Plate-Tectonics A review
... drifted apart to form the present arrangement of continents • He had no satisfactory mechanism to offer, but appealed to a less-dense continent “floating” and “drifting” over a more dense oceanic crust (Like icebergs in the ocean). Most Scientists were highly skeptical and the idea was NOT ...
... drifted apart to form the present arrangement of continents • He had no satisfactory mechanism to offer, but appealed to a less-dense continent “floating” and “drifting” over a more dense oceanic crust (Like icebergs in the ocean). Most Scientists were highly skeptical and the idea was NOT ...
Identify the Organelle
... Crust ↔ Mantle: The crust has a lower temperature than the mantle Crust ↔ Core: The crust has a lower temperature than the core Mantle ↔ Core: The mantle has a lower temperature than the core Inner Core ↔ Outer Core: The inner core has a higher temperature than the outer core Comparing Compo ...
... Crust ↔ Mantle: The crust has a lower temperature than the mantle Crust ↔ Core: The crust has a lower temperature than the core Mantle ↔ Core: The mantle has a lower temperature than the core Inner Core ↔ Outer Core: The inner core has a higher temperature than the outer core Comparing Compo ...
(PDF)
... marine particulate matter, is formed in surface waters throughout the ocean. Previous studies have shown that PNU is regenerated completely prior to burial of particles in sediments within well-oxygenated open-ocean regions. However, the fate of PNU has never been examined in ocean margin regions or ...
... marine particulate matter, is formed in surface waters throughout the ocean. Previous studies have shown that PNU is regenerated completely prior to burial of particles in sediments within well-oxygenated open-ocean regions. However, the fate of PNU has never been examined in ocean margin regions or ...
Theme Session T: Acoustic Seabed Classification – Applications in
... modify the propagation and scattering of sound. Shallow water littoral environments are often sufficiently well lit by sunlight to support diverse populations of benthic and epibenthic marine microalgae. Photosynthesis in marine algae produces oxygen. Oxygen saturation levels as high as 600% have be ...
... modify the propagation and scattering of sound. Shallow water littoral environments are often sufficiently well lit by sunlight to support diverse populations of benthic and epibenthic marine microalgae. Photosynthesis in marine algae produces oxygen. Oxygen saturation levels as high as 600% have be ...
Tectonic controls on the nature of large silicic calderas in volcanic arcs
... preserved as plutons and batholiths, understanding the factors that control their abundance and composition will aid in interpreting the tectonic settings of ancient arcs. In addition, this study quantifies the occurrence of silicic caldera formation during normal arc volcanism, and thereby provides ...
... preserved as plutons and batholiths, understanding the factors that control their abundance and composition will aid in interpreting the tectonic settings of ancient arcs. In addition, this study quantifies the occurrence of silicic caldera formation during normal arc volcanism, and thereby provides ...
Asthenospheric flow and origin of volcanism in the Baikal Rift area
... flow in the mantle beneath the Baikal Rift Zone and argue that it is sub-horizontal asthenospheric flow that may give rise to volcanism in this and perhaps many other rift areas. The Baikal Rift Zone is located at the boundary of the stable Siberian Platform and deforming Baikal-Sayan fold belt (Fig ...
... flow in the mantle beneath the Baikal Rift Zone and argue that it is sub-horizontal asthenospheric flow that may give rise to volcanism in this and perhaps many other rift areas. The Baikal Rift Zone is located at the boundary of the stable Siberian Platform and deforming Baikal-Sayan fold belt (Fig ...
TTGs and adakites: are they both slab melts?
... derived from the hot descending plate. These adakitic magmas share many geochemical features with the type adakites from Adak Island in the Aleutians, such as similar incompatible element distributions and similar high Sr contents (Figs. 1 and 2). Another feature of the Andean adakites is relatively ...
... derived from the hot descending plate. These adakitic magmas share many geochemical features with the type adakites from Adak Island in the Aleutians, such as similar incompatible element distributions and similar high Sr contents (Figs. 1 and 2). Another feature of the Andean adakites is relatively ...
Continental Margin Deformation along the Andean Subduction zone
... In addition, the precise nature of Benioff zones at depths greater than 50 km depth remains unclear, as well as their relation to subducted oceanic crust. Whether there still is a subduction channel (see for example recent seismic imaging by Rondenay et al., 2008), or whether it has been completel ...
... In addition, the precise nature of Benioff zones at depths greater than 50 km depth remains unclear, as well as their relation to subducted oceanic crust. Whether there still is a subduction channel (see for example recent seismic imaging by Rondenay et al., 2008), or whether it has been completel ...
