Weakening of the subduction interface and its effects on surface
... Cascadia and Nankai, to be discussed in section 5.1. ETS may be rare in cold-slab subduction zones. (b) Surface heat flow (solid curve). Heat flow patterns for cold-slab subduction zones are similar, except that values near the trench and further seaward are much lower. Models that do not include ma ...
... Cascadia and Nankai, to be discussed in section 5.1. ETS may be rare in cold-slab subduction zones. (b) Surface heat flow (solid curve). Heat flow patterns for cold-slab subduction zones are similar, except that values near the trench and further seaward are much lower. Models that do not include ma ...
ecology of cold seep sediments
... Ecosystems known as cold seeps are found where reduced sulphur and methane emerge from seafloor sediments without an appreciable temperature rise. Cold seep environments are among the most recently discovered marine habitats; the first such system was found just 20 yr ago, on the Florida Escarpment ...
... Ecosystems known as cold seeps are found where reduced sulphur and methane emerge from seafloor sediments without an appreciable temperature rise. Cold seep environments are among the most recently discovered marine habitats; the first such system was found just 20 yr ago, on the Florida Escarpment ...
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... and anaerobic chemolithoautotrophs [4]. This unique subsurface microbial community does not receive input of energy from the surface (i.e., sunlight or photosynthetically-derived organic matter) and could serve as an analogue for life in the subsurface of other planets. • Firmicutes dominate deep me ...
... and anaerobic chemolithoautotrophs [4]. This unique subsurface microbial community does not receive input of energy from the surface (i.e., sunlight or photosynthetically-derived organic matter) and could serve as an analogue for life in the subsurface of other planets. • Firmicutes dominate deep me ...
Provided by the author (s) and NUI Galway in accordance with
... considering continental margins and lateral transport when assessing the relative role in the marine environment was conclusively demonstrated by such projects (see publications from these projects e.g. Walsh et al., 1988; Lampitt et al., 1995; van Weering et al., 1998; Nittrourer, 1999; van Weering ...
... considering continental margins and lateral transport when assessing the relative role in the marine environment was conclusively demonstrated by such projects (see publications from these projects e.g. Walsh et al., 1988; Lampitt et al., 1995; van Weering et al., 1998; Nittrourer, 1999; van Weering ...
The Statistical Upper Mantle Assemblage, Earth
... layered mantle model. As a result of vigorous convection and mixing and formation of the continental crust, the upper mantle (its size not precisely de¢ned) is well homogenized, depleted, degassed and essentially isothermal, or adiabatic. Subducted slabs of oceanic crust and sediments (red) are conv ...
... layered mantle model. As a result of vigorous convection and mixing and formation of the continental crust, the upper mantle (its size not precisely de¢ned) is well homogenized, depleted, degassed and essentially isothermal, or adiabatic. Subducted slabs of oceanic crust and sediments (red) are conv ...
Simple Kinematics of Subduction Zones
... from eastern Africa, the Indian Ocean, and the Himalayas. In the hotspot reference frame a “westward” rotation of the lithosphere can be observed (Gripp and Gordon, 2002). The origin of this net rotation of the lithosphere (Bostrom, 1971) is still under debate (Scoppola et al., 2006), but it amounts ...
... from eastern Africa, the Indian Ocean, and the Himalayas. In the hotspot reference frame a “westward” rotation of the lithosphere can be observed (Gripp and Gordon, 2002). The origin of this net rotation of the lithosphere (Bostrom, 1971) is still under debate (Scoppola et al., 2006), but it amounts ...
Scientific Synthesis of the Impacts of Ocean Fertilization
... As early as the 1930s, scientists had speculated that iron deficiency could account for areas of the world’s oceans with scarce phytoplankton growth. In the 1980s, the studies of the oceanographer John Martin confirmed that the scarcity of iron micronutrients was indeed a major factor in limiting ph ...
... As early as the 1930s, scientists had speculated that iron deficiency could account for areas of the world’s oceans with scarce phytoplankton growth. In the 1980s, the studies of the oceanographer John Martin confirmed that the scarcity of iron micronutrients was indeed a major factor in limiting ph ...
Characterization of contaminant phases in foraminifera carbonates
... underlying basement which has been well constrained in regions of the central equatorial Pacific [Baker et al., 1991]. The high organic carbon supply to the bottom enhances the consumption of oxygen, and results in oxygen depletion within a few centimeters of the sediment-water interface [Pedersen a ...
... underlying basement which has been well constrained in regions of the central equatorial Pacific [Baker et al., 1991]. The high organic carbon supply to the bottom enhances the consumption of oxygen, and results in oxygen depletion within a few centimeters of the sediment-water interface [Pedersen a ...
1994 Annual Report - Woods Hole Oceanographic Institution
... ocean at the scale of a few meters is one still too small to measure reliably with of the less-routinely measured quantigeneral-purpose current meters. The ties, and it requires special instrumentameasurement is exploratory because tion. Vertical shearing of horizontal the probes will drift freely f ...
... ocean at the scale of a few meters is one still too small to measure reliably with of the less-routinely measured quantigeneral-purpose current meters. The ties, and it requires special instrumentameasurement is exploratory because tion. Vertical shearing of horizontal the probes will drift freely f ...
