【作者】 李明松；

【导师】 孙跃武；

【作者基本信息】 吉林大学 ， 古生物学与地层学， 2012， 硕士

【摘要】 石炭—二叠纪全球发育四大植物群：华夏植物群、欧美植物群、安加拉植物群和冈瓦纳植物群。中国东北地区南、北分属于华夏植物地理大区和安加拉植物地理大区，两大区系的界线位置位于西拉木伦河一线。然而，两大植物地理区系界线在东北东部的延伸位置仍不明晰。同时，吉林延边地区的地层学研究极其混乱，甚至有人认为延边石炭—二叠系属于蛇绿杂岩、浊积—混杂岩系。上述问题的存在严重影响了索伦—西拉木伦河缝合带在延边地区延伸位置的确定。为了确定东北东部二叠纪华夏植物群与安加拉植物群区系界线位置、查明延边地区地层发育序列、分析索伦—西拉木伦河缝合带在延边地区的延伸位置，本文首次对中国吉林省汪清县大兴沟镇和盛植物群进行了系统的古植物学研究，对植物化石产地进行了深入的地层学探讨，对植物化石夹层的碎屑岩进行了碎屑锆石LA-ICP-MS U-Pb年代学分析。和盛植物群由18属31种组成，名单如下：Lepidophylloides sp.，Stigmariaficoides (Sternb.) Brongn.， Trizygia oblongifolium (Germ. et Kaulf.) Asama，Calamites cistii Brongn.，C. sp.，Paracalamites stenocostatus Gu et Zhi，Annulariastellata (Schloth.) Wood， A. sp.， Schizoneura sp.， Sphenopteridiumpseudogermanicum (Halle) Sze，Sphenopteris rotunda Sze，Pecopteris arborescens(Schloth.) Sternb.，P. candolleana Brongn.，P. cyathea (Schloth.) Brongn.，P.huichensis Hsü，P. marginata Gu et Zhi，P. cf. P.(Asterotheca) orientalis (Schenk)Pot.，P. yabei Kaw.，P. sp.，Neuropteris ovata Hoffm.，N. plicata Sternb.，Odontopterissubcrenulata (Rost) Zeill.，Emplectopteris cf. E.triangularis Halle，E. sp.(cf. E.sinensis Huang)，Taeniopteris cf. T. multinervis Weiss，T. yernauxii Stockm. et Math.，Cordaites principalis (Germ.) Gein.， C. schenkii Halle， Cardiocarpus sp.，Rhabdocarpus sp.，Radicites sp.。和盛植物群主要由真蕨与种子蕨纲以及楔叶纲分子组成；多数属种为华夏植物群的重要和常见分子，其中不乏标志或特有分子，如Emplectopteris，Taeniopteris yernauxii，Pecopteris huichensis，P. marginata等。和盛植物群具有华夏植物群性质，在古植物地理上属于华夏植物地理大区华北植物区。该植物群可以与以Emplectopteris triangularis—Emplectopteridium alatum为代表的早二叠世华夏植物群进行对比，其地质时代为亚丁斯克期—空谷期早期。和盛植物群产出层位——和盛组是以灰色、灰黑色含砾砂岩、砂岩、粉砂岩及粉砂质泥岩为主的陆相沉积，属于上石炭—下二叠统山秀岭组海相碳酸盐岩沉积和下—中二叠统大蒜沟组海相碳酸盐岩及碎屑岩沉积之间的一套陆相碎屑岩沉积。该组的地质时代被其自身所含的植物化石和其上下层位中的海相化石（蜓）共同限定为早二叠世晚期（亚丁斯克期—空谷期早期）。和盛组碎屑锆石年龄分布区间为2541—2535Ma、1897—1832Ma，458—452Ma，390—280Ma，测年结果约束的和盛组的最大沉积年龄为280Ma。支持了将和盛植物群与和盛组的时代定为亚丁斯克—空谷期早期的认识。物源分析结果表明和盛组物源来自华北板块，缺乏佳蒙地块的特征物源，说明早二叠世中—晚期延边汪清和盛地区仍属于华北板块，与佳蒙地块相距甚远。结合古植物学、地层学、碎屑锆石年代学以及地球物理学等资料，提出华夏植物地理大区与安加拉植物地理大区的区系界线及索伦—西拉木伦河缝合带在延边地区的延伸位置应位于汪清—珲春一线。嘎呀河—图们江很可能为华北板块与佳蒙地块的主碰撞带的位置。和盛植物群的发现和研究成果，不但提高了华夏植物群华北区的研究程度，将华夏植物群的分布范围向北扩展到汪清地区；而且较好地限定了延边地区华夏植物地理大区与安加拉植物地理大区的分界线，为恢复东北东部晚古生代地质历史、重建东北亚区域构造演化提供了重要的资料。更多还原

