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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"bottom currents"”.
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Bottom currents and abyssal sedimentation processes south of Iceland
… out to observe the geologic effects of steady bottom currents on sediments of East Katla Ridge on the southern insular rise of Iceland. Near-bottom southwest to west-flowing currents exceeded 20 cm sec-1 for two weeks over a 25-kilometer wide section of the ridge flank between approximately …
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Bottom currents and abyssal sedimentation processes south of Iceland
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1980.
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Do Muds Sort? Experimental Test of a Hypothesis Key to Understanding Marine Bottom Currents
… has been hypothesized to be directly related to bottom-current behavior. This is known as the 'sortable silt' hypothesis and states that the non-cohesive, coarse silt in the 10 to 63 µm size range within a deposit can be used as a proxy for paleocurrent velocity. Slow deposition rates on …
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Sedimentary processes on the continental slope off New England
… seismic profiles, suspended sediment analysis, bottom photographs, television laboratory flume experiments, studies of surface sediments, and piston cores were combined to form the basis for understanding the sedimentary processes which control transportation, deposition, and erosion of …
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Volcanic reconstruction of the paleoproterozoic powderhouse formation, Snow Lake, Manitoba, Canada: implications for controls on volcanogenic massive sulfide formation
… deposited pyroclastic units by debris flows and bottom currents, and localized emplacement of rhyolite domes. The rhyolite domes are spatially associated with the Chisel, Chisel North, Lost, Ghost, Photo and Lalor deposits. The Chisel, Lalor and Lost members comprise the Powderhouse formation and …
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On the dynamics of shallow water currents in Massachusetts Bay and on the New England continental shelf
… is partially blocked by a shallow bank. The bottom sediment distribution in the Bay is complex; fine grained material is found in the deep basin, sand and gravel on the shallow bank, and mixtures of sand, gravel and fine material nearshore. Richardson current meters were moored 1 m from the …
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The dynamics of bottom boundary currents in the ocean
… presents an investigation of the dynamics of bottom boundary currents in the ocean. The major emphasis is to develop simple mathematical models in which various dynamical features of these complex geophysical flows may be isolated and explored. Two separate models are formulated and the …
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On subannual variability in the abyssal ocean
… the structure and variability of the bottom mixed layer (BML) in a region targeted for deep-sea mining. The observations reveal a spatially and temporally variable BML with a mean thickness of ∼250m and influenced by interactions with mesoscale eddies and abyssal thermal fronts. A …
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On Subannual Variability in the Abyssal Ocean
… the structure and variability of the bottom mixed layer (BML) in a region targeted for deep-sea mining. The observations reveal a spatially and temporally variable BML with a mean thickness of ~250 m and influenced by interactions with mesoscale eddies and abyssal thermal fronts. A …
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Marine Snow Settling Velocities at an Oil Spill Site and a Control Site in the Northern Gulf of Mexico
… degradation and to redistribution due to bottom currents. To assist in characterizing redistribution of particles near the seafloor, sediment traps, marine snow cameras, and acoustic Doppler current profilers (ADCPs) were deployed at two sites below the continental shelf break. One site …
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Deep submarine volcanoes in two geodynamic settings (Canary Basin and Gulf of Cadiz): morphology and shallow structure
… scars and mass transport or mud lobe deposits), bottom currents (contourite moats and plastered and mounded contourite drifts), and tectonics (bulge-like structures clearly deformed by faulting). Some of these seafloor edifices have been discovered recently and are reported for the first time in …
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Caracterização das unidades sísmicas, processos sedimentares e idade do cânion Almirante Câmara, bacia de Campos
… whether caused by gravitational flows, bottom currents or tectonics. These features are observed in the ocean floor as well along the geologic column and can be use in sedimentary processes identification. The main sedimentary processes occurring during the establishment and evolution of …
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Investigating sediment size distributions and size-specific Sm-Nd isotopes as paleoceanographic proxy in the North Atlantic Ocean: reconstructing past deep-sea current speeds since Last Glacial Maximum
… sediments from continents to the North Atlantic (bottom currents, turbidity currents, ice-rafting events, airborne inputs) can be well distinguished through the size-specific physical and geochemical records. When primarily advected by the bottom currents, Holocene sediments show that the …
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Upper slope geomorphology of Sardinian southern continental margin, applications to habitat mapping supporting marine strategy
… by affecting sediment accumulation rates, bottom currents and, ultimately, the rates of food supply. These biocoenosis hosts relevant commercially relevant species, as the blue and the giant red shrimp which represent the most important demersal resources for trawling fleet of Sardinia.
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Turbidity current processes and deposits on the northwest African Margin
… background sedimentation, alongslope bottom currents, and downslope gravity flows. A large section of the margin can be classified as a fine-grained clastic slope apron, although the presence of numerous volcanic islands and seamounts leads to a more complex distribution of sedimentary …
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Mechanisms for enhanced turbulence in the Drake Passage region of the Southern Ocean
… due to intense winds and storm forcing, strong currents in the form of the Antarctic Circumpolar Current (ACC) interacting with steep topography, and enhanced mesoscale activity. Consequently, the Southern Ocean is believed to be a hotspot for enhanced oceanic mixing. Due to the remote location …
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Mechanisms for enhanced turbulence in the Drake Passage Region of the Southern Ocean
… due to intense winds and storm forcing, strong currents in the form of the Antarctic Circumpolar Current (ACC) interacting with steep topography, and enhanced mesoscale activity. Consequently, the Southern Ocean is believed to be a hotspot for enhanced oceanic mixing. Due to the remote location …
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DEPOSITIONAL SYSTEMS INTERPRETATION OF EARLY PERMIAN MIXED SILICICLASTICS AND CARBONATES, MIDLAND BASIN, TEXAS
… Their main features are summarized from bottom to top of the cored interval. The Wolfcamp B2 and B1 intervals consist of multiple facies types, but are dominated by organic rich silty mudstone, skeletal argillaceous packstone, and bioclast-lithoclast floatstone. The Wolfcamp A3 and A2 …
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Sedimentology and micropalaeontology of gravity cores from the N.E. Atlantic continental slope south west of Ireland
… physical processes e.g. ice-rafting, contour currents etc. Striking variations in the populations of planktonic foraminifera were noted, alternating between Arctic and Sub-Arctic assemblages, reflecting the waxing and waning of glacial activity. The coccolith-carbonate minima correlate with …
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Megaturbidites and the late Quaternary regional sedimentology of the eastern and central Mediterranean Sea
… sedimentary environments. Climate-controlled bottom currents scour the region, creating sediment drifts (contourites) with heightened sedimentation rates via a process herein termed '<i>bottom current flow lofting</i>' and interaction with downslope processes. Local volcanism, relatively …
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