[1] We have estimated patterns and rates of crustal movement across 800 km of the Basin and Range at 39 north latitude with Global Positioning System surveys in 1992, 1996, 1998, and 2002. The total rate of motion tangent to the small circle around the PacificNorth America pole of rotation is 10.4 ± 1.0 mm/yr, and motion normal to this small circle is 3.9 ± 0.9 mm/yr compared to the east end of...

Atmospheric deposition of nitrogen (N) and phosphorus (P) into Lake Tahoe appears to have been a major factor responsible for the shifting of the lake's nutrient response from N-limited to P-limited. To characterize atmospheric N and P in and around the Lake Tahoe Basin during summer, samples were collected using an instrumented aircraft flown over three locations: the Sierra Nevada foothills e...

[1] The northwest Argentine Andes constitute a premier natural laboratory to assess the complex interactions between isolated uplifts, orographic precipitation gradients, and related erosion and sedimentation patterns. Here we present new stratigraphic observations and age information from intermontane basin sediments to elucidate the Neogene to Quaternary shortening history and associated sedi...

The western segment of the Churchill Province of Canada, west of Hudson Bay, was divided by Hoffman (1988) into the Archean Rae and Hearne domains separated by the Snowbird Tectonic Zone (STZ) (Fig. 1), defined on the basis of potential field data. The Hearne domain has been further subdivided into the northern Hearne and southern Hearne subdomains (Davis et al., this volume). There is little d...

Despite the arid to hyperarid climate of the Great Sahara of North Africa, pluvial climates dominated the region. Radar data shed some light on the postulated Trans-African Drainage System and its relationship to active and inactive tributaries of the Nile basin. Interpretations of recent elevation data confirm a source of the river water from the Red Sea highlands did not connect the Atlantic ...

Atokan-age units in the Permian Basin record a 2-order transgression, with aerially restricted, lower Atokan fluvial to shallow-marine siliciclastics followed by pervasive carbonate deposition. In general, Atokan-age siliciclastics dominated deposition in the west of the Permian Basin while carbonate deposition dominated throughout the rest of the basin. Predominance of carbonate facies across ...

Many important hominid-bearing fossil localities in East Africa are in regions that are extremely hot and dry. Although humans are well adapted to such conditions, it has been inferred that East African environments were cooler or more wooded during the Pliocene and Pleistocene when this region was a central stage of human evolution. Here we show that the Turkana Basin, Kenya--today one of the ...

Ecosystem uptake and transfer processes of Sellafield-derived radiocarbon (14C) within the Irish Sea were examined. Highly variable activities in sediment, seawater and biota indicate complex 14C dispersal and uptake dynamics. All east basin biota exhibited 14C enrichments above ambient background while most west basin biota had 14C activities close to background, although four organisms includ...

Background The research that informs this study was conducted in Chapra village, Kushtia District, Bangladesh, located about 20 km east of the Indian border. Chapra is located within the Ganges Dependent Area (GDA) in Bangladesh which, in turn, is located within the Ganges–Brahmaputra Basin (GBB), one of the largest river basins in the world by area and second only to the Amazon in terms of the...

[1] Extension during the middle Cenozoic (43–26 Ma) in the north end of the West Antarctic rift system (WARS) is well constrained by seafloor magnetic anomalies formed at the extinct Adare spreading axis. Kinematic solutions for this time interval suggest a southward decrease in relative motion between East and West Antarctica. Here we present multichannel seismic reflection and seafloor mappin...