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Trends in streamflow and concentration of total nitrogen, nitrite plus nitrate, ammonia, total phosphorus, orthophosphorus, and suspended sediment were determined for the period from 1993 to 2003 at selected stream sites in the Missouri River Basin. Flow-adjusted trends in concentration (the trends that would have occurred in the absence of...

Because of the paucity of exposed rock, the direct physical record of Antarctic Cenozoic glacial history has become known only recently and then largely from offshore shelf basins through seismic surveys and drilling. The number of holes on the continental shelf has been small and largely confined to three areas...

The Antarctic Seismic Data Library System for Cooperative Research (SDLS) has served for the past 16 years under the auspices of the Antarctic Treaty (ATCM Recommendation XVI-12) as a role model for collaboration and equitable sharing of Antarctic multichannel seismic reflection (MCS) data for geoscience studies. During this period, collaboration...

Site NBP0602A-9, drilled during the SHALDRIL II cruise of the RV/IB Nathaniel B. Palmer, includes two holes located in the northern James Ross Basin in the western Weddell Sea, very close to the eastern margin of the Antarctic Peninsula. Sediment from both holes consists of very dark grey, pebbly, sandy...

When 12 countries established scientific stations in Antarctica for the 1957-58 (IGY), the Cold War was at its height, seven countries had made claims in Antarctica, and the Antarctic Treaty was in the future. The only major field project of the U.S. IGY Antarctic program was series of oversnow traverses,...

The Ellsworth Mountains, first mapped under the leadership of Campbell Craddock, pose critical geological enigmas, solved and unsolved. The isolation of the mountains, their abrupt structural terminations and Paleozoic stratigraphic affinities are explained by rotation from the cratonic margin during Gondwanaland breakup. The mechanism remains obscure. The absence of intense...

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This contribution owes its origins to a paper presentation by Dr. Calloway H. Dodson at the Second International Conference on Neotropical Orchidology held in San José, Costa Rica in May of2003 (Dodson 2003). Dr. Dodson outlined some ofthe reasons to suspect that regional geological fac-tors may play important roles in...

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The Hamra Basin Province encompasses approximately 244,100 square kilometers (94,250 square miles) and is entirely within Libya. One composite total petroleum system (TPS) was defined for this assessment; it extends from Libya westward into adjacent parts of Algeria and southern Tunisia. The Hamra Basin part of the TPS was subdivided...

Evidence that earthquakes threaten the Mississippi, Ohio, and Wabash River valleys of the Central United States abounds. In fact, several of the largest historical earthquakes to strike the continental United States occurred in the winter of 1811-1812 along the New Madrid seismic zone, which stretches from just west of Memphis,...

Two large, regional ground-water flow systems occur in the Coconino Plateau and adjacent areas: the C aquifer and the Redwall-Muav aquifer. The C aquifer occurs mainly in the eastern and southern parts of the 10,300-square-mile Coconino Plateau study area, and the Redwall-Muav aquifer underlies the entire study area. The C...

The United States Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Association (NOAA) to interpret the surficial geology in estuaries along the coast of the northeastern United States. The purpose of our present study is to determine the distributions of surficial sediments and sedimentary environments in...

Recent studies have documented strong, top-down predation effects of sea ducks on mussel populations in rocky intertidal communities. However, the impact of these gregarious predators in soft-bottom communities has been largely unexplored. We evaluated effects of predation by wintering surf scoters Melanitta perspicillata and white-winged scoters M. fusca on clam populations in soft-bottom intertidal...

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Many sediment records from the margins of the Californias (Alta and Baja) collected in water depths between 60 and 1200 m contain anoxic intervals (laminated sediments) that can be correlated with interstadial intervals as defined by the oxygen-isotope composition of Greenland ice (Dansgaard–Oeschger, D–O, cycles). These intervals include all or parts...

The Hanson Formation of the Central Transantarctic Mountains has yielded a diverse Early Jurassic terrestrial fauna, which includes the nearly complete theropod dinosaur, Cryolophosaurus ellioti, and a fragmentary basal sauropodomorph dinosaur. The Hanson Formation dinosaurs are important for understanding early dinosaur evolution because: 1) they preserve a mosaic of morphological traits that render...

The Antarctic Multibeam Bathymetry and Geophysical Data Synthesis(AMBS) is a web-accessible data resource for marine geoscience research in the Southern Ocean. The primary focusisto preserve and provide public accessto multibeam bathymetry acquired during expeditions of research vesselssupported by the U.S. National Science Foundation. Since itsinception in 2003, our primary goal has been to...

Antarctica has geometric significance for global plate kinematic studies, because it links seafloor spreading systems of the African hemisphere (Indian and Atlantic Oceans) with those of the Pacific. Inferences of plate motions back to 44 Ma, around the onset of rapid spreading south of Australia and formation of a new...