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What began in the mid-seventies as a research effort in designing an expert system to aid geologists in exploring for hidden mineral deposits has in the late eighties become a full-sized knowledge-based system to aid geologists in conducting regional mineral resource assessments. Prospector II, the successor to Prospector, is interactive-graphics...

The Spatial Data Transfer Standard (SDTS), or Federal Information Processing Standard (FIPS) 173, is designed to support all types of spatial data. Implementing all of the standard's options at one time is impractical. Therefore, implementation of the SDTS is being accomplished through the use of profiles. Profiles are clearly defined,...

Whole-rock analyses of samples of pelite, psammite, and psammopelite from the Early Proterozoic Broken Hill Group (Willyama Supergroup) in the Broken Hill Block, New South Wales, Australia, reveal distinctive geochemical signatures. Major-element data show high Al2O3 and K2O, low MgO and Na2O,...

The solubility of sphalerite (ZnS) was measured in KCl-HCl-H2O solutions at 300–600°C and 0.5–2.0 kbar. The silicate assemblage K-feldspar-muscovite (or andalusite)-quartz was used to buffer the solution to acid conditions, resulting in the total solubility reaction 2K+ + KAl2AlSi3O10(OH)2 + 6SiO2 + ZnS + nCl− = ZnCln(2−n) + 3KAlSi3O8 + H2S. (muscovite) (quartz) (sphalerite) (K-feldspar) A computer retrieval technique was used to...

The sensitivity of streamflow to climate change was investigated in the American, Carson, and Truckee River Basins, California and Nevada. Nine gaging stations were used to represent streamflow in the basins. Annual models were developed by regressing 1961-1991 streamflow data on temperature and precipitation. Climate-change scenarios were used as inputs...

On the basis of a preliminary experiment in 1985 (KRISP 85), a seismic refraction/wide-angle reflection survey and a teleseismic tomography experiment were jointly undertaken to study the lithospheric structure of the Kenya rift down to depths of greater than 200 km. This report serves as an introduction to a series...

Trends in snow acidity reflect the balance between strong acid inputs and reactions with neutralizing materials. Carbonate dust can be an important contributor of buffering capacity to snow however, its concentration in snow is difficult to quantify because it dissolves rapidly in snowmelt. In snow with neutral or acidic pH,...

The US Geological Survey, in cooperation with the National Drilling Company of Abu Dhabi, is conducting a 4-year study of the fresh and slightly saline groundwater resources of the eastern Abu Dhabi Emirate. Most of this water occurs in a shallow aquifer, generally less than 150 m deep, in the...

Many calderas are located along regionally important fault zones that are intermittently active before and after the caldera cycle. In mineralized calderas, the ore deposits are controlled by structures developed during caldera formation and by regional faults which intersect and reactivate the caldera-related structures. In the earliest phase of the...

Aeromonas salmonicida is a principal pathogen that contributes to mortality in hatchery-maintained Atlantic salmon that originated from the Connecticut and Merrimack rivers in the northeastern United States. Field tests were conducted to assess a filtration method for detection of A. salmonicida in water used to rear fishes. A presumptive identification of typical A. salmonicida was...

Kaolinitic tonsteins of altered synsedimentary volcanic ash-fall origin are well developed in the Late Permian coal-bearing formations of eastern Yunnan Province. Because of their unique origin, wide lateral extent, relatively constant thickness and sharp contacts with enclosing strata, great importance has...

Has established a stream gaging network for the three major lake basins in Taylor Valley. These data are critical for determining nutrient budgets for the lake ecosystems and for understanding physical factors controlling microbial mats in the streams....

Short‐term cold storage of fish sperm with oxygen, an established fisheries technique, was successfully used to preserve milt from Atlantic sturgeon (Acipenser oxyrhynchus oxyrhynchus). All milt samples stored for 5 d on ice and replenished daily with oxygen retained at least 80% motility and at least 99% viability. One sample...

Fingerling lake trout (Salvelinus namaycush) were reared for 64 d at three pressures of dissolved gases, expressed in relation to saturation values (▵P)–untreated (control) water, ▵P = 10 mm Hg; water treated by column degassing with air, ▵P = 9 mm Hg; and water treated with an oxygen injection system,...

The record flood on the Mississippi River during the summer of 1993 provided a rare opportunity to collect data on scour of the streambed at bridges and to test data collection equipment under extreme hydraulic conditions. Detailed bathymetric and hydraulic information were collected at two bridges crossing the Mississippi River...

For unsteady open-channel flows having N interacting unknown variables, a system of N mutually independent, partial differential equations can be used to describe the flow-field. The system generally belongs to marching-type problems and permits transformation into characteristic equations that are associated with N distinct characteristics directions. Because characteristics can be...

Saline seeps are an increasingly serious problem in semi-arid regions of the southwestern United States. They result when excessive recharge of the shallow ground water in soils raises the water table locally to within one meter of the land surface, and the salinity of the shallow water is increased through...

Results of accelerated erosion on certain constructed surfaces in southeastern Arizona appear similar to those described by Bryan (1940) as gully gravure. Twenty cross-section excavations in eight rills incised into silt-rich lacustrine and fluvial deposits reveal partial filling of the rills by debris derived from overlying fluvial sand, gravel, and...

A subsidence research program began in 1985 to document the extent and magnitude of land subsidence in Sacramento Valley, California, an area of about 15 600 km2, using Global Positioning System (GPS) surveying. A brief description of GPS surveying is followed by a summary of each of four surveys between...

Aftershocks of large earthquakes tend to occur close to the main rupture zone, and can be used to constrain its dimensions. But following the 1992 Landers earthquake (magnitude M(w) = 7.3) in southern California, many aftershocks were reported in areas remote from the mainshock. Intriguingly, this remote seismicity occurred in...

East Siberia comprises three petroleum provinces—Lena-Tunguska, Lena-Vilyuy, and Yenisey-Anabar—that occupy the area of the Siberian craton. Petroleum has been generated and has accumulated in Precambrian rifts beneath the sedimentary basins and, more importantly, within the section of the basin itself. The platformal deposits of the basins extend beneath...

We infer the composition of the crust beneath and on the flanks of the Kenya rift based on a comparison of the KRISP-90 crustal velocity structure with laboratory measurements of compressional-wave velocities of rock samples from Kenya. The rock samples studied, which are representative of the major lithologies exposed in...

Water resources data for the 1993 water year for Wyoming consists of records of stage, discharge and water quality of streams; stage and contents of lakes and reservoirs, and water levels and water quality of ground water. This report contains discharge records for 190 gaging stations; stage and contents for...