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The chi-squared test of independence and cluster analysis of Otsuka similarity coefficients of fossil beetle assemblages from the Chilean Lake Region in the mid-latitudes of South America support the following conclusions: (1) the mean summer temperature of the glacial climate was 4-5??C lower than today's climate; (2) the climatic change...

At convergent margins where oceanic crust is subducted beneath continental or island-arc crust, sediment on the igneous oceanic crust divides into an accreted and a subducted fraction. Although the subducted fraction is larger, it is obscured in many seismic reflection records because of its depth and the effects of the...

The Adriatic microplate was previously considered to be a unique block, tectonically active only along its margins. The seismic sequences that took place in the basin from 1986 to 1990 give new information about the geodynamics of this area. Three subsets of well recorded events were relocated by the joint hypocentre...

The Pliocene—Quaternary pattern of contourite deposits on the eastern Gulf of Cadiz continental slope results from an interaction between linear diapiric ridges that are perpendicular to slope contours and the Mediterranean undercurrent that has flowed northwestward parallel to the slope contours and down valleys between the ridges since the late...

Most continental flood basalts are enriched in incompatible elements and have high initial 87Sr/86Sr ratios and low ϵNd values. Many are depleted in Nb and Ta. The commonly-held view that these characteristics are inherited directly from a source in metasomatized lithospheric mantle is inconsistent with the following arguments: (1) thermomechanical modelling demonstrates that flood basalt...

The Grenvillian-Appalachian boundary is characterized by pervasive mylonitic deformation and retrograde alteration of a suite of imbricated allochthonous and parautochthonous gneisses that were thrust upon the Grenvillian continental margin during the lower Paleozoic. Seismic reflection profiling across this structural boundary zone reveals...

No abstract available,...

We used a decorrelation-stretched image of Landsat Thematic Mapper (TM) Bands 1, 4, and 7 and field data to map and describe the main surficial units in the hyperarid Safsaf region in south-central Egypt. We show that the near-infrared bands on Landsat TM, which are sensitive to very subtle changes...

Efflorescent salt crusts in Death Valley, California, were mapped by using Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data and a recently developed least-squares spectral band-fitting algorithm. Eight different saline minerals were remotely identified, including three borates, hydroboracite, pinnoite, and rivadavite, that have not been previously reported from the Death Valley efflorescent...

Fossil records from sites overridden by or adjacent to the Laurentide Ice Sheet indicate that the climate of the last interglaciation (Oxygen-Isotope Substage 5e, ca. 130-116 ka) was warmer than today. Following the last interglaciation, the Laurentide Ice Sheet first developed during Stage 5 over Keewatin, Quebec and Baffin Island....

The development of a large northeastern Atlantic shelf ostracod database has confirmed that an intrinsic relationship exists between watermass temperature and the spatial (latitudinal) distribution of benthonic shelf Ostracoda. A second Pliocene ostracod database, using assemblages from four boreholes in The Netherlands and a number of localities from the East...

Recently acquired COCORP and proprietary seismic reflection data in the southern part of the Illinois Basin, combined with other geological and geophysical data, indicate that a WNW-trending Proterozoic terrane boundary (40 km wide) lies within basement. The boundary is characterized by the termination of subhorizontal Proterozoic reflectors and associated diffraction...

No abstract available....

No abstract available....

Mount Rainier is a young volcano whose slopes are undergoing rapid change by a variety of geologic processes, including debris flows. Debris flows are churning masses of water, rock and mud that travel rapidly down the volcano's steep, glacially carved valleys, leaving in their wake splintered trees, picnic sites buried...

Many landslides and debris flows have originated from Mount Rainier since the retreat of glaciers from Puget Sound about 10,000 years ago. The recurrent instability is due to several factors--height of the steep-sided volcanic cone, frequent volcanic activity, continuous weakening of rock by steam and hot, chemical-laden water, and exposure...

The fiscal year 1992 Yearbook summarizes the activities of the U.S. Geological Survey in response to its scientific and regulatory missions....

Emissions from zinc smelters in Palmerton, Pennsylvania, deposited large quantities of heavy metals, predominantly Zn, Pb, Cu, and Cd, on the surrounding landscape from 1898 to 1980. From 1986 to 1987 we studied four small headwater streams that were about 8 to 25 km downwind of the smelters to determine...

Public water supply in the Rockaway River valley depends almost entirely on ground water from wells in the valley-fill deposits. Ground-water withdrawals from these deposits in 1986 were about 9.1 million gallons per day. A steady-state ground-water flow model was developed to quantify the effects of ground-water withdrawals on water...