Moho and magmatic underplating
... to form magma that, after solidification, will have the characteristic low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, whi ...
... to form magma that, after solidification, will have the characteristic low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, whi ...
Moored observations of upper-ocean response to the monsoons in
... precipitation at WHOI during the year totalled less than 50 mm, with 21.4 mm of this falling during the squall of October 22, 1994, which produced the spike in wind stress on that day in Fig. 3. Surface forcing for salinity was thus strongly evaporative. The ocean lost an average 4.2 mm of freshwate ...
... precipitation at WHOI during the year totalled less than 50 mm, with 21.4 mm of this falling during the squall of October 22, 1994, which produced the spike in wind stress on that day in Fig. 3. Surface forcing for salinity was thus strongly evaporative. The ocean lost an average 4.2 mm of freshwate ...
Rudnick and Lee.fm - Cin
... cratons is observed to be cold, thick (up to ~250 km), and chemically buoyant compared to lithosphere of off-craton regions (Boyd, 1989; Jordan, 1975; Jordan, 1988) and may have played a role in the stabilization of these cratons. Thus, understanding the formation and evolution of the continents req ...
... cratons is observed to be cold, thick (up to ~250 km), and chemically buoyant compared to lithosphere of off-craton regions (Boyd, 1989; Jordan, 1975; Jordan, 1988) and may have played a role in the stabilization of these cratons. Thus, understanding the formation and evolution of the continents req ...
Flat versus steep subduction: Contrasting modes for the formation
... subduction to collision. Slab inclination conditions for these two stages can be strongly dissimilar, which is taken into account by our models in a simplified manner: the initial slab dip angle corresponds to the early subduction stage and the final slab inclination characterizes the later collision ...
... subduction to collision. Slab inclination conditions for these two stages can be strongly dissimilar, which is taken into account by our models in a simplified manner: the initial slab dip angle corresponds to the early subduction stage and the final slab inclination characterizes the later collision ...
Earth Science Ch. 4 Practice Test
... by determining the age of rock samples obtained by drilling on the sea floor d. by measuring how fast sea-floor spreading occurs ____ 22. What did scientists in a submersible see when they observed the mid-ocean ridge? a. a colliding boundary b. rocks formed by the rapid hardening of molten material ...
... by determining the age of rock samples obtained by drilling on the sea floor d. by measuring how fast sea-floor spreading occurs ____ 22. What did scientists in a submersible see when they observed the mid-ocean ridge? a. a colliding boundary b. rocks formed by the rapid hardening of molten material ...
Sect. 7-3 and 7-4 Practice Quiz
... ____ 17. What can tectonic plates form when they converge? a. mid-ocean ridges c. sea floor b. mountains d. asthenosphere ____ 18. The southern portion of Pangaea that broke apart about 180 million years ago is known as a. Pangaea. c. Gondwana. b. Panthalassa. d. Laurasia. ____ 19. Continental-ocean ...
... ____ 17. What can tectonic plates form when they converge? a. mid-ocean ridges c. sea floor b. mountains d. asthenosphere ____ 18. The southern portion of Pangaea that broke apart about 180 million years ago is known as a. Pangaea. c. Gondwana. b. Panthalassa. d. Laurasia. ____ 19. Continental-ocean ...
Sedimentation of organic and inorganic
... planktonic organisms living below this zone. The sinking of particles is also of interest for chemical and geochemical processes in the water column as well as in the sediment. Small, land-locked fjords ('polls') are very common along the west coast of Norway. Despite extensive investigations of 'po ...
... planktonic organisms living below this zone. The sinking of particles is also of interest for chemical and geochemical processes in the water column as well as in the sediment. Small, land-locked fjords ('polls') are very common along the west coast of Norway. Despite extensive investigations of 'po ...
Copepod carcasses in the ocean. I. Over seamounts
... loss of appendages typical of net damage; and (3) time from capture to preservation was insufficient to explain the extent of decay observed (Wheeler 1967, Harding 1973).This latter fact also suggests feeding in the cod end was not an important source of carcasses. In addition, Genin et al. (1995) g ...
... loss of appendages typical of net damage; and (3) time from capture to preservation was insufficient to explain the extent of decay observed (Wheeler 1967, Harding 1973).This latter fact also suggests feeding in the cod end was not an important source of carcasses. In addition, Genin et al. (1995) g ...
The Biology, Ecology and Vulnerability of Deep
... Influence on biodiversity Deep -water coral reefs like shallow water tropical reefs consist of a complex three -dimensional coral framework with many sub-habitats that can be occupied by other animals. These sub -habitats include the living coral itself, the spaces between the coral branches, expos ...
