Workman, Hart, 2005 - University of Maryland, Department of Geology
... reaction [17]. We show that melt impregnation can be recognized and therefore filtered from the abyssal peridotite data set and suggest that melt/rock reaction in the data set we have used has had more effect on major element chemistry than trace element chemistry. Overall, it seems that, for the mo ...
... reaction [17]. We show that melt impregnation can be recognized and therefore filtered from the abyssal peridotite data set and suggest that melt/rock reaction in the data set we have used has had more effect on major element chemistry than trace element chemistry. Overall, it seems that, for the mo ...
church_hall
... The chemistry of the clinopyroxenes of the stratiform unit of the Troodos plutonic series (Dion 1987; Thibault 1987; Thy; 1987) indicates that the latter is entirely related to the low-Ti series, and is characterized by the crystallization sequence 01-Cpx-Opx-Plag-Amph or 01-Cpx-Plag-Opx-Amph (Dion ...
... The chemistry of the clinopyroxenes of the stratiform unit of the Troodos plutonic series (Dion 1987; Thibault 1987; Thy; 1987) indicates that the latter is entirely related to the low-Ti series, and is characterized by the crystallization sequence 01-Cpx-Opx-Plag-Amph or 01-Cpx-Plag-Opx-Amph (Dion ...
The Lithosphere – Asthenosphere System: Nature of the Tectonic
... Seismological studies reveal distinct reflectors (G discontinuity) in the uppermost oceanic mantle that are sometimes interpreted as the LAB. These reflectors roughly correlate with the location of discontinuities in radial seismic anisotropy but do not correlate with the location of discontinuities ...
... Seismological studies reveal distinct reflectors (G discontinuity) in the uppermost oceanic mantle that are sometimes interpreted as the LAB. These reflectors roughly correlate with the location of discontinuities in radial seismic anisotropy but do not correlate with the location of discontinuities ...
Can slab melting be caused by flat subduction
... produces a cooler thermal structure (i.e., both upper and lower lithospheres are cooler) (Fig. 3D), (Sacks, 1983; Vlaar, 1983; Henry and Pollack, 1988; Dumitru et al., 1991), during the initiation of flat subduction the leading edge of the undersliding slab can be anomalously heated. An analytic sol ...
... produces a cooler thermal structure (i.e., both upper and lower lithospheres are cooler) (Fig. 3D), (Sacks, 1983; Vlaar, 1983; Henry and Pollack, 1988; Dumitru et al., 1991), during the initiation of flat subduction the leading edge of the undersliding slab can be anomalously heated. An analytic sol ...
Formation of plate boundaries: The role of mantle volatilization
... is hydrated/carbonated by a plume is shown in green. Features like mid-ocean ridges (MOR) appear in divergent zones, arising due to weakening by melting (Sleep, 2000). Toroidal motions occur in a diffuse way (upper and lower). (b) Convection with a weak boundary layer and thick basaltic crust (a cro ...
... is hydrated/carbonated by a plume is shown in green. Features like mid-ocean ridges (MOR) appear in divergent zones, arising due to weakening by melting (Sleep, 2000). Toroidal motions occur in a diffuse way (upper and lower). (b) Convection with a weak boundary layer and thick basaltic crust (a cro ...
Annual report 2007
... The development of new research facilities has been another important task during the ‘startup’ phase. We have now established geomicrobiology and biogeochemistry laboratories that will be important for the interdisciplinary research at the centre. The centre has also contributed to the establishmen ...
... The development of new research facilities has been another important task during the ‘startup’ phase. We have now established geomicrobiology and biogeochemistry laboratories that will be important for the interdisciplinary research at the centre. The centre has also contributed to the establishmen ...
Derived From a Flow Model of Subduction
... the strengthof this regionis significantlyweakerthan that number(Gr = 0) indicatesthat buoyancyforcesare negliof the continental lithosphere or of the subducting oceanic gible,whileinfinite Gras_h_of nnrnh•r(_f•-r--* c•_)rep•o•o,,t•a lithosphere. Correspondingly, we define a very weak slip flow that ...
... the strengthof this regionis significantlyweakerthan that number(Gr = 0) indicatesthat buoyancyforcesare negliof the continental lithosphere or of the subducting oceanic gible,whileinfinite Gras_h_of nnrnh•r(_f•-r--* c•_)rep•o•o,,t•a lithosphere. Correspondingly, we define a very weak slip flow that ...
Chapter 51. Biological Communities on Seamounts and Other
... Ridges typically contain seamounts and sedimented slopes; not surprisingly, similarities in the abundance, diversity, and species composition of ridge habitats are found with both seamounts and continental margins (Priede et al., 2013). Priede et al. (2013) also noted that a deep ridge system, such ...
