Nappe structure revealed by thermal constraints in the Taiwan metamorphic belt

Vitrinite reflectance and Raman spectroscopy of carbonaceous material data are used to better resolve the thermal history of the Hsuehshan Range, which is accreted between the foreland fold-thrust belt and bulldozer hinterland units in the Taiwan mountain belt. The observed thermal data indicate that the strata in the northern Hsuehshan Range underwent dynamic metamorphism during the Neogene orogeny, while the strata in the southern Hsuehshan Range may have predominantly experienced burial metamorphism during Palaeogene sedimentation. Based on the thermal constraints, the Hsuehshan Range is interpreted to consist of nappe stacks, originating from the rifted Eurasian continental margin. This interpretation is consistent with well-documented cases in the European Alps and the Himalayas and is also shown in physical modelling and thermo-kinematic studies invoking underplating and erosion processes.