A geochemical and thermochronological study designed for the elucidation of the burial and exhumation history of an extensive pullapart basin was conducted on the East Eurasian longstanding convergent margin. The trace element compositions of apatite yields from volcanic ashes intercalated in a marine siliciclastic alternating beds of the Izumi Group, which buried a late Cretaceous tectonic basin in southwestern Japan, were determined in this study. It was shown that acidic ashes with a similar appearance can be successfully discriminated using binary plots of selected elements, and a firm basis to compare thermal histories independently reconstructed for selected horizons was established. Apatite fission track (FT) analysis was executed for the same ash samples from two sites, and their anomalous track length distributions were found to be suggestive of tracks having annealed under thermo-tectonic events after initial cooling. In combination with zircon FT ages obtained from five volcanic layers of the host sedimentary sequence, a numerical model for the FT annealing processes indicates the occurrence of two postdepositional cooling (uplift) periods beginning 81-36 Ma (Campanian to Eocene) and 38-18 Ma (late Eocene to early Miocene). The former probably reflects regional contraction episodes exemplified by the K/T gap, whereas the latter is synchronous with the initiation of back arc rifting around the area of the present-day Japan Sea, which inevitably provoked a prevailing uplift.
|Title of host publication||Horizons in Earth Science Research|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||28|
|Publication status||Published - 2017 Jan 1|
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)