[关键词]
[摘要]
文中描述了采自贵州省兴义市乌沙镇泥麦古剖面和安顺市关岭县麻洼剖面三叠系法郎组竹杆坡段的康尼克贝类腕足动物:Koninckella guizhouensis,Koninckella zhenfengensis和Koninckina sp.。结合牙形石、菊石生物地层及同位素测年等证据,对黔西南地区法郎组竹杆坡段的时代进行了详细讨论,认为其下部属拉丁阶(Ladi-nian),上部属卡尼阶(Carnian),在此基础上对黔西南地区报道的康尼克贝类的层位进行了讨论。综合全球已报导的三叠纪康尼克贝类化石记录可知,该类群于中三叠世起源于中国黔西南地区,在晚三叠世逐渐繁盛并向特提斯洋西部的欧洲地区和特提斯洋中部的西藏地区进行迁移扩散。受三叠纪末期生物大灭绝影响,康尼克贝类的多样性在瑞替期(Rhaetian)显著降低,直至早侏罗世辛涅缪尔期(Sinemurian)才再度复苏。
[Key word]
[Abstract]
Koninckinids,a peculiar group of athyrids(brachiopod) with concavo-convex morphology,were widely reported in Middle Triassic to Lower Jurassic of the Tethys Ocean region.Recently,abundant specimens of koninckinids were collected from the Zhuganpo Member of the Falang Formation at the Nimaigu Section,Xingyi,and the Mawa Section,Guanling,southwestern Guizhou Province,and were identified as Koninckella guizhouensis, Koninckella zhenfengensis, and Koninckinasp.The age of the Zhuganpo Member of Falang Formation,from which these konin- ckinids were found,has long been controversial. On the basis of conodont and ammonoid bios- tratigraphy and absolute age data,the lower and upper part of the Zhuganpo Member are respectively correlated to the Ladinian and Carnian,and the age of the hitherto reported koninckinids from southwestern Guizhou were accordingly discussed.Geological and geographic distribution of the Triassic koninckinids strongly suggests that this brachiopod group may have its origin in southwestern Guizhou Province,China, at least in the late Middle Triassic,flourished and spread across the Paleo-Tethys Ocean to southern Europe during the Carnian period, and then migrated to the Tibetan Plateau area later in the Norian.The biodiversity of koninckinids notably declined during the end-Triassic mass extinction, and did not recover until the Sinemurian,Early Jurassic.
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[基金项目]
国家自然科学基金(40920124002,41102011)资助