Provenance Characteristics of Uranium-Bearing Sediments of Upper Saihan Formation and Its Implications for Sandstone-Type Uranium Mineralization in Manite Depression,Erlian Basin
The Luhai and Zhundalai uranium deposits in southwestern margin of the Manite Depression in Erlian Basin are large sandstone-type uranium deposits newly discovered in recent years.The ore-bearing strata are mainly the upper Saihan Formation of the Lower Cretaceous.Provenance analysis of the upper Saihan Formation is of great significance to enrich the sandstone-type uranium metallogenic theory and guide the prospecting work in this area.In this paper,petrology,heavy minerals,and detrital zircon U-Pb geochronology were carried out on the ore-hosting sand bodies.The ore-hosting sandstone type is dominated by lithic feldspar sandstone,followed by feldspar lithic sandstone,indicating that the clastic material is mainly derived from the re-rotational collisional orogenic zone,followed by the island arc magmatic zone,with mixed characteristics.The characteristics of heavy minerals reflect the paleogeographical pattern that two main channels,NE-SW and SE-NW,converged in the Zhundalai area during the depositional period of the upper Saihan Formation.The age composition of detrital zircon can be divided into four age ranges of 120-140 Ma、200-240 Ma、260-360 Ma、390-510 Ma.The Early Paleozoic and Mesozoic zircon ages have a higher proportion in Luhai area,while the Late Paleozoic zircon ages in Zhundalai area have increased significantly.After comparing with the age spectrum of the surrounding rock mass and combined with the analysis results of heavy minerals,it believes that the provenance of the upper Saihan Formation in Luhai area may come from the Bayinbaolige rise in the north of the study area and the northern part of the Sunite rise in the south.The clastic material in Zhundalai area is mainly from the southern part of the Sunite rise.In general,the study area presents a north-south two-way supply model.On the basis of understanding the provenance conditions,it has analyzed the uranium supply capacity of the erosion source area.The uplift of Sunite rise since Early Cretaceous and the denudation of high uranium-bearing plutons have more significant effect on the sandstone-type uranium mineralization in the study area.This indicates that the southwestern margin of the Manite Depression has good sandstone-type uranium mineralization prospects.
万方数据
维普
