T121 New Frontiers in Cave and Karst Research (Posters): In Honor of the International Year of Caves and Karst

Monday, 11 October 2021
2:30 PM - 6:30 PM
Exhibit Hall A

ORIGIN AND SIGNIFICANCE OF SULFATE MINERAL CRUSTS IN THE CAVERNS OF SONORA, SUTTON COUNTY, TEXAS

Paper number: T121-12
Program: Technical Sessions
Time: 2:30 PM – 6:30 PM

Authors

  • Daniel Jones Presenting Author
    New Mexico Institute of Mining and Technology, Socorro, NM
  • Daniel Jones Presenting Author
    National Cave and Karst Research Institute, Carlsbad, NM
  • George Veni
    National Cave and Karst Research Institute (retired); currently at George Veni and Associates, Carlsbad, NM
  • Zoe Havlena
    New Mexico Institute of Mining and Technology, Socorro, NM
  • Amanda Labrado
    Department of Geological Sciences, El Paso, TX
  • Benjamin Brunner
    Institute of Tectonic Studies, El Paso, TX

Abstract

Caverns of Sonora is a popular tourist cave that is world renown for its spectacular carbonate speleothems. The cave is located in the central portion of Edwards Plateau and has approximately 10 km of explored passage. The cave is thought to have a hypogenic origin because of its maze pattern and characteristic morphological features, including a large fault that is exposed in a substantial portion of the cave and may represent a possible source for hypogene fluids. The cave also contains some rare and compelling deposits of metatyuyamunite and gypsum, which are commonly associated with hypogene and even sulfuric acid speleogenesis. Here we evaluated this possible mineral evidence for hypogene speleogenesis by characterizing white mineral crusts found throughout the cave. White crusts were sampled from three different cave levels. Powder XRD showed that white crusts were composed of nearly pure gypsum and, in some cases, calcite. The gypsum crusts were located in areas where calcite speleothems are absent and appear to have been protected from dripping water, although in one case, a gypsum crust was overlaying calcite speleothems. Stable isotope ratios (δ34Ssulfate) of the gypsum crusts range from +6.2 to +11.5‰, enriched in 34S compared to gypsum from sulfuric acid caves like the Frasassi Caves and Carlsbad Cavern, but lighter than dissolved sulfates in the Edwards Aquifer. The isotopic data does not clearly support but also does not entirely exclude a sulfuric acid origin, and future work will put these isotopic values in a regional and stratigraphic context to determine possible sources for the sulfur. We will also present data on microbial communities associated with gypsum and microcrystalline calcite deposits in the cave and discuss the implications for microbial contributions to calcite speleothem deposition.

Geological Society of America Abstracts with Programs. Vol. 53, No. 6

doi: 10.1130/abs/2021AM-368527

© Copyright 2021 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.