Abstract: Distribution of Sulfur in Continental and Nearshore Coals from Hanna and Green River Basins of Wyoming

Sanford Sandy Kaplan

The relative abundance of sulfate in marine waters has led many authors to suggest the use of sulfur as a paleosalinity indicator. In addition, it has been postulated that the brackish-water environment, which represents a mixing of marine and iron-rich fresh waters, will encourage maximum iron sulfide production in sediments deposited there. Iron sulfide has been suggested as being responsible for the difference in total sulfur between the two environments in deposition.

Comparison of the sulfur and forms of sulfur values of coals deposited in a freshwater environment in the Hanna basin and coals deposited in a brackish-water environment in the Hanna and Green River basins indicates that sulfur content cannot be used to differentiate the two environments. The two environments of deposition were substantiated by paleontologic evidence and well-documented stratigraphy. Samples from the freshwater Hanna Formation exhibited higher iron sulfide values than samples from the brackish-water Mesaverde Group. It is proposed that possible meromictic lake conditions in the Hanna basin were responsible for the high pyritic content and the termination of coal formation.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC