A cool model for the Iceland hot spot
... flow, although a weak indicator of mantle temperature, shows no anomaly west of the Reykjanes ridge but a small positive anomaly on the European plate to the east (Stein and Stein, 2003; DeLaughter et al., 2004). This is the opposite of what is predicted for an eastward-migrating plume. ...
... flow, although a weak indicator of mantle temperature, shows no anomaly west of the Reykjanes ridge but a small positive anomaly on the European plate to the east (Stein and Stein, 2003; DeLaughter et al., 2004). This is the opposite of what is predicted for an eastward-migrating plume. ...
Seafloor weathering controls on atmospheric C02 and global climate
... thermodynamic data are not available to assess the solubility of basaltic glass in aqueous solutions. However, it is clear that such glass will have a higher solubility than any of the minerals as the glass has retained more energy (heat of crystallization) from its parent magmatic environment than ...
... thermodynamic data are not available to assess the solubility of basaltic glass in aqueous solutions. However, it is clear that such glass will have a higher solubility than any of the minerals as the glass has retained more energy (heat of crystallization) from its parent magmatic environment than ...
Lecture 40 - Cornell geology
... and oceanic crust. Boron is readily incorporated into the alteration products of basalt, so that even slightly altered basalts show a dramatic increase in B concentration and an increase in δ11B, with altered oceanic crust having δ11B in the range of 0 to +25‰. Smith et al. (1995) estimated that ave ...
... and oceanic crust. Boron is readily incorporated into the alteration products of basalt, so that even slightly altered basalts show a dramatic increase in B concentration and an increase in δ11B, with altered oceanic crust having δ11B in the range of 0 to +25‰. Smith et al. (1995) estimated that ave ...
7. plate tectonic evolution of the cocos
... Coiba Ridge south of Panama has been suggested to have been formed not as a hotspot trace but rather by uplift beside a long meridional transform fault during the late Miocene and Pliocene (Lonsdale and Klitgord, 1978). Its origin, however, remains unclear because of the lack of data. The Carnegie R ...
... Coiba Ridge south of Panama has been suggested to have been formed not as a hotspot trace but rather by uplift beside a long meridional transform fault during the late Miocene and Pliocene (Lonsdale and Klitgord, 1978). Its origin, however, remains unclear because of the lack of data. The Carnegie R ...
GEF4400 “The Earth System”
... • 50 times more carbon than in the atmosphere, presently absorbing about 30% of human emissions of carbon dioxide (CO2); • ocean changes may result in climate feedbacks that either increase or reduce the rate of climate change; ...
... • 50 times more carbon than in the atmosphere, presently absorbing about 30% of human emissions of carbon dioxide (CO2); • ocean changes may result in climate feedbacks that either increase or reduce the rate of climate change; ...
Driving the upper plate surface deformation by slab
... reproduction of first-order Tethyan tectonic structures such as back-arc rifting and large-scale strike-slip faults accommodating continental escape. These models suggest that mantle flow due to slab rollback and tearing can modulate the surface strain and kinematics by locally enhancing trench retrea ...
... reproduction of first-order Tethyan tectonic structures such as back-arc rifting and large-scale strike-slip faults accommodating continental escape. These models suggest that mantle flow due to slab rollback and tearing can modulate the surface strain and kinematics by locally enhancing trench retrea ...
Geology
... Subduction of the lithosphere at convergent-plate boundaries takes place asymmetrically— the subducted slab sinks downward, while the overriding plate moves horizontally (one-sided subduction). In contrast, global mantle convection models generally predict downwelling of both plates at convergent ma ...
... Subduction of the lithosphere at convergent-plate boundaries takes place asymmetrically— the subducted slab sinks downward, while the overriding plate moves horizontally (one-sided subduction). In contrast, global mantle convection models generally predict downwelling of both plates at convergent ma ...
Plate Tectonics - The Web site cannot be found
... Plate tectonics is an expression of the Earth’s long term loss of internal heat. In a first approximation the Earth comprises two different liquids, the core with a diameter of ca. 3200 km and the mantle with a thickness of ca. 2900 km which surrounds the core. Since the temperature outside the Eart ...
... Plate tectonics is an expression of the Earth’s long term loss of internal heat. In a first approximation the Earth comprises two different liquids, the core with a diameter of ca. 3200 km and the mantle with a thickness of ca. 2900 km which surrounds the core. Since the temperature outside the Eart ...
Nature template - PC Word 97 - University of Colorado Boulder
... hydrous wadsleyite we use 162 GPa (~1 wt% H2O) and 155 GPa (~2.5 wt% H2O) from Holl et al. [2003] and Yusa and Inoue [1997]. For ringwoodite, values are 175 GPa (~1 wt% H2O) and 165 GPa (~2.8 wt% H2O) from the studies of Manghnani et al. [2005] and Wang et al. [2003]. The data indicate similar elast ...
