Earth and Planetary Sciences ETDs

Kooser Ara

Publication Date

2-1-2012

Abstract

The study of the chemistry of waters in cave pools in the Guadalupe Mountains, NM was conducted to determine the variation in cave pool water geochemistry, explain hydrogeologic variations in a geologic context, identify the processes that control cave pool hydrologic variations and determine geochemical controls on modern and paleo-bacterial communities. Structural studies indicate cave pools align along NE and NW structures in the karst system. The intersection of Permian structures and Cenozoic related structures provide pathways for infiltrating water. Water samples were collected from 19 new cave pools; the results were integrated with published geochemistry from 192 cave pools, aquifer samples, and surface sites. The waters were analyzed for major and minor ions, modeled to explain flow paths, connected with structural data, examined for thermodynamic potential to support metabolic reactions, and to elucidate the relationship between current geochemistry and presence of biothems (biogenically mediated speleothems, including pool fingers). Infiltrating waters dominant the character of the cave pool waters. Variations in geochemistry of the cave pools can be explained by several geochemical processes: 1) infiltrating water-rock interactions 2) outgassing of CO2 3) precipitation of minerals and 4) evaporation. The thermodynamic data of available energy for use by microbial communities predicted the potential for nitrate, nitrite, oxygen, and sulfate to be used as terminal electron acceptors. The geochemical trends of pools containing biothems showed no connection between pool geochemistry and the presence of biothems. The small number of processes governing the variation in geochemistry give rise to a complex, unique geochemical signature and history for each cave pool thus unique microbial communities.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Brearley, Adrian

Second Committee Member

Spilde, Mike

Third Committee Member

Northup, Diana

Project Sponsors

National Science Foundation

Language

English

Keywords

cave pools, Gaudalupe Mountains, Lechuguilla, Carlsbad Cavern, Geochemistry, Geomicrobiology

Document Type

Thesis

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