Dynamics of temperature and chlorophyll
... conducted over Minami-kasuga Seamount, in the northwest Pacific (21°36'N, 143°38'E). A cold dome, similar to a Taylor column, was observed above the seamount top during the first survey. Uplifted isotherms penetrated to the lower euphotic zone and were associated with higher chlorophyll concentratio ...
... conducted over Minami-kasuga Seamount, in the northwest Pacific (21°36'N, 143°38'E). A cold dome, similar to a Taylor column, was observed above the seamount top during the first survey. Uplifted isotherms penetrated to the lower euphotic zone and were associated with higher chlorophyll concentratio ...
Geological Society of America Bulletin
... et al., 2009). They are generally found along suture zones in both collisional-type (i.e., Alpine, Himalayan, Appalachian) and accretionary-type (i.e., North American Cordilleran) orogenic belts (Fig. 1) that mark major boundaries between amalgamated plates or accreted terranes (Lister and Forster, ...
... et al., 2009). They are generally found along suture zones in both collisional-type (i.e., Alpine, Himalayan, Appalachian) and accretionary-type (i.e., North American Cordilleran) orogenic belts (Fig. 1) that mark major boundaries between amalgamated plates or accreted terranes (Lister and Forster, ...
Aluminium in an ocean general circulation model compared with the
... locations in the ocean. Generally, profiles of Aldiss have a reversible-scavenging profile (increasing with depth) and often with a minimum near 1 km depth and a maximum at the surface because of dust deposition. However, observations in the Mediterranean Sea (Hydes et al., 1988; Chou and Wollast, 1 ...
... locations in the ocean. Generally, profiles of Aldiss have a reversible-scavenging profile (increasing with depth) and often with a minimum near 1 km depth and a maximum at the surface because of dust deposition. However, observations in the Mediterranean Sea (Hydes et al., 1988; Chou and Wollast, 1 ...
Ocean Storage of CO2
... from the Mediterranean Sea. Because this water is saltier than average seawater, the higher density would cause the CO2 to sink into the depths of the Atlantic Ocean (Marchetti 1977). As illustrated in Figure 3, a number of options have been considered since then, including introducing the CO2 as a ...
... from the Mediterranean Sea. Because this water is saltier than average seawater, the higher density would cause the CO2 to sink into the depths of the Atlantic Ocean (Marchetti 1977). As illustrated in Figure 3, a number of options have been considered since then, including introducing the CO2 as a ...
pdf file - University of Victoria
... Europe. How did they get there, and what lifted them up? How did they persist when erosion was recognized as an effective levelling process? There were many theories that now appear fantastic, with some quite perceptive analyses such as by the Swiss geologist Émile Argand (Argand 1924), but a simple ...
... Europe. How did they get there, and what lifted them up? How did they persist when erosion was recognized as an effective levelling process? There were many theories that now appear fantastic, with some quite perceptive analyses such as by the Swiss geologist Émile Argand (Argand 1924), but a simple ...
Lower crustal earthquakes near the Ethiopian rift induced by
... rift axis may currently be particularly concentrated near volcanic centers, geophysical data suggest a small fraction of aligned partial melt is widespread in the lower crust beneath the NW plateau and may be important in accommodating minor amounts of extensional strain outside the MER [Keranen et ...
... rift axis may currently be particularly concentrated near volcanic centers, geophysical data suggest a small fraction of aligned partial melt is widespread in the lower crust beneath the NW plateau and may be important in accommodating minor amounts of extensional strain outside the MER [Keranen et ...
Elsevier Publishing Company, Amsterdam
... a complicated depositional history and consists of two units, an upper succession of internally reflective beds, and a lower sequence of more weakly reflecting strata (Fig.6, 7 and 8). Except beneath the sloping flanks of Bering and Bristol Canyons, the two units are generally conformable. Strata of ...
... a complicated depositional history and consists of two units, an upper succession of internally reflective beds, and a lower sequence of more weakly reflecting strata (Fig.6, 7 and 8). Except beneath the sloping flanks of Bering and Bristol Canyons, the two units are generally conformable. Strata of ...
Phosphorus Cycling in the Sargasso Sea: Investigation Using the
... the ocean are extremely low (<10 nM) and phosphorus (P) availability could limit primary productivity in these regions. We explore the use of oxygen isotopic signature of dissolved phosphate (d18OPO4) to investigate biogeochemical cycling of P in the Sargasso Sea, Atlantic Ocean. Additional techniqu ...
... the ocean are extremely low (<10 nM) and phosphorus (P) availability could limit primary productivity in these regions. We explore the use of oxygen isotopic signature of dissolved phosphate (d18OPO4) to investigate biogeochemical cycling of P in the Sargasso Sea, Atlantic Ocean. Additional techniqu ...
