Unstable extension of the lithosphere: A mechanical model for basin-and-range structure

摘要: To investigate the behavior of lithosphere undergoing extension, we use a simple rheological model broadly consistent with experimental data on rock creep and nature brittle/ductile transition. A plastic surface layer overlies substrate that deforms by power law stress exponent n = 3 an effective viscosity decreases depth. In extension this shows strong necking instability, provided thermal gradient is sufficiently large; otherwise, stable uniform indicated. The predicted structures display uniformly spaced necks or regions enhanced (basins) alternating reduced (ranges). If depth to transition roughly 10 km, as suggested maximum seismic faulting, yields spacings for incipient Basin Range about 25–60 in excellent agreement observation.