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We assessed a construction site in the northern Las Vegas Valley that was initially reported as an "ice age" deposit. Alluvial deposits exposed at the site were inset into the Las Vegas Formation and contained semi-articulated Equus remains. Calibrated radiocarbon dates on two different materials associated with the remains centered on 1957, thus rendering the horse bones as modern.
Categories: Data;
Tags: Climatology,
Equus,
Las Vegas Valley,
Nevada,
USGS Science Data Catalog (SDC),
This digital dataset release of the La Junta, Colorado and Kansas quadrangle is composed of previously published elevation contours, structure contours on the limits of the Morrison, Dakota, and Purgatorie Formations, and geologic formational data. The digitizing of this map is to provide a more accessible dataset to be available for public usage. The original dataset was part of an eight-part series of maps in Colorado and Kansas, this map modified in part by reconnaissance by G.R. Scott in 1968. The entirety of this dataset includes both spatial and non-spatial data held in a singular, GeMS compliant geodatabase. This geodatabase includes a geologic map, geologic map feature class holding contact and fault lines,...
Categories: Data;
Types: ArcGIS REST Map Service,
ArcGIS Service Definition,
Downloadable,
Map Service;
Tags: Big Basin Formation,
Colorado,
Cretaceous,
Dakota Sandstone,
Dockum Group,
Post-Eocene (predominantly Pliocene) continental sedimentary rocks of the Sacramento Valley, CA are up to 1,200 m thick beneath the valley. These rocks contain most of the fresh ground water in the valley, forming a key component of the total water budget for the valley. A 1974 study by the U.S. Geological Survey was an early attempt to develop detailed knowledge of the subsurface geology of the Sacramento Valley. The study delineated the configuration of the base post-Eocene continental sedimentary rocks of the Sacramento Valley and mapped the thickness of those deposits. This digital dataset contains spatial datasets corresponding to the contoured base and thickness of the post-Eocene continental sedimentary rocks...
Categories: Data;
Tags: California,
Central Valley aquifer system,
Sacramento,
Sedimentology,
Stratigraphy,
Fire history metrics enable rapidly increasing amounts of burned area data to be collapsed into a handful of data layers that can be used efficiently by diverse stakeholders. In this effort, the U.S. Geological Survey's Landsat Burned Area product was used to identify burned area across CONUS over a 40-year period (1984-2023). The Landsat BA product was consolidated into a suite of annual BA products, which in-turn were used to calculate a series of contemporary fire history metrics (30 m resolution). Fire history metrics included: (1) fire frequency (FRQ), (2) time since last burn (TSLB) and (3) year of last burn (YLB), (4) longest fire-free interval (LFFI), and (5) average fire interval length (FIL). All metrics...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Landsat,
USGS Science Data Catalog (SDC),
United States,
burned area,
fire frequency,
This data release provides a digital inventory of the Robert S. Thompson packrat midden collection consisting of 1,740 midden samples and subsamples primarily collected in the Great Basin region of Nevada, as well as in Arizona, California, Colorado, Oklahoma, Utah, and Washington, USA, by Robert S. Thompson (USGS scientist emeritus) and others between 1977 and 2006. Middens are waste piles composed of the urine and feces of packrats (Neotoma spp.) also containing plant materials, bones, and insects. Radiocarbon dating of middens indicates they can be preserved for as long as 50,000 years, and their fossil plant assemblages document changes in plant community composition through time, providing important records...
The Bureau of Reclamation's Scoggins Dam lies within the Gales Creek fault zone southwest of Hillsboro, Oregon. Recent geologic mapping shows the dam to overlie a potentially active strand of the fault. This report describes the geology of the dam in detail and confirms that the dam overlies a strand of the Gales Creek fault. The report documents small faults in the reservoir and off the north end of the dam along the Parsons Creek strand of the fault. The report further documents the geology of an alternative dam site downstream of the existing dam.
