A tale of two orogens- Taiwan and Mindoro

<p>The Taiwan and Mindoro islands are located on the northern and southern ends of the Malina trench, and both orogens result from the deformation of the continental margin of the Eurasia plate. Comparing the exhumation histories of both orogens allow us to discuss the mechanism of mountain building of two orogens.<br />In Taiwan orogen, the timing of the mountain building starts from ca. 6-8 Ma, which can be identified using ZrnFT, Ar-Ar, and the timing of the developing foreland basin.&#160;<br />For Mindoro island, we combine with ZrnFT, ApaFT, and ZrnHe to constrain the timing of the exhumation. It shows oldest ZrnFT ages are ca. 6-7 Ma. We further constrain that the latest stage of granite age in the rifted continental crust is ca. 13Ma indicating the collision should be later than this age. In addition, the ApaFT and ZrnHe ages for the granite are ca. 6Ma inferring a rapid cooling age which is consistent with regional ZrnFT dates. Those data imply the timing of mountain building of Mindoro orogen is ca. 6-7Ma which is similar to the Taiwan orogen.<br />Considering both orogens have similar timing of mountain building, we suggest that while the Philippine Sea changes the motion to NW trending at ca. 7-8Ma and Eurasia continental margin subducts to the Philippine Sea plate and Philippine Mobile belt, respectively, that results in both orogens deforming simultaneously.</p>