About This Item

This article has been peer-reviewed and accepted for publication in a future issue of the AAPG Bulletin. This abstract and associated PDF document are based on the authors' accepted "as is" manuscript.

Editorial Policy for Ahead of Print


Cite This Item

Display Citation

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Visit Publisher's Website  

Ahead of Print Abstract

AAPG Bulletin, Preliminary version published online Ahead of Print 15 September 2022.

Copyright © 2022. The American Association of Petroleum Geologists. All rights reserved.

DOI:10.1306/08042221112

Hydrocarbon-induced bleaching and copper mineralization in the Wingate Sandstone, Paradox Valley, Colorado: Two episodes of fluid migration during the evolution of the Paradox Basin

Timothy J. MacIntyre1 , Murray W. Hitzman2 , and Jon P. Thorson3

1 Consulting Geologist, 8213 W 54th Ave, Arvada, Colorado 80002, USA
2 iCRAG, O’Brien Centre for Science (East), University College Dublin, Belfield, Dublin 4, Ireland
3 Consulting Geologist, 3611 South Xenia Street, Denver, Colorado 80237, USA

Ahead of Print Abstract

Fluid generation and movement are key components of basin evolution, with important implications for hydrocarbon and mineral exploration. Unlike high-temperature hydrothermal systems, the low-temperature basinal brines associated with diagenesis and hydrocarbon maturation often leave subtle physical or chemical evidence making their passage difficult to recognize in the rock record. Exceptional outcrops in the Paradox Basin display bleaching and Fe-Mn, Cu, and U-V accumulations that provide a unique opportunity for detailed investigation into paleofluid flow. This study examines bleaching and Cu mineralization in the Jurassic Wingate Sandstone on the southwestern flank of the Paradox valley salt anticline near the Cashin mine. Bleaching within the Wingate Sandstone extends for more than 12 km along the southwestern flank of the Paradox anticline and is centered around minor subvertical normal faults orthogonal to the anticlinal crest. Bleaching affects the full thickness of the Wingate Sandstone along the Paradox salt anticline and pinches out down-dip and laterally toward the top contact of the eolian sandstone with the overlying Kayenta Formation. Petrographic studies of the Wingate Sandstone show that bleaching involved the dissolution of iron-oxides and reprecipitation of most of the iron as pyrite as well as alteration of quartz, feldspar, and Fe-Ti grains, precipitation of kaolinite and barite, dissolution of dolomite cements, and introduction of hydrocarbons. The bleached zones appear to represent an exhumed paleohydrocarbon reservoir. A second fluid flow event transmitted Cu-bearing saline brines along the Cashin fault creating the Cashin Cu deposit in highly receptive pyrite- and hydrocarbon-bearing bleached rocks.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Protected Document: $10
Internal PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].

Please cite this AAPG Bulletin Ahead of Print article as:

Timothy J. MacIntyre , Murray W. Hitzman , Jon P. Thorson: Hydrocarbon-induced bleaching and copper mineralization in the Wingate Sandstone, Paradox Valley, Colorado: Two episodes of fluid migration during the evolution of the Paradox Basin, (in press; preliminary version published online Ahead of Print 15 September 2022: AAPG Bulletin, DOI:10.1306/08042221112.

Close