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Title: Sulfur redox reactions: Hydrocarbons, native sulfur, Mississippi Valley-type deposits, and sulfuric acid karst in the Delaware Basin, New Mexico and Texas

Hydrocarbons, native sulfur, Mississippi Valley-type (MVT) deposits, and sulfuric acid karst in the Delaware Basin, southeastern New Mexico, and west Texas, USA, are all genetically related through a series of sulfur redox reactions. The relationship began with hydrocarbons in the basin that reacted with sulfate ions from evaporite rock to produce isotopically light ({delta}{sup 34}S = -22 to -12) H{sub 2}S and bioepigenetic limestone (castiles). This light H{sub 2}S was then oxidized at the redox interface to produce economic native sulfur deposits ({delta}{sup 34}S = -15 to +9) in the castiles, paleokarst, and along graben-boundary faults. This isotopically light H{sub 2}S also migrated from the basin into its margins to accumulate in structural (anticlinal) and stratigraphic (Yates siltstone) traps, where it formed MVT deposits within the zone of reduction ({delta}{sup 34}S = -15 to +7). Later in time, in the zone of oxidation, this H{sub 2}S reacted with oxygenated water to produce sulfuric acid, which dissolved the caves (e.g., Carlsbad Cavern and Lechuguilla Cave, Guadalupe Mountains). Massive gypsum blocks on the floors of the caves ({delta}{sup 34}S = -25 to +4) were formed as a result of this reaction. The H{sub 2}S also produced isotopically light cave sulfur ({delta}{sup 34}Smore » = -24 to -15), which is now slowly oxidizing to gypsum in the presence of vadose drip water. 16 refs., 10 figs.« less
Authors:
Publication Date:
OSTI Identifier:
61805
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Geology (New York); Journal Volume: 25; Journal Issue: 1; Other Information: PBD: Feb 1995
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; HYDROCARBONS; GEOLOGIC DEPOSITS; SULFUR; REDOX REACTIONS; EVAPORITES