The role of the mantle and lower crust in driving Transverse Range convergence
Abstract
Convergence in the Transverse Ranges is a consequence of lithosphere converging and sinking beneath the Transverse Ranges. By lying below the Pelona schist subduction complex, this lithosphere is not North America; it probably is a fragment of the Farallon oceanic plate. The schist outcrops on low-angle faults near the Transverse Ranges, suggesting that the aseismic lower crust is made largely of schist. The descending lithosphere pulls southern California crust toward the Transverse Ranges, maintaining the San Andreas as the dominant fault south of the Transverse Ranges. Lithospheric convergence is not matched by the crust, which avoids most convergence. This is a dynamic result of the mountains themselves, whose gravitational potential energy pushes back on the converging crust. Hence the upper crust and mantle are simultaneously dynamically coupled and kinematically decoupled by the viscous lower crust.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFM.T31C1314H
- Keywords:
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- 8102 Continental contractional orogenic belts;
- 7218 Lithosphere and upper mantle