... Ridges typically contain seamounts and sedimented slopes; not surprisingly, similarities in the abundance, diversity, and species composition of ridge habitats are found with both seamounts and continental margins (Priede et al., 2013). Priede et al. (2013) also noted that a deep ridge system, such ...
A free plate surface and weak oceanic crust
... Figure 1. Influence of a free surface and a weak crust. Comparison of temperature and viscosity fields over time between calculations using (a, b) a free slip upper boundary condition (case 1) showing double-sided subduction, (c, d) a free surface condition (using a “sticky air” layer) (case 2) and ...
... Figure 1. Influence of a free surface and a weak crust. Comparison of temperature and viscosity fields over time between calculations using (a, b) a free slip upper boundary condition (case 1) showing double-sided subduction, (c, d) a free surface condition (using a “sticky air” layer) (case 2) and ...
Seismic view on the svalbard passive continental margin
... The oceanic crust is generally similar in terms of thickness along all the profiles studied here but it is composed of more layers in those three southern profiles, where the opening of Northern Atlantic happened earlier. Differences in crustal thickness are the result of different spreading rate in ...
... The oceanic crust is generally similar in terms of thickness along all the profiles studied here but it is composed of more layers in those three southern profiles, where the opening of Northern Atlantic happened earlier. Differences in crustal thickness are the result of different spreading rate in ...
- White Rose Research Online
... The latest major tectonic events in the late Cenozoic geologic evolution of Anatolia are the development of the North Anatolian fault, the East Anatolian fault and the Dead Sea fault. The resulting northward relative differential plate motion between Arabia and Africa has accelerated the convergence ...
... The latest major tectonic events in the late Cenozoic geologic evolution of Anatolia are the development of the North Anatolian fault, the East Anatolian fault and the Dead Sea fault. The resulting northward relative differential plate motion between Arabia and Africa has accelerated the convergence ...
Do fracture zones define continental margin segmentation
... nature of the along-strike transition between these end-member types is poorly known. Similarly, these margins are structurally segmented by rift- and transform-style structures; the latter related to long-lived first- and second-order offsets in the Mid-Atlantic Ridge (MAR) which can be traced to ea ...
... nature of the along-strike transition between these end-member types is poorly known. Similarly, these margins are structurally segmented by rift- and transform-style structures; the latter related to long-lived first- and second-order offsets in the Mid-Atlantic Ridge (MAR) which can be traced to ea ...
Nutrient uptake
... production step of photosynthesis Shown in lab experiment to enhance phytoplankton growth May be crucial in parts of the ocean (eastern equatorial Pacific, parts of Antarctic, north Pacific where nitrogen appears not to be limiting factor ...
... production step of photosynthesis Shown in lab experiment to enhance phytoplankton growth May be crucial in parts of the ocean (eastern equatorial Pacific, parts of Antarctic, north Pacific where nitrogen appears not to be limiting factor ...
Applications of ocean transport modelling Hanna Corell
... Paper I reports a model experiment of how the wind in the southern hemisphere affects the global heat transport, and in particular the heat exchange between the Atlantic and the Indian Ocean. In Paper II the transport patterns of fine sediments in two coastal areas with different oceanographic setti ...
... Paper I reports a model experiment of how the wind in the southern hemisphere affects the global heat transport, and in particular the heat exchange between the Atlantic and the Indian Ocean. In Paper II the transport patterns of fine sediments in two coastal areas with different oceanographic setti ...
Analysis of Equatorial Currents Observed by Eastern Indian Ocean
... (Reppin et al., 1999). The jet also tends to occupy a deeper layer in the east because of an increased upper mixed layer (Fig. 3) induced by strong eastward surface transports (Schott and McCreary, 2001). The jet reached a depth of 80 m in the east but a depth of only 50 m in the west. Another weake ...
... (Reppin et al., 1999). The jet also tends to occupy a deeper layer in the east because of an increased upper mixed layer (Fig. 3) induced by strong eastward surface transports (Schott and McCreary, 2001). The jet reached a depth of 80 m in the east but a depth of only 50 m in the west. Another weake ...
Marine Ecology Progress Series 501:53
... sources, e.g. phytodetritus, terrigenous matter, chemosynthetic matter and wood falls, used by different taxonomic groups. At the continental shelf and upper slopes, phytodetritus from surface phytoplankton production was the main food source for consumers, while reworked POM including both marine a ...
... sources, e.g. phytodetritus, terrigenous matter, chemosynthetic matter and wood falls, used by different taxonomic groups. At the continental shelf and upper slopes, phytodetritus from surface phytoplankton production was the main food source for consumers, while reworked POM including both marine a ...
