don’t use less emphatic punctuation marks, such as commas and semicolons, to separate complete sentences:

  • Conglomerate member—Gray, cobble to boulder conglomerate; lithic clasts dominantly Paleozoic carbonate; bedding chaotic to crudely stratified. The member is a basal rift-basin deposit unconformably overlying carbonate marine strata.

If a member has been formally named, capitalize the word “member” (for example, the Tshirege Member of the Bandelier Tuff). Use lowercase “member” for informal units. See capitalization.

Compound modifiers

Compound modifiers (adjectives) consist of two or more words or numbers that combine to describe a noun. The words forming the compound modifier are usually, but not always, connected by hyphens. General guidelines for hyphen use are given in the punctuation/hyphen section. Descriptions of map units, however, are often full of compound modifiers, and hyphenation rules can be a source of confusion and frustration for writers and editors. Generally, a hyphen is used to connect compound modifiers that come before the word being modified, and a hyphen is not used for compound modifiers that come after the word being modified. Consult the Glossary of Geology for examples of compound modifiers that are always hyphenated.

Exceptions: No hyphen if the first word in the compound modifier is very or an adverb ending in ly. Don’t use a hyphen if the first word in a three-word unit modifier is an adverb that describes the second word.

  • Kirkman Limestone—Light-gray, thick- to medium-bedded, fine-grained dolomitic limestone; contains dark-gray, gray-weathering intraformational breccia.
  • Olivine basalt—Dark-gray, dense to vesicular basalt; calcite-filled vesicles contain 1/2-inch crystals.
  • Colluvium—Poorly to moderately sorted, clay- to boulder-sized, locally derived material on gently sloping surfaces.
  • Ankareh Formation—Thinly laminated, moderately indurated, greenish-gray, poorly exposed sandstone.
  • Kirkman Limestone—Light- to dark-gray dolomitic limestone.
  • Straight Cliffs Formation—Dominantly cliff-forming, fine-grained, moderately indurated sandstone.



different from – not different to or different than

dimension – abbreviate as 1D, 2D, and 3D

dip – Measured 90° clockwise from the direction of strike when using the right-hand rule. When reporting the inclination of a plane or lineation, include the angle with two digits (e.g., 03), degree mark (°), and a space before the direction of dip (for example, 09° E or “the northeast-striking fault dips at an angle of 33° to the southeast”). Dip measurements are normally paired with strike, which uses three digits in azimuth format (for example, 045°/33° SE or “the fault strikes 45° and dips 33° to the southeast”). The strike should be converted to dip direction in azimuth format in GIS.

dip direction – direction of the angle of dip, measured 90° clockwise from strike when following the right-hand rule; symbology in GIS follows this convention, and all measurements for the azimuth field in a Bureau of Geology geodatabase should be given as dip direction for planar features or trend for linear features

dip slip (n), dip-slip (adj) – for example, dip separation, strike slip, a dip-slip fault

dip slope

directionals – words indicating direction or describing location are lowercase when written out (for example, north, south, northwestern, north-northeast) and capitalized when abbreviated (for example, N, S, NW, NNE); recognized regions of the United States are capitalized (for example, Midwest, Northeast, Northwest, South, Southwest)


Use where needed in Bureau of Geology publications:

The data, views, and conclusions included in this report are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the New Mexico Bureau of Geology and Mineral Resources or the State of New Mexico. All data are for informational purposes only, and the user bears all responsibility in determining whether these data are fit for the intended use.

For maps:

Any use of this geologic map, directly or indirectly, to generate derivative products must include a citation to the authors, the publisher (New Mexico Bureau of Geology and Mineral Resources), the published year, the map series and number, and any contributing agencies providing funding to complete this publication.

doctorate, doctoral – see academic degrees


down – see prefixes and suffixes









downward – not downwards



drill hole

drill-stem test



dune field


Earth – capitalize only when used without an article and in reference to a body in the solar system (for example, we spotted Earth from the surface of the moon); use lowercase when talking about the ground (for example, the earth beneath our feet)

Earth’s orbit

earth science(s), earth scientist(s) – lowercase only

effect/affecteffect as a verb means to cause (for example, to effect change) and as a noun means a result (for example, the effect was quite positive); affect as a verb means to influence (for example, may affect flow patterns)

e.g. – abbreviation for exempli gratia, Latin for for example; always followed by a comma

elect – see prefixes and suffixes

electrical power generation – not electric power generation

ellipsis – see punctuation

email – not e-mail

EMPA – electron microprobe analysis

end member

eolian – not aeolian

eon – the largest division of geologic time; capitalize only if a proper name (for example, the Proterozoic Eon)

ephemeral stream – streams that only flow after a precipitation event

epoch – the division of geologic time between a period and an age; capitalize only if a proper name (for example, the Oligocene Epoch)

era – the second-largest division of geologic time, shorter than an eon; capitalize only if a proper name (for example, the Mesozoic Era)

Española Basin – see capitalization

Esri – ESRI (now deprecated) was formally an acronym for Environmental Systems Research Institute, an American GIS software company

Estancia Basin – see capitalization

et al. – abbreviation for et alia, Latin for and others; used for in-text citations with more than two authors and in reference entries with more than 10 authors; see citations and references

etc. – abbreviation for et cetera, Latin for and so forth or and the rest; avoid using etc. in technical publications

Exit 235 – capitalize in reference to a specific exit on an interstate or highway



Fahrenheit – see units of measurement and temperature

farther/furtherfarther refers to spatial, temporal, or metaphorical distance (for example, the outcrop is 5 km farther than the mine, the Permian is farther back in time than the Holocene, nothing could be farther from the truth); further indicates an addition and is used when there is no notion of distance (for example, she contacted me with further information)

fault – capitalize only as part of an official name (for example, San Andreas Fault)

fault-propagation fold

federal – lowercase unless part of a proper name (for example, the U.S. Federal Reserve)

feet – see units of measurement

fewer/less – use fewer for individual countable items (for example, fewer dollars, fewer outcrops); use less for uncountable singular mass nouns (for example, less money, less education)


figure callouts

Use Figure when the callout is in a line of text and Fig. when it’s inside parentheses:

  • For more detail, see Figure 21.
  • The location of the caldera (Fig. 1) is north of the study area.

When calling out multiple figures:

  • Figures 1 and 2, (Figs. 1 and 2); not Figures 1–2, not Figs. 1–2
  • Figures 3E and 3F, (Figs. 3E and 3F); not Figures 3, E and F, not (Fig. 3, E and F)
  • Use an en dash for ranges of 3 or more: Figures 1–4, (Figs. 1–4)

fire – don’t capitalize fire after a proper name (for example, Whitewater-Baldy fire)


fiscal year, FY – for example, FY2023





flow path

flow rate

flow top

fold – not hyphenated with a number (for example, twofold, tenfold)

foot slope


Fort Sumner Dam

fresh water (n), freshwater (adj) – for example, the spring is a source of fresh water, a freshwater spring

front end (n), front-end (adj) – for example, the application’s front end, a front-end developer


Ga – giga-annum, or billions of years ago; the scientific notation for geologic time; use with geochronologic dates; don’t use interchangeably with Gyr

gage/gaugegage is specific to stream gage, while gauge is used for other measuring devices (for example, pressure gauge), wire thickness (for example, 12-gauge electrical wire), and estimating or determining (for example, gauge the severity)

gamma ray

gamma-ray log

gases – not gasses

genus/species – Genus names are capitalized, species names are lowercase, and both are italicized (for example, Homo sapiens, Canis lupus, Tyrannosaurus rex). In subsequent mentions, the genus may be abbreviated (for example, E. woodii, E. coli). When listing the common and scientific names, the common name comes first, followed by the scientific name in parentheses (for example, broom snakeweed (Gutierrezia sarothrae))

geographic names – currently accepted formal geographic names are listed in the USGS Geographic Names Information System (GNIS) database; authors should clearly identify all informal geographic names used in Bureau of Geology reports

geologic – used to refer to rock or Earth features (for example, geologic sample, geologic time scale)

geologic names

Geologic names are assigned to formal and informal geologic units and structural features. Rules applying to the use of geologic names are summarized below. The North American Stratigraphic Code gives detailed discussions of the issues associated with the use of geologic names. Authors should consult the USGS National Geologic Map Database (aka Geolex) to determine if a unit is formally recognized.

Geologic units

Formal geologic units are defined in accordance with the current or previously accepted versions of the North American Stratigraphic Code. Informal geologic units are sometimes useful locally, but, for whatever reasons, they don’t comply with the requirements of the current stratigraphic code. Use informal geologic units in Bureau of Geology reports with care, and always clearly identify them as informal units using lowercase words (for example, member, unit, sandstone).