A model for the layered upper mantle
... the experimentally determined high melting temperatures of (Mg,Fe)SiO 3 perovskite (Zerr and Boehler, 1993) would prohibit convection in the lower mantle unless the melting temperatures are decreased by volatiles. Any estimate of the rheological properties of the Earth, for example from a postglacia ...
... the experimentally determined high melting temperatures of (Mg,Fe)SiO 3 perovskite (Zerr and Boehler, 1993) would prohibit convection in the lower mantle unless the melting temperatures are decreased by volatiles. Any estimate of the rheological properties of the Earth, for example from a postglacia ...
Dynamical effects of subducting ridges: insights from 3
... Funiciello et al. (2004). We model the upper mantle asthenosphere, between the base of the lithosphere and the 660 km discontinuity, using honey. Honey fills a rigid Plexiglas tank. In the centre of the tank, a silicone plate is deposited above honey to simulate the oceanic lithosphere before subduc ...
... Funiciello et al. (2004). We model the upper mantle asthenosphere, between the base of the lithosphere and the 660 km discontinuity, using honey. Honey fills a rigid Plexiglas tank. In the centre of the tank, a silicone plate is deposited above honey to simulate the oceanic lithosphere before subduc ...
Rheological Response to Tectonic and Volcanic
... ~150–200°C km-1 in the flank zone of the active volcanic zone (Flóvenz & Sæmundsson 1993). Flank zones are characterized by volcanic activity that is not connected with the plate boundary. The two most important flanks are the Snæfallsjökull in the west and the Öræfajökull in the east (Fig. 2). Diff ...
... ~150–200°C km-1 in the flank zone of the active volcanic zone (Flóvenz & Sæmundsson 1993). Flank zones are characterized by volcanic activity that is not connected with the plate boundary. The two most important flanks are the Snæfallsjökull in the west and the Öræfajökull in the east (Fig. 2). Diff ...
The Impact of Submesoscale Physics on Primary Productivity of
... and nutrients are regarded as the primary drivers of phytoplankton primary production. Phytoplankton abundance is also affected by grazing, and although such top-down control (Behrenfeld & Boss 2014) is important, I address only the bottom-up drivers of primary production in this review. Photosynthe ...
... and nutrients are regarded as the primary drivers of phytoplankton primary production. Phytoplankton abundance is also affected by grazing, and although such top-down control (Behrenfeld & Boss 2014) is important, I address only the bottom-up drivers of primary production in this review. Photosynthe ...
Crust and upper mantle discontinuity structure beneath eastern
... 1968; McNutt, 1980]. Data from the MOMA array allow us to systematically investigate crustal thickness and isostasy in the northern Appalachians. The MOMA array also provides new constraints on Moho topography into the Proterozoic craton, a region where very few refraction studies exist. Also of par ...
... 1968; McNutt, 1980]. Data from the MOMA array allow us to systematically investigate crustal thickness and isostasy in the northern Appalachians. The MOMA array also provides new constraints on Moho topography into the Proterozoic craton, a region where very few refraction studies exist. Also of par ...
The NOAA Ship Okeanos Explorer To Boldly Go…
... CIRCULATIONv 4(# WHICH PLAYS AN IMPORTANT ROLE IN transporting heat, dissolved oxygen and nutrients. Dense water sinking in the North Atlantic Ocean is one of the principal forces that drives the circulation of the THC, and there are growing concerns about how these forces may be affected by cha ...
... CIRCULATIONv 4(# WHICH PLAYS AN IMPORTANT ROLE IN transporting heat, dissolved oxygen and nutrients. Dense water sinking in the North Atlantic Ocean is one of the principal forces that drives the circulation of the THC, and there are growing concerns about how these forces may be affected by cha ...
Mantle Influence, Rifting and Magmatism in the East African Rift
... field extensional stress on the African plate since that time has been slab pull from the zone of plate convergence in the north and northeast. Otherwise, ridge-push from the MidAtlantic and West-Indian oceanic ridges has caused compression on this plate. Thus EARS development had been due to an in- ...
... field extensional stress on the African plate since that time has been slab pull from the zone of plate convergence in the north and northeast. Otherwise, ridge-push from the MidAtlantic and West-Indian oceanic ridges has caused compression on this plate. Thus EARS development had been due to an in- ...
Slab behaviour and its surface expression: new insights
... different by an order of magnitude, the crustal thickening effect (Fig. 1b) being far greater than that of the lithospheric thickening (Fig. 1d). Reasons for the smaller anomalies in the lithospheric thickening model are the greater depth of the lithospheric root and the lower density contrast betwe ...
... different by an order of magnitude, the crustal thickening effect (Fig. 1b) being far greater than that of the lithospheric thickening (Fig. 1d). Reasons for the smaller anomalies in the lithospheric thickening model are the greater depth of the lithospheric root and the lower density contrast betwe ...
