ABSTRACT
Hot and cold spring travertine deposits record integrated histories reflecting changing hydrologic conditions, informing our understanding of the driving forces behind factors impacting local hydrology. We present results from a geologic and geochemical investigation of Cottonwood Travertine, located in Dixie Valley, NV, where it is unclear if the paleospring system that deposited the travertine was driven by deeply sourced hydrothermal fluids, or high fluid flow driven by wetter paleoclimate conditions. The temperature of the spring water that precipitated the Cottonwood Travertine has implications for the relative importance of hydrothermal versus climatic processes
influencing the formation and cessation of this enigmatic deposit. We identified four groups of samples based on geologic setting, sample textures, and stable and clumped isotopic analysis: 1) calcite cemented upper gravels, 2) a mound area at the upper bench of the deposit, 3) samples from the flanks and from vuggy veins and fault zone cements from the base of the deposit, and 4) fibrous sub-travertine veins. The calcite-cemented gravels yielded δ18OC values as low as -18.4‰ (VPDB) and apparent TΔ47 of 52°C. The top mound of the deposit returned calcite δ18OC values between -12.8‰ and -11.7‰
(VPDB) and clumped isotope temperatures (TD47) of 24 – 32°C. Higher d13C and d18Oc values at the mound site are interpreted to reflect off gassing of CO2 and disequilibrium conditions. δ18OC and TD47 values from the slopes and base of the deposit are between -15.9‰ and -14.5‰ (VPDB) and around 20°C, respectively. Structurally, texturally, and isotopically (δ18OC = -29.4‰ (VPDB); TΔ47 = 93°C), the fibrous sub-travertine veins are more consistent with the local Jurassic host rock and probably do not reflect recent hot spring conditions. Our analysis suggests that, despite the impressive volume, Cottonwood Travertine formed from springs that were not particularly hot, and the deposit instead reflects vigorous warm spring activity in a wetter climactic regime rather than fluid flow from an extinct higher temperature hydrothermal system.
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High-resolution structure-from-motion models of hydrothermal sites in the Central Nevada Seismic Belt: applications in tectonic, climate, and hydrothermal investigations
ABSTRACT
Hot spring travertine and sinter deposits record discharge from hydrothermal systems through evolving hydrothermal, hydrologic, and tectonic regimes. The location and volume of the largest deposits may reflect persistent or particularly robust periods of hydrothermal
flow. As part of a broader investigation into the chemical evolution of travertine deposits, we used unoccupied aerial vehicles (UAVs) coupled with high-precision GPS surveys to collect and assemble orthorectified photomosaics and high-resolution digital elevation models (DEMs) using structure-from-motion (SfM) software for eight sites in the northern Central Nevada Seismic Belt. These sites range from large, intrabasin travertine mounds to travertine and sinter deposits offset by Quaternary faults. Some highlights of the research made possible by the acquisition of these topographic datasets include: 1) geomorphic evidence that hydrothermal flow at Hyder Hot Springs has persisted since at least the last highstand of glacial Lake Dixie, 2) documenting the impact of hot spring sinter and hydrothermal alteration on the preservation and morphology of Quaternary fault scarp profiles, 3) mapping the extent of a large extinct travertine deposit in the Stillwater Range, and 4) constraints on the offset of hot spring deposits affected by Quaternary faulting at Kyle Hot Springs. Areas between 0.51 – 1.23 km^2 (126-303 acres) were easily acquired with less than half a day of surveying and flying, and models capable of producing orthorectified photomosaics and DEMs with average resolution of 2.5 cm/pixel and 9.7 cm/pixel, respectively, were built on a desktop computer with 1-10 days of processing time. In desert landscapes, the resolution of the resulting DEMs approaches that of bare earth LiDAR datasets at a fraction of the cost, with little to no special permitting in most cases, and with limited preplanning. The imagery and models described herein are freely available from the NSF-EAR-funded data facility OpenTopography
(https://portal.opentopography.org/datasets) for use in commercial, academic, and educational applications with proper attribution.
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- Award ID(s):
- 2040716
- NSF-PAR ID:
- 10400573
- Date Published:
- Journal Name:
- Proceedings 48th Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California.
- Page Range / eLocation ID:
- SGP-TR-224
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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