Formal geologic unit names should always be written out to avoid confusion (for example, Chinle Formation versus Chinle, Arizona). Abbreviations may be used in figures and tables to save space.


Table 1. Names and abbreviations of lithologic and time-stratigraphic terms.
Term/Lithology Abbreviation Period/System
  Formal Informal    
Group Gp. gp. Quaternary Q
Formation Fm. fm. Neogene N
Member Mbr. mbr. Paleogene :
Claystone Clst. clst. Cretaceous K
Conglomerate Cgl. cgl. Jurassic J
Dolomite Dol. dol. Triassic ^
Gneiss Gn. gn. Permian P
Granite Gr. gr. Pennsylvanian *
Limestone Ls. ls. Mississippian M
Mudstone Mdst. mdst. Devonian D
Quartzite Qtzt. qtzt. Silurian S
Rhyolite Rhy. rhy. Ordovician O
Sandstone Ss. ss. Cambrian _
Shale Sh. sh. Precambrian =
Siltstone Sltst sltst. Cenozoic {
Volcanics Volc. volc. Mesozoic }
      Paleozoic |
      Neoproterozoic Z
      Mesoproterozoic Y
      Paleoproterozoic X
      Neoarchean W
      Mesoarchean V
      Paleoarchean U

Structural geologic features

There are no rules equivalent to the North American Stratigraphic Code for naming structural geologic features. Authors may choose names as they see fit, provided the feature has not been previously named in the literature. Common sense, good taste, and close adherence to the rule of precedence should guide authors who propose to name structural features in Bureau of Geology publications.

geological – used to refer to things related to the study of geology (for example, geological survey, geological society)

GIS – geographic information system


Goodnight-Loving Trail

gorge – lowercase unless in a proper name (for example, Rio Grande Gorge)

GPS – Global Positioning System, the global navigation satellite system (GNSS) owned by the U.S. government

gray – not grey

gray water

Great Plains

grid cell – for example, 1/24-degree grid cell

ground cover



GSA – Geological Society of America

guidebook – lowercase unless in a proper name (for example, Geologic Guidebooks of North America)

Gyr – a billion years; use for durations and intervals of time (for example, for geologic processes); don’t use interchangeably with Ga


Hadley cell, Hadley circulation

half century, half cycle – no hyphen


hanging wall (n), hanging-wall (adj) – for example, the hanging wall of the uplift, the hanging-wall dip slope

hard rock

HAWQS – Hydrologic and Water Quality System (web-based modeling)



historic/historicalhistoric is something with significant and lasting importance (for example, a historic flood); historical is anything relating to history (for example, historical data, historical records); use a rather than an with both

HPLC – high-performance liquid chromatograph or high-performance liquid chromatography

hydrologic – not hydrological


hydrometeorological report – abbreviated HMR

hyphen – see punctuation


IC – ion chromatography

ice age (n), ice-age (adj) – not capitalized (for example, the last ice age, ice-age glacial erratics)

ICP-MS – inductively coupled plasma mass spectrometry

ICP-OES – inductively coupled plasma optical emission spectrometry

IDF – intensity, duration, frequency (of precipitation events)

i.e. – abbreviation for id est, Latin for that is; aways followed by a comma

in – by convention, we say in figures and tables

indigenous/Indigenous – lowercase when not used as a proper noun (for example, the species is indigenous to the island); uppercase when used in Indigenous American; when referring to a specific tribe, nation, or pueblo, use that group’s preferred name (for example, Jicarilla Apache Nation, Pueblo of Acoma); if possible, verify the usage with the tribe, nation, or pueblo

INFIL model – USGS groundwater software, also INFIL3.0

in situ – not italicized, no hyphen (for example, in situ leaching)

inter – see prefixes and suffixes

intermittent stream – a stream that flows regularly or predictably, but not year-round

internet – lowercase

Interstate 25, I-25 – on first mention, spell out Interstate; may be abbreviated on subsequent mention; see abbreviations/acronyms

IPCC – Intergovernmental Panel on Climate Change

isotopes – in isotope abbreviations, the mass number is shown as a superscript and precedes the element with no space between (for example, 14C)


Italics are not used in Bureau of Geology publications for emphasis or for words from other languages (for example, versus and acequia are both not italicized). Italics are used for the following.

  • Titles of works that are individually published or produced, including books, maps, journals, magazines, newspapers, plays, and movies; titles of smaller components in these publications, such as journal articles, book chapters, and newspaper articles, take quotation marks instead:
    • The article “Critical Minerals in New Mexico,” which appeared in the winter 2023 issue of New Mexico Earth Matters.
  • Note that these conventions apply to text, not reference list entries. For reference list formatting, see references. For more on quotation marks, see quotation marks.

  • Formal names of genera, species, subspecies, and varieties of plants and animals; don’t italicize names of kingdoms, phyla, classes, orders, or families.
  • Names of vessels, aircraft, and spacecraft (for example, the research vessel Glomar Challenger, the Voyager spacecraft).
  • The preposition in when referencing a source contained in another document:
    • Seager, W.R., Mack, G.H., Raimonde, M.S., and Ryan, R.G., 1986, Laramide uplift and basins in south-central New Mexico, in Clemons, R.E., King, W.E., Mack, G.H., and Zidek, J., eds., Truth or Consequences Region: New Mexico Geological Society Fall Field Conference Guidebook 37, p. 123–130.
  • Names of legal cases (for example, Jones v. Entwhistle et al.).


Jemez lineament – see capitalization

Jemez Mountains volcanic field – see capitalization


ka – (both letters lowercase) kilo-annum, or thousands of years ago; the scientific notation for geologic time; use with geochronologic dates; don’t use interchangeably with kyr

K/Ar – potassium-argon dating, a method of radiometric dating

Kelvin – see units of measurement and temperature

kW – see units of measurement

kWh – see units of measurement

kyr – (all letters lowercase) a thousand years; use for durations and intervals of time (for example, for geologic processes); don’t use interchangeably with ka




land-surface water budget

LANL – Los Alamos National Laboratory (not Laboratories)

less/fewer – use less for uncountable singular mass nouns (for example, less money, less education); use fewer for individual countable items (for example, fewer dollars, fewer outcrops)

lidar – light detection and ranging or laser imaging, detection, and ranging; not LIDAR, LiDAR, or Lidar

like – see prefixes and suffixes


It’s often necessary to display or organize a group of related items in a publication. For large volumes of related material or data, use a graph or table when possible. For smaller volumes, incorporate a list within a sentence or display it vertically.

Sentence lists

  • If a list is short and simple, incorporate it directly into a sentence, separating each list item with a comma:
    • Descriptions of samples collected by the authors accompany analytical data for Au, Ag, Cu, Pb, Zn, and As.
  • If the items themselves include commas, use semicolons to separate the items:
    • The board members present included J. Berry, chairman; R. Hughes, secretary-treasurer; L.E. Smith, chief financial officer; and R. Kinley, ex officio member.
  • Numerals (preferred) or letters enclosed in double parentheses may be used to identify each item. Commas rather than semicolons separate numbered list items:
    • Much of the unit is (1) red, pink, or gray, (2) medium to coarse grained, and (3) equigranular or slightly porphyritic.
  • Sentence lists are not preceded by a colon if the list follows a preposition or a verb:
    • The three types of rock are igneous, sedimentary, and metamorphic.
  • Use a colon when the list follows a noun:
    • There are three types of rocks: igneous, sedimentary, and metamorphic.

Vertical lists

A list that is long, contains complete sentences, or merits special emphasis should be indented and displayed vertically.

Numbers, letters, bullets, or dashes may be used to delineate list items. Numbers and letters may or may not imply an order or hierarchy among the items and are useful if items are referred to in the text. Bullets and dashes imply no particular order or hierarchy among items.

If the items in a vertical list complete their introductory sentence, a colon is used, the items are not capitalized, each item is followed by a comma (or semicolon when appropriate), and the last item in the list ends with a period:

  • The investigation of the Red Rock fault zone proceeded by:
    1. mapping the surficial geology along the fault zone at 1:12,000 scale,
    2. excavating trenches across single- and multiple-event scarps identified during the mapping,
    3. logging the trench walls to determine the number and size of paleoearthquakes, and
    4. collecting samples of organic material for radiocarbon dating.

