用户名： 密码： 验证码：
Geochemistry and Taphonomy of Late Cretaceous Dinosaur Bonebeds in Zhucheng, Eastern Shandong Province, China
详细信息   
摘要
Kugou,Konglongjian,Xijiantun and Zangjiazhuang of Zhucheng,Eastern Shandong,China are famous for the world-class dinosaur bone beds of the early Late Cretaceous. Based on analyses by thin section and Electronic Probe Microanalyzer( EPMA) and the analyses of Major element,rare-earth element( REE) and trace element,the paper systemically studies the micro structure and geochemical characteristics of dinosaur bones,analyzes the taphonomy and diagenetic process of dinosaur bones,clarifies the interrelationships of the four bone beds stratigraphically and the resource provenance direction of dinosaur bones and discusses the possible facts causing the death of the dinosaurs. Apatite and calcite are the main mineral composition of dinosaur bones in study areas,with a small amount of odd Fe,Mn,BaSO4and SiO2,etc. Analysis the principle and Major element,REE and trace element of the dinosaur bones and the host matrix shows that the values of CaO,P2O5,F,REE,Y,Sr,Ba and U in the former are much higher than in the latter. The high value of CaO,P2O5,F,Sr and Ba in dinosaur bones may have been resulted from a high background value in life; whereas the abnormal high values of REE,Y and U may have been caused by postmodern absorption during the diagenetic process. Since Rb,Th,Nb,SiO2,Al2O3,TiO2,Zr and Hf belong to sedimentophile clastics elements from the weathering products of parent rocks,they occupy less in dinosaur bones than the host rock. REE of dinosaur bones belong to the enriching type of light rare earth element( LREE),similar to that of the upper crust,with a slight positive anomaly of Eu and a passive anomaly of Ce. Our study suggests that shallow burying diageneses under a draught climate and oxide environment may have caused the high content of Sr,Ba and REE such as Eu and Ce in dinosaur bones and the host rock.Based on comparisons between apatite and calcite,molecular weathering ratios between dinosaur bones and the host rock,and the correlation of many elements,such as REE,HREE( high rare earth element),LREE and( La / Yb)N,( Ce / Yb) N and( La / Sm) N,δEu,δCe,the four dinosaur bone beds are stratigraphically redefined as,in ascending order,Kugou,Xijiantun,Konglongjian and Zangjiazhuan. The provenances of the host rack are mainly from the volcanite of the underlying Qingshan Group and the erosion products of the Laiyang group’s sedimentary rocks. The frequent discovery of dinosaur bone beds in the lower strata( less than 100 meters) of the Hongtuya Formation of the Late Cretaceous suggest that the taphonomy of those fossil bones is not an isolated event. Draught climate,especially the high Sr and Ba anomaly in the background environment may have played important roles in the mortality of dinosaurs. Moreover,the shortage of water and food may have been another critical factor causing the death of dinosaurs. Then dinosaur bones were transported and accumulated by seasonal floods or surging debris flows in the direction of the northwest to southeast of Zhucheng.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址：北京市海淀区学院路29号 邮编：100083

电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700