Meso-cenozoic tectono-thermal evolution history in Bohai Bay Basin, North China

Abstract

The thermal history of sedimentary basins is a key factor for hydrocarbon accumula- tion and resource assessment, and is critical in the exploration of lithospheric tectono-thermal evo- lution. In this paper, the Cenozoic thermal histories of nearly 200 wells and the Mesozoic thermal histories of 15 wells are modeled based on the vitrinite reflectance and apatite fission track data in Bohai Bay Basin, North China. The results show that the basin experienced Early Cretaceous and Paleogene heat flow peaks, which reveals two strong rift tectonic movements that occurred in the Cretaceous and the Paleogene in the basin, respectively. The thermal evolution history in Bohai Bay Basin can be divided into five stages including (1) the low and stable heat flow stage from the Trias- sic to the Jurassic, with the heat flow of 53 to 58 mW/m 2 ; (2) the first heat flow peak from the Early Cretaceous to the middle of the Late Cretaceous, with a maximum heat flow of 81 to 87 mW/m 2 ; (3) the first post-rift thermal subsidence stage from the middle of the Late Cretaceous to the Paleocene, with the heat flow of 65 to 74 mW/m 2 at the end of the Cretaceous; (4) the second heat flow peak from the Eocene to the Oligocene, with a maximum heat flow of 81 to 88 mW/m 2 ; and (5) the second thermal subsidence stage from the Neogene to present, with an average heat flow of 64 mW/m 2 .