If a vertical list consists of a series of complete sentences, capitalize the first letter of each item and end each item with a period:

  • Northwest-striking, extension-related faulting in the area largely preceded mineralization and alteration. Faults produced during this deformation host all known occurrences of mineralized veins.
  • Eruption of rhyolitic flows and intrusion of possible subvolcanic rocks occurred 8.5 to 8.4 Ma.
  • Heat derived from the emplacement of rhyolitic magmas induced a hydrothermal system in the surrounding host rocks. Extensional structures served as conduits for rising, dominantly meteoric, hydrothermal solutions.

Introductory sentences should end with a period only if the sentence is long and the anticipatory word or phrase occurs early in the sentence, or if another sentence comes between the introductory sentence and the list.

All lists must maintain parallel structure by beginning each item with the same part of speech (usually a noun, verb, or adjective).

LL or L – single L is preferred in American English (for example, canceled, not cancelled; modeled, not modelled)

Llano de Albuquerque – see capitalization

longshore bars

longwall mining

Los Alamos National Laboratory – not Laboratories; abbreviated LANL


Ma – mega-annum, or millions of years ago; the scientific notation for geologic time; use with geochronologic dates; don’t use interchangeably with Myr

MA – see academic degrees

main stem (n), main-stem (adj) – not mainstem (for example, the main stem of the Rio Grande, a main-stem river)

master’s degree, master of science – see academic degrees

megadrought – see prefixes and suffixes

Mesilla Basin – see capitalization

metamorphism – can use in relation to rocks

metamorphosis – not the same as metamorphism; use in relation to insects, not rocks

metaquartzite – see prefixes and suffixes

mg/kg – see units of measurement

μg/kg – see units of measurement

mg/L – see units of measurement

μg/L – see units of measurement

mid – see prefixes and suffixes

Middle Rio Grande – capitalize Middle in relation to the district or the conservancy; use lowercase middle in relation to an indefinite stretch of the river (for example, middle Rio Grande)

Middle Rio Grande Basin – see capitalization

Midwest – capitalize only as a proper name for a region (for example, the American Midwest); see directionals

minable – try to avoid; use economic instead if possible

minerals – Mineral names are governed by the International Mineralogical Association (IMA) Commission on New Minerals, Nomenclature and Classification (CNMNC; An up-to-date list of all IMA-approved mineral names can be found at, and IMA-approved symbols or abbreviations for minerals can be found in Mineral names are not capitalized unless they are at the beginning of a sentence.

mine-water recovery

mini – see prefixes and suffixes

modeling – see LL or L

Mogollon-Datil volcanic field – not Datil-Mogollon; see capitalization

molecules – see abbreviations and acronyms and capitalization

most – see prefixes and suffixes

mountain/mountains – capitalize only if part of a proper name (for example, Franks Mountain, Sandia Mountains); in text, don’t abbreviate in proper names (for example, Sandia Mountains, not Sandia Mtns.); may be abbreviated to Mtn. or Mtns. in figures and maps

MS – see academic degrees

m/s – see units of measurement

mud cracks


mud log


multi – see prefixes and suffixes

MW – see units of measurement

MWh – see units of measurement

Myr – a million years; use for durations and intervals of time (for example, for geologic processes); don’t use interchangeably with Ma


ñ – the eñe (an n with a tilde) is used in many Spanish words and should be preserved when possible in Bureau of Geology publications (for example, piñon, Española)

names – For mastheads and title pages, be consistent; for authors, always use the exact same name for publications (for example, don’t use nicknames; if you use a middle initial for one publication, use it for all; if you have a junior/senior, use it). Academic titles are not listed in author bylines. Phil Miller is attempting to maintain a database of official author names for Bureau of Geology publications, so please inform him of your and your co-authors’ preferred author listing.

NASA – National Aeronautics and Space Administration

National Academy/Academies – check whether singular or plural (for example, National Academies of Sciences, Engineering, and Medicine, but National Academy of Sciences)

national laboratories – the 17 national labs of the U.S. Department of Energy; use plural for the collective (for example, the nation’s national laboratories); use singular for a specific lab (for example, Los Alamos National Laboratory); the exception is Sandia National Laboratories

Native American – acceptable for general use (for example, Native American cultures); when referring to a specific tribe, nation, or pueblo, use that group’s preferred name (for example, Jicarilla Apache Nation, Pueblo of Acoma); if possible, verify the usage with the tribe, nation, or pueblo

natural gas

natural gas production – no hyphen

Navajo Nation Environmental Protection Agency – abbreviated NNEPA, not Navajo EPA


New Mexico – don’t abbreviate as NM except in an address (for example, Socorro, NM 87801) or in figures and maps

New Mexico Administrative Code – abbreviated NMAC (for example, NMAC 19.25.12)

New Mexico Bureau of Geology and Mineral Resources, NMBGMR, the bureau – For technical publications, use the full name with the acronym in parentheses at the first mention, then the acronym only for subsequent mentions. For general audiences, it’s acceptable to use New Mexico Bureau of Geology first, then the bureau. Don’t use an ampersand (&) in the full name or acronym. Don’t abbreviate as NMBG. The New Mexico Bureau of Geology and Mineral Resources is the New Mexico state geological survey (not New Mexico State Geologic Survey).

New Mexico Energy, Minerals and Natural Resources Department – abbreviated EMNRD

New Mexico Environment Department – abbreviated NMED

New Mexico Institute of Mining and Technology, New Mexico Tech, NMT – For technical publications, use the full name with the acronym in parentheses at the first mention, then the acronym only for subsequent mentions. Use New Mexico Tech only for general audiences.

New Mexico Office of the State Engineer – abbreviated OSE

non – see prefixes and suffixes

Northeast – capitalize only as a proper name for a region (for example, the Northeast comprises nine states); see directionals

North Valley – of Albuquerque; see capitalization

Northwest – capitalize only as a proper name for a region (for example, the Pacific Northwest); see directionals

noun – a word that identifies a specific object or set of objects, such as a person, place, thing, action, or idea (for example, canyon, layer, doctor); see parts of speech

number – The abbreviations no., No., and # lead to confusion, so use them sparingly. Lowercase no. refers to serial numbers (for example, no. 14558-789-D) as well as issue numbers in a reference entry (for example, v. 6, no. 12). Uppercase No. identifies individual data points in a series or collection (for example, specimen No. 567). The # symbol has historically been used for a wide range of purposes, from a shorthand for “number” (for example, #2 pencil), a shorthand for “pound” (for example, 5# sack of flour), or as a hashtag (for example, #winning).


General rules

  • Use numerals in the text for numbers of 10 or larger. Numbers smaller than 10 are spelled out, except for serial numbers and expressions of time, measurement, money, and percent:
    • 8:00 a.m.
    • 3 meters
    • $20.00
    • 7%
    • 24 samples
    • eight people
    • three wells
  • Use a comma to separate groups of three digits to the left of a decimal point in numbers of 1,000 or larger except for serial numbers. Don’t use commas to the right of a decimal point:
    • 5,271
    • 14,629
    • 3.1415926
  • Use a combination of numerals and words for round numbers larger than 1 million; exact figures can be written with numerals:
    • $37.5 million
    • 4 billion years
    • $13,256,630.56
  • Write out numbers that begin a sentence. Try to avoid beginning a sentence with a very large number.
  • Form the plural of a number expressed as a numeral by adding a lowercase s, without an apostrophe:
    • The organization doubled in size during the 1980s.
    • Temperatures will reach the high 90s today.
  • Write out indefinite expressions or exaggerations, but use numerals for approximations based on experience or fact:
    • We must have received a thousand inquiries today.
    • The conclusions are based on about 2,000 analyses.
  • Use numerals when related numerical expressions that include numbers both greater and less than 10 are grouped together in a sentence:
    • The inventory consisted of 6 lengths of drill pipe, 2 drill bits, 14 bags of cement, and 3 core boxes.

Ranges of numbers

An en dash may be used with ranges of numbers (for example, 24–14 Ma). However, don’t use an en dash to substitute for the words to, through, or until if the word from precedes the phrase (for example, from 10 to 15 m thick), or to substitute for the word and if the word between precedes the phrase (for example, between 24 and 14 Ma). With ranges of numbers, use only one unit symbol at the end. See dash.


  • Always use numerals for people and animals, but spell out for inanimate objects (unless the age is 10 or greater):
    • Michael Phelps first swam in the Olympics when he was 15 years old.
    • The Kentucky Derby is a race for 3-year-olds.
    • The rule change is two years old.
    • The rule book is 16 years old.

Decimals and fractions

  • Use decimals rather than fractions wherever possible.
  • If a decimal is not associated with a whole number, insert a zero before the decimal point (0.56, not .56).
  • Zeros are retained after a decimal point only if they are significant figures (3.208 but not 3.200 unless both zeros are significant).

