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The U.S. Geological Survey conducted hydrologic investigations in San Francisco Bay during Water Years 1988, 1989, 1990 and 1991. Dissolved inorganic plant nutrients, nitrate, nitrite, ammonium, silica, and reactive phosphorus were measured in surface and in near-bottom waters at previously established locations in both northern and southern reaches of the...

Hydrologic data were collected near Summit Lake Reservoir for 2 years beginning October 1, 1988, and ending September 30, 1990. The data-collection network consisted of 1 reservoir-stage gage, 2 precipitation gages, 1 evaporation pan, 2 streamflow gages, and 13 observation wells. Stage-area and stage-storage relations for the reservoir were used...

This study provides brief discussions of the petroleum geology, play descriptions, and resource estimates of 220 individually assessed exploration plays in all 80 onshore geologic provinces within nine assessment regions of the continental United States in 1989; these 80 onshore provinces were assessed in connection with the determination of the...

The Edwards-Trinity Regional Aquifer-System Analysis (RASA) is one of 25 completed or ongoing studies conducted by the U.S. Geological Survey on regional aquifer systems that individually provide essential quantities of ground water to large parts of the country. Underlying about 42,000 mi2 of west-central Texas, the Edwards-Trinity aquifer system extends...

Test drilling near two sewage lagoons in The Basin area of the Chisos Mountains, Big Bend National Park, Texas, has shown that the alluvium and colluvium on which the lagoons are located is not saturated in the immediate vicinity of the lagoons. A shallow aquifer, therefore, does not exist in...

Regional aquifers are described within a 370,000-square-mile area extending from the foothills of the Rocky Mountains in Colorado to the Missouri and Mississippi Rivers in eastern Nebraska and Missouri, and from South Dakota to the Ouachita, Arbuckle, and Wichita Mountains of Arkansas and Oklahoma. The present geohydrologic framework of aquifers and...

This circular presents a summary of the geographic location, amount, and results of petroleum exploration, including an atlas showing explored and delineated prospective areas through 1990. The data show that wildcat well drilling has continued through the last decade to expand the prospective area by about 40,000 to 50,000 square...

No abstract available. ...

Many of the high-Ti quartz-normative tholeiitic intrusive sheets in the early Mesozoic rift basins of the Eastern USA exhibit lateral differentiation from mafic cumulate units, through diabase, to relatively evolved iron-rich rock types. We have investigated a representative example in detail, the York Haven sheet in the Gettysburg basin of...

No abstract available....

A 40‐km aperture trilateration network centered on the 1959 Hebgen Lake earthquake epicenter has been surveyed in 1973, 1974, 1976, 1978, 1981, 1984, and 1987. The deformation inferred from those surveys is described roughly by a uniaxial, 0.266 ± 0.014 μstrain/yr, N15°E ± 1°extension that is uniform in both time...

Deformation of a 50 × 60 km trilateration network that spans the epicenter of the 1992 Landers earthquake(Ms = 7.5) was measured by seven surveys over the 19 years preceding the earthquake. Three moderate earthquakes (1979 Homestead Valley, Ms = 5.6; 1986 North Palm Springs, Ms = 6.0; and 1992 Joshua Tree, Ms =...

Selected herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) metabolites, and NO−3 were examined in near-surface unconsolidated and bedrock aquifers in the midcontinental USA to study the hydrogeologic, spatial, and seasonal distribution of these contaminants. Groundwater samples were collected from 303 wells during the spring and late summer of 1991. At least one herbicide or atrazine...

Earthquakes struck the Klamath Falls area on Monday night, September 20, 1993, resulting in two deaths and extensive damage. The quakes were felt as far away as Coos Bay to the west, Eugene to the north, Lakeview to the east, and Chico, California, to the south. A foreshock recorded at...

The 40Ar/39Ar ages of a sanidine clast from a melt-matrix breccia of the Manson, Iowa, impact structure (MIS) indicate that the MIS formed 73.8 ± 0.3 million years ago (Ma) and is not coincident with the Cretaceous-Tertiary boundary (64.43 ± 0.05 Ma). The MIS sanidine is 9 million years older than 40Ar/39Ar...

The National Oil and Gas Assessment of undiscovered recoverable conventional oil and gas resources assigned nearly 36% of the undiscovered U.S. onshore oil resources and 28% of the commercially developable undiscovered oil resources to onshore northern Alaska. Economic screening models were applied to the geologic play assessment to estimate the...

We explored the seasonal characteristics in wet deposition chemistry for two sites located at different elevations along the east slope of the Colorado Front Range in Rocky Mountain National Park. Seasonally separated precipitation was stratified into highly concentrated (high salt), dilute (low salt), or acid-dominated precipitation groups. These groups and...

Using 1-km AVHRR satellite data, relative temperature difference caused by conductivity and inertia were used to distinguish urban and non urban land covers. AVHRR data that were composited on a biweekly basis and distributed by the EROS Data Center in Sioux Falls, South Dakota, were used for the classification...

The inorganic geochemistry and mineralogy of three cores from the Anderson-Dietz 1 coal bed, a 15.2-m-thick subbituminous coal bed in the Tongue River Member (Paleocene) of the Fort Union Formation, were examined (1) to determine if the cores could be correlated by geochemical composition alone over a total distance of...

Within eastern Kentucky, organic petrographic and geochemical data indicate a southeastwards increase in maturation of the Cleveland Shale Member of the Ohio Shale (Devonian-Mississippian). Reflectance levels of dispersed organic material in the Cleveland Shale increase from 0.5% in the outcrop belt in central Kentucky, to slightly over 1.0% in Pike...

Walnut Creek National Wildlife Refuge-Prairie Learning Center (Walnut Creek or the Refuge) is one of the newest additions to the National Wildlife Refuge System, which consists of over 480 units throughout the United States operated by the U.S. Department of the Interior, Fish and Wildlife Service (the Service). Located...

Mid‐Cretaceous crustal extension played a fundamental role in the structural evolution of the Yukon‐Tanana terrane (YTT) in the northern Cordilleran interior. In the central portion of the YTT northwest of Delta Junction, Alaska, a mylonitic shear zone juxtaposes greenschist facies rocks in the upper plate against middle to upper amphibolite...

In agricultural landscapes, much of the remaining forest is in linear tracts along streams. These riparian forests provide habitat for forest birds, but their use by forest interior birds may depend on forest width. We conducted point-count surveys of birds in riparian forests on the Eastern shore of Maryland and...

Cores of granite and deformed sediment from the walls of Monterey Canyon were successfully recovered from December 30 to 31, 1992, by Monterey Bay Aquarium Research Institute's (MBARI) Remotely Operated Vehicle (ROV) Ventana using a small-diameter, double-barrel drill with a diamond bit. This HSTR (Holloway-Stakes-Tengdin-Rajcula) drill was developed to drill cores horizontally...

Strong offshore winds in early 1989 produced a shore polynya that reached along the entire north coast of Alaska and eastward beyond the mouth of the Mackenzie River in Canada. From January through April, this open water periodically exposed the shelf to sediment entrainment by suspension freezing. This process requires...