Crustal and upper mantle structure of Taiwan Imaged by Magnetotellurics

摘要

The Taiwan orogeny is young and presently very active, in which the Luzon arc is actively being accreted onto the southeast China continental margin. Arc accretion is regarded as the fundamental mode by which Taiwan grow. To improve understanding of the tectonics of Taiwan, more than 50 magnetotelluric (MT) soundings stations were surveyed along three east-west transect highways by using long-period MT soundings during 2006-2007. Three profiles almost perpendicular to the regional strike of Taiwan were obtained. Each 2-D inversion profile was implemented and included static shift and the ocean effect; each inverted 2-D model is characterized by two main resistive anomalies, R1 and R2, located in the mid-crust beneath the Coastal Plains and Central Range, respectively. Tracing the mass transfer of these volumes through the orogenic system of Taiwan suggest that the Taiwan orogeny could be explained by the tectonic model of active continental subduction followed by crustal exhumation.