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Geologic framework and hydrostratigraphy of the Edwards and Trinity aquifers within northern Bexar and Comal Counties, Texas
During 2020–22, the U.S. Geological Survey, in cooperation with the Edwards Aquifer Authority, revised a previous publication that described the geologic framework and hydrostratigraphy of the Edwards and Trinity aquifers within northern Bexar and Comal Counties, Texas. This report presents the refined maps and descriptions of geologic framework and hydrostratigraphy of the Edwards and Trinity aqu
Stratigraphic Cross Sections of the Lewis Shale in the Eastern Part of the Southwestern Wyoming Province, Wyoming and Colorado
Three stratigraphic cross sections A–A', B–B', and C–C' were created for the Lewis Shale and associated strata in the eastern part of the Southwestern Wyoming Province of Wyoming and Colorado. The cross sections highlight 15 clinothems within the Lewis Shale, Fox Hills Sandstone, and Lance Formation progradational system (also referred to as the Lewis Shale system). Additionally, the cross section
Groundwater potentiometric-surface altitude in 2022 and groundwater-level changes between 1968, 1991, and 2022, in the alluvial aquifer in the Big Lost River Valley, south-central Idaho
The U.S. Geological Survey and the Idaho Department of Water Resources measured groundwater levels during spring 2022 and autumn 2022 to create detailed potentiometric-surface maps for the alluvial aquifer in the Big Lost River Valley in south-central Idaho. Wells were assigned to shallow, intermediate, and deep water-bearing units based on well depth, groundwater potentiometric-surface altitude,
Mapping karst groundwater flow paths and delineating recharge areas for Fern Cave, Alabama, through the use of dye tracing
Fern Cave in Jackson County, Alabama, is a 15.6-mile-long (25.1-kilometer) cave system, managed by the U.S. Fish and Wildlife Service and Southeastern Cave Conservancy, that has the second highest biodiversity of any cave in the southeastern United States. Groundwater in karst ecosystems is known to be susceptible to impacts from human-induced land-use activities in watersheds that contribute rech
Aeromagnetic map of northeastern California
Aeromagnetic surveys were conducted to improve understanding of the geology and structure in northeastern California, a region predominantly covered by Quaternary and Tertiary, mainly Neogene, volcanic rocks including Medicine Lake volcano. New aeromagnetic data are a substantial improvement over existing data and reveal structural details not resolved by older surveys. Here we show how these data
Estimating streambed hydraulic conductivity for selected streams in the Mississippi Alluvial Plain using continuous resistivity profiling methods—Delta region
Introduction The Mississippi Alluvial Plain is one of the most important agricultural regions in the United States, and crop productivity relies on groundwater irrigation from an aquifer system whose full capacity is unknown. Groundwater withdrawals from the Mississippi River Valley alluvial aquifer have resulted in substantial groundwater-level declines and reductions in base flow in streams with
Geologic and geophysical maps of the Stockton 30’ × 60’ quadrangle, California
This pamphlet and accompanying geologic and geophysical maps are the products of cooperative efforts by the California Geological Survey (CGS) and United States Geological Survey (USGS) to compile a comprehensive, digital representation of the bedrock geology, Quaternary surficial deposits, and potential-field anomalies within the boundaries of the Stockton 30’ × 60’ quadrangle. The Stockton 30’ ×
Percent-slope map showing historical anthracite coal-mining infrastructure at the northern end of the Lackawanna syncline, Wayne, Susquehanna, and Lackawanna Counties, Pennsylvania
Introduction Abandoned railroads and infrastructure from the anthracite coal-mining industry are significant features in abandoned mine lands and are an important part of history; however, these features are often lost and masked by the passage of time and the regrowth of forests. The application of modern light detection and ranging (lidar) topographic analysis, combined with field verification,
Potentiometric surface map of the Southern High Plains aquifer in the Cannon Air Force Base area, Curry County, New Mexico, 2020
Declining water levels and the potential impact on water resources on and around Cannon Air Force Base (AFB), New Mexico, has necessitated an up-to-date review of the potentiometric surface to evaluate the availability of water resources for future use. Analysis of groundwater-flow directions and hydraulic gradients can provide an understanding of depletion by heavy groundwater pumping and recharg
Landslides triggered by the 2016–2017 storm season, eastern San Francisco Bay region, California
DiscussionThe winter rainy season of 2016–2017 brought abundant rainfall to the State of California and to the San Francisco Bay region. In January and February of 2017, intense rainfall from strong winter storms saturated soils in the region and triggered thousands of shallow landslides. The highest concentration of these landslides was in the eastern part of the bay region, where landslides in t
Logs and data from the Starthistle trench across a scarp within the Wallula Fault Zone, southeastern Washington
IntroductionThe Wallula Fault Zone is composed of a series of northwest-trending faults and folds that coincide with a prominent magnetic anomaly that extends uninterrupted for approximately 120 kilometers within the Cascadia back arc of southeastern Washington and northeastern Oregon. It is part of the geologic structures associated with the topographic lineament known as the Olympic-Wallowa line
Using the potassium-argon laser experiment (KArLE) to date ancient, low-K chondritic meteorites
Several laboratories have been investigating the feasibility of in situ K-Ar dating for use in future landing planetary missions. One drawback of these laboratory demonstrations is the insufficient analogy of the analyzed analog samples with expected future targets. We present the results obtained using the K-Ar laser experiment (KArLE) on two old and K-poor chondritic samples, Pułtusk and Hvittis