DEEP STRUCTURE AND GEOPHYSICAL PROCESSES BENEATH
... greatly effect the gross thermal structure calculated for the slab. ...
... greatly effect the gross thermal structure calculated for the slab. ...
Massive marine methane emissions from near
... the coastline contains sediments with shallow gas, associated to a peat-rich layer from the late Pleistocene25. The high near-shore CH4 concentrations in surface waters were observed within this band of gassy sediments (Figs 1 and S1) that was most probably the source of CH4. The nearshore BCZ has s ...
... the coastline contains sediments with shallow gas, associated to a peat-rich layer from the late Pleistocene25. The high near-shore CH4 concentrations in surface waters were observed within this band of gassy sediments (Figs 1 and S1) that was most probably the source of CH4. The nearshore BCZ has s ...
Seamounts of the North-East Atlantic - Mar-Eco
... In 1997 an international research programme known as the “Census of Marine Life” was set up with the aim of assessing and explaining the diversity, distribution and abundance of marine organisms throughout the world's oceans. A key objective was to focus on poorly known ecosystems and/or communitie ...
... In 1997 an international research programme known as the “Census of Marine Life” was set up with the aim of assessing and explaining the diversity, distribution and abundance of marine organisms throughout the world's oceans. A key objective was to focus on poorly known ecosystems and/or communitie ...
Seamounts of the North-East Atlantic
... In 1997 an international research programme known as the “Census of Marine Life” was set up with the aim of assessing and explaining the diversity, distribution and abundance of marine organisms throughout the world's oceans. A key objective was to focus on poorly known ecosystems and/or communitie ...
... In 1997 an international research programme known as the “Census of Marine Life” was set up with the aim of assessing and explaining the diversity, distribution and abundance of marine organisms throughout the world's oceans. A key objective was to focus on poorly known ecosystems and/or communitie ...
Lithosphere, Asthenosphere, and Perisphere
... to 550ø-600øC [De Rito et al., 1986; McNutt, 1984] or geochemical literature. The chemical connotations about half the absolute melting temperature. A useful have preempted the original physical characteristicsof role of thumb is that the strong, high-viscosityplate is lithosphereand asthenosphere.T ...
... to 550ø-600øC [De Rito et al., 1986; McNutt, 1984] or geochemical literature. The chemical connotations about half the absolute melting temperature. A useful have preempted the original physical characteristicsof role of thumb is that the strong, high-viscosityplate is lithosphereand asthenosphere.T ...
Composition and degradation of organic matter in sediments from
... the oxygen-minimum-zone, reflecting both, intense bacterial reworking at these shallow sites and accumulation of bacterial biomass in the absence of oxygen. Sediments from the oxygenminimum-zone also displayed the highest concentrations of the fatty acid 10-methyl-16:0, indicative for the presence o ...
... the oxygen-minimum-zone, reflecting both, intense bacterial reworking at these shallow sites and accumulation of bacterial biomass in the absence of oxygen. Sediments from the oxygenminimum-zone also displayed the highest concentrations of the fatty acid 10-methyl-16:0, indicative for the presence o ...
Crust recycling in the sources of two parallel volcanic chains in
... (not shown). In a primitive-mantle normalized incompatible element diagram (Figure 3), these basalts resemble many ocean island basalts in terms of enrichment in Nb and Ta, relative to LREEs. Except for the basalts from Shanwang and a few samples from Liushan, most samples show slightly negative Pb ...
... (not shown). In a primitive-mantle normalized incompatible element diagram (Figure 3), these basalts resemble many ocean island basalts in terms of enrichment in Nb and Ta, relative to LREEs. Except for the basalts from Shanwang and a few samples from Liushan, most samples show slightly negative Pb ...
Olivier MARCHAL
... observations from marine sediments, December 2009 (INVITED) A58 Marchal O.*, Workshop ‘Data Assimilation’, Program PAGES (’Past Global Changes’), Vienna, Austria: Interpretation of tracer observations from marine sediments: Effects of data and model ...
... observations from marine sediments, December 2009 (INVITED) A58 Marchal O.*, Workshop ‘Data Assimilation’, Program PAGES (’Past Global Changes’), Vienna, Austria: Interpretation of tracer observations from marine sediments: Effects of data and model ...
Primitive off-rift basalts from Iceland and Jan Mayen: Os
... mantle source. A positive correlation between 143Nd/144Nd and 187Os/188Os ratios in Iceland and Jan Mayen lavas likely reflects the presence in their source of ancient subcontinental lithosphere that has undergone incompatible trace element enrichment that did not affect the Re–Os system. In addition, ...
... mantle source. A positive correlation between 143Nd/144Nd and 187Os/188Os ratios in Iceland and Jan Mayen lavas likely reflects the presence in their source of ancient subcontinental lithosphere that has undergone incompatible trace element enrichment that did not affect the Re–Os system. In addition, ...