Holocene sediments at Emerald Lake in central Utah (3090 m a.s.l), document the paleohydroclimatic history of the western Upper Colorado River headwater region. Multi-proxy analyses of sediment composition, mineralogy, and stable isotopes of carbonate (d18O and d13C) show changes in effective moisture for the past ca. 10,000 years at millennial to decadal timescales. Emerald Lake originated as a shallow closed-basin cirque pond during the early Holocene. By ca. 7000 cal yr BP, higher lake levels and carbonate d18O values indicate rising effective moisture and higher proportions of summer precipitation continued at least until ca. 5500 cal yr BP when a landslide entered the lake margin. Between ca. 4500 and 2400...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Ecology,
Geomorphology,
Great Basin,
Holocene,
Hydrology,
This data release provides output produced by a statistical, aridity threshold fire model for 11 extensively forested ecoregions in the western United States. We identified thresholds in fire-season climate water deficit (FSCWD) that distinguish years with limited, moderate, and extensive area burned for each ecoregion. We developed a new area burned model using these relationships and used it to simulate annual area burned using historical climate from 1980 - 2020 and output from global climate models (GCMs) from 1980 - 2099. The data release includes a comparison of mean annual FSCWD for 13 GCMs that we used to select five GCMs that bracket the range of conditions projected for the RCP 8.5 emissions scenario....
Africa terrestrial ecosystems were modeled using a biophysical stratification approach based on mapping the major structural components of ecosystems. New 90 meter base resolution continental datasets were developed for several key physical environment datalayers including coastlines, land surface forms, surficial lithology, and bioclimates. These unique physical components, considered as the fundamental building blocks of ecosystems, were reviewed by regional vegetation and landscape ecology experts and used in a classification and regression tree (CART) inductive model to map intermediate scale Africa terrestrial ecosystems. In the final dataset a total of 126 terrestrial ecosystem types were mapped, each with...
The Fort Morgan 7.5' quadrangle is located on the semiarid plains of northeastern Colorado, along the South Platte River corridor where the river has incised into Upper Cretaceous Pierre Shale. The Pierre Shale is largely covered by surficial deposits that formed from alluvial, eolian, and hillslope processes operating in concert with environmental changes from the late Pliocene to the present. The South Platte River, originating high in the Colorado Rocky Mountains, has played a major role in shaping surficial geology in the map area, which is several tens of kilometers downstream from where headwater tributaries join the river. Recurrent glaciation (and deglaciation) of basin headwaters has affected river discharge...
The Upper Missouri River headwaters (UMH) basin (36 400 km2 ) depends on its river corridors to support irrigated agriculture and world-class trout fisheries. We evaluated trends (1984–2016) in riparian wetness, an indicator of the riparian condition, in peak irrigation months (June, July and August) for 158 km2 of riparian area across the basin using the Landsat normalized difference wetness index (NDWI). We found that 8 of the 19 riparian reaches across the basin showed a significant drying trend over this period, including all three basin outlet reaches along the Jefferson, Madison and Gallatin rivers. The influence of upstream climate was quantified using per reach random forest regressions. Much of the interannual...
The late Pleistocene was a climatically dynamic period, with abrupt shifts between cool-wet and warm-dry conditions. Increased effective precipitation supported large pluvial lakes and long-lived spring ecosystems in valleys and basins throughout the western and southwestern U.S., but the source and seasonality of the precipitation are debated. Here we present stable carbon and oxygen isotope data from tooth enamel of late Pleistocene herbivores recovered from paleowetland deposits at Tule Spring Fossil Beds National Monument in the Las Vegas Valley of southern Nevada, as well as modern herbivores from the surrounding area, to investigate whether winter or summer precipitation was responsible for driving the wet...
This dataset includes tables with physical information and isotopic data that are used to calculate uranium-series ages (230Th/U method) and initial 234U/238U activity ratios on a suite of mastodon bones from the Cerutti Mastodon site near San Diego, CA area.
