Thermal models of the Mexico subduction zone
... of 200 m on the incoming oceanic plate was used for all model profiles. Sediment deposition has occurred at a rate of 135 m Myr 1 over the last 0.78 Ma, and at a rate of 3– 30 m Myr 1 before that [Shephard and McMillen, 1981]. Because of the small sediment thickness, uncertainties in the thickness a ...
... of 200 m on the incoming oceanic plate was used for all model profiles. Sediment deposition has occurred at a rate of 135 m Myr 1 over the last 0.78 Ma, and at a rate of 3– 30 m Myr 1 before that [Shephard and McMillen, 1981]. Because of the small sediment thickness, uncertainties in the thickness a ...
one world ocean
... – That means that all the rivers, lakes, glaciers, rain, snow, and groundwater make up the <3% remainder! ...
... – That means that all the rivers, lakes, glaciers, rain, snow, and groundwater make up the <3% remainder! ...
Thoughts on the evolution of modern oceans
... Indian and Atlantic oceans originated during the middle Meso zoic, and that the Arctic Ocean probably began somewhat later, that is, in the late Mesozoic or possibly as late as the Cenozoic. These Russian authors suggested that the world ocean system initially consisted of relatively shallow marine ...
... Indian and Atlantic oceans originated during the middle Meso zoic, and that the Arctic Ocean probably began somewhat later, that is, in the late Mesozoic or possibly as late as the Cenozoic. These Russian authors suggested that the world ocean system initially consisted of relatively shallow marine ...
Lesson Plan - ScienceA2Z.com
... above downgoing plates producing surface volcanism is the subject of some debate in the geologic community, the general consensus from ongoing research suggests that the release of volatiles is the primary contributor. As the subducting plate descends, its temperature rises driving off volatiles (mo ...
... above downgoing plates producing surface volcanism is the subject of some debate in the geologic community, the general consensus from ongoing research suggests that the release of volatiles is the primary contributor. As the subducting plate descends, its temperature rises driving off volatiles (mo ...
Initiation of subduction in nature and models
... later due to the cooling and thickening of the lithosphere along the margin wand. This sequence of events explains why mature passive margins are typically very stable [4]. The issue of induced versus spontaneous subduction initiation also remains partially controversial in both nature and within n ...
... later due to the cooling and thickening of the lithosphere along the margin wand. This sequence of events explains why mature passive margins are typically very stable [4]. The issue of induced versus spontaneous subduction initiation also remains partially controversial in both nature and within n ...
3 The Theory of Plate Tectonics
... sinks into the mantle at subduction zones. The rising hot material and the sinking cold material form convection currents. Until the 1990s, many scientists thought that these convection currents pulled the tectonic plates over Earth’s surface. Today, most scientists think that slab pull is the main ...
... sinks into the mantle at subduction zones. The rising hot material and the sinking cold material form convection currents. Until the 1990s, many scientists thought that these convection currents pulled the tectonic plates over Earth’s surface. Today, most scientists think that slab pull is the main ...
Earth and Environmental Science
... (A) An increase in rainfall due to the loss of vegetation cover (B) An increase in average temperature due to the heat released by the erupting volcano (C) A decrease in average temperature due to the increase in fine particles reflecting solar radiation (D) A decrease in average temperature due ...
... (A) An increase in rainfall due to the loss of vegetation cover (B) An increase in average temperature due to the heat released by the erupting volcano (C) A decrease in average temperature due to the increase in fine particles reflecting solar radiation (D) A decrease in average temperature due ...
Contribution of multibeam bathymetry to understanding
... topography occupies the ridge-transform intersection. This broad high is curved toward the active transform and extends from the ridge axis onto the older plate (e.g., Fig. 4). It is interpreted to form as excess volcanism at the ridge axis extends across the ridge-transform intersection onto the ol ...
... topography occupies the ridge-transform intersection. This broad high is curved toward the active transform and extends from the ridge axis onto the older plate (e.g., Fig. 4). It is interpreted to form as excess volcanism at the ridge axis extends across the ridge-transform intersection onto the ol ...
