USGS Science⌕ Search
Home/Archive/USGS

USGS · 70221150

Aeolian sediments in paleowetland deposits of the Las Vegas Formation

Harland L. Goldstein·Kathleen B. Springer·Jeffrey S. Pigati·Marith C. Reheis·Gary L. Skipp
View original source ↗Export metadata ↓

Abstract

The Las Vegas Formation (LVF) is a well-characterized sequence of groundwater discharge (GWD) deposits exposed in and around the Las Vegas Valley in southern Nevada. Nearly monolithologic bedrock surrounds the valley, which provides an excellent opportunity to test the hypothesis that GWD deposits include an aeolian component. Mineralogical data indicate that the LVF sediments are dominated by carbonate minerals, similar to the local bedrock, but silicate minerals are also present. The median particle size is ~35 μm, consistent with modern dust in the region, and magnetic properties contrast strongly with local bedrock, implying an extralocal origin. By combining geochemical data from the LVF sediments and modern dust, we found that an average of ~25% of the LVF deposits were introduced by aeolian processes. The remainder consists primarily of authigenic groundwater carbonate as well as minor amounts of alluvial material and soil carbonate. Our data also show that the aeolian sediments accumulated in spring ecosystems in the Las Vegas Valley in a manner that was independent of both time and the specific hydrologic environment. These results have broad implications for investigations of GWD deposits located elsewhere in the southwestern U.S. and worldwide.

Explore related subjects

Quaternary ResearchArticle
90° N90° S · 180° W ← longitude → 180° E
Source-reported bounding extent: 35.68407153314097° to 36.465471886798134° latitude; -115.71899414062499° to -114.49951171875° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Harland L. Goldstein, Kathleen B. Springer, Jeffrey S. Pigati, Marith C. Reheis, Gary L. Skipp. 2021-05-17. Aeolian sediments in paleowetland deposits of the Las Vegas Formation. https://doi.org/10.1017/qua.2021.14

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Age reassignment using luminescence dating for the Mammoth Site, Black Hills, South Dakota, USA

The Mammoth Site (MS) at Hot Springs, South Dakota, provides a unique opportunity to reconstruct paleoenvironmental conditions on the Northern Great Plains of the United States. Previous radiocarbon analyses of mammoth bone apatite suggested the MS sinkhole was deposited ∼42–23 cal ka BP. However, two U-series ages and one thermoluminescence (TL) age ranged between 150 and 101 ka, suggesting the bones were considerably older. We analyzed six samples from the bone bed using infrared-stimulated luminescence (IRSL) on feldspars, because the quartz luminescence was saturated; the ages ranged from approximately 232 to 160 ka, showing better agreement with previous U-series and TL analyses. In addition, we dated three samples on two terraces that are at lower elevation than the MS. Our new IRSL ages show that the sediments of the MS were likely well bleached, derived from pond margin runoff events, and deposited as sandy-silt laminae couplets. Our chronology indicates that the 6-m-thick bone-bearing sediments accumulated at a rate of approximately 12 mm/yr and that deposition occurred during Marine Isotope Stage (MIS) 6 and MIS 7, not MIS 2 and MIS 3 as previously published.

South Dakota↗
USGS2026

A multiproxy reconstruction of changes in sea ice and primary productivity at IODP Site U1339 (Umnak Plateau, Bering Sea) during Marine Isotope Stage 11

The extreme warmth of Marine Isotope Stage (MIS) 11 has been extensively studied in the terrestrial realm; however, less is known about its expression in the North Pacific. Here, we present a multiproxy record from Integrated Ocean Drilling Program (IODP) Site U1339 in the southeastern Bering Sea (Umnak Plateau). We use sedimentology, diatoms, and organic geochemistry to reconstruct sea ice and primary productivity from the end of MIS 12 to the beginning of MIS 10 (430–368 ka) at this site. In late MIS 12, the Umnak Plateau experienced extensive seasonal sea ice cover, with spring sea ice concentration near 100%. Based on diatoms and ice-rafted debris, sea ice declined to year-round ice-free conditions during deglaciation but readvanced during the interglacial climatic optimum. In contrast, sea ice has not been present at the Umnak Plateau throughout the Holocene. During MIS 11, sea ice at this site may have persisted due to a more easterly and/or weaker Aleutian Low. Laminated sediments indicate enhanced seasonal productivity during deglaciation. However, productivity does not remain high throughout the interglacial. The decline in productivity during MIS 11 occurs independently of fluctuations in sea ice and upwelling and may be due to increasing nutrient limitation.

Alaska↗