Sometimes established convention makes using fractions preferable to decimals. Rules for using fractions include the following.

  • Use numerals when fractions express a measurement:
    • 1/2-inch pipe
    • 6-1/2-inch O.D. well casing
  • Spell out and hyphenate fractions that stand alone in the text:
    • The project is two-thirds complete.


Use numerals with meters, centimeters, inches, feet, yards, grams, kilograms, etc., to indicate depth, height, length, width, and mass:

  • The outcrop is 75 m long.
  • The sample weighs 3 g.
  • The 10-m-thick bed shows thin-bedding.
  • The sampling site is 4 mi from Lexington.

Use common abbreviations for units in publications aimed at a scientific audience; spell out units for a general audience. Don’t use periods after ft, yd, m, etc. Exception: Use a period after in. to distinguish it from the preposition. See units of measurement.

Negative numbers

Use a minus sign (Unicode 2212, Alt + 8722), not a hyphen:

  • WRONG: -25
  • RIGHT: −25

NVTD – net vertical tectonic displacement


off site (adv), off-site (adj) – for example, the seminar will be held off site, at an off-site location

oil-bearing shale

oil field

on – by convention, we say on maps, plates, and sheets

oneseed juniper



on site (adv), on-site (adj) – for example, the seminar will be held on site, at an on-site location

Open-File Geologic Map – abbreviated OF-GM

open pit (n), openpit (adj) – for example, an open pit, open pit mining

optical cathodoluminescence – abbreviated OP-CL

orebody, orebodies

over – see prefixes and suffixes


paleo – no hyphen when used as a prefix (for example, paleovalley, paleocanyon, etc.); the exception is Paleo-Indian



parentheses – see punctuation

parts of speech

  • Noun – refers to a person, place, thing, or concept
  • Verb – describes an action, occurrence, or state of being
  • Adjective – modifies a noun or pronoun
  • Adverb – modifies a verb, adjective, adverb, or whole sentence
  • Pronoun – takes the place of a noun
  • Preposition – shows the relationship between the different parts of a sentence
  • Conjunction – connects different parts of a sentence
  • Interjection – used to express a feeling, give a command, or greet someone

pay-off (n), pay off (v) – for example, a big lottery pay-off, pay off a debt

PDF – Portable Document Format, a file format created by Adobe

peak flow (n), peak-flow (adj) – for example, the river is at peak flow, a peak-flow meter

Pecos Valley Artesian Conservancy District – abbreviated PVACD

percent – use the percent symbol (%) with numerals (for example, 95%); for other uses, write out percent or percentage (for example, the percent of customers lacking water, a large percentage)

perennial stream – a stream that has flowing water year-round

period – see punctuation

period – the division of geologic time between an era and an epoch; capitalize only if a proper name (for example, the Jurassic Period)

Permian Basin – see capitalization

PhD – see academic degrees


pinch out


plane table


point-source (adj), non-point-source (adj) – for example, point-source and non-point-source pollution

ponderosa pine – not Ponderosa pine

post – see prefixes and suffixes

postfire (adj), post-wildfire (adj) – for example, postfire recovery, post-wildfire reforestation

post-mine land use

potential evapotranspiration – abbreviated PET


ppb – see units of measurement

ppm – see units of measurement

pre – see prefixes and suffixes

prefixes and suffixes

The trend in modern writing is away from using hyphens with prefixes and suffixes. Consult the Glossary of Geology and Merriam-Webster Dictionary for specific examples. Otherwise, follow the guidance below. Hyphens should always be used if the word following a prefix is capitalized or a number (for example, pro-Belgian, pre-1950).

anti-  no hyphen unless there’s a double i (anti-immigration)

bi-/bio-  no hyphen

co-  use a hyphen for words that indicate occupation or status (for example, co-host, co-worker); otherwise, no hyphen unless there’s a double o (for example, coexist, coed, co-occupant)

de-  don’t use a hyphen unless there’s a double e (for example, deregulate, de-emphasize)

down-  no hyphen (for example, downwind, downslope)

-elect  always use a hyphen (for example, President-elect Pat Jones)

inter-  no hyphen (for example, interglacial, interbasin)

-like  no hyphen unless the letter L would be tripled or the first word is a proper noun (for example, businesslike, rocklike, bell-like, Albuquerque-like)

mid-  no hyphen unless followed by a capitalized word or a numeral (for example, midterm, midcontinent, mid-American, mid-1990s)

mini-  no hyphen unless there’s a double i (for example, minivan, mini-intrusion)

-most  no hyphen (for example, lowermost, uppermost)

multi-  no hyphen unless there’s a double i (for example, multinational, multi-instrumental)

non-  no hyphen unless followed by a proper noun or if the combination is awkward (for example, nonhazardous, nonprofit, non-nuclear, non-British)

over-  no hyphen (for example, overextend, overbank, overlie)

post-  no hyphen unless there’s a double t (for example, postdate, post-traumatic)

pre-  no hyphen, even with a double e (for example, preread, preenrollment, preeminent)

pro-  use a hyphen when indicating support for something (for example, pro-union, pro-chocolate); otherwise, no hyphen (for example, pronoun, prorate)

re-  no hyphen, even with a double e (for example, reinject, reevaluate).

semi-  no hyphen unless there’s a double i (for example, semiarid, semi-intermittent)

sub-  no hyphen, even with a double b, unless the second word is capitalized (for example, subregion, subreach, subbasin, sub-Saharan)

super-  no hyphen unless the second word is capitalized (for example, supervolcano, super-Democrat)

ultra-  no hyphen (for example, ultramafic, ultraviolet)

un-  no hyphen, even with a double n (for example, undammed, unnamed)

under-  no hyphen, even with a double r (for example, underground, underregulated); an exception is under-delivery

up-  no hyphen unless there’s a double p (for example, upgradient, upriver, up-passage)

vice  write as two words with no hyphen (for example, vice president, vice chair)

-ward  no hyphen (for example, eastward, basinward)

-wide  no hyphen if the word is listed in Merriam-Webster (for example, statewide); if it is not listed, hyphenate it (for example, basin-wide)

principal/principleprincipal means first in rank, authority, or importance (for example, principal investigator, principal of the school, principal cause); principle means a fundamental law, doctrine, assumption, or personal conviction (for example, the geologic principle of uniformitarianism, a principle of equity)

pro – see prefixes and suffixes

probable maximum precipitation – abbreviated PMP

proforeland basin

Public Land Survey System – abbreviated PLSS; also known as township and range; format as:

  • NW1/4SE1/4 section 16, T. 17 N., R. 11 W., Salt Lake Base Line and Meridian
  • sections 12 and 16, T. 42 S., R. 3 E., Uinta Base Line and Meridian
    sec., secs., T., Tps., R., or Rs. are acceptable abbreviations; coordinates are preferred for location information, but PLSS is often the only information provided with some data

pullout (n), pull out (v) – for example, we parked at the pullout, the army will pull out of the region



apostrophe  '

Apostrophes have two primary uses: to indicate possession and to make contractions.

To indicate possession:

  • Add ’s to a singular noun to make it possessive (for example, the layer’s thickness).
  • Add only an apostrophe to plural nouns ending in s (for example, the layers’ thicknesses).
  • Add ’s to singular nouns ending in s (for example, Dr. Jones’s research). This is an exception to some style guides, but it indicates the correct pronunciation.
  • Don’t use an apostrophe with possessive pronouns: ours, yours, his, hers, its, theirs, whose.
  • Don’t use an apostrophe with a word ending in s when its use is descriptive rather than possessive (for example, Masters swimming, Beatles music, Titans game).
  • Don’t use an apostrophe in place names unless it is part of the formal name (for example, Pikes Peak, Tates Creek, Martha’s Vineyard).

To make contractions:

  • Use an apostrophe to form contractions and to indicate omitted letters or numerals (for example, don’t, won’t, can’t, rock ’n’ roll, class of ’74).
  • Avoid contractions in technical writing, but use them sensibly for a general audience to prevent the prose from being overly formal.
  • Don’t use ’s to pluralize numerals or multiple-letter combinations (for example, 1890s, not 1890’s; ABCs, not ABC’s).
  • Don’t use an apostrophe as a substitute for the prime symbol.
  • Don’t use an apostrophe as an abbreviation for feet (for example, 6 ft, not 6’).

brackets [ ]

Brackets serve the same function as parentheses—to enclose incidental information or explanatory material—but they’re restricted to situations where it’s necessary to enclose information within an existing set of parentheses:

  • ...or thin dolomitic beds (note, however, that Bauch [1982, p. 42] included salt-cast-bearing gray siltstones in the upper Abo Formation).

