Exhumation Time Of Jiamusi-Uplift: Constrained By Geochoronology Of Detrital Minerals

Jiamusi Uplift is situated in the northern part of Jiamusi Block, mainly consists of Huanan Uplift and Mishan Uplift, surrounded by Sanjiang Basin, Boli Basin, Jixi Basin and Hulin Basin. The crystal basement of Mishan Uplift and Huanan Uplift is mainly composed by Mashan Group, Heilongjiang Group and mid-late Proterozoic granitic gneiss. Many recent researches show that detrital mineral chronology is an effective method to reveal information on continental and oceanic source regions that have been eroded or metamorphosed as a result of subsequent tectonic events. Therefore, several provenance analysis methods are carried out in the basins around the Jiamusi Uplift to fix the uplift time of the Jiamusi Uplift.Based on both of the field work and indoor investigation, the analysis of sandstone provenance, conglomerate provenance, paleo-current and facial paleogeography characteristics point out that the basins surrounding the Jiamusi Uplift (including Sanjiang Basin, Hulin Basin, Boli Basin, Jixi Basin and other small ones) should be a large– scale epicontinental off shore basin in early period of early Cretaceous, Jiamusi Uplift didn't exist at that time, and the provenance is mainly from Xiao Hinggan Mountain Range–Zhangguangcai Mountain Range in the west. The Jiamusi Uplift began to uplift in the late period of early Cretaceous, was up to some certain height in the early stage of Late Cretaceous, and afforded provenance to the surrounded basins. Meanwhile, the whole basin formed in the early Cretaceous were broke into several separated basins, as a result of the uplifting of the Jiamusi Uplift.Contrast to the detrital zircons and white micas ages from Muling Formation in the Boli Basin and the Didao Formation in Jilin Basin around Jiamusi Uplift, show that no age of 500Ma represented the Jiamusi Block's basement or over 500Ma ages are found in the Didao Formation and Muling Formation's sandstones. It indicated that the Jiamusi Uplift hadn't yet uplifted during the deposition of the Muling Formation.