Geological Structures As Reflection of Mantle Convection and Plumes
Abstract
The origin and evolution of geological structures could be a clue for understanding of crust-mantle interaction. For simulation of geological processes and geological struc- tures evolution in connection with deep mantle movements all possible geological- geophysical data were combined and analysed and the mechanical-mathematical mod- els of different rheology were used. Interpretation of petrological, geological, geother- mal and geophysical data was made also on the base of deep drilling and geotransects. Mantle activity of different scale can be reflected in surface dynamics. So on the base- ment of super plume can arise instability of smaller scale (diapirs). As plume is re- sponsible for whole Alpine belt activization as diapirs are connected with evolution of the belt sedimentary basins and rifts. The next problems were considered: form- ing and evolution of sedimentary basins, geothermal evolution of sedimentary cover, interaction of changeable sedimentary cover with crust and mantle lithosphere, re- construction of deep mantle motions by movements of basement surface, simulation of back-arc spreading, geodynamics of collision zones of lithospheric plates, geody- namics of rifts, stress state of the lithosphere, stress distribution and change in the lithosphere and asthenosphere during mantle upwelling and geological structures evo- lution. Modelling gives possibility to calculate P-T parameters distribution in the lay- ers of lithosphere and asthenosphere in the process of the evolution. Some geological effects can be explained by mantle dynamics. The existing of stretching zones in back arc basins can be explained by upwelling of mantle diapirs as a result of geothermal effect and raising of asthenosphere in the process of collision of deep mantle flows. In analitical decision it is possible to find critical parameters of the problem, connecting the form of diapir, its depth and velocity with structure of the Earth's surface. Defin- ing boundary conditions on the basement surface it is possible to make some conclu- sions about deep mooving in asthenosphere. Mantle upwelling can be evaluated by geothermal-gravity data. The results of modelling are investigated on the examples of the Pre-Caspian Depression, Russian Platform, Baikal rift, sedimentary basins of Brazil, Pacific and Alpine belts geological structures and give good agreement with geological-geophysical data.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.3681S