The Dripping Continents and Their Role in the Development of Plateaus in Central Anatolia and the Central Andes: Models and Observations
Abstract
The relatively rapid rise of earth's surface and short-lived orogenic activities may be controlled by mantle upwellings and downwellings, operating collectively since the Archean. More recent discoveries on the origin of Central Anatolian and Central Andean hinterland plateaus suggest that convective/gravitational instabilities in the form of viscous "drips" are involved with surface uplift (ranging from 1 to 3 km). However, how drip dynamics and related transient surface displacements evolve, as well as they compare to the geological records, are not well established. Here, we use numerical and scaled laboratory (analogue) experiments to show that the surface response to lithospheric drips/instabilities may consecutively develop in two major phases: the initial surface subsidence/basin formation; and subsequently surface high/uplift. Depending on the variation of model parameters, such as viscosity, density, boundary conditions/imposed plate convergence-extension, the process may develop faster or more lithospheric portions may be involved with the descent and removal process. Specifically, results from the numerical experiments show that the maximum surface elevation may increase > 1.5 km in 8 Myrs through only the lithospheric removal and the resulting mantle upwelling process -without any crustal shortening accommodation. This suggests that approximately ¼ of the present-day surface elevation of the Central Andean orogenic plateau (Altiplano-Cordilleras) may be compensated by viscous drips/instabilities, if crustal shortening does not account for the evolution of the plateau since the Late Cenozoic. For Central Anatolia, a plateau of thinned lithosphere--inferred from seismic tomography and melt equilibration /petrological data--underwent > 1 km of surface uplift since the last 10 Myrs and this is consistent with drip type lithospheric removal. In this presentation, we will emphasize the important role of lithosphere and mantle dynamics in the development of plateaus and basins, whether they are located near or away (intraplate) from the plate margins.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T11B..04G
- Keywords:
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- 8110 Continental tectonics: general;
- TECTONOPHYSICS;
- 8122 Dynamics: gravity and tectonics;
- TECTONOPHYSICS;
- 8169 Sedimentary basin processes;
- TECTONOPHYSICS;
- 8177 Tectonics and climatic interactions;
- TECTONOPHYSICS