The Early Carboniferous zircon U-Pb chronology and its sedimentary significance in the northern Chaohu area, Anhui, East China

The Carboniferous system is well developed in the northern Chaohu area, the sequence and boundaries of different formations are clear, sedimentary types are very abundant. This area is one of the key places for the Carboniferous researches in China. Based on sedimentary characteristics, and detrital zircon U-Pb chronology characteristics, provenance of the Lower Carboniferous debris in this area are discussed. Samples for LA-ICP-MS zircon U-Pb dating were taken from the sandstones in the middle part of the Gaolishan Formation and biocalcarenites in the top of the Hezhou Formation respectively. Zircon concordant ages of the Gaolishan Formation are in the range of 404.4 +/- 10.2Ma to 3194.1 +/- 40.7Ma, peak ages are 435 +/- 6Ma and 846 +/- 14Ma; zircon concordant ages of the Hezhou Formation are in the range of 410.0 +/- 10.8Ma to 2779.9 +/- 46.0Ma, peak ages are 849 +/- 12Ma and 448 +/- 20Ma. Such sedimentary characteristics and zircon ages indicate that, the provenance region were closely related to the old lands around the Lower Yangtze ocean which were Formed in Jinning Period and Caledonian Period, part of the sediment may come from other ancient land.