The role of gravitational potential energy in active deformation in the southwestern United States

Crustal thickness variations across the northern Tien Shan from teleseismic receiver functions

“…For a region supported by Airy isostasy, the mean Moho depth (Zrn) should vary linearly with the mean elevation (s) at each station through the equation Zrn = (Pt/APrn)S + ZrnREF, where Pt is the density of the topography (crust above sea level), Apr n is the density contrast across the Moho, and ZrnRE F is the crustal thickness of a section at sea level. Mean elevation is determined by averaging topography around the measurement point using a function describing the flexure of a plate from a point load [Jones et al, 1996]. In our case, the elastic thickness of the plate is assumed to be 25 km, based on previous studies of the Apm is consistent with our data.…”

Mantle control of plate boundary deformation

“…In the non-plate dynamics of distributed continental strain, one school of thought would attribute active control to local buoyancy forces intrinsic to the lithosphere [Jones et al, 1996]; [England and Molnar, 1997], while another would argue the sub-crustal mantle generates plate boundary forces which control not only margin deformation but strain interior to continents as well [Wernicke and Snow, 1998]. Field evidence would seem to support both hypotheses: regional minimization of crustal potential energy has been successful in predicting some localized regimes of distributed continental extension, but palinspastic reconstructions of the Basin and Range province, the archetype of distributed continental extension, show clear changes in extension direction which closely track simultaneous shifts in the relative motion of the Pacific plate [Atwater and Stock, 1998].…”

Lithospheric scale gravitational flow: the impact of body forces on orogenic processes from Archaean to Phanerozoic

“…In Tibet as well as in the Basin and Range Province of the western USA, it has been argued that present-day crustal flow is strongly influenced by forces induced by large gradients in gravitational potential energy (England & Molnar 1997;Jones et al 1996;Flesch et al 2000). A warmer geotherm reduces the strength of the continental lithosphere and, as a rule of thumb, it is inferred that a thickened continental crust spreads under its own weight (i.e., Argand Ratio !1 for a given effective strain rate) when the temperature at the Moho is above c. 7008C (e.g., Sonder et al 1987).…”