Basin formation by thermal subsidence of accretionary orogens

Subsidence patterns of 18 stratigraphic sections from five sedimentary basins around the world are analysed by forward and inverse modelling, in order to explain the mechanisms by which basins form on the juvenile crust generated by accretionary orogens. Study areas are the Paraná Basin (Brazil), Karoo Basin and Cape Fold Belt (South Africa), the Arabian Platform, Scythian and Turan platforms (Central Asia) and eastern Australia. The form of the tectonic subsidence curves derived from backstripping analysis is consistent with results from a forward model, which produces thermal subsidence of crust with normal thickness (~35km) but low initial mantle lithosphere thickness. This high thickness ratio of crust:mantle lithosphere is the plausible initial configuration of lithosphere produced by accretionary tectonics. Our results do not require late stage orogenic extension or lithosphere delamination as a precursor to the thermal subsidence phase. •We propose that thermal subsidence can explain sedimentary basins on accretionary crust.•We present backstripped subsidence curves from five sedimentary basins worldwide.•Backstripped subsidence curves match forward modelling of thermal subsidence.•Our model does not need late stage orogenic extension or lithosphere delamination.