A5077510451- Geochemistry and Geologic Mapping
- Geology and Paleoclimatology Research
- Geological and Geochemical Analysis
- Geological and Tectonic Studies in Latin America
- Archaeology and Natural History
- Water Quality and Resources Studies
- Hydrocarbon exploration and reservoir analysis
- Geological formations and processes
- Geological Studies and Exploration
- Mineralogy and Gemology Studies
- Water Quality and Pollution Assessment
- Evolution and Paleontology Studies
- Groundwater flow and contamination studies
- Botany and Geology in Latin America and Caribbean
- Environmental and Cultural Studies in Latin America and Beyond
- Botany, Ecology, and Taxonomy Studies
- Geomagnetism and Paleomagnetism Studies
- Coral and Marine Ecosystems Studies
- Landslides and related hazards
- Fire effects on ecosystems
- Mining Techniques and Economics
- Atmospheric and Environmental Gas Dynamics
- Fish Biology and Ecology Studies
- Clay minerals and soil interactions
- earthquake and tectonic studies
United States Geological Survey
1989-2020
United States Department of the Interior
1989
A paleomagnetic pole calculated from 64 virtual geomagnetic poles for Miocene volcanic rocks of the Baja California Peninsula (86.1°N, 142.6°E, α 95 = 3.9°) is similar to a reference North American craton (87.4°N, 129.7°E, 3.0°), consistent with having been adjacent Mexican mainland in its pre‐Gulf position at least early time Pliocene opening Gulf. This result agreement marine geophysical and geologic evidence Gulf does not support long‐period nondipole field region during time, or 10°...
Accurate characterization of the magmatic compositions flood basalt lavas is fundamental to interpretations magma genesis, stratigraphy, and correlation across these extensive provinces. Analysis geochemistry Sentinel Bluffs Member Grande Ronde Basalt, Columbia River Basalt Group (northwestern USA), demonstrates that a mass-based methodology, similar those routinely used in studies weathering soil formation, enables identification subtle previously unrecognized low-temperature alteration,...
First posted October 8, 2020 For additional information, contact: Director,Geology, Minerals, Energy, & Geophysics Science CenterMenlo Park, CaliforniaU.S. Geological Survey345 Middlefield RoadMenlo CA 94025-3591 The Portland-Vancouver-Hillsboro Metropolitan Area (metro area) has great scenic, natural, and cultural resources is the major economic hub of Oregon. metro area subject to a variety geologic hazards. Underthrusting oceanic plate along Cascadia boundary fault, or megathrust, deforms...
This digital map database and the PDF derived from were created analog geologic map: Wells, R.E. (1981), “Geologic of eastern Willapa Hills, Cowlitz, Lewis, Wahkiakum Counties, Washington.” The geodatabase replicates mapping 1981 report with minor exceptions along water boundaries also north south boundaries. Slight adjustments to contacts made correct differences between topographic base used in compilation (analog USGS 15-minute series quadrangle maps at 1:62,500 scale) for this (scanned...
First posted March 22, 2017 For additional information, contact: Volcano Science Center—Menlo Park U.S. Geological Survey 345 Middlefield Road, MS 910 Menlo Park, CA 94025 https://volcanoes.usgs.gov/ The age of the youngest volcanism at Eagle Lake, California, was investigated using stratigraphic, paleomagnetic, and 40Ar/39Ar techniques. three volcanic lava flows Lake yielded ages 130.0±5.1, 127.5±3.2 123.6±18.7 ka, are statistically indistinguishable. Paleomagnetic results demonstrate that...