32 Peeling the Onion: Building on a Century and a Half of Geologic Research in the Illinois Basin

Tuesday, 19 April 2016
1:30 PM - 5:30 PM
Chancellor Ballroom

A SULFATE CONUNDRUM: DISSOLVED SULFATES OF DEEP-SALINE BRINES AND CARBONATE ASSOCIATED SULFATES

Paper number: 32-2
Program: Theme Sessions
Time: 1:35 PM – 1:55 PM

Authors

  • Dana Labotka Presenting Author
    Illinois State Geological Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, IL
  • Samuel V. Panno
    Prairie Research Institute, University of Illinois, Champign, IL
  • Randy Locke
    Illinois State Geological Survey, Champaign, IL

Abstract

Sulfates in deep-circulating brines and carbonate associated sulfates (CAS) within sedimentary units of Cambrian strata in the Illinois Basin record a complex groundwater history. Dissolved sulfate in the Mt. Simon Sandstone brines appears to be related to Cambrian seawater sulfate, either original seawater or sourced from evaporite deposits. Dissolved sulfate from the Ironton-Galesville Sandstone shows influences from younger groundwater. CAS and evaporites from carbonate units between the Mt. Simon and Ironton-Galesville Sandstones show distinctly different isotope values that are related to the Late Pennsylvanian-Early Permian Mississippi Valley-type (MVT) ore pulses which deposited large sulfide minerals in the Viburnum Trend/Old Lead Belt ore districts. The isotopic disparity between consecutive Cambrian sedimentary lithologies is not well understood. Greater fluid densities of the Mt. Simon brines may have prevented significant interaction with the less dense MVT fluids. The Mt. Simon brines appear to be a mixture of evaporated Cambrian seawater, recirculating deep-seated crystalline basement brines, and meteoric water.

Geological Society of America Abstracts with Programs. Vol. 48, No. 5

doi: 10.1130/abs/2016NC-275309

© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.