Geochemical characteristics of sandstone and sedimentary background of Neoproterozoic Qiaotou Formation in Liaoning

This paper is the result of geological survey engineering.

Objective The sedimentary period of the Qiaotou Formation in Liaoning is still not accurately determined, which leads to controversial discussions about its depositional background, especially the palaeoclimate. It is of great significance to discuss its depositional background by using petrogeochemical characteristics and other methods.

Methods We reconstructed the palaeo−weathering climate conditions, palaeo−salinity and palaeo−oxidation−reduction conditions by analysing the elemental ratios of CaO/(CaO+Fe), Sr/Ba, and V/(Ni+V), as well as the parameters of CIA, ICV, and Ce_anom from the petrogeochemical data of the sandstones of the Qiaotou Formation.

Results Most of the CIA values of the sandstone samples from the Qiaotou Formation are located in the warm and humid region, while most of the ICV values are located in the cold and dry region. Most of the CaO/(CaO+Fe) and Sr/Ba values of the samples fall into the medium saline region, and a small amount is in the slightly saline region. V/(Ni+V) and Ce_anom values of sandstone samples are in the reduced region, and a small amount is in the oxidised region.

Conclusions The Qiaotou Formation was not deposited in the Nanhua Period, and its depositional period was generally in an anoxic reducing environment with medium saline water and a warm and humid climate.