When and why the continental crust is subducted: Examples of
... et al., 2006). Hindu Kush and Burma in the Himalayas, although continental crust is converging there, accompany intermediate-depth seismicities apparently without any oceanic plate. Why they accompany intermediate-depth seismicities has been an enigma long time. High lithostatic pressure makes the o ...
... et al., 2006). Hindu Kush and Burma in the Himalayas, although continental crust is converging there, accompany intermediate-depth seismicities apparently without any oceanic plate. Why they accompany intermediate-depth seismicities has been an enigma long time. High lithostatic pressure makes the o ...
slide1
... If Colorado KT boundary chromites turn out to be terrestrial it is strongly implied that the Chicxulub crater is not the only large KT boundary crater. Chicxulub crater is on continental crust away from any plate boundaries, and based on scaling considerations, the impact was not large (energetic) e ...
... If Colorado KT boundary chromites turn out to be terrestrial it is strongly implied that the Chicxulub crater is not the only large KT boundary crater. Chicxulub crater is on continental crust away from any plate boundaries, and based on scaling considerations, the impact was not large (energetic) e ...
Palaeoproterozoic Crustal Evolution of the Southern Eyre Peninsula
... Australian Proterozoic terrains (eg, Etheridge et al., 1987), suggesting significantly different mechanisms for both crustal growth and return of continental material to the mantle than presently in operation on the plate tectonic earth. Most scenarios however, involve mass balance arguments that re ...
... Australian Proterozoic terrains (eg, Etheridge et al., 1987), suggesting significantly different mechanisms for both crustal growth and return of continental material to the mantle than presently in operation on the plate tectonic earth. Most scenarios however, involve mass balance arguments that re ...
Piezophiles: Microbial Adaptation to the Deep-Sea
... hosts, exist in the deep sea at hydrothermal vents and cold seeps. Hydrothermal vents are fissures in the ocean floor that leak hot, acidic water. Cold seeps are additional sites of fluid release from the seafloor that are frequently present along the borders of continental plates. Adult animals liv ...
... hosts, exist in the deep sea at hydrothermal vents and cold seeps. Hydrothermal vents are fissures in the ocean floor that leak hot, acidic water. Cold seeps are additional sites of fluid release from the seafloor that are frequently present along the borders of continental plates. Adult animals liv ...
Plate Tectonics
... Drill cores recovered from the ocean floor show that Earth's magnetic field has reversed many times in the past several million years. Some of the cores' "slices" indicate that the North Pole was in its present position when the sediments were laid down. We call this a time of normal polarity. Other ...
... Drill cores recovered from the ocean floor show that Earth's magnetic field has reversed many times in the past several million years. Some of the cores' "slices" indicate that the North Pole was in its present position when the sediments were laid down. We call this a time of normal polarity. Other ...
South Equatorial Current (SEC) driven changes at DSDP Site 237
... Thomas, 2003). As a result, they are studied intensively in order to understand their role in the evolution of the benthic ecosystem. More recently, some species of deep-sea benthic foraminifera have been used to study productivity changes in the surface water column (Schmiedl and Mackensen, 1997; G ...
... Thomas, 2003). As a result, they are studied intensively in order to understand their role in the evolution of the benthic ecosystem. More recently, some species of deep-sea benthic foraminifera have been used to study productivity changes in the surface water column (Schmiedl and Mackensen, 1997; G ...
Geodynamics of congested subduction zones
... configuration are influenced by buoyant material colliding with a subduction zone. raised question: how does subduction continue after accretion of one terrane ? How does a microcontinent / plateau switch to the over-riding plate ? This is important at many different scales Can we understand this pr ...
... configuration are influenced by buoyant material colliding with a subduction zone. raised question: how does subduction continue after accretion of one terrane ? How does a microcontinent / plateau switch to the over-riding plate ? This is important at many different scales Can we understand this pr ...
Crust-mantle structures and Neogene
... define two distinct mantle domes, in the Tuscan-Latial area and in the South Tyrrhenian Sea, respectively [Moho map in Fig. 1; Morelli (1973); Locardi and Nicolich (1988); Nicolich and Dal Piaz (1991)]. The two domes are divided by the 41° parallel lineament (Fig. 1). These domes are uplifted by mor ...
... define two distinct mantle domes, in the Tuscan-Latial area and in the South Tyrrhenian Sea, respectively [Moho map in Fig. 1; Morelli (1973); Locardi and Nicolich (1988); Nicolich and Dal Piaz (1991)]. The two domes are divided by the 41° parallel lineament (Fig. 1). These domes are uplifted by mor ...