Reheating of old oceanic lithosphere: Deductions from observations
... of the reasons for this phenomenon is the high population of seamounts and oceanic plateaus on old seafloor: these are known to have thicker crust than the deep ocean basins. This is most obvious in the western Pacific. Another reason is the increase in sediment thickness. This is prevalent in many ...
... of the reasons for this phenomenon is the high population of seamounts and oceanic plateaus on old seafloor: these are known to have thicker crust than the deep ocean basins. This is most obvious in the western Pacific. Another reason is the increase in sediment thickness. This is prevalent in many ...
Manned Submersibles, the Efficient Tools for Exploring Deep
... Vehicles (AUVs), Underwater Gliders and Human Occupied Vehicles (HOVs) and other new type ones. Starting from nascent navigation and control algorithm research in laboratories, applied underwater technology has developed considerably and at present the manned submersibles are able to dive thousands ...
... Vehicles (AUVs), Underwater Gliders and Human Occupied Vehicles (HOVs) and other new type ones. Starting from nascent navigation and control algorithm research in laboratories, applied underwater technology has developed considerably and at present the manned submersibles are able to dive thousands ...
Plate Tectonics: Evolution of the Ocean Floor
... is upwelled and downwelled. As discussed later in this chapter, the convection processes in the mantle are complex, probably chaotic (CC11), possibly multilayered, and as yet very poorly understood. However, we do know that upwelling material has been heated by the Earth’s core and radioactive decay ...
... is upwelled and downwelled. As discussed later in this chapter, the convection processes in the mantle are complex, probably chaotic (CC11), possibly multilayered, and as yet very poorly understood. However, we do know that upwelling material has been heated by the Earth’s core and radioactive decay ...
Innovative, non-destructive techniques and methodologies
... The eustatically driven global sea level rise after the last Ice Age has led to the drowning of numerous prehistoric and historic sites and their preservation in the shallow coastal zone. Regional and local processes like the isostatic rebound (uplift) effect in Northern Europe and the active, verti ...
... The eustatically driven global sea level rise after the last Ice Age has led to the drowning of numerous prehistoric and historic sites and their preservation in the shallow coastal zone. Regional and local processes like the isostatic rebound (uplift) effect in Northern Europe and the active, verti ...
Chapter 5: Marine Sediments
... Deposit by settling through water column Oceanographers decipher Earth history through studying sediments ...
... Deposit by settling through water column Oceanographers decipher Earth history through studying sediments ...
Mantle transition zone thickness beneath Cameroon
... study. The time domain iterative deconvolution method of Ligorrı́a & Ammon (1999), applied to seismograms rotated into vertical, radial and transverse components, is used to generate the receiver functions. The ray-theoretical Ps conversion points at a depth of 410 km for the 2210 station-event pair ...
... study. The time domain iterative deconvolution method of Ligorrı́a & Ammon (1999), applied to seismograms rotated into vertical, radial and transverse components, is used to generate the receiver functions. The ray-theoretical Ps conversion points at a depth of 410 km for the 2210 station-event pair ...
Seismogenic zones in Eastern Turkey
... concentrated in the middle portion of the EAFZ in and around Lake Hazar. Of the class A and B events, only one depth value in the entire region exceeded 30 km depth. This event has a reasonably well constrained hypocentral depth with The vast majority of our well-constrained hypocentral depths are l ...
... concentrated in the middle portion of the EAFZ in and around Lake Hazar. Of the class A and B events, only one depth value in the entire region exceeded 30 km depth. This event has a reasonably well constrained hypocentral depth with The vast majority of our well-constrained hypocentral depths are l ...
Ocean Exploration - Division on Earth and Life Studies
... been identified during the past 30 years, many with unique properties useful in fighting disease. “Biodiscovery” researchers have had success in all types of ocean environments. A 1991 expedition by the Scripps Institution of Oceanography’s Paul Jensen and William Fenical resulted in the discovery o ...