... Influence on biodiversity Deep -water coral reefs like shallow water tropical reefs consist of a complex three -dimensional coral framework with many sub-habitats that can be occupied by other animals. These sub -habitats include the living coral itself, the spaces between the coral branches, expos ...
Urea decomposition by bacteria in the Southern California Bight and
... sinking N flux (PON plus DON) follows the pathway: sinking-N + urea + ammonium. This also raises the question of the mechanisms and organisms responsible for large-scale urea production in the mesopelagic zone. Bacteria may play a role in urea production as well because they are known to account for ...
... sinking N flux (PON plus DON) follows the pathway: sinking-N + urea + ammonium. This also raises the question of the mechanisms and organisms responsible for large-scale urea production in the mesopelagic zone. Bacteria may play a role in urea production as well because they are known to account for ...
Professional Fax Cover Sheet - Panda
... the level of exploitation that these fish populations (stocks) can sustain is lacking in many cases. Deep-water fisheries are often characterized as ‘serial’ or ‘sequential’ depletion fisheries because fishing vessels find and deplete a stock, then move on and repeat the practice. Little is known ab ...
... the level of exploitation that these fish populations (stocks) can sustain is lacking in many cases. Deep-water fisheries are often characterized as ‘serial’ or ‘sequential’ depletion fisheries because fishing vessels find and deplete a stock, then move on and repeat the practice. Little is known ab ...
Thermal and petrophysical characterization of the lithospheric
... heat flow and crustal seismic data show LAB depth varying from more than 130 km beneath the Pyrenees to less than 70 km beneath the western Mediterranean basins (Zeyen and Fernandez, 1994; Ayala et al., 1996, 2003; Roca et al., 2004). All these models however are based on a pure thermal approach in w ...
... heat flow and crustal seismic data show LAB depth varying from more than 130 km beneath the Pyrenees to less than 70 km beneath the western Mediterranean basins (Zeyen and Fernandez, 1994; Ayala et al., 1996, 2003; Roca et al., 2004). All these models however are based on a pure thermal approach in w ...
Processes determining the marine alkalinity and calcium carbonate
... (Fig. 2c). Also, Alk∗ reaches its highest surface concentration in the Arctic (Figs. 2c and 3d) where phosphate is not greatly elevated (Figs. 2d and 4d). These surface differences are due to regional riverine Alk∗ inputs (Sect. 3.3). Another difference is that Alk∗ reaches a maximum below 2000 m in ...
... (Fig. 2c). Also, Alk∗ reaches its highest surface concentration in the Arctic (Figs. 2c and 3d) where phosphate is not greatly elevated (Figs. 2d and 4d). These surface differences are due to regional riverine Alk∗ inputs (Sect. 3.3). Another difference is that Alk∗ reaches a maximum below 2000 m in ...
Shape and origin of the East-Alpine slab constrained by the
... During the last two decades teleseismic studies yielded valuable information on the structure of the upper mantle below the Alpine–Mediterranean area. Subducted oceanic lithosphere forms a broad anomaly resting on but not penetrating the 670 km discontinuity. More shallow slabs imaged below the Alpi ...
... During the last two decades teleseismic studies yielded valuable information on the structure of the upper mantle below the Alpine–Mediterranean area. Subducted oceanic lithosphere forms a broad anomaly resting on but not penetrating the 670 km discontinuity. More shallow slabs imaged below the Alpi ...
Radiozoa (Acantharia, Phaeodaria and Radiolaria) and Heliozoa
... at 3000–4000 m depth and can contain as many as 100,000 skeletons per gram of sediment, but they may also occur abundantly in marine diatomaceous oozes or in Globigerina and coccolith oozes. With increasing depth and dissolution, the abundance of Radiolaria in deep sea sediments decreases, through a ...
... at 3000–4000 m depth and can contain as many as 100,000 skeletons per gram of sediment, but they may also occur abundantly in marine diatomaceous oozes or in Globigerina and coccolith oozes. With increasing depth and dissolution, the abundance of Radiolaria in deep sea sediments decreases, through a ...
A trace element perspective on the source of ocean island basalts
... Figure 3 Panels a-c on the left are based on the 115 island-averaged data given in Table 2 of Humphreys and Niu (2009). The thick arrowed lines are regression lines and point in the direction of increasing pressure and decreasing extent of melting with increasing lithosphere thickness (Humphreys and ...
... Figure 3 Panels a-c on the left are based on the 115 island-averaged data given in Table 2 of Humphreys and Niu (2009). The thick arrowed lines are regression lines and point in the direction of increasing pressure and decreasing extent of melting with increasing lithosphere thickness (Humphreys and ...
The American Cordillera: Part III, The North American Taphrogen
... suggested by Humphreys (1995). An important difference between the Med and the WUS is that in the latter, rollback occurred beneath an overthickened crust. The extension direction of the core complexes is nearly orthogonal to the rollback direction, suggesting it was probably controlled primarily by ...