Brackets are also used in equations and formulas, and to insert brief editorial comments or corrections into quoted material (see quotations).

colon :

Use a colon (not a semicolon) to introduce lists, long quotations, and for emphasis:

  • These are the three classes of rocks: igneous, sedimentary, and metamorphic.
  • Vanderbilt coach Bryce Drew said: “I’m really proud of our effort tonight. We could have ducked our heads when we got 10 points down, but we didn’t. We came back and became the aggressor late in the second half. That turned the game around for us.”
  • Malik Monk: All he does is win.

Don’t capitalize the first word after a colon unless it’s a proper noun or the beginning of a complete sentence:

  • The best songwriting team ever: Lennon and McCartney.
  • The worst thing that can happen: defeat.
  • You can count on one thing: The replay booth will rule against Vanderbilt.

Colons are also used after salutations in a formal letter (for example, Dear Dr. Jones:), to separate hours from minutes (for example, 3:45 p.m.), to separate the two halves of a ratio (for example, 4:1), and in reference entries to separate the title of a source from its publisher (see references).

For help with structuring lists with colons, see lists.

comma  ,

Commas have many uses.

To delineate items in a series:

  • John, Paul, George, and Ringo are the Beatles.
  • In lists of three items or more in technical publications, use a serial comma (also known as the Oxford comma) before the last item and its conjunction. In the above example, this is the comma after George.

Before and after a state name when a city is given:

  • Nashville, Tennessee, is my hometown.

To separate adjectives that are equal in rank (adjectives that can switch locations in the sentence with one another such that the sentence will still make sense):

  • tan, brown to reddish-brown, well-sorted silt and sand

No comma is needed before the last adjective if it’s critical to the meaning:

  • a stretched-out, transparent team swimsuit (not just any suit, but the suit designated for team members)

To set off introductory phrases:

  • When we arrived at the pool, we were overcome by chlorine fumes.

To set off two phrases joined by a conjunction when each phrase could stand alone as a sentence:

  • She came to Savannah to score points, but the highest she placed was the dreaded 11th place.

To introduce short quotations:

  • Phelps said, “I’m pleased with my time.”

In numbers greater than three digits (but not after a decimal):

  • The attendance was 12,060
  • The first 10 digits of pi are 3.141592653 (not 3.141,592,653)

To identify month, date, and year:

  • On September 5, 1893, the New Mexico School of Mines opened.

Don’t use a comma to separate months and years:

  • October 1956 (not October, 1956)

Don’t use a comma with Inc.:

  • Pendant Publishing Inc. (not Pendant Publishing, Inc.)

Don’t use a comma with Jr. and Sr.:

  • Garland Dever Jr. (not Garland Dever, Jr.)

dash – —

There are two types of dashes: en dashes (–) and em dashes (—).

An en dash (so called because it’s the width of the letter n) is used to connect inclusive words and numbers such as dates, page ranges, and ranges of values when given as equivalent units of measure in parentheses:

  • I usually swim 2,000–3,000 yards in a workout.
  • 1945–1978
  • p. 312–327
  • 20 to 30 ft (6–9 m)
  • cross section A–A’
  • snowpack–runoff relationship
  • north–south trajectory

As a test for when an en dash is appropriate over a hyphen, substitute the words to, through, or up to and including between the items.

An em dash (so called because it’s the width of the letter m) is used to set off extra information, such as examples, explanatory or descriptive phrases, or supplemental facts:

  • One can piece together from different locales—particularly the Caballo Mountains and Sierra de las Uvas—a seemingly conformable sequence of these rock units.
  • In central New Mexico, most now regard the Glorieta as a distinct formation—a practice followed in this study.

Don’t put spaces before or after either dash.

Don’t use a hyphen where a dash would be the correct choice and vice versa.

In reference list entries, use an em dash to replace a colon that appears within the document title to avoid possible confusion with the colon that is used to mark the end of the document title (see references):

  • Basins of the Rio Grande Rift—Structure, Stratigraphy, and Tectonic Setting: Geological Society of America Special Paper 291

Don’t use en dashes to substitute for the words to or and when used with from or between, respectively, to indicate a range of values. Don’t use an en dash when the two items in the range are hyphenated:

  • Nitrate concentration ranges from 2.6 to 9.3 mg/L. (not from 2.6–9.3 mg/L)
  • Fine-grained sediments accumulated in a shallow lake between 45 and 40 Ma. (not between 45–40 Ma)
  • We measured several 31- to 66-m-long profiles. (not 31–66-m-long)

PC/Mac controls for en dash:

  • PC: Alt + 0150 (Note: This method works only for keyboards that include a 10-key numeric pad; use a double hyphen [--] if the alt code doesn’t work.)
  • Mac: Option + Dash (-)

PC/Mac controls for em dash:

  • PC: Alt + 0151 (Note: This method works only for keyboards that include a 10-key numeric pad; use a triple hyphen [---] if the alt code doesn’t work.)
  • Mac: Shift + Option + Dash (-)

ellipsis  …

An ellipsis indicates that one or more words have been omitted from quoted material:

  • A previous author wrote, “We will examine the development of Brough’s Tunnel … within Clifty Falls State Park.”

Ellipses are formed by typing three periods in a row. Include a space before the first period and after the last period.

Ellipses are not used before the first word of a quotation, even if the beginning of the original sentence is omitted, or after the last word of a quotation, even if the end of the original sentence is omitted.

Ellipses are not meant to indicate a break in thought; don’t use them instead of an em dash.

hyphen -

A hyphen joins two or more words that work together to modify a subsequent noun:

  • a well-defined aquifer
  • pale-green shale
  • reddish-brown sandstone
  • light-gray limestone
  • 60-meter-wide graben
  • fine-grained sandstone
  • fine- to coarse-grained sandstone
  • 1/2-inch crystals
  • northwest-trending fault
  • east-central New Mexico

Don’t use a hyphen when the noun comes first:

  • an aquifer that is well defined
  • shale of pale green color
  • a graben that is 60 m wide
  • the sandstone is fine grained
  • sandstone that is fine to coarse grained
  • crystals of 1/2 inch
  • a fault trending northwest

Don’t use a hyphen with very or adverbs ending in ly:

  • a very porous layer
  • a finely crystalline rock

Don’t use a hyphen when the modifying words do not function as one unit and could be separated by a comma:

  • a small, blue mineral
  • a large, dry riverbed

Use a hyphen to prevent doubled vowels and tripled consonants:

  • anti-intellectual
  • well-liked

When describing rock units in stratigraphic sections, well logs, and other lists, compound modifiers following a rock name are traditionally hyphenated in the geologic literature:

  • Sandstone: blue-gray, thinly bedded, coarse-grained
  • Welded tuff: reddish-brown, flow-banded

A number of compound nouns exist in geological vocabulary. Some are hyphenated (acre-foot, cross-bed, cross-stratification, meta-arkose), and others are not (cross section, dip angle, dike swarm, solution banding). Consult the Glossary of Geology for the proper forms of compound nouns. (Note that the Glossary of Geology is an IP-based subscription and can only be accessed from on campus, or with a VPN connection if off campus).

Compound numbers between twenty-one and ninety-nine and fractions are hyphenated when written out:

  • thirty-three
  • four-fifths
  • one-third

Use a hyphen to separate noninclusive numbers, such as telephone numbers and serial numbers:

  • 801-537-3300
  • no. 14558-789-D
  • NMBGMR Miscellaneous Publication 03-7

Use a hyphen where numbers and units of measure form a compound modifier:

  • A 4-foot-thick fossiliferous limestone bed is at the top of the interval.

See prefixes and suffixes for more on the use of hyphens.

parentheses  ( )

Parentheses enclose incidental information or explanatory material and are the most common type of punctuation found in scientific reports after commas and periods. Parentheses are used in the following ways.

To enclose abbreviations the first time they appear:

  • Differences in the timing of the most recent event (MRE) along a fault zone are used to define fault segments.

For in-text citations (see brackets):

  • Wilpolt and Wanek (1951) were the first to map the geology of the Quebradas region.
  • Terranes accreted to the southern margin of Laurentia during the Proterozoic (Karlstrom et al., 2004).

To provide alternative units of measurement:

  • Deposition was rapid during the Pennsylvanian and Permian, resulting in a total accumulation of 25,000 to 30,000 ft (7,600–9,100 m) of marine sediments.

To call out figures, tables, chapters, and appendices:

  • In the Blackington Hills, the tuff is 90–150 m thick (Fig. 63).

