藏南亚东帕里地区早泥盆世沉积及古生物特征  

Sedimentary and Paleontological Characteristics of Early Devonian Sequence in the Pali Area in Yadong,South Tibet

作　　者：王建华 朱幼安 李强 WANG Jianhua;ZHU Youan;LI Qiang(Research Center of Natural History and Culture,Qujing Normal University,Qujing,Yunnan 655011,China;Key Laboratory of Yunnan Province Universities of Qujing Natural History and Early Vertebrate Evolution,Qujing,Yunnan 655011,China;Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences,Beijing 100044,China)

机构地区：[1]曲靖师范学院自然历史文化研究中心,云南曲靖655011 [2]云南省高校曲靖自然历史与古鱼演化重点实验室,云南曲靖655011 [3]中国科学院古脊椎动物与古人类研究所,北京100044

出　　处：《现代地质》2024年第1期224-229,共6页Geoscience

基　　金：现代古生物学和地层学国家重点实验室(中国科学院南京地质古生物研究所)开放课题(213117);云南省基础研究计划青年项目(202001AU070145);云南省张弥曼院士工作站项目(202205AF150002)。

摘　　要：青藏高原地区工作程度较低,至今尚未发现古生代的鱼类化石。近年来,第二次青藏高原综合科学考察(古生物科考队团队)选取了藏南几个泥盆系出露较好的区域开展调查研究,其中包括西藏南部(藏南)亚东县帕里地区。该区地处喜马拉雅南部造山带腹地,泥盆系出露于帕里镇西部和南西部的局部区域。本文通过野外地层古生物剖面实测、化石采集记录拍照、室内对比研究等方法,报道了帕里镇南西一带古生物化石种类相对丰富的下泥盆统凉泉组剖面并据此讨论了该区早泥盆世时期的沉积特征。研究结果表明,该区下泥盆统凉泉组下段岩性为粗粒与中细粒的碎屑岩互层;中段的下部为中厚层状灰岩,上部以生物碎屑灰岩为主;上段地层岩性则以碎屑岩、泥灰岩为主。自下段至中段下部,下粗上细的退积沉积序列反映了一次滨浅海范围内的海进过程,而中段上部含珊瑚的生屑灰岩指示海退过程;上段的碎屑岩、泥灰岩组合则反映滨岸的沉积环境,其中的碎屑岩内产有种类丰富的古生物化石,可见头足类菊石、腕足类、双壳类和植物碎片以及疑似的盾皮鱼类骨片化石。这些发现可为藏南地区早泥盆世沉积的对比研究提供新资料;而本次疑似盾皮鱼类骨片化石的发现,可有效指导该区域进一步的古鱼类化石追索工作,为对比藏南地区古特提斯时期的古地理格局(如藏南与华南、澳大利亚等区域的关系)研究提供潜在线索。In Qinghai-Tibet Plateau,no Paleozoic fish fossils have been found so far due to limited studies.Recently,the second comprehensive scientific expedition to Qinghai-Tibet Plateau-paleontological expedition selected several areas in Southern Tibet with good Devonian exposure to conduct investigations,in which the Pali area in Yadong County of South Tibet is located in the hinterland of the southern Himalayan orogenic belt,and the Devonian sequence was only found in the western and southern parts of Pali Town.Using field paleontological section measurements,fossil sampling,recording and photography,we report a new section of Lower Devonian Liangquan Formation which is enriched in paleontological fossils located in Southwest Pali.We also discussed the sedimentary characteristics during Early Devonian of the study area.The lithology of the lower member of The Lower Devonian Liangquan Formation is interbedded within the coarse-grained and medium-fine grained clastic rocks.The lower part of the middle section is medium-thick bedded limestone,and the upper part is mainly bioclastic limestone.The lithology of the upper strata is mainly clastic rock and marl.From the lower member to the lower part of the middle member in the section,the regressive sedimentary sequence of coarse sands at the bottom and fine at the top reflects a process of seawater deepening in the coastal and shallow sea.The coral-bearing bioclastic limestone in the upper part of the middle member indicates that the seawater begins to be shallower.The clastic rock and marl assemblage in the upper member of Liangquan Formation reflects a coastal sedimentary environment.There are rich paleontological fossils in clastic rocks in the upper member,including cephalopods,aminoids,brachiopods,bivalves,and plant fragments,and bone fragments,and fossils of suspected placodermi are also found.These new data provides a comparative study with the sedimentary characteristics of Early Devonian in the study area.The discovery of the suspected placodermi remains effectivel

关 键 词：帕里地区 藏南 泥盆纪沉积 鱼类化石 古特提斯 

分 类 号：P534.44[天文地球—古生物学与地层学] Q91[天文地球—地质学]