【Abstract】 There existed four major phytogeographic realms namely the Cathaysia,Euramerica, Angara and Gondwana during the Carboniferous-Permian period in theworld. South part and north part of Northeast China developed respectively theCathaysia and the Angara floras, which boundary lies in the Xar Moron River.However, eastern extension of the boundary in eastern Northeast China is still unclear.The last decades have witnessed a growing debate in research on Paleozoicstratigraphy in Yanbian area, Jilin Province. Some scientists even hold the opinionthat Carboniferous-Permian is dominated by ophiolite complex and turbidite-mélange rocks. The problems mentioned above seriously affect to determine theeastern extension of the Solonker-Xar Moron River suture zone.This thesis aims at fixing the boundary between Permian Cathaysia and Angaraflora in eastern Northeast China, ascertaining Paleozoic stratigraphic sequence inYanbian area, and confining the eastern extension of the Solonker-Xar Moron Riversuture. Systematic botany of a newly found Hesheng flora was done by the presentauthor and also the stratigraphy of fossil sites in the Daxinggou Town, WangqingCounty, Yanbian area, Jilin Province, NE China was investigated, and LA–ICP–MSU-Pb detrital zircon geochronology of clastic rocks from the fossil plants interbedewas analyzed. The results are as follows:The fossil plants of the Hesheng flora consist of31species of18genera, namelyLepidophylloides sp., Stigmaria ficoides (Sternb.) Brongn., Trizygia oblongifolium(Germ. et Kaulf.) Asama, Calamites cistii Brongn., C. sp., Paracalamitesstenocostatus Gu et Zhi, Annularia stellata (Schloth.) Wood, A. sp., Schizoneura sp.,Sphenopteridium pseudogermanicum (Halle) Sze, Sphenopteris rotunda Sze,Pecopteris arborescens (Schloth.) Sternb., P. candolleana Brongn., P. cyathea(Schloth.) Brongn., P. huichensis Hsü, P. marginata Gu et Zhi, P. cf. P.(Asterotheca)orientalis (Schenk) Pot., P. yabei Kaw., P. sp., Neuropteris ovata Hoffm., N. plicataSternb., Odontopteris subcrenulata (Rost) Zeill., Emplectopteris cf. E.triangularisHalle, E. sp.(cf. E. sinensis Huang), Taeniopteris cf. T. multinervis Weiss, T.yernauxii Stockm. et Math., Cordaites principalis (Germ.) Gein., C. schenkii Halle,Cardiocarpus sp., Rhabdocarpus sp., Radicites sp. The Hesheng flora is dominated byferns and seed ferns. Most of the fossil plants are important or peculiar of theCathaysia flora, such as Emplectopteris, Taeniopteris yernauxii, Pecopteris huicensisand P. maginata. This indicates the Hesheng flora has a typical Cathaysia floristiccharacter and situate in North China Province of the Cathaysia realm. The Heshengflora, which is comparative to Early Permian Emplectopteris triangularis-Emplectopteridium alatum assembles of Shanxi Formation in North China andNorthwest China, is Late Cisuralian of Permian (Artinskian-early Kungurian) in age.The plants fossil-bearing beds of the Hesheng Formation is of late Cisuralian(Artinskian-early Kungurian) in age. The formation consists of about230m of greyand dark grey conglomerate, coarse-grained sandstone, siltstone and mudstone, underlying by the Late Carboniferous–Early Permian marine carbonate of theShanxiuling Formation with an unconformable contact, and overlain by the Cisuralian-Guadalupian marine carbonate of the Dasuangou Formation.The U-Pb ages of detrital zircon grains from the Hesheng Formation are dividedinto four groups:2541-2535Ma,1897-1832Ma,458-452Ma and390-280Ma.Constrained results from detrital zircon U-Pb geochronology of clastic rock prove thatages of the Hesheng flora and Hesheng Formation is younger than280Ma.Provenance analysis shows the clast came from the North China Plate and no sourcefrom Jiamusi-Mongolia Block. Therefore, Hesheng district of Wangqing County,Yanbian area belongs to North China Plate during middle-late Cisuralian.Based on results of paleophytogeography, stratigraphy, detrital zircongeochronology and geophysical data, the boundary between Permian Cathaysia andAngara flora and the eastward extension of the Solonker-Xar Moron River sutureshould locate in the line of Wangqing-Hunchun in Yanbian area, Jilin Province.The discovery of the Hesheng flora advances the research on Cathaysia flora inNorth China Province, and the distribution of the Cathaysia flora extends northwardto Wangqing district. This confines the boundary between the Cathaysia and Angarafloristic realms in eastern Northeast China, and provides significant data for Paleozoicgeology in Northeast China, and for research on regional tectonic evolution ofNortheast Asia.更多还原