Recent organic-rich deposits on the Peru continental margin
occur along the upper slope (100-450 m) between about ll°S and 16°S
and along the lower continental slope (>2000 m). The upper slope
deposits reflect high biological production in response to coastal
upwelling, but preservation of organic matter is enhanced by the...
Seep characteristics at different geologic settings are the subject of this review primarily based on results of the Research Consortium SFB 574. Criteria are drawn from examples on the erosive convergent margin off Costa Rica, the accretionary margin off Chile supplemented by examples from the transform margin of the Golf...
Hydrate Ridge has the distinction of hosting the first documented subduction-driven cold seep system that supports chemosynthetic life by Anaerobic Oxidation of Methane as well as the most widely researched methane hydrate setting at any active continental margin. Today this site is a vital node of Northeast Pacific regional long-term...
The Blanco Trough, a deep depression located in the Blanco Fracture Zone near the intersection with the Juan de Fuca Ridge, contains unusual manganese-enriched layered sediments. Due to the Blanco Trough's bathymetric isolation and confinement, and its location in a tectonically active zone, three hypotheses concerning the origin and cause...
Sedimentation rate could become a new exploration tool for evaluating
the source rock potential of sedimentary basins in frontier regions.
Petroleum source rocks are defined on the basis of total organic carbon
by weight percent. An analysis of Deep Sea Drilling Project (DSDP)
cores indicates that there exists quantitative relationships...
Plankton and surface sediment samples from the Gulf of California
were analyzed to determine the present geographic distribution of silicoflagellate
species in this area. Variations in the composition of the
silicoflagellate assemblage are related to water mass distributions.
Seven species and three forms were identified in these samples. Octactis
pulchra...
Authigenic carbonates and chemosymbiotic biota are archives of seepage 1 history and record paleo-environmental conditions at seep sites. Based on mineral and stable isotope compositions and U/Th-isotope systematics of seep carbonates and Calyptogena sp shell fragments from three seep sites located at 22°02' ~22°09'N, 118°43'~118°52'E (water depths: 473 m to...
Submersible investigations of the Cascadia accretionary
complex have identified localized venting of methane gas
bubbles in association with gas hydrate occurrence. Acoustic
profiles of these bubble plumes in the water column in the
vicinity of Hydrate Ridge offshore Oregon provide new
constraints on the spatial distribution of these gas vents...
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To constrain the fluxes of methane (CH4) in the water column above the accretionary
wedge along the Cascadia continental margin, we measured methane and its stable carbon
isotope signature (δ¹³C-CH₄). The studies focused on Hydrate Ridge (HR), where
venting occurs in the presence of gas-hydrate-bearing sediments. The vent CH₄ has...
Geophysical and biogeochemical processes associated with fluid venting from active and passive continental margins will receive significant scientific and economic attention
into the next century and are of major societal relevance. An important unknown among these interrelated processes is the role played by methane gas hydrates, at and below the...
In this thesis anomalous downcore shallowing of paleomagnetic
inclinations is interpreted to be caused by sediment compaction. Thus,
compaction-induced inclination shallowing may influence tectonic
reconstructions that are based on inclinations from deep-sea sediment
cores.
Progressive downcore shallowing of the remanent inclination was
observed in a 120-m section of Plio- Pleistocene...
Although plant remains, such as opal phytolith and charcoal analyses, have been used since the beginning of the 20th century to reconstruct past environments by ecologists and botanists, only recently have these techniques been considered by archaeologists in understanding the past at the site level. This study employs opal phytolith...
Submarine hydrothermal systems provide all of the
conditions necessary for the abiotic synthesis of organic
compounds, polymers, and simple cell-like organisms. An
analysis of the Archaean rock and fossil record shows that
fossils of simple organisms are found in rocks deposited in hydrothermal environments. Biochemical experiments have
shown that thermal...
The atmospheric trace element abundances associated with slash
burning have been measured by instrumental neutron activation analysis
(INAA). On site ground level samples were collected during the slash
burning season using high volume samplers and a cascade impactor. In
addition to the air samples, soil, wood and ashed wood samples...
The mesoscale sea-surface circulation pattern within 400 km off Chile and between 18°S and 40°S latitude is described using chlorophyll and temperature images from the Coastal Zone Color Scanner NIMBUS-7 satellite. The data base is a set of four mosaics developed from band-3 (550 nm) images taken on June 4...
Magneto- and chemostratigraphic correlation underpins much of our understanding of Earth history, yet typical correlation techniques are neither quantitative nor objective. Within this dissertation, I detail my efforts to develop and apply dynamic programming-based algorithms that accomplish optimal and reproducible stratigraphic alignment. I apply these algorithms to three geologic intervals:...
Archaeological excavations of the Cooper's Ferry site in the Lower Salmon River Canyon, Idaho, have revealed a stratified record of cultural occupation, spanning the late Pleistocene and early Holocene periods. The purpose of this study was to contribute to the understanding of cultural adaptive strategies represented in the archaeological record...
The distribution patterns of quartz and opal contents and the distribution
patterns of radiolarian assemblages, in the sediments of the
southeastern Pacific, are largely controlled by both the surface winds
and the mixed-layer oceanic circulation. The distribution pattern of
quartz is related to eolian and ice-rafted transport, as well as...
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