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Wall-rock control of cortain pitchblende deposits in Golden Gate Canyon, Jefferson County, Colorado

Trace Elements Investigations 430

This report concerns work done on behalf of the Division of Raw Materials of the U.S. Atomic Energy Commission
By:
and
DOI: 10.3133/tei430

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Abstract

Carbonate veins cutting pre-Cambrian metamorphic rocks in Golden Gate Canyon contain pitchblende and base-metal sulfides. The veins occupy extensive faults of Laramide age but normally contain pitchblende only where the cut hornblende gneiss. At the Union Pacific prospect, which was studied in detail, pitchblende, hermatite, and some ankerite formed in advance of sulfides, except possibly for minor pyrite. Base-metal sulfides and the bulk of ankerite-calcite vein-filling were deposited after the pitchblende. Chemical analyses show a high ferrous iron content in the hornblende gneiss in contrast to low ferrous iron in the adjacent biotite gneiss. It is hypothesized that ferrous iron released by alteration of hornblende was partly oxidized to hematite by the ore-bearing solutions and, contemporaneously, uranium was reduced and deposited as pitchblende.


In other veins, biotite or iron sulfides may have been similarly effective in precipitating pitchblende. Apparently both the ferrous ion and the sulfide ion can serve as reducing agents and control pitchblende deposition. It is suggested that conditions particularly favorable for uranium deposition are present where uranium-bearing solutions had access to rocks rich in ferrous iron or pre-existing sulfides.

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Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Wall-rock control of cortain pitchblende deposits in Golden Gate Canyon, Jefferson County, Colorado
Series title:
Trace Elements Investigations
Series number:
430
DOI:
10.3133/tei430
Year Published:
1954
Language:
English
Publisher:
U.S. Geological Survey
Description:
Report: 34 p.; 1 Plate: 16.80 x 22.37 inches
Country:
United States
State:
Colorado
County:
Jefferson County
Other Geospatial:
Golden Gate Canyon