Analysis On Sedimentary Characteristics And Provenances Of Upper Cretaceous-Paleocene Of Tantou Basin In West Henan

Tantou basin is a typical Mesozoic-Cenozoic Basin with reddish strata and is located between the southern margin of the North China Craton and Qinling Mountains Thrust nappe belt. Previous studies of the Tantou basin in Western Henan concentrated mainly in the dinosaur fossils of late Cretaceous Qiuba Group, vertebrate fossils, paleo-climate analysis, and pollen-bearing flora, but sedimentary environment and provenance of Tantou basin were poorly analyzed. On the basis of detail work of the field sections, the evolution of sedimentary environments and provenances of upper Cretaceous-Paleocene and its controlling factors are studied using the theory and method of Petrology, Sedimentology and geochemistry. The following results are made.(1) The lithology of Qiuba Group in Tantou basin is the middle-thick purple-red silty mudstone layer with some lenticular conglomerates. There are some sedimentary positive cycles in Qiuba Group. The lower of Gaoyugou Group is mainly made up to conglomerate and glutenite and the upper grows silty mudstone with calcareous concretion. The lower of Dazhang group mainly develops argillaceous siltstone and the upper grows mudstone with calcareous concretion.(2) The provenance from Qiuba formation to Gaoyugou Formation is mainly Xiong’er volcanic rocks mixed with upper crust sedimentary rocks by the analysis the geochemical characteristic of the argillaceous rocks. The weathering from an exposing top-denudation of provenance area is from stronger in upper Cretaceous to weaker in Paleocene. The Cretaceous dinosaurs in Luanchuan area lived in a tropical-subtropical humid-semi-humid climate, and it grew dryer in early Paleocene.(3) Tantou basin mainly develops fan delta facies and lacustrine facies in the upper Cretaceous-Paleocene. Multiple cycles of fan delta facies-shallow lake shore developed in the age of Qiuba Group. The lower of Gaoyugou group develops fan delta facies and the upper shore and shallow lake facies. Dazhang group develops shore and shallow lake facies. The structure and paleoclimate is main controlling factors.This study can provide some basic information on the continental research of K-T boundary event, and provide evidence for Paleogeographic reconstruction of Tantou basin, and be very important for the evolution of Tantou basin in Meso-Cenozoic.