Abstract
We currently have a limited understanding of the tectonic framework that
governs Venus. Schubert and Sandwell (1995) identified over 10,000 km of
possible subduction sites at both coronae and chasmata rift zones.
Previous numerical and experimental studies have shown the viability of
regional-scale lithospheric recycling via plume-lithosphere interactions
at coronae, yet little work has been done to study the possibility of
resurfacing initiated at Venusian rift zones. We created 2D numerical
models to test if and how regional-scale resurfacing could be initiated
at a lateral lithospheric discontinuity. We observed several instances
of peel-back delamination - a form of lithospheric recycling in which
the dense lithospheric mantle decouples and peels away from the weak,
initially 30 km-thick crust, leaving behind a hot, thinned layer of
crust at the surface. Delamination initiation is driven by the negative
buoyancy of the lithospheric mantle and is resisted by the coupling of
the plate across the Moho, the significant positive buoyancy of the
crust arising from a range of crustal densities, and the viscous
strength of the plate. Initial plate bending promotes yielding and
weakening in the crust, which is crucial to allow decoupling of the
crust and lithospheric mantle. When there is sufficient excess negative
buoyancy in the lithospheric mantle, both positively and negatively
buoyant plates may undergo delamination. Following a delamination event,
the emplacement of hot, buoyant asthenosphere beneath the crust may have
consequences for regional-scale volcanism and local tectonic deformation
on Venus within the context of the regional equilibrium resurfacing
hypothesis.