Paper 3.2 Mb pdf - Miles F Osmaston
... for epeirogeny) to the plate tectonics armory, we will then derive an interpretation of Alpine history, concluding with brief comparative remarks on other HP-UHP belts. To complement the understanding of our proposed mechanism for differential thermal epeirogenic action in the context of block-and-b ...
... for epeirogeny) to the plate tectonics armory, we will then derive an interpretation of Alpine history, concluding with brief comparative remarks on other HP-UHP belts. To complement the understanding of our proposed mechanism for differential thermal epeirogenic action in the context of block-and-b ...
PDF (Chapter 23. The Upper Mantle)
... part of the mantle. It is not necessarily convectively homogenized. Attempts to establish an average composition for 'the upper mantle' focus on the most depleted MORB lavas or abyssal peridotites and involve major assumptions about melt generation, melt transport and differentiation processes that ...
... part of the mantle. It is not necessarily convectively homogenized. Attempts to establish an average composition for 'the upper mantle' focus on the most depleted MORB lavas or abyssal peridotites and involve major assumptions about melt generation, melt transport and differentiation processes that ...
Subduction erosion modes: Comparing finite
... During subduction erosion, the upper plate is tectonically eroded by the subducting plate and carried into the mantle. The geological record suggests that subduction erosion is a fundamental process at subduction margins; however the underlying causes are not well constrained. Finite-element numeric ...
... During subduction erosion, the upper plate is tectonically eroded by the subducting plate and carried into the mantle. The geological record suggests that subduction erosion is a fundamental process at subduction margins; however the underlying causes are not well constrained. Finite-element numeric ...
KeyNoteNew_Oct01_v9_sgb_edits
... the indicators for pressure and ecological impact of bottom trawling in three main seabed habitat types in ...
... the indicators for pressure and ecological impact of bottom trawling in three main seabed habitat types in ...
PDF (Chapter 8. Chemical Composition of the Mantle)
... When x, and k are found, equation 1 gives the mantle concentrations of the volatile and siderophile elements, elements not used in the inversion. The mixing ratios found from equations 2 and 3 are UMR, 32.6 percent, OPX, 59.8 percent, MORB, 6.7 percent, crust, 0.555 percent, and Q, 0.11 percent. Thi ...
... When x, and k are found, equation 1 gives the mantle concentrations of the volatile and siderophile elements, elements not used in the inversion. The mixing ratios found from equations 2 and 3 are UMR, 32.6 percent, OPX, 59.8 percent, MORB, 6.7 percent, crust, 0.555 percent, and Q, 0.11 percent. Thi ...
1 Imaging the transition from flat to normal subduction: Variations in
... result of vertical smearing of low velocity anomalies in the crust down into the mantle, resulting ...
... result of vertical smearing of low velocity anomalies in the crust down into the mantle, resulting ...
Behavioural observations on the scavenging fauna of the
... 1995). Myxine knappi and M. dorsum are also described in Falkland Island waters, but have a very small ventral ¢nfold and are not reported at depths greater than 650 m (Wisner & McMillan, 1995). It is, however, possible that more than one species was present, particularly during the long deployment ...
... 1995). Myxine knappi and M. dorsum are also described in Falkland Island waters, but have a very small ventral ¢nfold and are not reported at depths greater than 650 m (Wisner & McMillan, 1995). It is, however, possible that more than one species was present, particularly during the long deployment ...
Abyssal plain
An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 m. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface. They are among the flattest, smoothest and least explored regions on Earth. Abyssal plains are key geologic elements of oceanic basins (the other elements being an elevated mid-ocean ridge and flanking abyssal hills). In addition to these elements, active oceanic basins (those that are associated with a moving plate tectonic boundary) also typically include an oceanic trench and a subduction zone.Abyssal plains were not recognized as distinct physiographic features of the sea floor until the late 1940s and, until very recently, none had been studied on a systematic basis. They are poorly preserved in the sedimentary record, because they tend to be consumed by the subduction process. The creation of the abyssal plain is the end result of spreading of the seafloor (plate tectonics) and melting of the lower oceanic crust. Magma rises from above the asthenosphere (a layer of the upper mantle) and as this basaltic material reaches the surface at mid-ocean ridges it forms new oceanic crust. This is constantly pulled sideways by spreading of the seafloor. Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt. Much of this sediment is deposited by turbidity currents that have been channelled from the continental margins along submarine canyons down into deeper water. The remainder of the sediment is composed chiefly of pelagic sediments. Metallic nodules are common in some areas of the plains, with varying concentrations of metals, including manganese, iron, nickel, cobalt, and copper. These nodules may provide a significant resource for future mining ventures.Owing in part to their vast size, abyssal plains are currently believed to be a major reservoir of biodiversity. The abyss also exerts significant influence upon ocean carbon cycling, dissolution of calcium carbonate, and atmospheric CO2 concentrations over timescales of 100–1000 years. The structure and function of abyssal ecosystems are strongly influenced by the rate of flux of food to the seafloor and the composition of the material that settles. Factors such as climate change, fishing practices, and ocean fertilization are expected to have a substantial effect on patterns of primary production in the euphotic zone. This will undoubtedly impact the flux of organic material to the abyss in a similar manner and thus have a profound effect on the structure, function and diversity of abyssal ecosystems.