revised: 05-Feb-2015

NMBGMR Draft Geologic Data Model - v. 1.0.4
LINES: Metamorphic Isograds

In the interests of standardization and interoperability, we are migrating our geologic maps into the USGS NCGMP09 data model. However, our well data model is still actively being used. Documentation for the NMBGMR geology data model is being provided for users with legacy data in this model. We also hope that it will provoke discussion in the ongoing effort to improve NCGMP09 and other models.


This feature class represents metamorphic isograds. These lines bound areas of similar metamorphic grades and mineral assemblages that are portrayed by Metamorphic_poly.

Field Name Field Alias Length
(text fields)
Field Type Field Value Default Allow Nulls? Attributes / Examples Description / Notes
FGDC_code " 16 String variable [null] TRUE 30.3.12 FGDC geologic symbol reference number.
IsgrdClass IsogradClass 24 String variable [null] TRUE unspecified, prograde, retrograde, etc. Class of isograd.
IDmethod " 50 String CVD [null] TRUE see: IDmethod The basis for identification of this feature.
Confidence " 16 String CVD [null] TRUE unspecified, certain, probable, uncertain

Confidence regarding the existence/identification of this feature.

Name " 50 String variable [null] TRUE Second-sillimanite isograd Feature name (will generally be NULL)
Reaction " 255 String variable [null] TRUE Muscovite + Sio2 -> Kspar + Sil reactions that produce this assemblage
DsplyScale DisplayScale   Long Integer CVD 24000 TRUE see: DisplayScale Denominator of display scale: display feature at scales larger than number specified (=< denominator). Zero indicates data that should never be displayed.
SourceID " 128 String variable [null] TRUE unknown; unspecified; Smith, 2006b [variable] Feature level metadata (who mapped this); related to bibliographic detail
Comments " 255 String variable [null] TRUE Free text e.g. "identified from detailed stereo photos" Comments about this particular feature.