Paleolatitudes of the UHP terrane exhumation: Implications for interaction with climate-driven surface processes

How the ultrahigh-pressure (UHP) terranes are exhumed to shallow levels is among the most interesting but challenging topics in geosciences. In particular, little is known about how do climate-driven surface processes contribute to the UHP terrane exhumation. We investigate the paleolatitudes where the UHP terranes were exhumed. Our results show that all the UHP terranes in continental collision zones or oceanic accretionary wedges were exhumed within low latitudes (0°–30°), and the average paleolatitude for exhumations of the investigated 43 UHP terranes is ~5.1° N. Given that high temperature and precipitation of low latitudes would cause intense denudation, more sediment input at low latitudes into subduction zone could not only increase the buoyancy of deeply subducted mafic-ultramafic rocks, but also lubricate the subduction zone and reduce the downward friction in subduction channels, finally making it easier to exhume UHP rocks in low latitude regions. In contrast, those UHP xenoliths in mantle-derived igneous rocks could be brought to surface at higher paleolatitudes. Furthermore, the pattern of frequency for the UHP terranes exhumed at convergent boundaries is consistent with that of interglacial stages throughout the Earth history, indicating that the UHP exhumation is also controlled by the climate and thus suggesting that the exhumed UHP terranes may be useful paleoclimate indicators.