The crust floats above the mantle, and the volume change of the mantle is the driving force of crustal movement. The increase in mantle volume leads to crustal extensional movement, resulting in continental crust rupt...The crust floats above the mantle, and the volume change of the mantle is the driving force of crustal movement. The increase in mantle volume leads to crustal extensional movement, resulting in continental crust rupture and oceanic crust expansion. The decrease in mantle volume leads to crustal compression movement, resulting in continental crust superposition, folding, and oceanic crust subduction. The factors that contribute to the increase in mantle volume include a change in material state, where solid material in the mantle melts into liquid material. The factors leading to a decrease in mantle volume include: oceanic crust uplift, crustal crystallization, volcanic eruptions, magma intrusion, and hydrothermal upwelling. The change in mantle volume dominates the evolution pattern of the crust. When the mantle volume increases unidirectionally, the crust only has horizontally crystallized continental crust. When the volume of the mantle changes in both directions, blocky layered oceanic crust is formed. The expansion and subduction of oceanic crust, as well as the stretching and compression of continental crust, are the supporting mechanisms for changes in Earth’s surface area caused by changes in mantle volume.展开更多
The shape of island arc is formed by changing the axis of back-arc basin caused by rock expansion along the long axis of back-arc basin;that is, island arc is driven to bend along the subduction zone, so that the arc-...The shape of island arc is formed by changing the axis of back-arc basin caused by rock expansion along the long axis of back-arc basin;that is, island arc is driven to bend along the subduction zone, so that the arc-shaped island is formed.Rock expansion along the long axis of back-arc basin is attributed to lower part of continental crust melting (underplating) on the dehydration belt (along the long axis of back-arc basin) due to dehydration of subducted oceanic crust, and the arched melting plane is formed, so that rocks on the melting plane are subject to differentiated temperature rise and differentiated expansion. The length of rock expansion along the long axis of back-arc basin is in direct proportion to the radian of island arc. The arc length of island arc is equal to the sum of the length of the long axis of back-arc basin and the length of rock expansion. The displacement and the arc length of island arc can be calculated according to the length of rock expansion;on the contrary, the length of rock expansion can be calculated according to the displacement or the arc length of island arc. According to the length and the lithology of rock expansion, the value of temperature rise of rocks above the melting plane, the melting thickness (underplating) at the bottom of continental crust and the settlement depth of back-arc basin can be reckoned.展开更多
Oceanic crust expansion belt is the largest extensional structure on the earth. All the crustal movement theories have to face the phenomenon of oceanic crust expansion. The paper tries to interpret the phenomenon of ...Oceanic crust expansion belt is the largest extensional structure on the earth. All the crustal movement theories have to face the phenomenon of oceanic crust expansion. The paper tries to interpret the phenomenon of oceanic crust expansion by the volume change of the earth and the satellite data. The oceanic crust expansion is the result of the volume change of the earth. The volume change of the earth’s mantle is the element causing the volume change of the earth;the state variation of the solid matters within the earth is the element leading to the volume increase of the earth’s mantle;while the discharge of liquid matters within the earth is the element leading to the volume decrease of the earth’s mantle. The process of oceanic crust expansion can be divided into two phases—expansion and top mounting. The phase of expansion is the volume increase of the earth’s mantle, that is, the state variation of the solid matters within the earth leading to the oceanic crust expansion. The phase of top mounting is the volume decrease of the earth’s mantle;that is, the matters of the earth’s mantle (new oceanic crust) are uplifted to be the oceanic crust matters under the action of buoyancy, which is one of the ways to discharge the matters within the earth. The expansion phase of the oceanic crust is the extensional movement period of the earth’s crust. The top mounting phase of the oceanic crust is the compressive movement period of the earth’s crust, that is, the subduction period of the oceanic crust. The speed of oceanic crust expansion is related to the state variation speed of the matters within the earth. The width of the oceanic crust expansion is related to the temperature of the seawater. The temperature of the hydrothermal flow in the oceanic crust expansion belt is related to the speed of oceanic crust expansion. The oceanic ridge terrain in the oceanic crust expansion is related to the thickness of the same density stratification above the earth’s mantle.展开更多
