Date of Award
8-1-2022
Degree Name
Master of Science
Department
Geology
First Advisor
Pottern-McIntyre, Sally
Abstract
Mollies Nipple is a butte located in Kane County, Utah and is part of Grand Staircase-Escalante National Monument (GSENM). Mollies Nipple is now of particular interest to the Mars research community because of the presence of unusual diagenetic alunite and jarosite minerals. These minerals are present in sedimentary environments on Mars and have been used to interpret the diagenetic and depositional environments as acidic and/or arid. On Earth, these minerals are present in modern acid saline lakes, fumaroles, or acid mine drainage, but not commonly as diagenetic cements. The butte was mapped as Navajo Sandstone via photogeologic mapping, but the apex is 200 m higher than the surrounding upper extent of that unit in adjacent areas and there are some lithological inconsistencies that suggest the caprock may be a different overlying formation. Correctly understanding the diagenetic and depositional history of Mollies Nipple will inform future studies on Mars and has the potential to change the paradigm of these interpreted jarosite-bearing Martian environments. Stratigraphic sections were measured in the field and samples were collected for laboratory analysis. The dominant lithofacies is a cross-bedded quartz arenite. Structureless quartz arenite to wacke with lenticular green-gray quartz wacke (ash) is also present. Jarosite cement is common in upper sections of Mollies Nipple and is present, but sparse, in lower section of Mollies Nipple. Alunite is present in the upper section of Mollies Nipple. ANOVA conducted on point count data from samples collected from Nipple and representative samples of potential formations at Mollies Nipple do not differentiate between the possible formation candidate and Navajo Sandstone. Based on distribution of lithofacies, comparison with adjacent outcrops of Temple Cap Formation, Page Sandstone, and Carmel Formation, we conclude that the caprock at Mollies Nipple is most likely the Temple Cap Formation.
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