山东诸城晚白垩世王氏群恐龙化石层碎屑锆石定年和物源示踪

发布时间：2018-06-12 06:13

本文选题：山东诸城 + 王氏群　；参考：《地质论评》2016年02期

【摘要】：山东东部诸城晚白垩世王氏群大面积、高密度集群埋藏的恐龙化石是近年研究的热点,但其沉积物源与精确沉积时限目前尚不明确。本文通过对山东诸城王氏群恐龙化石层中6个砂岩样品的碎屑锆石U-Pb定年表明,样品090414-24-D中最年轻的单颗粒锆石年龄(YSG)为77.3 Ma,应代表王氏群恐龙化石层的最大沉积时限(下限),结合前人对王氏群红土崖组的年代学研究表明,其沉积时限应老于73.5 Ma(上限),也说明赋存恐龙化石层的王氏群上部红土崖组为Campanian期沉积;碎屑锆石定年揭示物源的锆石年龄组成分布在100～130 Ma之间,6个样品的年龄主峰值多在110 Ma或120 Ma左右,与下伏的早白垩世青山群火山岩年龄主峰较为吻合。王氏群恐龙化石层砾岩的砾石成分和古水流研究显示,其中3组砾石统计表明砾岩层砾石成分主要由火山岩或火山碎屑岩组成,3组古水流数据表明,诸城地区王氏群红土崖组砾岩层的古流向以南和南东方向为主,尚有1组显示古流向为向北,表明王氏群物源主要来自盆地北侧莱阳和北西侧沂沭断裂带的青山群火山岩,其次为盆地南缘。本研究为诸城王氏群化石层沉积时限的限定和沉积物源的判断,以及胶莱盆地王氏群时期古地理格局的恢复等提供了重要的依据。
[Abstract]:The dinosaur fossils buried in the late Cretaceous Wangshi group in Zhucheng, eastern Shandong Province, have been a hot research topic in recent years, but its sediment source and precise sedimentary time limit are still unclear. In this paper, the zircon U-Pb dating of 6 sandstone samples from the dinosaur fossils of the Wangshi Group in Zhucheng, Shandong Province has been studied. The youngest single grain zircon age of sample 090414-24-D is 77.3 Ma, which represents the maximum sedimentary time limit (lower limit) of the dinosaur fossils of the Wang's group, and combined with previous chronological studies of the red earth cliff formation of the Wang's group. The sedimentary time limit should be longer than 73.5 Ma (upper limit), which also indicates that the upper part of the Wangshi Group is Campanian sedimentary. The dating of detrital zircon reveals that the zircon age composition of the provenance is between 100 and 130 Ma, and the main peak age of 6 samples is about 110 Ma or 120 Ma, which is consistent with the main age peak of the lower Cretaceous volcanic rocks in Qingshan Group, early Cretaceous. The study of gravel composition and paleocurrent of dinosaur fossil bed conglomerate in Wangshi group shows that three groups of gravel statistics show that the gravel composition of conglomerate bed mainly consists of volcanic rock or pyroclastic rock. In Zhucheng area, the conglomerate of the Hongtuya formation of the Wangshi group mainly flows south and south to the east, and one group shows that the paleodirection is northward, indicating that the provenance of the Wangshi group mainly comes from the volcanic rocks of the Qingshan group in the Laiyang and Yushu fault zones on the north side of the basin. The next is the southern margin of the basin. This study provides an important basis for the determination of the sedimentary time limit and source of the fossil beds of the Wangshi Group in Zhucheng Basin and the restoration of the paleogeographic pattern of the Wangshi Group in the Jiaolai Basin.
【作者单位】：中国地质科学院地质研究所;山东省地质调查研究院;中国地质大学(北京)地球科学与资源学院;诸城市恐龙文化研究中心;
【基金】：国家自然科学基金项目(编号:41272021、41372109、90914003) 中国地质调查局项目(编号:1212011085477、12120114064301)联合资助的的成果~~
【分类号】：P597.3;Q915.2

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