文摘The crust floats above the mantle, and the volume change of the mantle is the driving force of crustal movement. The increase in mantle volume leads to crustal extensional movement, resulting in continental crust rupture and oceanic crust expansion. The decrease in mantle volume leads to crustal compression movement, resulting in continental crust superposition, folding, and oceanic crust subduction. The factors that contribute to the increase in mantle volume include a change in material state, where solid material in the mantle melts into liquid material. The factors leading to a decrease in mantle volume include: oceanic crust uplift, crustal crystallization, volcanic eruptions, magma intrusion, and hydrothermal upwelling. The change in mantle volume dominates the evolution pattern of the crust. When the mantle volume increases unidirectionally, the crust only has horizontally crystallized continental crust. When the volume of the mantle changes in both directions, blocky layered oceanic crust is formed. The expansion and subduction of oceanic crust, as well as the stretching and compression of continental crust, are the supporting mechanisms for changes in Earth’s surface area caused by changes in mantle volume.
文摘The shape of island arc is formed by changing the axis of back-arc basin caused by rock expansion along the long axis of back-arc basin;that is, island arc is driven to bend along the subduction zone, so that the arc-shaped island is formed.Rock expansion along the long axis of back-arc basin is attributed to lower part of continental crust melting (underplating) on the dehydration belt (along the long axis of back-arc basin) due to dehydration of subducted oceanic crust, and the arched melting plane is formed, so that rocks on the melting plane are subject to differentiated temperature rise and differentiated expansion. The length of rock expansion along the long axis of back-arc basin is in direct proportion to the radian of island arc. The arc length of island arc is equal to the sum of the length of the long axis of back-arc basin and the length of rock expansion. The displacement and the arc length of island arc can be calculated according to the length of rock expansion;on the contrary, the length of rock expansion can be calculated according to the displacement or the arc length of island arc. According to the length and the lithology of rock expansion, the value of temperature rise of rocks above the melting plane, the melting thickness (underplating) at the bottom of continental crust and the settlement depth of back-arc basin can be reckoned.
文摘Oceanic crust expansion belt is the largest extensional structure on the earth. All the crustal movement theories have to face the phenomenon of oceanic crust expansion. The paper tries to interpret the phenomenon of oceanic crust expansion by the volume change of the earth and the satellite data. The oceanic crust expansion is the result of the volume change of the earth. The volume change of the earth’s mantle is the element causing the volume change of the earth;the state variation of the solid matters within the earth is the element leading to the volume increase of the earth’s mantle;while the discharge of liquid matters within the earth is the element leading to the volume decrease of the earth’s mantle. The process of oceanic crust expansion can be divided into two phases—expansion and top mounting. The phase of expansion is the volume increase of the earth’s mantle, that is, the state variation of the solid matters within the earth leading to the oceanic crust expansion. The phase of top mounting is the volume decrease of the earth’s mantle;that is, the matters of the earth’s mantle (new oceanic crust) are uplifted to be the oceanic crust matters under the action of buoyancy, which is one of the ways to discharge the matters within the earth. The expansion phase of the oceanic crust is the extensional movement period of the earth’s crust. The top mounting phase of the oceanic crust is the compressive movement period of the earth’s crust, that is, the subduction period of the oceanic crust. The speed of oceanic crust expansion is related to the state variation speed of the matters within the earth. The width of the oceanic crust expansion is related to the temperature of the seawater. The temperature of the hydrothermal flow in the oceanic crust expansion belt is related to the speed of oceanic crust expansion. The oceanic ridge terrain in the oceanic crust expansion is related to the thickness of the same density stratification above the earth’s mantle.