Categories: Data;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: California,
Paradise Hills,
San Diego,
San Diego County,
USGS Science Data Catalog (SDC),
This release presents the GIS data (in GDB, shapefile, and e00 [coverage] formats) and metadata for a 1:24,000-scale geologic map of the Poncha Pass area in central Colorado. A cartographic version of the geologic map, including map unit descriptions, interpretative text, and accessory figures and tables, is being separately published as a U.S. Geological Survey Scientific Investigations Map (SIM). The map area is irregular in shape, covering all of one 7.5' quadrangle (Poncha Pass) and parts of five others (Mount Ouray, Maysville, Salida West, Salida East, and Wellsville). The map boundaries were drawn to cover all of the "Poncha mountain block", coincident with the approximately 15-kilometer-long northwestern...
In support of U.S. Geological Survey (USGS) Southwest Biological Science Center researchers, and in coordination with the Bureau of Land Management (BLM) and National Ecological Observatory Network (NEON), the USGS National Uncrewed Systems Office (NUSO) conducted uncrewed aircraft systems (UAS) remote sensing flights over two BLM Assessment, Inventory, and Monitoring (AIM) plots at the NEON Moab site in Utah for multi-scale carbon sequestration research on public lands. The UAS data collected include natural color, multispectral, and hyperspectral imagery, and lidar to capture diverse information about vegetation and soils on drylands. The first site (“site 1”) features intact sagebrush and was mapped on May 3,...
This data release contains: 1) the BIOME4-simulated biome data used to create Sommers et al. (2021) Figures 2, 6, S6, and S7; 2) the CESM2-CISM2 calendar-adjusted temperature data used to create Sommers et al. (2021) Figures 2, 7, S2-S5, and S8-S11; and 3) land, ice, and ocean mask data and continent and ice sheet outline files. Additional CESM2-CISM2 simulation data described in Sommers et al. (2021) are available from the University Corporation for Atmospheric Research (UCAR)/National Center for Atmospheric Research (NCAR) Digital Asset Services Hub (DASH; https://doi.org/10.5065/as0j-6387). The simulated biome data are on a global 0.5-degree grid for the Last Interglacial (LIG; 127.0-119.0 ka) at 500-year time...
This data release includes climatic variables and associated descriptive material created for the purpose of assessing uncertainties associated with climatic estimates based on vegetation assemblages (Thompson and others, 2021). The data are from the interior of the western United States, including all of Arizona, and portions of California, Colorado, Nevada, New Mexico, Texas, and Utah. The data are observed, interpolated, and estimated values for the mean temperature of the coldest month (MTCO, degrees C), mean temperature of the warmest month (MTWA, degrees C), and mean annual total precipitation (MAP, mm).
This document includes sandstone provenance data for Upper Cretaceous to Paleocene strata preserved in the Crazy Mountains Basin of western Montana, USA. The dataset includes detrital zircon data for six samples from the Upper Cretaceous Hoppers Formation (1 sample), Upper Cretaceous Billman Creek Formation (1 sample), and Paleocene Fort Union Formation (4 samples). Detrital zircon data were acquired at the University of Arizona LaserChron Center in 2017.
Categories: Data;
Tags: Montana,
Sedimentology,
Stratigraphy,
USGS Science Data Catalog (SDC),
basin,
This data release contains numerical U- and Th-isotopic data used to calculate uranium-series age estimates and initial 234U/238U activity ratios for samples of carbonate-rich clast coatings, oncoidal tufa rinds, calcite-replaced rhizoliths, carbonate nodules, and ostracod shells from sites associated with different lake levels of paleo Lake Manix near Barsow, CA. In addition, measured U concentrations and 234U/238U activity ratios for modern streamflow in the Mojave River and shallow groundwater from wells along the course of the Mojave River and nearby vicinity are included to help define the uranium-isotope composition of water that likely supplied paleolakes. Electronic data included herein support age interpretations...
Global trends in wetland degradation and loss have created an urgency to monitor wetland extent, as well as track the distribution and causes of wetland loss. Satellite imagery can be used to monitor wetlands over time, but few efforts have attempted to distinguish anthropogenic wetland loss from climate-driven variability in wetland extent. We present an approach to concurrently track land cover disturbance and inundation extent across the Mid-Atlantic region, United States, using the Landsat archive in Google Earth Engine. Disturbance was identified as a change in greenness, using a harmonic linear regression approach, or as a change in growing season brightness. Inundation extent was mapped using a modified version...
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