... suggested by Humphreys (1995). An important difference between the Med and the WUS is that in the latter, rollback occurred beneath an overthickened crust. The extension direction of the core complexes is nearly orthogonal to the rollback direction, suggesting it was probably controlled primarily by ...
Crustal thickness of V-shaped ridges south of the Azores: -39
... segments are associated with centered axial highs and mantle Bouguer gravity lows, indicating focused magmatic accretion [Lin et al., 1990] and representing crustal thickness variations of ~2 km in amplitude [Detrick et al., 1995]. Despite the proximity to the hostspot, the outcrop of peridotites at ...
... segments are associated with centered axial highs and mantle Bouguer gravity lows, indicating focused magmatic accretion [Lin et al., 1990] and representing crustal thickness variations of ~2 km in amplitude [Detrick et al., 1995]. Despite the proximity to the hostspot, the outcrop of peridotites at ...
- Wiley Online Library
... column depths, as well as nitrate, phosphate, and chlorophyll concentrations. Missing temperature, nitrate, or phosphate data were estimated from the World Ocean Atlas [Boyer et al., 2006]. The water column depth was estimated based on the ETOPO2v2 bathymetry (National Geophysical Data Center, 2006) ...
... column depths, as well as nitrate, phosphate, and chlorophyll concentrations. Missing temperature, nitrate, or phosphate data were estimated from the World Ocean Atlas [Boyer et al., 2006]. The water column depth was estimated based on the ETOPO2v2 bathymetry (National Geophysical Data Center, 2006) ...
AusMoho: the variation of Moho depth in Australia
... provide a dramatic increase in data coverage compared with previous studies, and reveal the complex structure of the Australian continent in considerable detail. A new comprehensive model for Moho depth across Australia and its immediate environment is developed by utilizing multiple sources of info ...
... provide a dramatic increase in data coverage compared with previous studies, and reveal the complex structure of the Australian continent in considerable detail. A new comprehensive model for Moho depth across Australia and its immediate environment is developed by utilizing multiple sources of info ...
Whales as Detritus in Marine Ecosystems
... a fresh whale fall sustains, in a single pulse, the equivalent of about 2000 yr of background POC ...
... a fresh whale fall sustains, in a single pulse, the equivalent of about 2000 yr of background POC ...
Alignment between seafloor spreading directions and absolute plate
... (MOR) processes, absolute plate motions, and mantle flow. Global anisotropic seismic tomography models show correlations between SSV fast axes and both fossil spreading fabric and present-day absolute plate motion (APM), the latter more apparent at greater depths and near MORs [Becker et al., 2014; B ...
... (MOR) processes, absolute plate motions, and mantle flow. Global anisotropic seismic tomography models show correlations between SSV fast axes and both fossil spreading fabric and present-day absolute plate motion (APM), the latter more apparent at greater depths and near MORs [Becker et al., 2014; B ...
Thermal, Density, Seismological, and Rheological Structure of the
... This thesis presents a first-of-its-kind combined geophysical-petrological methodology to study the thermal, compositional, density, rheological, and seismological structure of different lithospheric domains. The methodology is incorporated in a finite-element code (LitMod) that solves simultaneousl ...
... This thesis presents a first-of-its-kind combined geophysical-petrological methodology to study the thermal, compositional, density, rheological, and seismological structure of different lithospheric domains. The methodology is incorporated in a finite-element code (LitMod) that solves simultaneousl ...
Subduction tectonic erosion and Late Cretaceous subsidence along
... During the late Aptian-Cenomanian interval, detrital chrome spinel in sediments of both the Austroalpine NCA south and the South Penninic units north of the wedge proofs the emergence and erosion of slices of oceanic crust (Pober and Faupl, 1988) within the accretionary wedge due to continued underp ...
... During the late Aptian-Cenomanian interval, detrital chrome spinel in sediments of both the Austroalpine NCA south and the South Penninic units north of the wedge proofs the emergence and erosion of slices of oceanic crust (Pober and Faupl, 1988) within the accretionary wedge due to continued underp ...
Determining Thorpe Scales from Ship
... and easy to resolve on the scales of tens of centimeters and larger at which significant overturns occur [Stansfield et al. (2001) showed that although small Thorpe displacements are more probable than large ones, it is the latter, more easily measurable ones, that dominate LT]. Although T profiles ...
... and easy to resolve on the scales of tens of centimeters and larger at which significant overturns occur [Stansfield et al. (2001) showed that although small Thorpe displacements are more probable than large ones, it is the latter, more easily measurable ones, that dominate LT]. Although T profiles ...
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.