上扬子区志留系花瓣海百合动物群的古生物地理学  

Paleobiogeography of the Silurian Petalocrinidae fauna on the Upper Yangtze epicontinental sea

作　　者：毛颖颜[1] 李启剑[1] 邓小杰 李越[1] 史振华 Mao Yingyan;Li Qijian;Deng Xiaojie;Li Yue;Shi Zhenhua(State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment,Chinese Academy of Sciences,Nanjing 210008;Guizhou Geological Survey,Guiyang 550081)

机构地区：[1]中国科学院南京地质古生物研究所现代古生物学与地层学国家重点实验室,中国科学院生物演化与环境卓越创新中心,南京210008 [2]贵州省地质调查院,贵阳550081

出　　处：《地质科学》2022年第4期1130-1143,共14页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：江苏省青年科学基金项目(编号:BK20210993);现代古生物学和地层学国家重点实验室项目(编号:20192105);中国科学院战略性先导科技专项(编号:XDB26000000);国家基金委重大项目(编号:41290260);贵州省科技计划项目(编号:[2020]4Y033)资助。

摘　　要：志留系花瓣海百合动物群短暂分布于华南板块上扬子陆表海区兰多维列统埃隆阶上部地层中。本文依据花瓣海百合科腕部特化方式和形态学特征划分为6个类群,包括:Petalocrinus属中除Petalocrinus stenopetalus的所有种,Petalocrinus stenopetalus,Spirocrinus circularis,所有腕部左旋的Spirocrinus,腕部右旋的Spirocrinus dextrosus,以及腕部向反口面卷曲的Sinopetalocrinus。选择同期异相地层单元:黔北桐梓水坝塘剖面石牛栏组珊瑚—层孔海绵礁灰岩、黔东北石阡枫香剖面雷家屯组粉砂质泥岩以及鄂西荆门仙居剖面罗惹坪组生屑滩为实例,分析其中花瓣海百合科各类群的赋存状态和生物—岩相特征,从生物—环境协同演化的角度强调海底环境指标制约该科属种多样性、丰度的显著差异。水坝塘清澈度高的浅海底质环境形成珊瑚—层孔海绵礁核、礁翼和礁顶亚相均是花瓣海百合最佳栖居环境,6个类群在该剖面均有产出,丰富度和多样性最高;石阡枫香剖面雷家屯组安静偏深的粉砂质泥质海底,属种单调且个体稀少,产出3个类群;仙居薄层生屑滩灰岩中生物多样性低而丰度中等,产出2个类群。之后特列奇早期大量陆源碎屑漫入扬子区,制约了花瓣海百合动物群的生存时限以及上扬子区的土著分子的古地理扩增。Silurian Petalocrinidae fauna are temporally limited from the upper Aeronian of Llandoverian units on the epicontinental sea on the Upper Yangtze Platform,South China Block.The fossil taxa are subdivided into six clades according to their morphological specializations of arm fans;they are Petalocrinus,Petalocrinus stenopetalus,Spirocrinus circularis,Spirocrinus dextrosus,left-hand Spirocrinus and Sinopetalocrinus.Three equivalent units are employed for illustration of the palaeobiogeographic differentiations of the Petalocrinidae fauna;they are Shihniulan Formation at Shuibatang of Tongzi,northern Guizhou with coral-stromatoporoid reef-building,Leijiatun Formation at Fengxiang of Shiqian,northeastern Guizhou dominated by silty shales,and Lojoping Formation with bioclastic bank at Xianju of Jingmen,western Hubei.The present cases reveal co-evolutionary relationship between biotic structures and palaeoecological parameters of the marine-floor.Turbulent and high clarity of shallow marine at Shuibatang essentially promoted reef-building and supplied idealized niches for inhabitations of the Petalocrinidae fauna showing highest biodiversity and abundance in subfacies of reef-core,reef-flank and reef-top.Petalocrinidae taxa are extremely low in biodiversity and abundance within silty shales at turbidity marine-floor of Fengxiang.Bioclastic bank facies was formed in high clarity and turbulent setting at Xianju,where hosts low biodiversity and medium abundance of the fauna.Onward amount terrigenous debris depositions of the Telychian on the Yangtze Sea constrained wide expansion of endemic taxa paleobiogeographically.

关 键 词：花瓣海百合 生物古地理 志留纪 上扬子陆表海 

分 类 号：P736.221[天文地球—海洋地质]