High geothermal gradient metamorphism during thermal subsidence

Regional geochemistry and continental heat flow: implications for the origin of the South Australian heat flow anomaly

“…For the parameters appropriate to the SAHF A and thermal conductivities of 2.5-3 W m-I K-1 , a change in heat production depth of 1 km produces a long-term increase in temperature of 20-30°C at any depth below the heat production. As outlined by Sandiford et al [42], the sensitivity of crustal thermal regimes to the depth of the heat production distribution has important implications for the tectonic evolution of South Australia. By the earliest Phanerozoic, the high heat-producing Proterozoic basement of the SAHF A was differentially buried by virtue of the distribution of sedimentation associated with the development of the Adelaide Geosyncline.…”

“…In contrast, excellent outcrop in the Mount Painter Province allows for the construction of relatively well constrained heat production maps. Using both airborne radiometric data and whole rock geochemistry, Sandiford et al [42] were able to show that the area-integrated surface heat production for the province is 9.9 µW m-3 . We suggest that the area-integrated heat production for the transect is bracketed by the binned mean and median heat production estimates, with representative upper crustal heat production falling in the region highlighted by shading in Fig.…”

On Palaeozoic–Mesozoic brittle normal faults along the SW Barents Sea margin: fault processes and implications for basement permeability and margin evolution

“…Within early stages of continental rifting, both palaeo-and present geothermal gradients tends to be elevated, especially within subsiding rift-basins, and may exceed 50 °C km −1 (Ru & Pigott 1986;Qiu & Wang 1998;Sandiford et al 1998;Liu et al 2001;Wang et al 2011). The geothermal gradient of c. 30 °C km −1 calculated in this study suggest either that onshore faulting occurred during early phases of rifting along the SW Barents Sea margin, or that the faulting was located along the rift flanks, where geothermal gradients may have remained relatively unchanged.…”

Eocene magmatic processes and crustal thickening in southern Tibet: Insights from strongly fractionated ca. 43Ma granites in the western Gangdese Batholith

“…This is because normal geothermal gradients are insufficient to provide the heat required for partial melting of the thickened crust (cf. Sandiford et al, 1998). This is true for the Group 1 samples that yield high whole-rock zircon saturation temperatures (815C869C) (Watson and Harrison, 1983), suggesting a mantle-derived heat supply for their generation.…”