豫西汝阳盆地白垩系沉积特征与沉积环境

Deposit characters and sedimentary environment of Cretaceous in Ruyang basin,western Henan

豫西汝阳盆地白垩纪地层为一套以砾岩、砂岩和粉砂质泥岩为主的红色地层,产有Huanghetitan ruyangensis(汝阳黄河巨龙)和Zhongyuansaurus luoyangensis(洛阳中原龙)等恐龙化石.根据该地层中发育的岩性、沉积构造、遗迹化石和砂岩粒度以及多个由砾岩-砂岩-泥岩所组成的自下而上逐渐变细的正旋回沉积序列等特征分析,表明其沉积环境经历了由冲积扇扇根-扇中-扇端-扇中-扇端的发展过程,在扇中-扇端或扇缘发育辫状河道及漫流沉积,恐龙化石多保存在漫流沉积中,这为解释该盆地白垩纪恐龙生存的古环境和保存为化石的背景提供了科学依据.

A set of red terrigenous clasolite and cretaceous strata occured in Ruyang basin of western Henan province,which is mainly composed of conglomerate,sandstone and mudstones containing the dinosaur fossils Huanghetitan ruyangensis and Zhongyuansaurus luoyangensis and so on.On the basis of the characteristic of the lithology,sedimentary structures,ichnofossil and the grain size analysis of sandstones as well as the finingupward cycle characterized by grain size ranging from the conglomerate and sandstone to mudstones from the bottom to top,it is suggested that cretaceous sedimentary environment in the Ruyang basin had experienced a evolution from the root fan,middle fan and fan edge and on the middle fan and the fan edge developed a braided channel and overbank deposit,in which dinosaur fossils are common.This study provides the scientific evidence for explaining the palaeoenvironment of the Cretaceous dinosaur survival and geological setting of preservable fossils.