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At least 1,621 records · Page 90Linked to original sources
USGS1965

A final report on computed magneto-telluric curves for hypothetical models of crustal structure

Several mathematical models were investigated to determine the capa-bilities of the magneto-telluric method for determining the resistivity structure of the earth's crust. The model parameters were based on the crust model proposed by Keller (1963). The mathematical technique used was developed by Cagniard (1953). The investigations indicate that a three-layer model approximation of the crust and mantle is the most detailed model warranted in inter-preting the information provided by the magneto-telluric method about the lower crust. Only the thickness of the lower crust can be determined, and not the resistivity.

Crustal Studies Technical Letters↗
USGS1985

Preliminary description of a Miocene zone of structural complexity, Port Moller and Stepovak Bay quadrangles, Alaska: A section in The United States Geological Survey in Alaska: Accomplishments during 1983

A zone of structural disruption and complexity along the Pacific coast margin of the Alaska Peninsula (fig. 41) may be related to the Alaska Peninsula and the Chugach terrane boundary. The best exposure of this zone is located on the east shore of Humpback Bay (figs. 42, 43; also Burk, 1965, pl. 8, fig. 4); other exposures are located on the east side of Ivanof Bay, the north and south sides of Lefthand Bay, and in other coastal localities in the area. In some places, such as on the Kupreanof Peninsula, it is not recognized. This zone may extend discontinuously for 110-160 km along the coast; the width of the zone varies from 0.5 to 1 km. Our current data and tentative interpretations are described here, pending completion of additional field research, laboratory, and office studies.

Alaska↗
USGS1950

Stratigraphy and structure of the area of the upper Meade River, Alaska

The stratigraphic evidence in the upper Meade River area includes zones B to D of the Nanushuk group (Cretaceous). Zones B and C are not differentiated in mapping and description. South of the Meade River 2,100 feet of zones B-C and 1,500 feet of zone D are exposed. North of the fault zone along the Meade River, the only rocks present, estimated not over 1,000 feet thick, are zone D beds which may be at least in part younger than the zone D rocks south of the Meade River. Sands which barely meet the minimum requirements for potential reservoir beds are present in both zones. South of the Meade River the Kigalik anticline and the Falcon Creek anticline, both sharp-crested folds, trend east. The intervening synclines are broad with low dips on the flanks. Along the Meade River the major structure is a zone of reverse faults, about three-fourths of a mile wide, which brings rocks of zones B-C on the south opposite rocks of zone D on the north. Minimum displacement in this zone is 1,000 feet at longitude 157° 50'W. and 300 feet near the gas-seep lake. North of the fault zone, the Meade River anticline is a rather low fold, so poorly exposed that closure cannot be detected by surface geologic methods.

Alaska↗
USGS1950

Stratigraphy and structure of the Aupuk anticline

In addition to conducting an examination of the surface geology in the Southern Foothills province between the Killik River and east fork of the Etivluk River, Navy Oil Unit Party No. 5 was requested to map the Aupuk anticline during the 1950 field season, for the purpose of evaluating the petroleum possibilities thereof from the standpoints of favorable statigraphy and possible structural closure. Field mapping of the Aupuk anticline began on August 1, and about 1 month was devoted to the study. Party personnel consisted of G. Donald Eberlein and Charles D. Reynolds, geologists, W. L. D'Olier and W. D. Carter, field assistants, Richard Olson, camp cook, and Max H. Davis, weasel mechanic. Robort M. Chapman, geologist, visited the party for 1 week early in August to help start the work and shared, with Eberlein, the responsibilities associated with the final compilation of this report. Three weasels were used for daily transportation to the field and for moving camp. A 10-foot Link boat equipped with 5 hp. outboard motor was used to cross the Colville River. As field work progressed from west to east it became apparent that the camp equipment and weasels would have to be gotten across the Colville River if field work was to be completed by early September. This crossing was effected without incident at a point approximately 10 miles below the confluence of the Kurupa and Colville Rivers on August 26. The party reached Umiat on September 5.

Alaska↗
USGS1951

Stratigraphy and structure of the southern foothills section between the Etivluk and Kiligwa Rivers

The part of the Southern Foothill section, Arctic foothills province, that lies beteween the Etivluk and Kiligwa Rivers was investigated by Navy Oil Unit party 6 during the 1950 field season, A belt about 16 miles wide and 60 miles long (approximately 800 square miles) was mapped in considerable detail (see index map, pl. 1). The mapped area is in the west-central part of the Arctic Foothills province, wholly within the boundaries of Naval Petroleum Reserve No. 4. Major drainage consists of the middle reaches of the Etivluk, Ipnavik, Kuna, and Kiligwa Rivers. Principal objectives of the party, using previous geologic studies in. the Okpikruak-Kiruktagiak Rivers area 1/ ao an initial working base, were stratigraphic and structural studies of the outcrops in the interstream areas. In view of the former interest in possible Lisburne limestone plays, the Lisburne Ridge west of the Etivluk River and the northward nosing of the Triassic complex between the Ipnavik and Kuna Rivers were designated as areas for particular emphasis. The party included six men: two geologists; two field assistants, a cook, and a weasel mechanic. Three weasels were available for transportation; two of which were maintained in operating condition for daily field use. As many exposures as were pertinent or accessible were examined. Vertical photographs were used for plotting data and for areal control; relative vertical control was established with altimeters, The effective working radius from base camp as increased from 8 miles to 20 miles by making frequent 2- or 3-day spike trips.

