Vertical-axis rotation of rigid crustal blocks driven by mantle flow
Published:January 01, 2004
Scott Giorgis, Michelle Markley, Basil Tikoff, 2004. "Vertical-axis rotation of rigid crustal blocks driven by mantle flow", Vertical Coupling and Decoupling in the Lithosphere, J. Grocott, K. J. W. McCaffrey, G. Taylor, B. Tikoff
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Vertical-axis rotation of rigid crustal blocks occurs in a variety of obliquely convergent and divergent plate boundaries. We quantify the rotation of these blocks using models of transpressional and transtensional kinematics, and corroborate our results using physical models where rigid blocks rotate in response to flow of a ductile substrate. Consequently, one can explicitly demonstrate a relationship between the amount of rotation of a rigid crustal block and strain recorded in ductile substrate. This strain should be reflected directly by the orientation of rock fabrics, such as those measured by shear-wave splitting in the in situ upper mantle.s
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Vertical Coupling and Decoupling in the Lithosphere
Recent advancements in the understanding of mountain belts have focused on vertical coupling of the lithospheric layers. This volume describes the extent to which observed or inferred sub-horizontal coupling or attachment zones provide vertical kinematic linkage between rheologically distinct layers in the continental lithosphere. A common theme is whether the deformation, which partitioned differently in each layer, is linked kinematically across attachment zones and driven by flow in the deeper crust and mantle lithosphere.
The papers are divided into six sections. The first analyses the extent to which mantle flow controls deformation of the overlying layers. The Vertical axis block rotations section uses geological and palaeomagnetic data to constrain the role and magnitude of basal shear across mid-crustal attachment zones. The Lower crustal flow and topography section addresses the time-dependent development of orogenic plateaux and their role in the orogenic cycle. Multiple examples of the spatial and temporal development of lithospheric coupling are given in both the Orogenic examples and Subduction examples sections. Finally, rheological constraints of vertical coupling in the lithosphere are investigated.