To provide additional information:

  • The Emery high (or Piute platform as it is now called) and the Kaibab uplift (a poorly defined band of uplifts) have been identified by the thinning or absence of Pennsylvanian formations.

To enumerate points in a list:

  • Much of the unit is (1) red, pink, or gray, (2) medium to coarse grained, and (3) equigranular or slightly porphyritic.

Don’t use back-to-back parentheses; use a semicolon to separate items, for example, (Fig. 2; Hook, 1983), or rewrite to avoid back-to-back parentheses or ambiguity.

period  .

A period is used to mark the end of a declarative sentence (a sentence that makes a statement) or an imperative sentence (a sentence that gives an instruction or command or makes a request). When used between sentences, a period is followed by a single space, not a double space:

  • Sandstone is a type of sedimentary rock. Granite is a type of igneous rock.
    Give me the hand lens.

Periods are used with abbreviations that end in a lowercase letter:

  • etc.

Periods are also used for initials instead of full names, such as in a reference list:

  • White, E.B.
    Du Bois, W.E.B.

If a full sentence is placed inside parentheses, the period goes inside the closing parenthesis; otherwise, it is placed outside:

  • I will be there this week. (I was out sick last week.)
    Much of the variability in precipitation can be explained by natural fluctuations of Pacific Ocean temperatures (such as the El Niño cycle).

Periods and commas are always placed inside closing quotation marks:

  • “If we get up early,” she said, “we’ll be sure to make it on time.”

quotation marks “ ”

Quotation marks set off direct speech and material quoted verbatim from other sources (see quotations):

  • Hook and Cobban (2015, p. 27) defined it as “that portion of the Mancos Shale lying between the undifferentiated or main body of the Dakota Sandstone and the Tres Hermanos Formation.”

In text (but not reference entries), quotation marks enclose the titles of journal articles, book chapters, and newspaper articles and editorials. Italics are used for the names of the larger works these items are published in (see italics):

  • “The House Range, Western Utah—Cambrian Mecca” by Hintze and Robison (1987) in Rocky Mountain Section of the Geological Society of America Centennial Field Guide, Volume 2 provides a succinct description of an important fossil locality in Utah.

Quotation marks also enclose words used in a special way:

  • “Caliche” usually refers to an indurated layer of calcium carbonate accumulation in a soil; “hardpan” is a more general term that refers to any indurated soil layer resulting from the precipitation of soluble materials in the soil profile.

Commas and periods are always placed inside closing quotation marks; colons and semicolons are always placed outside closing quotation marks. All other punctuation marks are placed inside quotation marks only if they are part of the quoted material.

Don’t use a quotation mark as a substitute for the double-prime symbol (″; that is, seconds of angle; see prime symbol).

Don’t use a quotation mark as an abbreviation for inches (for example, 6 in., not 6”).

semicolon ;

A semicolon indicates a pronounced separation between grammatical units. It’s stronger than a comma and almost as full as a period, but it implies a closer relationship between the thoughts than a period would. A semicolon separates two or more complete thoughts (independent clauses) within a single sentence:

  • These bentonites range in thickness from 0.6 to 35.6 cm; most are white but weather orange.

When a semicolon is used to link complete thoughts, it doesn’t require a conjunction (and, but, or, if, so, etc.); however, a semicolon is necessary when an adverbial conjunction (accordingly, besides, consequently, furthermore, hence, however, instead, moreover, nevertheless, otherwise, still, therefore, thus) connects the thoughts:

  • The full extent of the Escalante silver vein was known only after extensive exploration; consequently, a number of smaller ore deposits in the district were overlooked for many years.

Don’t use a semicolon with the simple coordinating conjunctions and, or, for, nor, yet, so, and but. Instead use a comma.

Semicolons are also used to separate items in a list when one or more of the items requires a comma (see lists).

slash  /

Slashes are used to signify alternatives (for example, and/or, his/hers), in abbreviations (for example, m/s, acre-ft/yr), or in fractions (for example, 1/3, 1/4).


quadrangle – not capitalized in general area description (for example, the Park City East quadrangle); capitalized when citing a USGS geologic quadrangle map (for example, USGS Quadrangle Map GQ-126)

quadrant bearing (deprecated) – Used on older maps; for modern use, see strike. Use a degree mark for the angle portion of the measurement and directional letters with spaces between each element of the measurement (for example, N 66° E). Note that azimuth measurements are preferred for reporting strike and dip in reports, and dip direction is required in GIS.

quotation marks – see punctuation and quotations


Direct quotations contain the original words of a speaker or written material taken verbatim from another document. When quoting directly, especially from copyrighted material, clearly identify the quoted material by enclosing it in quotation marks, and give full credit (including page number for quoted text) to the speaker or author with a citation.

Indicate omissions in quoted matter with an ellipsis.

Short quotations are incorporated directly into the text (for example, Dr. Jones stated, “When fully grown, Tyrannosaurus rex stood more than 20 feet tall.”).

If there is quoted material within the material you are quoting, use single quote marks to denote such material.

  • “A brief discussion of the terms ‘aquifer,’ ‘aquifer system,’ ‘zone,’ and ‘confining unit’ provides a common reference base.”

Block quotations: Indent and use single space for long quotations (usually more than one sentence), but don’t enclose them with quotation marks; add the citation at the end:

It is useless to ask when this disaster [an earthquake] will occur. Our occupation of the country has been too brief to learn how fast the Wasatch grows; indeed, it is only by such disasters that we can learn. By the time experience has taught us this, Salt Lake City will have been shaken down.

G.K. Gilbert, Salt Lake Tribune, 1883 (Gilbert, 1884)

Reproduce titles and references exactly as written in the original except for obvious typographical errors. Reproduce other words in error exactly and then follow them by [sic] to indicate that the erroneous word or passage is exactly reproduced.

If necessary, use brackets to insert other comments or corrections into quoted material (for example, [an earthquake] in the block quote above).


Rail Runner – New Mexico train with service between Belen and Santa Fe


rare earth elements – no hyphen

Raton Basin – see capitalization

Rb-Sr – rubidium-strontium dating, a method of radiometric dating

re – see prefixes and suffixes

red beds – not redbeds


References are the complete list of sources used in a publication. The guidelines here are largely based on the GSA Reference Guidelines and Examples (

General rules

  • In the References section, list all references mentioned in the text, figures, captions, tables, appendices, and geodatabase.
  • List references alphabetically by author’s last name. For references with two authors, list alphabetically by first author and then alphabetically by second author. For references with more than two authors, list alphabetically by first author and then chronologically by publication date, beginning with the earliest year. For references with the same author(s) and date, use a, b, c, etc. after the publication date (for example, Jones, 2009a, 2009b).
  • For references with more than 10 authors, shorten the author list to the first author’s name plus “et al.” If the author list includes co-chief scientists, include all of their names, with the rest of the author names shortened to “et al.”
  • For any publication that is not yet published but is in preparation, has been submitted, is in review, or is in revision, cite it as “in press.”
  • Include DOI numbers if available, formatted as URLs (for example, To create a DOI link, add the DOI of the article to the end of (for example, DOI 10.58799/B-164 becomes Don't include a trailing period after the DOI unless that period is part of the DOI URL (uncommon).
  • For website sources, downloaded data, and any other online sources that readers can access, include the month and year the site was accessed in parentheses at the end of the reference.
  • In reference list entries, use an em dash to replace a colon that appears within the document title to avoid possible confusion with the colon that is used to mark the end of the document title.
    • Basins of the Rio Grande Rift—Structure, Stratigraphy, and Tectonic Setting: Geological Society of America Special Paper 291
  • For references that don’t match any of the following examples, include all information that would help a reader locate the reference.
  • Avoid using abbreviations in a reference list, except for abbreviations or acronyms used in a title; v., no., pt., and p.; Inc.; U.S. and D.C.; and [abs.].

For Bureau of Geology publications

  1. Author(s), last name first, followed by initials, followed by a comma. Specify editor(s) with ed. or eds.
  2. Year of publication, followed by a comma.
  3. Title (sentence case), followed by a colon.
  4. New Mexico Bureau of Geology and Mineral Resources and series name and number, followed by a comma.
  5. Total pagination (with p.), followed by a period.
  6. DOI (if available).