On the origin of noble gases in mantle plumes
... Strictly speaking, mantle convection implies stirring, i.e. stretching and folding, not mixing, since chemical di¬usion is negligible. The survival of highly deformed primitive veins in the mantle is likely. Even in the case of random distribution of subducted material in the mantle, the proportion ...
... Strictly speaking, mantle convection implies stirring, i.e. stretching and folding, not mixing, since chemical di¬usion is negligible. The survival of highly deformed primitive veins in the mantle is likely. Even in the case of random distribution of subducted material in the mantle, the proportion ...
Attachment between brittle and ductile crust at wrenching
... conditions (Thompson et al., 1997), permitting large strain to accumulate under relatively constant conditions over long periods of time. Therefore, wrench zones are excellent settings in which to study the coupling between lithospheric layers. Along plate boundaries where continental crust is invol ...
... conditions (Thompson et al., 1997), permitting large strain to accumulate under relatively constant conditions over long periods of time. Therefore, wrench zones are excellent settings in which to study the coupling between lithospheric layers. Along plate boundaries where continental crust is invol ...
Chapter 42 Cold-Water Corals
... continental margins and seamounts on hard substrata, as well as occasionally on softbottom in the case of the sea pens and a few species of bamboo corals. A combination of octocorals collections and observations along with a predictive habitat suitability model is displayed in Figure 3 (Yesson et al ...
... continental margins and seamounts on hard substrata, as well as occasionally on softbottom in the case of the sea pens and a few species of bamboo corals. A combination of octocorals collections and observations along with a predictive habitat suitability model is displayed in Figure 3 (Yesson et al ...
Oxygen and organic carbon fluxes in sediments of the
... The relationship between particulate organic carbon (POC) concentrations measured in modern sediment and fluxes of exported POC to the sediment surface needs to be understood in order to use POC content as a proxy of paleo-environmental conditions. The objective of our study was to compare POC concen ...
... The relationship between particulate organic carbon (POC) concentrations measured in modern sediment and fluxes of exported POC to the sediment surface needs to be understood in order to use POC content as a proxy of paleo-environmental conditions. The objective of our study was to compare POC concen ...
Why subduction zones are curved - Harvard John A. Paulson School
... While small loads lead to a gentle flattening of the sphere, initiation of a dimpled indentation occurs only when the applied load crosses a threshold. This implies, for example, that an intact eggshell can support much larger normal loads than a flat sheet of the same thickness and stiffness becaus ...
... While small loads lead to a gentle flattening of the sphere, initiation of a dimpled indentation occurs only when the applied load crosses a threshold. This implies, for example, that an intact eggshell can support much larger normal loads than a flat sheet of the same thickness and stiffness becaus ...
Constraints on the Lithospheric Structure of Venus from Mechanical
... Study Project, 1981,pp. 682-685]. A diabasecrustis assumed Stylesof UnstableDeformation on the basis of Venera lander results that show surface rocks ...
... Study Project, 1981,pp. 682-685]. A diabasecrustis assumed Stylesof UnstableDeformation on the basis of Venera lander results that show surface rocks ...
Primary magmas and mantle temperatures
... & Bickle, 1988). The crust and lithosphere are interpreted as a thin boundary layer over the asthenosphere, which is inferred to have a potential temperature of 1280°C and adiabatic temperature distribution with depth. The asthenosphere composition is inferred to be a reasonably wellmixed and slight ...
... & Bickle, 1988). The crust and lithosphere are interpreted as a thin boundary layer over the asthenosphere, which is inferred to have a potential temperature of 1280°C and adiabatic temperature distribution with depth. The asthenosphere composition is inferred to be a reasonably wellmixed and slight ...
Geology of Greenland Survey Bulletin 177, 89-95
... implies that it was also generally hotter, simply because cooling of the ocean floor is known to be a very slow process (see e.g. Martin, 1986, 1993; Drummond & Defant, 1990; Tarney & Jones, 1994). Some authors have taken this view even further, suggesting that the heat flow was so high that the upp ...
... implies that it was also generally hotter, simply because cooling of the ocean floor is known to be a very slow process (see e.g. Martin, 1986, 1993; Drummond & Defant, 1990; Tarney & Jones, 1994). Some authors have taken this view even further, suggesting that the heat flow was so high that the upp ...
Mechanisms for the Origin of Mid-Ocean Ridge Axial Topography: Implications
... Tm by 100øC then either vertical mantle flow or magma intrusion into the as suggestedfrom petrologic studies,this would increase the viscosity by approximatelytwo ordersof magnitude. While this effect has not been previously considered,it is potentially important and could result in the formation of ...
... Tm by 100øC then either vertical mantle flow or magma intrusion into the as suggestedfrom petrologic studies,this would increase the viscosity by approximatelytwo ordersof magnitude. While this effect has not been previously considered,it is potentially important and could result in the formation of ...
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.