Origin of Indian Ocean Seamount Province by shallow
... convection (even in the absence of plate motion) can entrain up to 30% dense eclogite (for example, subducted ocean crust) with a similar density to metasomatized Archaean SCLM (ref. 18) and bring it from the transition zone to the surface19 , which is even more likely beneath super-fast Cretaceous ...
... convection (even in the absence of plate motion) can entrain up to 30% dense eclogite (for example, subducted ocean crust) with a similar density to metasomatized Archaean SCLM (ref. 18) and bring it from the transition zone to the surface19 , which is even more likely beneath super-fast Cretaceous ...
Bathymetric stripping corrections to gravity gradient components Robert Tenzer and Pavel Nov´ak
... The nominal value of the ocean density contrast ρ0w is defined as the difference between the reference crustal density is everywhere positive. The maximum signal is over the ρ crust and the seawater density ρ0w , i.e., ρ0w = ρ crust − ρ0w . largest ocean mass concentration (central Pacific Ocean). ...
... The nominal value of the ocean density contrast ρ0w is defined as the difference between the reference crustal density is everywhere positive. The maximum signal is over the ρ crust and the seawater density ρ0w , i.e., ρ0w = ρ crust − ρ0w . largest ocean mass concentration (central Pacific Ocean). ...
P-wave crustal velocity structure in western Sichuan and eastern
... the shot of YJ where the rays penetrate shallowly (5ü7 km), the rays on the most of the profile penetrate down to 10 km, e.g. the penetrating depth reaches 13 km between HY and LD, and between LT and ZBL. In most parts at these depths, the ray number of each cell is above 10, partly from 5 to 10. Ne ...
... the shot of YJ where the rays penetrate shallowly (5ü7 km), the rays on the most of the profile penetrate down to 10 km, e.g. the penetrating depth reaches 13 km between HY and LD, and between LT and ZBL. In most parts at these depths, the ray number of each cell is above 10, partly from 5 to 10. Ne ...
Plate Tectonics
... mantle form as material near the core heats up. As the core heats the bottom layer of mantle material, particles move more rapidly, decreasing its density and causing it to rise. The rising material begins the convection current. When the warm material reaches the surface, it spreads horizontally. T ...
... mantle form as material near the core heats up. As the core heats the bottom layer of mantle material, particles move more rapidly, decreasing its density and causing it to rise. The rising material begins the convection current. When the warm material reaches the surface, it spreads horizontally. T ...
Extensive drilling program planned for Glomar Challenger in
... in that the three holes proposed for that area are designed to complement the Ross Ice Shelf drilling project, which provides for several holes through the Ross Ice Shelf. The scientific program of the project is multidisciplinary in nature (Zumberge, 1971), but the pilot hole planned for late 1972 ...
... in that the three holes proposed for that area are designed to complement the Ross Ice Shelf drilling project, which provides for several holes through the Ross Ice Shelf. The scientific program of the project is multidisciplinary in nature (Zumberge, 1971), but the pilot hole planned for late 1972 ...
North Atlantic-Arctic Gateways
... and seasonal ice covers, transfer of sensible and latent heat to the atmosphere, deep-water renewal, and deep-ocean ventilation, all of which control or influence both oceanic and atmospheric chemistry. Thus, any serious attempt to model and understand the Cenozoic variability of global climate must ...
... and seasonal ice covers, transfer of sensible and latent heat to the atmosphere, deep-water renewal, and deep-ocean ventilation, all of which control or influence both oceanic and atmospheric chemistry. Thus, any serious attempt to model and understand the Cenozoic variability of global climate must ...
Imaging the mantle transition zone beneath eastern and central
... found that the lithosphere beneath the Precambrian Ordos and Sichuan basins has substantially high seismic velocities and the high velocity regions extend to at least 250 km deep. The 410-km beneath the two basins are ∼10 km shallower than the surrounding areas, suggesting the shoaling of the 410-km ...
... found that the lithosphere beneath the Precambrian Ordos and Sichuan basins has substantially high seismic velocities and the high velocity regions extend to at least 250 km deep. The 410-km beneath the two basins are ∼10 km shallower than the surrounding areas, suggesting the shoaling of the 410-km ...
Lab/Fieldwork Activity Example
... surface in the photic zone where there is enough light for photosynthesis (<100 m approx.), while zooplankton are present in the photic zone as well as in much greater depths. One simple way in which oceanographers describe planktonic organisms, whether plants, animals, or bacteria, is to classify t ...
... surface in the photic zone where there is enough light for photosynthesis (<100 m approx.), while zooplankton are present in the photic zone as well as in much greater depths. One simple way in which oceanographers describe planktonic organisms, whether plants, animals, or bacteria, is to classify t ...
