Tonopah is a small town in the south-central portion of Nevada with a rich history of silver mining and a star sand dune complex known as Crescent (Tonopah) Sand Dunes just west of town. Because sand dunes accumulate sediments from broad geographic areas, sands from these environments are often used as a standard to describe the area’s surrounding geology. While extensive studies have been conducted investigating the geochemical and mineralogical characteristics of sands from large sand dune systems in the Basin and Range of the western United States, there have been few studies documenting the Crescent Sand Dunes. Oglesbee et al. (2019) investigated numerous characteristics of these sands (grain size, mineral abundances, bulk element compositions, etc.) to serve as an environmental reference for Tonopah and the greater area. Although the data from this reference material suggests these sands to be most chemically similar to nearby Miocene-aged volcanic deposits, it is still relatively unclear whether these sands originate from these rocks or another primary source. This study aims to further constrain the possible primary sources of the Crescent Dune sands by using scanning electron microscope (SEM) analyses and U-Pb dating of detrital zircons. Initial SEM imaging indicates a wide range of sand grain roundedness, shape, and texture. SEM imaging also reveals that lithics are widely present with some having vesiculated textures. U-Pb dating of the detrital zircons in the Crescent Dune sands will yield a crystallization age that can be compared to the well-documented igneous rocks nearby to determine if they have similar formation ages. Results from the SEM and U-Pb dating of zircons combined with previous reference material will be used to further constrain and possibly determine the primary sources of sediments for the Crescent Sand Dunes.
Author(s): Zachary Ellia
Advisor(s): Claire McLeod, Geology and Environmental Science; Mark Krekeler, Geology and Environmental Science
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