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The early Mesozoic Newark Supergroup consists of continental sedimentary rocks and basalt flows that occupy a NE-trending belt of elongate basins exposed in eastern North America. The basins were filled over a period of 30–40 m.y. spanning the Late Triassic to Early Jurassic, prior to the opening of the north...

In 1984, a 12-m sediment core (WLC84-8) was taken from the deepest part of Walker Lake. Samples of the core were analysed for diatoms, pollen, carbonate mineralogy, magnesium content, δ18O and δ13C values of the total inorganic fractin, δ18O and δ13C values of Limnocythere ceriotuberosa, δ13C values of the total organic fraction, grain size, and magnetic...

Soybean plants were grown in hydroponic solutions having three concentration levels of phosphorus. Spectral reflectance changes included higher reflectance in the green and yellow portions of the electromagnetic spectrum in phosphorus-deficient plants and a difference in position of the long wavelength edge (the red edge) of the chlorophyll absorption band...

The region of the present Rio Grande rift and southeastern Colorado Plateau underwent lithospheric extension during middle to late Cenozoic deformation affecting the entire southwestern U.S. Lithospheric mantle was disrupted, and in many regions displaced or replaced by asthenospheric mantle at depths from which basaltic magmas were derived and erupted...

New field and geochemical data place the Losee Metamorphic Suite (a tonalite/trondhjemite complex) of northern New Jersey into the context of a major Proterozoic continental are represented by a discontinuous belt of northern Appalachian metadacite. Samples of Losee rock range from extremely leucocratic trondhjemite locally associated with amphibolite, to banded...

The Susquehanna lateral ramp crosses the entire length of Pennsylvania in a NNE direction and extends into southern New York State. Its presence was first suspected because of a dramatic change in fold wavelength across the Susquehanna River, seen on both side-looking airborne radar (SLAR *) data and the geologic...

Paleomagnetic data have been obtained from two ophiolite sequences in the northern California Coast Ranges: from Mount Diablo in the San Francisco Bay area and from Potter Valley, north of Clear Lake. The ophiolite exposed at Mount Diablo is part of the late Middle to Late Jurassic Coast Range ophiolite,...

Crustal extension is evaluated based on the idea of mass and volume balance of material introduced into and removed from the initial volume of the crust. Extension in the Baikal rift increases southwestward from 0.9 km in the Chara depression to 19.3 km in the South Baikal depression. These values...

The continental margins of the southern and central Red Sea and most of Wilkes Land, Antarctica have bulk crustal configurations and detailed structures that are best explained by a prolonged history of magmatic expansion that followed a brief, but intense period of mechanical extension. Extension on the Red Sea margins...

Harrat As Sarat forms the second smallest and southernmost of the basalt fields of western Saudi Arabia and is part of a voluminous Red Sea rift-related continental alkali basalt province. The rocks of the As Sarat were emplaced during the first stage of Red Sea rifting and represent the northernmost...

Argon isotope data indicate retained argon in bulk amber (matrix gas) is radiogenic [40Ar/39Ar ≃32o] than the much more abundant surface absorbed argon [40Ar/39Ar ≃295.5]. Neutron-induced 39Ar is retained in amber during heating experiments to 150° -250°C, with no evidence of recoiled 39Ar found after irradiation. A maximum permissible volume diffusion coefficient...

The longest proposed suture zone in Saudi Arabia, the Nabitah suture, can be traced as a string of ophiolite complexes for 1200 km along the north-south axis of the Arabian Shield. Results of a field study in the north-central shield between 23° and 26°N indicate that the Nabitah suture is...

Solutions of the radiative transfer equation are used to derive relationships of water reflectance to the diffuse attenuation coefficient (K) in moderately turbid water (K > 0.5 m−1). Data sets collected from the NOAA AVHRR and in situ observations from five different dates confirm the appropriateness of these relationships, in particular the...

Coastal deposits along the western coastal margin of Australia, a region of relative tectonic stability, record Plio-Pleistocene events and processes affecting the inner shelf and adjacent hinterland. Tectonic deformation of these deposits is more apparent in the Carnarvon Basin, and rather less so in the Perth Basin. The most complete...

Suspended-sediment and dissolved-solid (salt) loads decreased after the early 1940s in the Colorado Plateau portion of the Colorado River basin, although discharge of major rivers - the Colorado, Green and San Juan - did not change significantly. This decline followed a period of high sediment yield caused by arroyo cutting....

Climatic changes that result from increasing concentrations of atmospheric carbon dioxide may affect the availability of water for vegetation, groundwater recharge, runoff, and human consumption. Most studies of the effects of climatic change on water resources focus on changes in mean characteristics of hydrologic variables and do not consider the...

Changes in groundwater flow were observed near four Experimental Wetland Areas (EWAs) constructed along a reach of the Des Plaines River in northeastern Illinois. These changes were observed during monthly monitoring of groundwater elevation in nested piezometers and shallow observation wells before and after the wetlands were filled with water....

Integrated studies of geohydrology, geochemistry, and geology of crystalline rocks in the vicinity of Conifer, Colorado, reveal that radon concentrations do not correlate with variations in concentrations of other dissolved species. Concentrations of major ions show systematic variations along selected groundwater flowpaths, whereas radon concentrations are dependent on local geochemical...

The Amargosa Desert of southern Nevada, in the Basin and Range province, is hydraulically downgradient from Yucca Mountain, the potential site of a repository for high-level nuclear waste. Groundwater flow paths and flow rates beneath the Amargosa Desert are controlled in part by the total saturated thickness and the hydraulic...

Middle Pliocene marine ostracodes from coastal and shelf deposits of North and Central America and Iceland were studied to reconstruct paleotemperatures of shelf waters bordering portions of the Western Boundary Current System (including the Gulf Loop Current, Florida Current, Gulf Stream and North Atlantic Drift). Factor analytic transfer functions provided...

The lithology and paleontology of Pliocene deposits from Karaginsky Island, off eastern Kamchatka Peninsula, U.S.S.R., are described in order to provide a paleoceanographic reconstruction of this region of the eastern North Pacific Ocean. The stratigraphic sequence is divided into three suites — the Limimtevayamian, the Ust-Limimtevayamian, and the Tusatuvayamian, which...

A simple temperature-sensitive modification to the Green and Ampt infiltration equation is described; this assumes that the temperature dependence of the hydraulic conductivity is reciprocally equal to the temperature dependence of the viscosity of liquid water, and that both the transmission zone saturation and the wetting front matric potential gradient...

The available evidence from the western United States suggests that the climate of the Early and Middle Pliocene (prior to ∼2.4 Ma) was less seasonal (more equable) and generally more humid than now. Along the Pacific coast, summer drought was less pronounced than today. In the interior of the Pacific...

Sea-surface temperature (SST) estimates based on quantitative analysis of planktic foraminifer faunas in North Atlantic deep sea cores suggest that high-frequency, low-amplitude variability related to orbital forcing was superimposed on long-term changes that delineate intervals within the Pliocene that were both warmer and cooler than today. SST estimates from several...

The application of quantitative and semiquantitative methods to assemblage data from dinoflagellate cysts shows potential for interpreting past environments, both in terms of paleotemperature estimates and in recognizing water masses and circulation patterns.Estimates of winter sea-surface temperature (WSST) were produced by using the Impagidinium Index (II) method, and by applying a winter-temperature...