... hydrous wadsleyite we use 162 GPa (~1 wt% H2O) and 155 GPa (~2.5 wt% H2O) from Holl et al. [2003] and Yusa and Inoue [1997]. For ringwoodite, values are 175 GPa (~1 wt% H2O) and 165 GPa (~2.8 wt% H2O) from the studies of Manghnani et al. [2005] and Wang et al. [2003]. The data indicate similar elast ...
G. Heinson, Electromagnetic studies of the lithosphere and
... the seismic attenuation factor Q (Lay and Wallace, 1995) suggest that shear-wave velocity heterogeneity can exist down to 350 km, while the compressional-waves heterogeneity is confined to the upper 250 km. It is more difficult to determine continental lithosphere thicknesses from heat flow measurem ...
... the seismic attenuation factor Q (Lay and Wallace, 1995) suggest that shear-wave velocity heterogeneity can exist down to 350 km, while the compressional-waves heterogeneity is confined to the upper 250 km. It is more difficult to determine continental lithosphere thicknesses from heat flow measurem ...
Field Relationships and Kinematic Indicators in the Virgin River
... Two conjugate brittle fault sets are recognized in the area: 1) oriented at 040° to 080° with near vertical dips, they show normal dextral offset and are commonly associated with fault breccia and drag folds; and 2) faults oriented at approximately 340" to 360° exhibit normal sinistral offset. These ...
... Two conjugate brittle fault sets are recognized in the area: 1) oriented at 040° to 080° with near vertical dips, they show normal dextral offset and are commonly associated with fault breccia and drag folds; and 2) faults oriented at approximately 340" to 360° exhibit normal sinistral offset. These ...
Origin and time evolution of subduction polarity reversal from plate
... from the late interaction of the Ryukyu subduction zone with the prestructured passive Eurasian margin rather than from a decreasing degree of maturity from north to south. The Ryukyu subduction zone does not play a major role during the orogeny (Clift et al., 2003). In contrast, it is the Mesozoic ...
... from the late interaction of the Ryukyu subduction zone with the prestructured passive Eurasian margin rather than from a decreasing degree of maturity from north to south. The Ryukyu subduction zone does not play a major role during the orogeny (Clift et al., 2003). In contrast, it is the Mesozoic ...
PDF
... continuing plate convergence following jamming of a subduction zone by buoyant crust. This results in regional compression, uplift and underthrusting that may yield a new subduction zone. Two subclasses of INSZ, transference and polarity reversal, are distinguished. Transference INSZ moves the new s ...
... continuing plate convergence following jamming of a subduction zone by buoyant crust. This results in regional compression, uplift and underthrusting that may yield a new subduction zone. Two subclasses of INSZ, transference and polarity reversal, are distinguished. Transference INSZ moves the new s ...
Origin of the Earth`s Crust and its Evolution
... foundation of cratonic area or the originally cratonic area like platform or paraplatform were built through repeated orogenic movements of the Archean and the older Proterozoic prior to Sinian or Riphean time. Actually the granitic crust of the older Precambrian age in the cratonic and subcratonic ...
... foundation of cratonic area or the originally cratonic area like platform or paraplatform were built through repeated orogenic movements of the Archean and the older Proterozoic prior to Sinian or Riphean time. Actually the granitic crust of the older Precambrian age in the cratonic and subcratonic ...
Large-scale fluctuations in Precambrian atmospheric and oceanic
... Precambrian. Since the redox state of the Earth's oceans and atmosphere are linked, anoxia is generally thought to have been more prevalent in Proterozoic oceans under low atmospheric oxygen levels (Wilde, 1987; Canfield, 1998). Therefore, the redox state of the oceans in the past provides insight in ...
... Precambrian. Since the redox state of the Earth's oceans and atmosphere are linked, anoxia is generally thought to have been more prevalent in Proterozoic oceans under low atmospheric oxygen levels (Wilde, 1987; Canfield, 1998). Therefore, the redox state of the oceans in the past provides insight in ...
Hydrography shapes bacterial biogeography of the deep
... It has been long debated as to whether marine microorganisms have a ubiquitous distribution or patterns of biogeography, but recently a consensus for the existence of microbial biogeography is emerging. However, the factors controlling the distribution of marine bacteria remain poorly understood. In ...
... It has been long debated as to whether marine microorganisms have a ubiquitous distribution or patterns of biogeography, but recently a consensus for the existence of microbial biogeography is emerging. However, the factors controlling the distribution of marine bacteria remain poorly understood. In ...
Evidence and implications for a widespread magmatic shutdown for
... and Nelson, 1998; Eriksson et al., 1999; Barley et al., 2005). In typical cases where mid-crustal metamorphic rocks are exposed beneath such unconformities, it is evident that 10–15 km of crust was removed by erosion before deposition of the overlying sediments. A possible reason we do not see exten ...
