Geology of the Gypsum Gap quadrangle, Colorado

Trace Elements Memorandum 697
This report concerns works done partly on behalf of the Division of Raw Materials of the U.S Atomic Energy Commission



The Gypsum Gap quadrangle is one eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comparative study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through a arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The core consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title Geology of the Gypsum Gap quadrangle, Colorado
Series title Trace Elements Memorandum
Series number 697
DOI 10.3133/tem697
Year Published 1953
Language English
Publisher U.S. Geological Survey
Description Report: 36 p.; 1 Plate: 34.69 x 28.56 inches
Country United States
State Colorado
Other Geospatial Gypsum Gap Quadrangle
Additional Online Files (Y/N) Y
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