Alaska↗
USGS1947

Stratigraphy and structure of the area of the Kurupa, Oolamnagavik, Killik, and Colville Rivers

The area between 68° 3C' and 69° 08 N. latitude and between 154° and 155° 20 W. longitude was covered by U. S. Geological Survey party 4 during the period May 18 to September 2. Traverses were confined mainly to the valleys of the Kurupa, Oolamnagavik, and Colville Rivers inasmuch as very little rock is exposed in the interstream areas. This report is a compilation of the field data and of the results of office and laboratory work on rock specimens, fossils, and aerial photographs of the area. An interpretation of the structure and stratigraphy of this area is presented, and possible correlations with the Killik River area to the east are suggested. Some revisions of the conclusions in this report may become necessary in the light of further field work in adjacent areas and heavy mineral studies, but it is believed that any changes will not materially alter the geologic picture of the area.

Alaska↗
USGS1947

Preliminary report on stratigraphy and structure of the area of the Colville River north of Umiat, Alaska

The stratigraphy and structure of the area of the Colville north of Umiat was studied by U. S. GeologicaI Survey Party No. 1 during the period of May 31 to July 19, 1947. The. party, consisting pf two geologists, a cook, and a "weasel" mechanic, left Umiat in two "weasels”. The weasels were used to transport the party and equipment from camp to camp, and also made it possible for the geologists to work as far as 15 to 20 miles out from a camp in one day. A ten-foot canvas-boat was carried along. During most of the month of June even the smaller tributaries to the Kogohokruk carried enough melt and run off water to make them navigable in the 10-foot boat. The party returned to Umiat on June 23, after traversing both the Kikiakrorak and the Kogohokruk Rivers, and several smaller tributaries to the Kogohokruk.

Alaska↗
USGS1950

Preliminary report on the stratigraphy and structure of part of the Carbon Creek and Ketik anticlines

U. S. Geological Survey Party No. 4 mapped the stratigraphy and structure of parts of the Carbon Creek and Ketik anticlines during the summer of 1950. The area, which lies in quadrangles I-19 and I-20 is shown in figure 1. Large-scale maps, compiled from plane-table surveys, give a more detailed picture of two parts of the area, the west plunge of the Carbon Creek anticline (fig. 2) and a segment near the middle of the Ketik anticline (fig. 3).

Alaska↗
USGS1999

Processing of single channel air and water gun data for imaging an impact structure at the Chesapeake Bay

Processing of 20 seismic profiles acquired in the Chesapeake Bay area aided in analysis of the details of an impact structure and allowed more accurate mapping of the depression caused by a bolide impact. Particular emphasis was placed on enhancement of seismic reflections from the basement. Application of wavelet deconvolution after a second zero-crossing predictive deconvolution improved the resolution of shallow reflections, and application of a match filter enhanced the basement reflections. The use of deconvolution and match filtering with a two-dimensional signal enhancement technique (F-X filtering) significantly improved the interpretability of seismic sections.

Bulletin↗
USGS2011

Photographic images captured while sampling for bald eagles near the Davis Pond freshwater diversion structure in Barataria Bay, Louisiana (2009-10)

The implementation of freshwater diversions in large-scale coastal restoration schemes presents several scientific and management considerations. Large-scale environmental restructuring necessitates aquatic biomonitoring, and during such field studies, photographs that document animals and habitat may be captured. Among the biomonitoring studies performed in conjunction with the Davis Pond freshwater diversion structure south of New Orleans, Louisiana, only postdiversion study images are readily available, and these are presented here.

Data Series↗
USGS1996

South Florida Ecosystem Program: Quantifying freshwater discharge for coastal hydraulic control structures in eastern Dade County, Florida

The South Florida Ecosystem Restoration Program is an intergovernmental effort, involving a number of agencies, to reestablish and maintain the ecosystem of south Florida. One element of the restoration effort is the development of a firm scientific basis for resource decision making. The U.S. Geological Survey (USGS), one of the agencies, provides scientific information as part of the South Florida Ecosystem Restoration Program. The USGS began their ow program, called the South Florida Ecosystem Program, in fiscal year 1995 for the purpose of gathering hydrologic, cartographic, and geologic data that relate to the mainland of south Florida, Florida Bay, and the Florida Keys and Reef ecosystems. As part of the South Florida Ecosystem Program, the USGS, in cooperation with the South Florida Water Management District (SFWMD), has conducted a study to determine discharge ratings for 16 coastal hydraulic control structures in eastern Dade County, Fla. Discharge data are needed to quantify water that can be made available for water supply and ecosystem restoration and to calibrate regional hydrologic models.