... and Nelson, 1998; Eriksson et al., 1999; Barley et al., 2005). In typical cases where mid-crustal metamorphic rocks are exposed beneath such unconformities, it is evident that 10–15 km of crust was removed by erosion before deposition of the overlying sediments. A possible reason we do not see exten ...
How Accurately Can We Predict Optical Clarity in the Littorals?
... with depth; orange and green indicate a substantial increase with depth. In both cases the increase often is seen as an abrupt stepindicate a relatively minor increase of c532 with depth, like change at various depths ranging from less than 20 to 55 m. and orange and green indicate a substantial inc ...
... with depth; orange and green indicate a substantial increase with depth. In both cases the increase often is seen as an abrupt stepindicate a relatively minor increase of c532 with depth, like change at various depths ranging from less than 20 to 55 m. and orange and green indicate a substantial inc ...
Limitation of egg production in Calanus finmarchicus in the field: A
... these sites. We hypothesis that marine zooplankton, their faecal material, and other sedimenting particles, represent these anaerobic microsites in oxygenated pelagic waters. We have now clearly identified methanogens within marine zooplankton faecal pellets and sedimenting particles. This, along wi ...
... these sites. We hypothesis that marine zooplankton, their faecal material, and other sedimenting particles, represent these anaerobic microsites in oxygenated pelagic waters. We have now clearly identified methanogens within marine zooplankton faecal pellets and sedimenting particles. This, along wi ...
Geological understanding of plate tectonics
... Fig. 4. a. The ocean-lithosphere-asthenosphere system illustrating “mean” density differences due to thermal or compositional differences, indicating the thick oceanic plateau lithosphere (OPL) to be less dense than the normal oceanic lithosphere (NOL). b. Two groups (A and B) of conjugate faults de ...
... Fig. 4. a. The ocean-lithosphere-asthenosphere system illustrating “mean” density differences due to thermal or compositional differences, indicating the thick oceanic plateau lithosphere (OPL) to be less dense than the normal oceanic lithosphere (NOL). b. Two groups (A and B) of conjugate faults de ...
A Dynamic Model of Rifting Between Galicia Bank and Flemish Cap
... Regardless of the complexities of late rift-stage and early spreading phase melt production, there is broad consensus that for most of the rift history the margins were amagmatic, or at least involved very little melt production. Volcanism that occurred prior to the onset of seafloor spreading appea ...
... Regardless of the complexities of late rift-stage and early spreading phase melt production, there is broad consensus that for most of the rift history the margins were amagmatic, or at least involved very little melt production. Volcanism that occurred prior to the onset of seafloor spreading appea ...
Lithospheric thickness under the Dinarides
... the "slab gap" beneath the Dinarides (taken from Handy et al. 2014). ...
... the "slab gap" beneath the Dinarides (taken from Handy et al. 2014). ...
On the influence of the asthenospheric flow on the tectonics and
... collision-subduction system characterized by along-strike differential slab kinematics constrained by the wealth of observations from southeast Asia through self-consistent high-resolution 3D numerical thermo-mechanical modelling. We use the numerical model I3ELVIS to solve the 3D momentum, continui ...
... collision-subduction system characterized by along-strike differential slab kinematics constrained by the wealth of observations from southeast Asia through self-consistent high-resolution 3D numerical thermo-mechanical modelling. We use the numerical model I3ELVIS to solve the 3D momentum, continui ...
© Terra Antartica Publication
... Oceanic Crust The sector between the eastern end of Princess Elizabeth Trough and the western flank of Bruce Rise encompasses much of the area that was referred to as the ‘southern Labuan Basin’ by Borissova et al. (2002). The name ‘Shackleton Basin’ (in the geological sense of a basin) was introduc ...
... Oceanic Crust The sector between the eastern end of Princess Elizabeth Trough and the western flank of Bruce Rise encompasses much of the area that was referred to as the ‘southern Labuan Basin’ by Borissova et al. (2002). The name ‘Shackleton Basin’ (in the geological sense of a basin) was introduc ...
IBDIOCC - Scientific Committee on Oceanic Research
... This proposal is timely owing to the increasing interest of “Oceans in the High Carbon World.” The proposed work is truly global in scale encompassing Exclusive Economic Zones (EEZs), Extended Continental Shelves and the High Seas (Areas Beyond National Jurisdiction) in all world oceans. There are a ...
... This proposal is timely owing to the increasing interest of “Oceans in the High Carbon World.” The proposed work is truly global in scale encompassing Exclusive Economic Zones (EEZs), Extended Continental Shelves and the High Seas (Areas Beyond National Jurisdiction) in all world oceans. There are a ...
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.