  1. Dunbar, N.W., Gutzler, D.S., Pearthree, K.S., Phillips, F.M., Bauer, P.W., Allen, C.D., DuBois, D., Harvey, M.D., King, J.P., McFadden, L.D., Thomson, B.M., and Tillery, A.C., 2022, Climate change in New Mexico over the next 50 years—Impacts on water resources: New Mexico Bureau of Geology and Mineral Resources Bulletin 164, 218 p.
  2. Rawling, G., 2021, Evaluation of water-level trends using spatiotemporal kriging in the Mimbres Basin, southwest New Mexico: New Mexico Bureau of Geology and Mineral Resources Open-File Report 616, 57 p.

For journal articles

  1. Author(s), last name first, followed by initials (or organization if no author can be found), followed by a comma.
  2. Year of publication, followed by a comma.
  3. Title (sentence case), followed by a colon.
  4. Name of journal (title case), followed by a comma.
  5. Volume and number (use the abbreviations “v.” and “no.”), followed by a comma.
  6. Pagination span (with p., en dash with no spaces), followed by a period.
  7. DOI (if available).


  1. Heller, P.L., and Liu, L., 2016, Dynamic topography and vertical motion of the U.S. Rocky Mountain region prior to and during the Laramide Orogeny: Geological Society of America Bulletin, v. 128, no. 5–6, p. 973–988.
  2. Amato, J.M., Mack, G.H., Jonell, T.N., Seager, W.R., and Upchurch, G.R., 2017, Onset of the Laramide Orogeny and associated magmatism in southern New Mexico based on U-Pb chronology: Geological Society of America Bulletin, v. 129, no. 9–10, p. 1209–1226.

For individual works in an edited volume

  1. Author(s), last name first, followed by initials (or organization if no author can be found), followed by a comma.
  2. Year of publication, followed by a comma.
  3. Title (sentence case), followed by a comma and the word in (in italics).
  4. Name(s) of editor(s), last name first, followed by initials, followed by ed. or eds., followed by a comma.
  5. Name of edited volume (title case), followed by a colon.
  6. Publisher and type of publication and number (if applicable, for example, Guide Book, Special Report), followed by a comma. For conference proceedings or abstracts, include the name, location, and date of the conference (if known).
  7. Pagination span (with p., en dash with no spaces), followed by a period.
  8. DOI (if available).


  1. Seager, W.R., and Mack, G.H., 2018, Geology of the Doña Ana Mountains, south-central New Mexico—A summary, in Mack, G.H., Hampton, B.A., Ramos, F.C., Witcher, J.C., and Ulmer-Scholle, D.C., eds., Las Cruces Country III: New Mexico Geological Society Fall Field Conference Guidebook 69, p. 71–81.
  2. Dickinson, W.R., 2009, Anatomy and global context of the North American Cordillera, in Kay, S.M., Ramos, V.A., and Dickinson, W.R., eds., Backbone of the Americas—Shallow Subduction, Plateau Uplift, and Ridge and Terrane Collision: Geological Society of America Memoir 204, p. 1–29.
  3. Humphreys, E., 2009, Relation of flat subduction to magmatism and deformation in the western United States, in Kay, S.M., Ramos, V.A., and Dickinson, W.R., eds., Backbone of the Americas—Shallow Subduction, Plateau Uplift, and Ridge and Terrane Collision: Geological Society of America Memoir 204, p. 85–98.

For maps

  1. Author(s), last name first, followed by initials (or organization if no author can be found), followed by a comma.
  2. Year of publication, followed by a comma.
  3. Title (sentence case), followed by a colon.
  4. Name of publisher and title of series (if applicable, for example, Open-File Geologic Map, Map and Chart Series, Scientific Investigation Map), followed by a comma.
  5. Scale, followed by a comma, number of sheets (if more than one), followed by a period.


  1. Rinehart, A.J., Love, D.W., and Miller, P.L., 2014, Geologic map of the Black Butte 7.5-minute quadrangle, Socorro and Valencia Counties, New Mexico: New Mexico Bureau of Geology and Mineral Resources Open-File Geologic Map 235, scale 1:24,000.
  2. Aby, S., Timmons, J.M., and Miller, P.L., 2016, Geologic map of the El Vado 7.5-minute quadrangle, Rio Arriba County, New Mexico: New Mexico Bureau of Geology and Mineral Resources Open-File Geologic Map 257, scale 1:24,000.
  3. Bauer, P.W., Kelson, K.I., Aby, S.B., Helper, M.A., and Mansell, M.M., 2021, Geologic map of the Picuris Mountains, Rio Arriba and Taos Counties, New Mexico: New Mexico Bureau of Geology and Mineral Resources Open-File Geologic Map 294, scale 1:24,000, 2 sheets.

For books

  1. Author(s), last name first, followed by initials (or organization if no author can be found), followed by a comma. Specify editor(s) with ed. or eds.
  2. Year of publication, followed by a comma.
  3. Title (title case), followed by a colon.
  4. City and state or country of publication, followed by a comma. Don’t include state/country with major cities (for example, New York, Boston, London, Amsterdam).
  5. Name of publisher, followed by a comma.
  6. Total pagination (with p.), followed by a period.


  1. Bates, R.L., and Jackson, J.A., eds., 1980, Glossary of Geology (second edition): Falls Church, VA, American Geological Institute, 749 p.
  2. Allmendinger, R.W., Cardozo, N., and Fisher, D., 2011, Structural Geology Algorithms—Vectors and Tensors in Structural Geology: New York, Cambridge University Press, 304 p.

For other references not covered above

  1. Author(s), last name first, followed by initials (or organization if no author can be found), followed by a comma.
  2. Year of publication/presentation/etc., followed by a comma.
  3. Title (sentence case), followed by a colon.
  4. Name of conference, etc., followed by a comma.
  5. Number of the conference, etc., followed by a comma.
  6. Place of conference, etc., followed by a comma.
  7. Year of conference, etc., followed by a comma.
  8. Series, volume, part (if any), followed by a comma.
  9. Full pagination (if entire publication is being cited) or pagination span (if only a section is being cited).

Additional examples can be found at




Rio Grande – not Rio Grande River

Rio Grande rift – see capitalization



road beds


road log



rock shelter


runoff (n), run off (v) – for example, the runoff reached the stream, the water will run off the roof


salt cedar – not saltcedar


Sandia National Laboratories – not Laboratory

San Juan-Chama Project

San Juan Generating Station

Santa Fe Railroad – not Santa Fe Railway


seafloor spreading

sea-level rise

sea-surface temperature


sedimentary-copper deposits

SEM – scanning electron microscopy

SEM-CL – scanning electron microscopy cathodoluminescence

semi – see prefixes and suffixes

semicolon – see punctuation

sentence case – a capitalization style in which only the first word of a sentence and proper nouns are capitalized

sequence stratigraphy, sequence-stratigraphic analysis


Ship Rock – the geologic and geographic feature; Shiprock – the community nearby




shutoff (n, adj), shut off (v) – for example, the power plant experienced a shutoff, a shutoff valve, we shut off the power


SIMS – secondary ion mass spectroscopy


slash – see punctuation

slope former



soil-moisture reservoir

soil stages – capitalize Stage I–VI for carbonate soil stages; use an en dash to indicate the range; if referring to Stage I+ do not use Stage I(+)

soil-water storage

Sonoran Desert – see capitalization

South – capitalize only as a proper name for a region (for example, the American South); see directionals

South Valley – of Albuquerque; see capitalization

Southern Rocky Mountains – the province; see capitalization

Southwest – capitalize only as a proper name for a region (for example, the U.S. Southwest); see directionals

southwest/southwestern – for example, southwest winds, the southwestern United States; see directionals





state – don’t abbreviate state names (for example, Maine, not ME); capitalize state only when in a proper name (for example, State of New Mexico [meaning the state government], New Mexico State Office of the Bureau of Land Management, New Mexico is the fifth-largest state by area)

state engineer – capitalize only when part of a title (for example, State Engineer Mike Hamman, but the state engineer of New Mexico)




strike – Strike for planar features is measured 90° counter-clockwise from the direction of dip when using the right-hand rule. Strike should be reported in azimuth format for modern maps with three digits and a degree mark (for example, 066°). When using the right-hand rule, directional letters are unnecessary, but it is good practice to include the direction after the dip value (for example, 066°/09° SE); the deprecated quadrant bearing format may be seen on older maps (for example, strike N 66° E). Strike in azimuth is preferred for modern reports, and dip direction is required in GIS.

strip mine

sub – see prefixes and suffixes

Sumner Lake, Sumner Lake State Park

super – see prefixes and suffixes


surface mining

surface water (n), surface-water (adj) – for example, surface water was plentiful, surface-water data

SWAT – Soil and Water Assessment Tool (public domain water modeling)


+, −, ÷, ×, and =   Use a space before and after these arithmetic symbols.
<, >, ≤, and ≥   Use with numbers only, with no space between the symbol and number (for example, >5). When used with text, write out greater than, less than, etc.
±   Use a space between the number and symbol (for example, ± 14).
%   Use with numbers only, with no space between the number and symbol (for example, 98%).
~   For imprecise measurements, avoid using ~ in the text and instead use approximately or about. The ~ symbol may be used in figures and figure captions, with no space after the symbol. See approximately.

degree mark

The degree mark (°) is used with numbers in statements of temperature, strike, dip, slope inclination, azimuth, latitude, and longitude. No space is used with the degree mark. Don’t use a degree mark when reporting Kelvin temperature. Don’t spell out degree.

