The Bonneville Salt Flats form a saline pan in western Utah, USA. This modern saline pan has a unique history of land‐speed racing and potash mining. Multi‐decadal measurements record decreasing evaporite volume and extent, spurring multiple environmental studies. The goal of this work is to describe saline pan evaporite morphologies within the context of environmental measurements. Environmental data include field observations, groundwater and dust trap samples, precipitation, albedo, time‐lapse photography, groundwater level, and temperature measurements of air, groundwater and the shallow evaporite crust. Petrographic data include thick sections, evaporite slabs and sediments, and X‐ray computed tomography of evaporites. Diverse halite morphologies are formed at the surface, vadose and phreatic zones. The presence and preservation of these morphologies are influenced by spatially heterogenous natural and anthropogenic processes, including daily to seasonal changes in brine salinity, mineral saturation states, and water level within and across saline pan stages. In addition to hydrological balances delineated by the saline pan stages of flooding, evapoconcentration and desiccation, changes in vertical brine movement, temperature and surficial sedimentary structures influence evaporite morphologies. These results are transferable to the interpretation of altered evaporites and enhancing saline pan depositional models.
The Bonneville basin, located in north‐western Utah, is a vast evaporite basin which is home to the world‐renowned Bonneville Salt Flats international speedway and is a highly valued landscape undergoing rapid change and anthropogenic influence. Air quality, snowpack, the local hydrological system, and state tourism are all impacted by the nature of the surface sediments exposed in the Bonneville basin. Mapping the Bonneville basin over time with remote sensing methods provides insight into the dynamics and impacts of the changing surface landscape. Utilizing the Landsat‐5 Thematic Mapper (TM) and Landsat‐8 Operational Land Imager (OLI) sensors, a set of band math indices are empirically established to map the predominant halite, gypsum, and carbonates mineralogical zones of the Bonneville basin. Spectral comparisons of representative samples from the study area and image‐derived spectra indicate the halite of the Bonneville basin is wet and that gypsum deposits are slightly mixed with halite. The established indices are assessed in four ways, all of which support the ability of the indices to accentuate the associated mineralogical endmembers. Two study areas within the Bonneville basin are investigated temporally from 1986, 1995, 2005, and 2016 and show changing patterns in mineral distribution that align with surface processes active through these timescales. These indices provide a resource for mapping mineralogy though time in evaporite basins globally with diverse applications for questions about land use and environmental change.
more » « less- NSF-PAR ID:
- 10385419
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Earth Surface Processes and Landforms
- Volume:
- 46
- Issue:
- 6
- ISSN:
- 0197-9337
- Page Range / eLocation ID:
- p. 1160-1176
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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