... been identified during the past 30 years, many with unique properties useful in fighting disease. “Biodiscovery” researchers have had success in all types of ocean environments. A 1991 expedition by the Scripps Institution of Oceanography’s Paul Jensen and William Fenical resulted in the discovery o ...
- ANU Repository
... liquid water, and where there could be liquid water but there is no Earth. The details of our Earth model, including estimates of uncertainties, are described in Table 2 and Appendix A Table A. The subsurface pressure and temperature gradients of Earth are proportional to each other and are related ...
... liquid water, and where there could be liquid water but there is no Earth. The details of our Earth model, including estimates of uncertainties, are described in Table 2 and Appendix A Table A. The subsurface pressure and temperature gradients of Earth are proportional to each other and are related ...
The Ocean Floor - NVHSEarthScienceOlsen
... Key Points • The three major regions of the ocean floor are the continental margins, the ocean basin floor and the mid-ocean ridges. • The gently sloping submerged surface extending from the shoreline toward the deep ocean is called the continental shelf. • At the continental margin in the Pacific ...
... Key Points • The three major regions of the ocean floor are the continental margins, the ocean basin floor and the mid-ocean ridges. • The gently sloping submerged surface extending from the shoreline toward the deep ocean is called the continental shelf. • At the continental margin in the Pacific ...
Depth-dependent geometry of margin-parallel strike-slip
... depends on several factors, including the temperature profile, its particular composition and past history of deformation. Considering the earthquake cycle, with complementary coseismic and interseismic periods both having maximum shear stresses near the downdip depth, it is likely that the planes r ...
... depends on several factors, including the temperature profile, its particular composition and past history of deformation. Considering the earthquake cycle, with complementary coseismic and interseismic periods both having maximum shear stresses near the downdip depth, it is likely that the planes r ...
Crustal thinning of the northern continental margin of the South
... structures of the northern continental margin of the SCS. We have also performed gravity modeling by using a simple four-layer crustal model to understand the geometry of the Moho surface and the crustal thicknesses beneath this transition zone. In general, we can distinguish the crustal structures ...
... structures of the northern continental margin of the SCS. We have also performed gravity modeling by using a simple four-layer crustal model to understand the geometry of the Moho surface and the crustal thicknesses beneath this transition zone. In general, we can distinguish the crustal structures ...
II. THE ROCK CYCLE Chapter 5: Earth Kinematics
... Ridge’ mountain chain in the middle of the Atlantic Ocean was younger than its flanks. There were no sediments on the tops of the mountain, only very fresh (unaltered) volcanic rock. The rocks in the middle of the oceans were erupted very recently, and decidedly not the oldest material on the planet ...
... Ridge’ mountain chain in the middle of the Atlantic Ocean was younger than its flanks. There were no sediments on the tops of the mountain, only very fresh (unaltered) volcanic rock. The rocks in the middle of the oceans were erupted very recently, and decidedly not the oldest material on the planet ...
Melt-rich channel observed at the lithosphere
... mantle H2O contents of 50–200 p.p.m., which are too low for the 275 p.p.m. H2O needed to sustain partial melts at 45 km depth. However, uncertainties in partition coefficient measurements may accommodate this discrepancy; the resulting statistical lower bound of 190 p.p.m. H2O is within the range of ...
... mantle H2O contents of 50–200 p.p.m., which are too low for the 275 p.p.m. H2O needed to sustain partial melts at 45 km depth. However, uncertainties in partition coefficient measurements may accommodate this discrepancy; the resulting statistical lower bound of 190 p.p.m. H2O is within the range of ...
Subduction of the Rivera plate beneath the Jalisco block as imaged
... ohm-m) at depths shallower than 10 km are associated to dewatering of the oceanic crust below the accretion prism in the SW of the profile. Away from the coast, observed upper crustal conductors (<10 km) are interpreted as partial melt related to the Central Jalisco volcanic lineament. The source of ...
... ohm-m) at depths shallower than 10 km are associated to dewatering of the oceanic crust below the accretion prism in the SW of the profile. Away from the coast, observed upper crustal conductors (<10 km) are interpreted as partial melt related to the Central Jalisco volcanic lineament. The source 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.