  • 32°F equates to 0°C and 273.15 K
  • a bearing of S35W equates to an azimuth of 215°
  • strike 66°, dip 46°; unless in a sentence, for example, striking 66° with a dip of 46° to the SE
  • latitude 40°45′15″ N or 40°45.25′ N
  • longitude 112°33′30″ W or 112°33.5′ W
  • the ground surface slopes 33° to the north
  • a right angle equates to 90°

PC/Mac controls for degree mark:

  • PC: Alt + 0176 or Alt + 248
  • Mac: Shift + Option + 8

prime symbol (′) and double prime symbol (″)

Don’t use an apostrophe (') or quotation mark (”) as a substitute for the prime (′) or double prime symbol (″), for example, latitude 38°12′30″ N (not 38°12'30” N).

Prime: PC: Alt + 8242, Mac: Option + 2032
Double prime: PC: Alt + 8243, Mac: Option + 2033



temperature – Don’t spell out Fahrenheit or Celsius; abbreviate them (°F, °C). Kelvin can be spelled out or abbreviated (K). Use a degree symbol instead of spelling out degrees for Fahrenheit or Celsius; Kelvin has no degree symbol. Use only Celsius or Kelvin for technical documents; use Fahrenheit for general publications.


Tertiary – this term is considered out of date and should be avoided; instead, be specific in naming periods or epochs of the Cenozoic era

that/which – Use that for phrases that are essential to the meaning of the sentence (for example, the six quadrangles that form the study area [the fact that the quadrangles form the study area identifies them and distinguishes them from other quadrangles]). Use which for nonessential phrases that convey additional information (for example, the six quadrangles, which form the study area, contain great variation [the fact that the quadrangles form the study area is only an interesting aside]); which should be preceded by a comma.



time line – not timeline

time scale – not timescale

time span – not timespan

TIMS – thermal ionization mass spectrometry

title case – a capitalization style in which all words are capitalized, except for minor words (articles [for example, a, an, the, etc.], prepositions [for example, on, for, after, etc.], and short conjunctions [for example, and, but, or, etc.]) that are not the first or last word of the title

TMDL – total maximum daily load

Toledo Caldera – see capitalization

Topo to Raster tool (in ArcGIS) – not Topo To Raster, not Topo-to-Raster

toward – not towards



trail – capitalize only in proper names (for example, along the trail, Bright Angel Trail)


Transcontinental Arch

transgressive-regressive cycles

traveled, traveling – see LL or L

tree-ring dating

tribe/tribal – capitalized when referencing a specific tribe or tribal governments and leaders (for example, Mescalero Apache Tribe, Tribal Chairman Pat Jones), lowercase when not referencing a specific tribe (for example, projects on tribal lands, the tribal perspective)

trip meter – not tripmeter

turnout (n), turn out (v) – for example, the event had good turnout, voters will turn out in droves


ultra – see prefixes and suffixes

un – see prefixes and suffixes

under – see prefixes and suffixes

under-delivery (as in the Pecos River Compact)


unique – don’t include any modifiers (for example, don’t use very unique)

United States (n), U.S. (adj) – not US, no spaces (for example, we live in the United States, the U.S. government); an exception is when US appears in abbreviations (for example, USGS)

units of measurement

In general, use metric units in scientific or technical reports and imperial units in publications for a general audience. By convention, however, certain measurements are frequently reported in imperial units (for example, water levels and elevation).

Don’t convert numbers unless necessary. If necessary for a technical audience, use metric first, followed by imperial in parentheses. If necessary for a general audience, use imperial first and metric in parentheses. For added clarity, a conversion chart could be added to the front matter of a report.

Abbreviate units of measurement when used with a number. Don’t abbreviate if a unit falls in the middle of the sentence without a number (for example, the zone of alteration is several meters thick).

Abbreviate units of measurement mostly without punctuation.








acre-feet per year




barrels per day


British thermal unit


degrees Celsius




cubic feet per second






degrees Fahrenheit




feet per year




grams per liter






gallons per minute














inches per year




joules per Kelvin


joules per kilogram per degree Celsius




hydraulic conductivity




thousands of acre-feet




kilograms per cubic meter






kilometers per hour





kyr kiloyear










square meters




milliequivalents per liter


milligrams per kilogram


micrograms per kilogram


milligrams per liter


micrograms per liter






millimeters per month




miles per hour


meters per second


millisiemens per centimeter


microsiemens per centimeter






milliwatts per square meter


meters per year








ohm-meter squared per meter

per mill (per thousand)




percent modern carbon


parts per billion


parts per million


parts per thousand



sq mi, mi2

square miles


metric ton


tritium units


vertical anisotropy


weight percent (for solutions)

unpublished – spell out, don’t abbreviate; see citations

up – see prefixes and suffixes

Upper Colorado River – see capitalization

Upper Colorado River basin – see capitalization

U-Pb – uranium-lead dating, a method of radiometric dating

up to – avoid where possible; use as much as instead

upward – not upwards

U.S. Bureau of Indian Affairs – abbreviated BIA

U.S. Bureau of Land Management – abbreviated BLM

U.S. Bureau of Reclamation – the preferred U.S. Department of the Interior style is to shorten to Reclamation after first mention; however, abbreviated as BOR is common usage

U.S. Environmental Protection Agency – abbreviated EPA

U.S. Forest Service – abbreviated USFS

U.S. Geological Survey – abbreviated USGS

U.S. National Park Service – abbreviated NPS; in later mentions, “park service” can be used (for example, the decision was made in conjunction with the park service)

UTM – Universal Transverse Mercator, a map projection system for assigning coordinates to locations on Earth’s surface; example format: 13S 324231m E, 3771369m N NAD83


Valles Caldera – see capitalization

Valles Caldera National Preserve

valley – lowercase unless part of a proper name (for example, the river valley, Mesilla Valley)

verb – a word used to describe an action (for example, read, learn), occurrence (for example, happen, become), or state of being (for example, be, exist); see parts of speech

versus – not italicized; don’t abbreviate unless in court case name (for example, Texas v. New Mexico)

VIC model – hydrologic model (by Liang et al., 1994, Journal of Geophysical Research Atmospheres, vol. 99, n. D7, p. 14415–14428)

vice – see prefixes and suffixes

visitor center, visitors’ center – not visitor’s center; check individual centers to confirm which punctuation is used; capitalize only if a proper name (for example, Carlsbad Caverns National Park Visitor Center, but “the family stopped at the visitor center”)

volcanic center

volcanic province


volcanology – not vulcanology


ward – see prefixes and suffixes


water balance (n), water-balance (adj) – for example, a low water balance, a water-balance equation

water chemistry (n), water-chemistry (adj) – for example, we sampled the water chemistry, sampling produced water-chemistry data

water level (n), water-level (adj) – for example, a low water level, water-level data


water planning (n), water-planning (adj) – for example, the committee is engaged in water planning, they are water-planning specialists

water resources (n), water-resource (adj) – for example, our precious water resources, water-resource planning


water table (n), water-table (adj) – for example, the water table is low, water-table elevation

web – in relation to the internet, not Web









well log (n), well-log (adj) – for example, we examined the well log, well-log data

West – capitalize only as a proper name for a region (for example, the American West); see directionals


who/whomwho is a subject and performs the action of a verb (for example, the geologist who wrote the chapter); whom is an object and receives the action of a verb (for example, For whom was the plan designed? To whom did you send the samples?); whom comes after a preposition

wide – see prefixes and suffixes

wilderness – capitalize only in official designations (for example, in wilderness areas, Sabinoso Wilderness, Ignacio Chavez Wilderness Study Area)




woolly – as in “woolly mammoth” (not wooly)




X-ray – the X is always capitalized

X-ray computed tomography – abbreviated CT

XRD – X-ray diffraction

XRF – X-ray fluorescence


year-round – hyphenated


zip code – for all Socorro Bureau of Geology addresses, use 87801-4796