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Title: Diagenesis of amorphous organic matter as an essential aspect of genesis and alteration of tabular-type uranium-vanadium deposits, Colorado Plateau

Abstract

Organic matter was the key to the initial concentration of uranium and vanadium (during the sulfate reduction stage of early diagenesis) in all sandstone-hosted, tabular deposits in the Morrison Formation, Colorado Plateau. In deposits rich in amorphous organic matter, as are many in the Grants uranium region (GUR), diagenesis did not proceed beyond sulfate reduction. In contrast, in organic-poor, chlorite deposits of the Henry Mountains district, /sup 13/C- and /sup 18/O-enriched dolomites preserve evidence of a subsequent methanogenic stage. In these and similar organic-poor deposits in the Slick Rock district and in parts of the GUR, aluminosilicate dissolution (including a distinctive, organic-acid-induced etching of garnets) and growth of coarse-grained coffinite, albite, ankerite, and chlorite suggest diagenesis reached the organic acid stage. Temperature and thermal maturation indicators (vitrinite reflectance, type IIb chlorite, ordered illite/smectite, and fluid inclusion data) are consistent with temperatures of organic-acid stage diagenesis (approx. 100/sup 0/C). The localization of these alterations in and around organic-poor, clay-rich ore; the similarities in type and sequence of these alterations to the normal alteration of organic-bearing sediments; the alteration of iron-titanium oxides (attributed to the action of soluble organic complexes) around both organic-rich and organic-poor deposits; and the gradation from organic-rich tomore » organic-poor, chlorite-rich deposits (in GUR) suggest that (1) amorphous organic matter was involved in the genesis of all of these deposits and (2) differences among deposits may reflect varying degrees of diagenesis of the organic matter.« less

Authors:
;
Publication Date:
Research Org.:
Geological Survey, Denver, CO
OSTI Identifier:
5996029
Report Number(s):
CONF-870606-
Journal ID: CODEN: AABUD; TRN: 88-000007
Resource Type:
Conference
Journal Name:
AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)
Additional Journal Information:
Journal Volume: 71:5; Conference: American Association of Petroleum Geologists annual meeting, Los Angeles, CA, USA, 7 Jun 1987
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; ARIZONA; URANIUM DEPOSITS; COLORADO; NEW MEXICO; ORIGIN; UTAH; CARBONACEOUS MATERIALS; CLAYS; DIAGENESIS; DOLOMITE; GEOLOGIC FORMATIONS; ALKALINE EARTH METAL COMPOUNDS; CALCIUM CARBONATES; CALCIUM COMPOUNDS; CARBON COMPOUNDS; CARBONATE MINERALS; CARBONATES; FEDERAL REGION IX; FEDERAL REGION VI; FEDERAL REGION VIII; GEOLOGIC DEPOSITS; MAGNESIUM CARBONATES; MAGNESIUM COMPOUNDS; MATERIALS; MINERAL RESOURCES; MINERALS; NORTH AMERICA; OXYGEN COMPOUNDS; RESOURCES; USA; 050100* - Nuclear Fuels- Reserves, Exploration, & Mining

Citation Formats

Spirakis, C S, and Hansley, P L. Diagenesis of amorphous organic matter as an essential aspect of genesis and alteration of tabular-type uranium-vanadium deposits, Colorado Plateau. United States: N. p., 1987. Web.
Spirakis, C S, & Hansley, P L. Diagenesis of amorphous organic matter as an essential aspect of genesis and alteration of tabular-type uranium-vanadium deposits, Colorado Plateau. United States.
Spirakis, C S, and Hansley, P L. Fri . "Diagenesis of amorphous organic matter as an essential aspect of genesis and alteration of tabular-type uranium-vanadium deposits, Colorado Plateau". United States.
@article{osti_5996029,
title = {Diagenesis of amorphous organic matter as an essential aspect of genesis and alteration of tabular-type uranium-vanadium deposits, Colorado Plateau},
author = {Spirakis, C S and Hansley, P L},
abstractNote = {Organic matter was the key to the initial concentration of uranium and vanadium (during the sulfate reduction stage of early diagenesis) in all sandstone-hosted, tabular deposits in the Morrison Formation, Colorado Plateau. In deposits rich in amorphous organic matter, as are many in the Grants uranium region (GUR), diagenesis did not proceed beyond sulfate reduction. In contrast, in organic-poor, chlorite deposits of the Henry Mountains district, /sup 13/C- and /sup 18/O-enriched dolomites preserve evidence of a subsequent methanogenic stage. In these and similar organic-poor deposits in the Slick Rock district and in parts of the GUR, aluminosilicate dissolution (including a distinctive, organic-acid-induced etching of garnets) and growth of coarse-grained coffinite, albite, ankerite, and chlorite suggest diagenesis reached the organic acid stage. Temperature and thermal maturation indicators (vitrinite reflectance, type IIb chlorite, ordered illite/smectite, and fluid inclusion data) are consistent with temperatures of organic-acid stage diagenesis (approx. 100/sup 0/C). The localization of these alterations in and around organic-poor, clay-rich ore; the similarities in type and sequence of these alterations to the normal alteration of organic-bearing sediments; the alteration of iron-titanium oxides (attributed to the action of soluble organic complexes) around both organic-rich and organic-poor deposits; and the gradation from organic-rich to organic-poor, chlorite-rich deposits (in GUR) suggest that (1) amorphous organic matter was involved in the genesis of all of these deposits and (2) differences among deposits may reflect varying degrees of diagenesis of the organic matter.},
doi = {},
journal = {AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)},
number = ,
volume = 71:5,
place = {United States},
year = {1987},
month = {5}
}

Conference:
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