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Geophysical, geochemical, and mineralogical data from the Pebble Cu-Au-Mo porphyry deposit area, southwest Alaska: Contributions to assessment techniques for concealed mineral resources
In 2007, the U.S. Geological Survey began a multidisciplinary study in southwest Alaska to investigate the setting and detectability of mineral deposits in concealed volcanic and glacial terranes. The study area hosts the world-class Pebble porphyry Cu-Au-Mo deposit, and through collaboration with the Pebble Limited Partnership, a range of geophysical and geochemical investigations was carried out in proximity to the deposit. The deposit is almost entirely concealed by tundra, glacial deposits, and post-mineralization volcanic rocks. The discovery of mineral resources beneath cover is becoming more important because most of the mineral resources at the surface have already been discovered. Research is needed to identify ways in which to assess for concealed mineral resources. This report presents the uninterpreted geophysical measurements and geochemical and mineralogical analytical data from samples collected during the summer field seasons from 2007 to 2010, and makes the data available in a single Geographic Information System (GIS) database.
Investigating the Environmental Effects of Agriculture Practices on Natural Resources: Scientific Contributions of the U.S. Geological Survey to Enhance the Management of Agricultural Landscapes
The U.S. Geological Survey (USGS) enhances and protects the quality of life in the United States by advancing scientific knowledge to facilitate effective management of hydrologic, biologic, and geologic resources. Results of selected USGS research and monitoring projects in agricultural landscapes are presented in this Fact Sheet. Significant environmental and social issues associated with agricultural production include changes in the hydrologic cycle; introduction of toxic chemicals, nutrients, and pathogens; reduction and alteration of wildlife habitats; and invasive species. Understanding environmental consequences of agricultural production is critical to minimize unintended environmental consequences. The preservation and enhancement of our natural resources can be achieved by measuring the success of improved management practices and by adjusting conservation policies as needed to ensure long-term protection.
Northern Gulf of Mexico: USGS science contributions to a resilient coast, 2006-2011
The devastating hurricane season of 2005 challenged U.S. Geological Survey (USGS) to develop a science base for resource managers and policy makers that could provide an understanding of the multiple stressors and influence affecting the northern Gulf of Mexico coast and to rack changes in linked coastal systems. The complexity of the Gulf Coast requires a science strategy for data collection and data reporting that is consistent across regional ecosystems and that can be applied to both short-term and long-term responses to stressors.
Recent scientific contributions by the U.S. Geological Survey in the San Francisco Bay and Sacramento–San Joaquin Delta Estuary
Introduction The San Francisco Bay and Sacramento–San Joaquin Delta Estuary (hereafter, Bay-Delta) is the largest estuary on the West Coast of the United States. The Bay-Delta covers more than 1,600 square miles and drains a watershed of more than 75,000 square miles, which is greater than 40 percent of California. The region surrounding the Bay-Delta is home to about 10 million people, and its habitats (fig. 1) support more than 800 plant and animal species. The waterways of the Bay-Delta are the central hub of California’s extensive freshwater delivery system, supplying water to more than 27 million Californians and 4 million acres of farmland in the Central Valley. The U.S. Geological Survey (USGS) is the primary science agency of the U.S. Department of the Interior, providing a broad range of Earth, water, biological, and mapping data and expertise to inform natural resource management across the country. This fact sheet focuses on research conducted by the USGS in the Bay-Delta region, mostly within the past 5 years. The fact sheet is organized across five major themes: water flow and water quality, fish and wildlife, wetland restoration, invasive species, and hazards. In each of these areas, the USGS works closely with Federal, State, and local agencies; academia; and non-governmental organizations to provide objective, evidence-based science. The data and knowledge gained from USGS research and monitoring are publicly available and are routinely used by agencies, including the U.S. Bureau of Reclamation, U.S. Army Corps of Engineers, U.S. Fish and Wildlife Service, California Department of Water Resources, California Department of Fish and Wildlife, California State Water Resources Control Board, Delta Stewardship Council, and many additional organizations and stakeholders to inform management of the Bay-Delta region and its resources.
Gravity map of the Trinidad quadrangle, Colorado: A contribution to the Upper Mantle Project
No abstract available.
River discharge to the sea from the shores of the conterminous United States, Alaska, and Puerto Rico: A contribution to the International Hydrological Decade
No abstract available.
Hydrologic basins contributing to outflow from Lake Tahoe, California-Nevada
No abstract available.
Map of major lithologic units in the Pacific Northwest: A contribution to the Interior Columbia Basin Ecosystem Management Project
No abstract available.
Geologic and crustal cross section of the United States along the 37th parallel a contribution to the Upper Mantle project
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Contributions to the knowledge of the older Mesozoic flora of Virginia
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Chemical composition of selected solid-phase samples from the Snake River Plain aquifer system and contributing drainages, eastern Idaho and western Wyoming
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Levi Noble; geologist; his life and contributions to understanding the geology of Death Valley, the Grand Canyon, and the San Andreas Fault
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Geology of the Right Stepover region between the Rodgers Creek, Healdsburg, and Maacama faults, northern San Francisco Bay region: A contribution to Northern California Geological Society Field Trip Guide, June 6-8, 2003
This Open file report was written as part of a two-day field trip on June 7 and 8, 2003, conducted for the Northern California Geological Society. The first day of this field trip (June 7) was led by McLaughlin and Sarna-Wojcicki in the area of the right- step between the Rodgers Creek- Healdsburg fault zone and the Maacama fault. The second day of the trip (June 8), was led by David Wagner of the California Geological Survey and students having recently completed MS theses at San Jose State University (James Allen) and San Francisco State University (Carrie Randolph-Loar), as well as a student from San Francisco State University whose MS thesis was in progress in June 2003 (Eric Ford). The second day covered the Rodgers Creek fault zone and related faults of the Petaluma Valley area (the Tolay and Petaluma Valley fault zones).
Determining age and vertical contribution of ground water pumped from wells in a small coastal river basin: a case study in the Sweetwater River valley, San Diego county, California
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Contribution of atmospheric deposition to pesticide loads in surface water runoff
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The contribution of geomagnetic observatories and magnetic models to the study of secular variation and jerks in Antarctica
Some of the most interesting features of the geomagnetic field and its time variations are displayed in polar areas. Observatory monthly means usually provide an excellent opportunity to study the temporal changes of the magnetic field at a given location. Unfortunately, on the Antarctic continent the distribution of the permanent ground- based observatories does not permit a uniform coverage of the examined area. Furthermore, the magnetic records are characterized by intense external disturbances and noise that make the analysis of the magnetic field difficult. To improve our knowledge of the secular variation and detect the presence of secular variation impulses (geomagnetic jerks) in Antarctica, we use both observatory data and the CM4 quiet time magnetic field model. In particular CM4 improves our knowledge of geomagnetic jerks over Antarctica through the study of the sign changes of the secular acceleration maps.