Tectonic evolution of a continental collision zone
... [7] Subduction of lithosphere requires that the lower plate remains cold enough to preserve its strength and negative buoyancy as it sinks into the mantle. Otherwise the plate may detach, thicken, fold and/or develop an R-T instability. In the sense of plate tectonics, subduction refers to the state ...
... [7] Subduction of lithosphere requires that the lower plate remains cold enough to preserve its strength and negative buoyancy as it sinks into the mantle. Otherwise the plate may detach, thicken, fold and/or develop an R-T instability. In the sense of plate tectonics, subduction refers to the state ...
Evolution of the Atmosphere and Oceans: Evidence from Geological
... concentration is estimated to take 13500 years to precipitate a metre thick layer of gypsum. As the stability of evaporite environments longer than 100,000 years is unlikely, Walker concluded that SO /- ion concentrations of < 10-3 mole/litre could not have given rise to massive evaporite gypsum. In ...
... concentration is estimated to take 13500 years to precipitate a metre thick layer of gypsum. As the stability of evaporite environments longer than 100,000 years is unlikely, Walker concluded that SO /- ion concentrations of < 10-3 mole/litre could not have given rise to massive evaporite gypsum. In ...
9.3 Theory of Plate Tectonics
... the western United States, like the Basin and Range region, is actually a “plate boundary” area and is internally deforming. The San Andreas fault is part of a wide system of faults and deformation many hundreds of kilometers across. In fact, about 15% of Earth’s surface can be considered plate boun ...
... the western United States, like the Basin and Range region, is actually a “plate boundary” area and is internally deforming. The San Andreas fault is part of a wide system of faults and deformation many hundreds of kilometers across. In fact, about 15% of Earth’s surface can be considered plate boun ...
... in either the sinking rate of suspended matter or the depth of the euphotic zone are not responsible for this pattern. The negative relationship between water transparency and chlorophyll concentrations (Carlson 1977) should result in greater losses of particles by sinking from the euphotic zone as ...
Chapter 5 – Sea/Air Interactions
... through the generation of organic matter, is at the basis of most marine food webs in the ocean. Oxygen production by plants is a critical ecosystem service that keeps atmospheric oxygen from otherwise declining. However, in many regions of the ocean, phytoplankton growth is limited by a deficit of ...
... through the generation of organic matter, is at the basis of most marine food webs in the ocean. Oxygen production by plants is a critical ecosystem service that keeps atmospheric oxygen from otherwise declining. However, in many regions of the ocean, phytoplankton growth is limited by a deficit of ...
Cascadia subducting plate fluids channelled to fore
... depth where the temperature reaches 200–400°C, much of this water is released from basalt porosity collapse. At greater depths where the temperature reaches 400–500°C, much of the water in crustal hydrated mineral assemblages should be released. Although the breakdown temperatures and pressures are ...
... depth where the temperature reaches 200–400°C, much of this water is released from basalt porosity collapse. At greater depths where the temperature reaches 400–500°C, much of the water in crustal hydrated mineral assemblages should be released. Although the breakdown temperatures and pressures are ...
tectonics - GeoKniga
... F I G U R E 1 4 . 3 (a) Earthquake P-waves (compressional waves) generated at a focus travel into the Earth. We can represent the path that they follow by the use of “rays.” A “ray” is an arrow drawn perpendicular to the wave front at a point. Note that waves bend or “refract” as they pass downwards ...
... F I G U R E 1 4 . 3 (a) Earthquake P-waves (compressional waves) generated at a focus travel into the Earth. We can represent the path that they follow by the use of “rays.” A “ray” is an arrow drawn perpendicular to the wave front at a point. Note that waves bend or “refract” as they pass downwards ...
The report Oceanographic and biological features in the Canary
... Senegalese upwelling zone. The patterns in the distribution of the warming trends correspond to the dynamical regimes of the region. Using the mean SST distribution as a proxy that characterized the different dynamical regimes in the region, it is observed (Figure 6.1.1a) that near ...
... Senegalese upwelling zone. The patterns in the distribution of the warming trends correspond to the dynamical regimes of the region. Using the mean SST distribution as a proxy that characterized the different dynamical regimes in the region, it is observed (Figure 6.1.1a) that near ...
Exploration Technologies for the Utilization of Ocean Floor Resources
... and nickel are also high and platinum is contained in addition, which makes economical values of cobalt-rich crust very high. In the adjacent waters within 200 nautical miles, manganese crust and hydrothermal ore deposits exist in a large quantity, but these deposits contain less cobalt and platinum ...
... and nickel are also high and platinum is contained in addition, which makes economical values of cobalt-rich crust very high. In the adjacent waters within 200 nautical miles, manganese crust and hydrothermal ore deposits exist in a large quantity, but these deposits contain less cobalt and platinum ...
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.