Provenance Change and Its Influence in Late Paleocene, Jiaojiang Sag, East China Sea Shelf Basin

Abstract:

To fully recovery provenance of Mingyuefeng Formation of Well W6 in upper Paleocene in Jiaojiang Sag and probe research methods for provenance analysis applied to sea area, this research used detrital framework grains, heavy minerals and detrital zircon UPb dating for the comprehensive provenance analysis. The result shows that the Lower Mingyuefeng Formation(LMF) and Upper Mingyuefeng Formation(UMF) have entirely different provenance in the east part of Jiaojiang Sag. The main source of LMF is from Haijiao Uplift located to the east of the sag and is mainly acid intrusive rocks formed in transitional arcdissected arc with zircon UPb age ranging from 183 to 209 Ma. In addition, there is a small amount of contribution of the metamorphic and Mesozoic igneous in other age range. The main source of UMF in Jiaojiang Sag is possibly from Zhemin Uplift to the west of the sag with acid volcanic rocks and intrusive rocks formed in transitional arc with the zircon age about 106～116 Ma. It has nearly the same source rocks with the adjacent areas whose provenance area is located in the western Minzhe Uplift. This conclusion is also supported by the depositional system evolution. The change of provenance is the resulted from the tectonic and deposition environment change in late Paleocene, which has a great impact on the cap rock and the sealing capability to the oil and gas bearing in this area.