Gravimetric examination of thin-skinned detachment vs basement-involved models for the Taiwan Orogen

Newly available gravity data are used to test two thin-skinned models and a recently proposed basement-involved model for the Taiwan Orogen, with the latter model requiring the discrete incorporation of autochthonous basement material into the shallow parts of the orogen. A comparison between the calculated and observed gravity anomalies shows that the basement-involved model significantly surpasses the thin-skinned models in fitting the data. This result suggests that the kinematics of mountain building in the hinterland of the Taiwan fold-and-thrust belt may be significantly different from that suggested in the thin-skinned models. Thus, a re-evaluation of the mechanics of fold-and-thrust belts may be required.