Filters: Tags: optically-stimulated luminescence (X)
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The following report summarizes the dating results from Bradley Lake, Oregon. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and datingrelated calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.
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.
Stone rows, enclosures, structures and chambers can be found in the landscapes of Massachusetts and Rhode Island. Structures similar to those shown in the cover photo are documented elsewhere. The age, cultural affiliation, and purpose of these stone structures--which are found in a variety of forms, such as piles arranged in spatial configurations across landscapes, shapes suggesting animal effigies, platforms and chambers--have been the subject of much debate. Some have argued they are remnants of colonial agricultural and storage practices; others that they are prehistoric Native American ceremonial structures. Ascertaining the time periods of their creation had previously been impossible. We felt that optically...
Despite its subdued expression and isolated location within the Great Plains of southeastern Colorado, the 80-km-long Cheraw fault may be one of the most active faults in North America east of the Southern Rocky Mountains. We present geomorphic analyses, geochronology, and paleoseismic trenching data to 1) document the rupture history of the ~45-km-long southwestern section of the Cheraw fault over the past ~19 ka, and 2) evaluate slip-rate changes for the entire fault over the past ~200 ka. Results from new trenches excavated at the Old Ranch site show evidence of four surface-rupture events since ~19 ka, each with an average vertical displacement of 0.75 m. An additional event is likely only slightly older than...
Categories: Data;
Tags: Arkansas River,
Basin and Range,
Cheraw Fault,
Eastern Colorado,
Geomorphology,
The following report summarizes the dating results from the. Within this report, we detail the methodology used to determine the storage time distribution for a 17 km length of Powder River in Montana, U.S.A. by the age distribution of eroded sediment. This data is used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating-related calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.
Categories: Data;
Tags: Fort Union Formation,
Geomorphology,
Kaycee Terrace,
Lightening Terrace,
Montana,
The following report summarizes the dating results from the San Luis Valley-Pioneer Fan 2017-2019 dating project. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating-related calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report.
Categories: Data;
Tags: Geomorphology,
Pioneer Fan,
San Luis Valley,
Sangre de Cristo Mountains,
Sedimentology,
The following report summarizes the dating results from the Natural Trap Cave 2018-2019 dating project. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating-related calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.
Categories: Data;
Tags: Big Horn County,
Big Horn Mountains,
Geochemistry,
Geomorphology,
Natural Trap Cave,
La Botica is positioned on a topographic bench sharply inset into the gentle eastern slope of the high San Juan Mountains and perched ~70-80 meters above La Jara Creek (fig. 1), a tributary to the Rio Grande. Quaternary surface processes have modified the Tertiary bedrock deposits that underlie La Botica to shape the physical environment. Bedrock deposits consist of Oligocene to Pliocene volcanic and sedimentary deposits related to the Rio Grande rift and the San Juan volcanic locus of the Southern Rocky Mountains volcanic field. Bedrock deposits are mildly deformed by normal faulting and eastward tilting related to the onset of extensional deformation in the Oligocene and formation of the San Luis Basin. Bedrock...
Categories: Data;
Tags: La Botica,
La Jara Creek,
Rio Grande,
San Juan Mountains,
South-Central Colorado,
The following report summarizes the dating results from Aeolian deposits within and around Edwards Air Force Base in California. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating related calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.
Categories: Data;
Tags: California,
Edwards Air Force Base,
Geochemistry,
Geomorphology,
Kern County,
The following report summarizes the dating results from sedimentary deposits exposed by soil pits in Panamint Valley, CA. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating-related calculations.
Categories: Data;
Tags: Ash Hill Fault,
Death Valley,
Eastern California Shear Zone,
Geochemistry,
Geomorphology,
Observations of widespread liquefaction and stratigraphic and structural relationships in a trench across an ambiguous scarp are used to constrain the timing of Holocene earthquakes on the northwest-striking Wallula fault zone in southeast Washington and Oregon. Additional observations and age constraints from OSL analysis of samples collected from large-scale liquefaction features that crosscut the Mount St Helens J tephra (13.8-13.7 ka) exposed at a nearby outcrop suggest up to 3 Holocene regional liquefaction events, any of which were likely triggered by seismic shaking sourced from either the Wallula fault and/or faults of the Yakima fold and thrust belt. Our observations provide plausible evidence supporting...
Categories: Data;
Tags: Columbia Plateau,
Columbia River,
Geochemistry,
Geomorphology,
Sedimentology,
This data release includes geochronological data for a natural exposure of the Wasatch fault, Utah at the Deep Creek site (39.507462°, -111.861790°). Laboratory data include 11 optically stimulated luminescence (OSL) ages for quartz, 23 charcoal radiocarbon ages, and 342 portable OSL (bulk luminescence) measurements. The radiocarbon and luminescence samples were collected November 2019 and October 2020.
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Central Utah,
Juab County,
USGS Science Data Catalog (SDC),
Utah,
Wasatch fault,
Deep Springs Valley (DSV) is a hydrologically isolated valley between the White (north and west) and Inyo (south and east) Mountains that is commonly excluded from regional paleohydrologic and paleoclimate studies. Previous studies showed that uplift of Deep Springs ridge (informal name) by the Deep Springs fault defeated streams crossing DSV and hydrologically isolating the valley sometime after eruption of the Bishop Tuff. Here we present tephrochronology, clast counts, paleontology, and infrared stimulated luminescence (IRSL) data that reaffirms interruption of the Plio-Pleistocene hydrology and formation of DSV during the Pleistocene. Fossil gastropod, ostracodes, and charophytes along with IRSL dating document...
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