Late Cretaceous and Paleogene tectonic evolution of
... plate motions from fracture zone trends and Late Cretaceous seafloor spreading magnetic anomalies allows formulation of a reasonable sequence of events that accounts for all the geologic features of that region, especially the Emperor and Chinook troughs. The primary event in our reconstruction is t ...
... plate motions from fracture zone trends and Late Cretaceous seafloor spreading magnetic anomalies allows formulation of a reasonable sequence of events that accounts for all the geologic features of that region, especially the Emperor and Chinook troughs. The primary event in our reconstruction is t ...
Evolution of the Earth as an andesite planet: water
... The presence of a high-temperature metallic core, common to all terrestrial planets (Fig. 1) (Aitta, 2012; Smith et al., 2012; Stevenson, 2001), causes convection in the mantle with a high Rayleigh number. Since mantle viscosity strongly depends on temperature (e.g., Karato and Wu, 1993), the top th ...
... The presence of a high-temperature metallic core, common to all terrestrial planets (Fig. 1) (Aitta, 2012; Smith et al., 2012; Stevenson, 2001), causes convection in the mantle with a high Rayleigh number. Since mantle viscosity strongly depends on temperature (e.g., Karato and Wu, 1993), the top th ...
Physics of the Earth and Planetary Interiors Bulldozing the core
... As shown in Fig. 3, the amplitude ratios for the weak/no precursor group remain very low through all the distance range of 130–138◦ , while those of the strong precursor group are significantly higher. In general, scatterers located at both the source and receiver sides can produce PKIKP precursors ( ...
... As shown in Fig. 3, the amplitude ratios for the weak/no precursor group remain very low through all the distance range of 130–138◦ , while those of the strong precursor group are significantly higher. In general, scatterers located at both the source and receiver sides can produce PKIKP precursors ( ...
The status of natural resources on the high-seas
... a) the vast majority of harmful human impacts occur in shallow water, and b) the inshore environment is visible to, and understood by, the ‘public’. In contrast, deep-sea and open ocean environments are out of sight, poorly known and there is little perceived threat to these areas. It is only in rec ...
... a) the vast majority of harmful human impacts occur in shallow water, and b) the inshore environment is visible to, and understood by, the ‘public’. In contrast, deep-sea and open ocean environments are out of sight, poorly known and there is little perceived threat to these areas. It is only in rec ...
A numerical investigation of continental collision styles
... < 650 ◦ C) or a slower driving velocity (<5 cm yr−1 ), which allows the lithosphere to warm up by heat conduction. RT-type of instabilities occur only in hot systems (TMoho > 800 ◦ C), in which high temperatures reduce the effective viscosity of the continental lithosphere, but the lithosphere still ...
... < 650 ◦ C) or a slower driving velocity (<5 cm yr−1 ), which allows the lithosphere to warm up by heat conduction. RT-type of instabilities occur only in hot systems (TMoho > 800 ◦ C), in which high temperatures reduce the effective viscosity of the continental lithosphere, but the lithosphere still ...
Topography and geoid due to lithospheric mass anomalies
... important observations. First, the oceanic floor everywhere follows the same topography versus age relationship, indicating that the long-wavelength topography of deep origin over the ocean basins has a small amplitude. If the flattening of the sea-floor topography at age larger than 100 Ma is assoc ...
... important observations. First, the oceanic floor everywhere follows the same topography versus age relationship, indicating that the long-wavelength topography of deep origin over the ocean basins has a small amplitude. If the flattening of the sea-floor topography at age larger than 100 Ma is assoc ...
Evolution of the Earth as an andesite planet: water, plate tectonics
... The presence of a high-temperature metallic core, common to all terrestrial planets (Fig. 1) (Aitta, 2012; Smith et al., 2012; Stevenson, 2001), causes convection in the mantle with a high Rayleigh number. Since mantle viscosity strongly depends on temperature (e.g., Karato and Wu, 1993), the top th ...
... The presence of a high-temperature metallic core, common to all terrestrial planets (Fig. 1) (Aitta, 2012; Smith et al., 2012; Stevenson, 2001), causes convection in the mantle with a high Rayleigh number. Since mantle viscosity strongly depends on temperature (e.g., Karato and Wu, 1993), the top th ...
Clay Mineral Distribution in Surface Sediments of the
... 1992) leads to mechanical crushing, but causes less degradation of phyllosilicates than observed elsewhere. Glacially affected clay mineral ...
... 1992) leads to mechanical crushing, but causes less degradation of phyllosilicates than observed elsewhere. Glacially affected clay mineral ...
illuminating earth`s
... impacts of such events on individual microorganisms to whole ecosystems, including hominid evolution. Earth Connections examines the links between surface, lithospheric, and deep Earth processes. Enhanced drilling capabilities are essential for extending the vertical dimension of subseafloor studies ...
