Memoir 51—Geology of the Quebradas Region, Socorro County, Central New Mexico

By Steven M. Cather and Daniel J. Koning, editors, 2024, 189 pp.

This report describes the geology of six 7.5—minute quadrangles—Mesa del Yeso (Cather et al., 2004), Sierra de la Cruz (Cather et al., 2012), Loma de las Cañas (Cather and Colpitts, 2005), Bustos Well (Cather et al., 2014), San Antonio (Cather, 2002), and Cañon Agua Buena (Cather et al., 2007). These geologic quadrangles encompass about 950 km2 in what is known as the Quebradas region—the eastern part of the Socorro Basin and its uplifted eastern rift flank. The name Quebradas is short for las tierras quebradas—Spanish for "the broken lands." An apt physiographic description, the name is also appropriate in a geologic sense; the area is one of the most stratigraphically diverse and structurally complex in New Mexico.

Exposed rocks are of Proterozoic, Pennsylvanian, Permian, Middle and Late Triassic, Late Jurassic, Late Cretaceous, Paleogene, Neogene, and Quaternary age. Tectonic episodes recorded in the study area include Proterozoic plutonism and deformation, Pennsylvanian (Ancestral Rocky Mountain) and Late Cretaceous-middle Eocene (Laramide) dextral-oblique contraction, middle Eocene—middle Miocene top-east detachment faulting, and Neogene-Quaternary rift-related extension. The structural geology of the Quebradas region is complex. Structures include (1) Laramide west-up reverse faults and associated fault-propagation folds, fault-bend folds, and monoclines; (2) northeast-striking zones of dextral Laramide strike-slip faults with linking contractile and extensional step-overs; (3) a regional middle Eocene to middle Miocene, top-east decollement developed mostly within the gypsiferous upper Yeso Group that is associated with splay faults and rollover anticlines in its hanging wall; and (4) Neogene and Quaternary normal faults related to rifting. The report also contains chapters on two mining districts (Socorro and Chupadero) and two coal fields (Carthage and Jornada del Muerto) that are present in the Quebradas region.

---

NOTES

Geologic maps associated with this publication are subject to revisions and may be unavailable when being revised. Map Reference dates show the time of initial compilation; Map Revision dates, when given, indicate the most current version of the map; Last Modified dates for files may not, accurately reflect the time the map was last revised.

• FONTS
  • Many of our Geologic Maps use the USGS FGDC Fonts. If you are accessing the GIS files, please download these fonts and install them on your computer before opening the GIS Project. This will ensure you get the correct symbology for the features in the map.
  • Download FGDC Fonts
  1. Before you open our GIS Map Project Packages, you will need to install the FGDC Geologic Symbology Fonts.
  2. Right-click on the FGDCGeoSymFONTS.zip.
  3. unzip the compressed fonts package by right-clicking on the zip file and selecting "Extract All...".
  4. Once extracted and the folder opens, select all of the fonts.
  5. Right-click and select install fonts.

• GeMS
  • Additionally Many of our Geologic Maps are in the USGS GeMS Data Model. There are a few places where the NMBGMR varies from GeMS. These Variations are as follows:
    • This is an Open-File Geologic Map and has not undergone the highest level of external peer review of publication so that we can get the geologic information out in as timely a manner as possible. This Geologic map is presented "as is."
    • The New Mexico Bureau of Geology and Mineral Resources (NMBGMR) has created this GeMS compliant geodatabase or as near as we can get from our understanding and needs.
    Additions or deviations from GeMS are listed below.
    • FGDC_Symbols data table added to geodatabase. This is used to provide consistent descriptions of the symbols used in the database and their definition and for building the Explanation of Map Units legend.
    • In the DMU the Symbol field is used as a complete legend description of each map unit and heading, and as such, is a combination of the HierarchKey, ParagraphStyle, MapUnit, FullName, and Description fields so that the legend can be made in the layout with all of this pertinent information sorted as the author intends.
    • As such, the Symbol field in MapUnitPolys, MapUnitLines, and MapUnitPoints, is not calculated off of the DMU Symbol field as described in the GeMS documentation. It is instead a human-readable version of the Label field where we record the capital geologic time letters as plain text instead of FGDCGeoAge font symbols in addition to any ?/, or + used in the "label" field.The map unit symbology based on the MapUnit field can be found in an accompanying style file.
    • ObservedMapUnit field added to the following point feature classes: GenericPoints, GenericSamples, OrientationPoints, and GeochronPoints. This is only required for the Stations feature class in GeMS.
    • Label field has been added to DataSourcePolys.

• ACCESS AND USE LIMITATIONS
  • Any use of this geologic map, directly or indirectly, or for the purpose of generating derivative products, must include a citation to the Authors, the Publisher (The New Mexico Bureau of Geology and Mineral Resources), the published year, the map series and number, and any contributing agencies like the USGS, with regard to maps that were partially funded under the STATEMAP program.