Florida↗
USGS2010

Aligning USGS senior leadership structure with the USGS science strategy

The U.S. Geological Survey (USGS) is realigning its management and budget structure to further enhance the work of its science programs and their interdisciplinary focus areas related to the USGS Science Strategy as outlined in 'Facing Tomorrow's Challenges-U.S. Geological Survey Science in the Decade 2007-2017' (U.S. Geological Survey, 2007). In 2007, the USGS developed this science strategy outlining major natural-science issues facing the Nation and focusing on areas where natural science can make a substantial contribution to the well being of the Nation and the world. These areas include global climate change, water resources, natural hazards, energy and minerals, ecosystems, and data integration.

Fact Sheet↗
USGS2013

Chemistry and age of groundwater in the Piceance structural basin, Rio Blanco County, Colorado, 2010-12

Fourteen monitoring wells were sampled by the U.S. Geological Survey, in cooperation with the Bureau of Land Management, to better understand the chemistry and age of groundwater in the Piceance structural basin in Rio Blanco County, Colorado, and how they may relate to the development of underlying natural-gas reservoirs. Natural gas extraction in the area has been ongoing since at least the 1950s, and the area contains about 960 producing, shut-in, and abandoned natural-gas wells.

Colorado↗
USGS2025

A partnership between the USGS and the Klamath Tribes to apply structured decision making for chronic wasting disease management

Project Overview: The Klamath Tribes (TKT) are the Klamath, Modoc, and Yahooskin Paiute peoples, and are the first peoples of the land, having lived in ancestral lands of Oregon and California since time immemorial. Members of TKT have rights to hunt, fish, trap, and gather, including the harvest of mule deer ( Odocoileus hemionus ) and elk ( Cervus canadensis nelsoni ) within the 1.19 million acres of their Reserved Treaty Rights Area. Anthropogenic changes threaten the well-being of mule deer and elk and of the Tribes that rely on them. Today, these species are a primary protein source for TKT. They are traded within TKT and among other Tribes and provide materials for cultural and sacred items such as regalia. However, mule deer numbers have been declining across the western states for the past several decades because of multiple stressors, including persistent and frequent drought and wildfires, habitat loss and degradation, vehicle mortality, and increasing barriers to migratory movements between summer and winter ranges. The migratory movements of mule deer, which allow deer to access the best available seasonal habitats, put them at risk of another potential stressor—infection with chronic wasting disease (CWD). Chronic wasting disease is a fatal prion disease of deer that has been detected in 36 U.S. states. It was detected in free-ranging mule deer in northern Idaho in 2021, prompting the Tribes to initiate a planning process for CWD surveillance, prevention, and response measures to preserve and protect the deer and elk within the Reserved Treaty Rights Area. In 2023, the Klamath Tribes Natural Resources Department began to develop their CWD plan by incorporating preliminary input provided by the Klamath Indian Game Commission (KIGC) and working with scientists from the U.S. Geological Survey (USGS). This collaborative effort includes the application of structured decision making and the development of mathematical models to analyze potential CWD management strategies. The result will be a transparent assessment that incorporates TKT values throughout the process and can inform place-based management of the cultural, natural, and physical resources upon which the Tribes depend. In addition, this process may provide opportunities for broader coordination by natural resource management agencies to work together to ensure the long-term health and sustainability of deer and elk populations within the Reserved Treaty Rights Area and throughout the state of Oregon.

Oregon↗
USGS1983

Structure, temperature, pressure, and salinity of Cenozoic aquifers of south Texas

A study of the hydrogeology of deep sedimentary basins using the Neogene deposits of the northern Gulf of Mexico basin as a model was initiated by the U.S. Geological Survey in the 1960's (Jones, 1969). This study led to investigations of geopressured-geothermal resources in this basin (Papadopulos and others, 1975; Wallace and others, 1979) and of the waste storage capabilities of the Wilcox Group in Texas (Jones and others, 1976). Techniques for delineating pressure, temperature, and salinity variations within the geologic framework were developed in conjunction with these and related studies. The purpose of this hydrologic atlas is to delineate the hydrogeology of the onshore Cenozoic aquifers of south Texas, using these techniques. The location of the study area in Texas is shown in figure 1. Hydrogeologic cross section A-A' is shown in figure 2. The surface geology of the area and the line of section A–A' are shown in figure 3. Geophysical logs of oil tests provided the framework for this section. Interpretations presented are based upon data from these logs; information from published ground water and geological reports; and structural and geologic interpretations from maps prepared by Peppard, Souders and Associates for the U.S. Geological Survey under Purchase Order Numbers 67482 and 67.483.

Texas↗