... impacts of such events on individual microorganisms to whole ecosystems, including hominid evolution. Earth Connections examines the links between surface, lithospheric, and deep Earth processes. Enhanced drilling capabilities are essential for extending the vertical dimension of subseafloor studies ...
Illuminating Earth`s Past, Present and Future
... impacts of such events on individual microorganisms to whole ecosystems, including hominid evolution. Earth Connections examines the links between surface, lithospheric, and deep Earth processes. Enhanced drilling capabilities are essential for extending the vertical dimension of subseafloor studies ...
... impacts of such events on individual microorganisms to whole ecosystems, including hominid evolution. Earth Connections examines the links between surface, lithospheric, and deep Earth processes. Enhanced drilling capabilities are essential for extending the vertical dimension of subseafloor studies ...
Pyrenean orogeny and plate kinematics
... existed, they have possibly subducted now under Iberia. [8 ] The consequences of our new identification of chron M0 in the Bay of Biscay are significant. Seafloor spreading may have started in the Bay of Biscay as early as anomaly M3 (124 Ma, lower Barremian). The presence of transitional crust betw ...
... existed, they have possibly subducted now under Iberia. [8 ] The consequences of our new identification of chron M0 in the Bay of Biscay are significant. Seafloor spreading may have started in the Bay of Biscay as early as anomaly M3 (124 Ma, lower Barremian). The presence of transitional crust betw ...
1. LEG 209 SUMMARY: PROCESSES IN A 20-KM
... (2004) for a more thorough treatment of the overall results of Leg 209. Understanding the creation of oceanic plates at spreading ridges provides the simplest template for understanding creation and evolution of Earth’s crust and shallow mantle in all tectonic settings. Some aspects of ridge process ...
... (2004) for a more thorough treatment of the overall results of Leg 209. Understanding the creation of oceanic plates at spreading ridges provides the simplest template for understanding creation and evolution of Earth’s crust and shallow mantle in all tectonic settings. Some aspects of ridge process ...
GEOPHYSICAL CHARACTERISTICS OF THE NINETYEAST RIDGE
... Ninetyeast Ridge, Andaman Nicobar Ridge, a sharp bathymetric depression forming the Nicobar deep east of the Andaman Nicobar Ridge, forearc basin, inner volcanic arc and the Andaman backarc basin (see Fig.1). NER is a major aseismic ridge, which extends from 30°S northwards into the Bay of Bengal wh ...
... Ninetyeast Ridge, Andaman Nicobar Ridge, a sharp bathymetric depression forming the Nicobar deep east of the Andaman Nicobar Ridge, forearc basin, inner volcanic arc and the Andaman backarc basin (see Fig.1). NER is a major aseismic ridge, which extends from 30°S northwards into the Bay of Bengal wh ...
A detailed study of the Gagua Ridge: A fracture zone uplifted during
... sonar and multi-beam echo sounder. Many seafloor topographic features can now be recognized with good resolution, especially the oceanic spreading centers and subduction trenches. However, the largest areas of the bottom of oceans consist of sedimented abyssal plains, in which we can observe submari ...
... sonar and multi-beam echo sounder. Many seafloor topographic features can now be recognized with good resolution, especially the oceanic spreading centers and subduction trenches. However, the largest areas of the bottom of oceans consist of sedimented abyssal plains, in which we can observe submari ...
Aquatic biomes
... » currents and waves constantly renew nutrients » light penetrates to ocean floor allowing photosynthesis – easily degraded by » pollution » development » high water temperatures ...
... » currents and waves constantly renew nutrients » light penetrates to ocean floor allowing photosynthesis – easily degraded by » pollution » development » high water temperatures ...
Weakness of the lower continental crust: a condition for
... constant creep rate obtained from average plate tectonic movements. In the examples, this is 10 17 s 1 , but other constant values, such as 10 14 s 1 , do not change the shape of the curves, but only reduce the viscosity scale by about two orders of magnitude. As it is nearly impossible to predict t ...
... constant creep rate obtained from average plate tectonic movements. In the examples, this is 10 17 s 1 , but other constant values, such as 10 14 s 1 , do not change the shape of the curves, but only reduce the viscosity scale by about two orders of magnitude. As it is nearly impossible to predict t ...
Experimental tests of simple models for the dynamics
... boundary itself. Prior analytical and numerical models apply the further simplified balance between driving plate-edge forces and retarding viscous forces to address the question of why the pole of rotation tends to lie in a complete diffuse oceanic plate boundary (Zatman et al. 2001, 2005). In part ...
... boundary itself. Prior analytical and numerical models apply the further simplified balance between driving plate-edge forces and retarding viscous forces to address the question of why the pole of rotation tends to lie in a complete diffuse oceanic plate boundary (Zatman et al. 2001, 2005). In part ...
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.