File - VarsityField
... Absolute ages obtained from igneous rocks samples recovered from mid-ocean ridges reveal that: A. rocks ages get older with greater distance from the axis of the spreading ridge B. the pattern of rock ages is mirrored on each side of the spreading ridge C. the duration of each magnetic interval is t ...
... Absolute ages obtained from igneous rocks samples recovered from mid-ocean ridges reveal that: A. rocks ages get older with greater distance from the axis of the spreading ridge B. the pattern of rock ages is mirrored on each side of the spreading ridge C. the duration of each magnetic interval is t ...
... sandwiched between the Central Range of the Eurasian plate and the Costal Range of the Philippine Sea plate (Fig. 1). It is considered as the collision suture between the two fastconverging plates (Ho, 1986; Tsai, 1986). The Longitudinal Valley extends for about 160 km along the north-northeast– sou ...
Geophysical and Geochemical Constraints at Converging Plate
... percentage of tephra in the total volcanic products was defined as explosion index ' E ', by Rittman (1936). Circum-Pacific volcanoes have E generally higher than 80, whereas E rarely exceeds 3 in oceanic island volcanoes. (2) Subduction requires the underthrusting of a cold lithospheric plate deep ...
... percentage of tephra in the total volcanic products was defined as explosion index ' E ', by Rittman (1936). Circum-Pacific volcanoes have E generally higher than 80, whereas E rarely exceeds 3 in oceanic island volcanoes. (2) Subduction requires the underthrusting of a cold lithospheric plate deep ...
Unit 4 The importance of oceans
... Indian Ocean is the third largest of the earth’s four oceans, bounded on the west by Africa, on the north by Asia, on the east by Australia, and on the south by Antarctica. The total area of the Indian Ocean is 73 400 000 km². The average depth is 4 210 m and the deepest point is 7 725 m, off the ...
... Indian Ocean is the third largest of the earth’s four oceans, bounded on the west by Africa, on the north by Asia, on the east by Australia, and on the south by Antarctica. The total area of the Indian Ocean is 73 400 000 km². The average depth is 4 210 m and the deepest point is 7 725 m, off the ...
HG World Map - North Kitsap School District
... Our last continent is at the southern most part of our sphere (use hands). It is Antarctica. Say Antarctica. Antarctica literally means, NOT the Arctic. Draw and label. Read it with me. For comparison, Antarctica is twice the size of Australia. 98% of this continent is covered by an ice sheet. Show ...
... Our last continent is at the southern most part of our sphere (use hands). It is Antarctica. Say Antarctica. Antarctica literally means, NOT the Arctic. Draw and label. Read it with me. For comparison, Antarctica is twice the size of Australia. 98% of this continent is covered by an ice sheet. Show ...
Passive Continental Margin Around East Coast India
... be largely volcanic in nature, but there is no agreed upon model for their origin. Nevertheless it is generally thought that they lie at or close to the boundary between continent and ocean, and as such they are extremely important structural markers that may yield important evidence concerning the ...
... be largely volcanic in nature, but there is no agreed upon model for their origin. Nevertheless it is generally thought that they lie at or close to the boundary between continent and ocean, and as such they are extremely important structural markers that may yield important evidence concerning the ...
Chapter 9 - Oceans @ Duke
... these habitats obtain energy from the oxidation of hydrogen, hydrogen sulfide, or methane from the vent fluid. The microbes can be found either suspended in the water column or forming mats on different substrata, populating seafloor sediments and ocean crust, or living in symbiosis with several maj ...
... these habitats obtain energy from the oxidation of hydrogen, hydrogen sulfide, or methane from the vent fluid. The microbes can be found either suspended in the water column or forming mats on different substrata, populating seafloor sediments and ocean crust, or living in symbiosis with several maj ...
HABITAT QUESTIONNAIRE 1. Could you please send us a short bio
... The deep sea is thought to contain more species than any habitat on earth, including representatives of all major phyla. Dominant life forms in the deep-sea benthic habitats vary with location, and are dependent on a number of factors, such as water depth, organic inputs, currents, sediment type, an ...
... The deep sea is thought to contain more species than any habitat on earth, including representatives of all major phyla. Dominant life forms in the deep-sea benthic habitats vary with location, and are dependent on a number of factors, such as water depth, organic inputs, currents, sediment type, an ...
on the edge of the abyss
... which also probably gets much of its food from bacteria, this time attached to the outside of the worm’s body. Many typically live together in large honeycomb-like colonies around vent openings from which floods superheated water in excess of 150°C.9 These and other worms around these vents may well ...
... which also probably gets much of its food from bacteria, this time attached to the outside of the worm’s body. Many typically live together in large honeycomb-like colonies around vent openings from which floods superheated water in excess of 150°C.9 These and other worms around these vents may well ...
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.