摘要
拉贡塘组是拉萨地体一套中侏罗世至早白垩世碎屑岩沉积,关于其孢粉学研究,迄今暂无相关的研究和报道。本文研究了拉贡塘组命名所在地洛隆县腊久乡拉贡塘村附近的一条剖面——扎乌沟剖面的孢粉化石,从其中上部共获得49属21种(不含不能鉴定的种),其中裸子植物花粉10属,占主要地位,苔藓和蕨类植物孢子含量相对稍低,但分异度比裸子植物花粉高。根据孢粉组合中的优势分子Classopollis和特征分子Dicheiropollis及Cicatricosisporites,洛隆县腊久乡扎乌沟剖面拉贡塘组孢粉组合可称为Classopollis-DicheiropollisCicatricosisporites组合,时代为早白垩世早期,也可能包括部分晚侏罗世。该孢粉植物群以喜干旱的掌鳞杉科植物为主,同时含有喜暖湿环境的苔藓和蕨类植物,指示炎热、干旱-半干旱或湿润气候但泄水性良好的海岸环境。当前材料发现揭示了拉贡塘组孢粉化石组合面貌,提供了其地质时代的孢粉学证据,丰富了早白垩世新特提斯古植被和古气候信息,对其他研究具有参考价值。
The Lagongtang Formation is a set of Middle Jurassic to Early Cretaceous clastic rock deposits in the Lhasa terrane.It was first discovered and reported as the Lagongtang Bed by Lee(1955)from Nagjog District,Lhorong County,eastern Xizang.So far few palynological report has been published on this formation.This paper studies a section at Zhawugou village,Nagjog District,Lhorong County,where the Lagongtang Formation has been set up.A total of 49 genera and 21 species(excluding indeterminable species)of moss,ferns and gymnosperms are encountered.Of them,ten genera are gymnospermous,which dominate the assemblage.Moss and fern spores are relatively low in abundance but higher in diversity than gymnosperm pollen.The palynological assemblage of the Lagongtang Formation at Zhawugou village,Nagjog District,Lhorong County is named Classopollis-Dicheiropollis-Cicatricosisporites assemblage according to the dominance of Classopollis and the occurrence of Dicheiropollis and Cicatricosisporites,and assigned to the early Early Cretaceous with possible extension to the Late Jurassic at the lower part.The palynoflora is featured by the dominance of coniferous plants of Cheiropidiaceae,a family in fond of warm and dry condition,but also contains mosses and ferns that are usually in favor of warm and humid environments,indicating a hot,arid to semiarid or moist coastal environment with good water draining overall.The current palynological discovery from the named site of the Lagongtang Formation provides helpful palynostratigraphic evidence for the geological age of this formation and the palaeovegetation and palaeoclimate information of eastern Neo-Tethyan realm during the Early Cretaceous as well,which will provide significant help for other studies.
作者
谭覃
李建国
吴一笑
TAN Tan;LI Jianguo;WU Yixiao(University of Chinese Academy of Sciences,Nanjing 211135;Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008)
出处
《微体古生物学报》
CSCD
北大核心
2023年第2期131-143,共13页
Acta Micropalaeontologica Sinica
基金
中国科学院战略先导科技专项(XDB26000000)
国家自然科学基金(41888101,41872004,42288201)
第二次青藏高原综合科学考察(2019QZKK0706)项目的联合资助。
关键词
孢粉
古植被
古气候
拉贡塘组
下白垩统
昌都
西藏
palynology
palaeovegetation
palaeoclimate
Lagongtang Formation
Lower Cretaceous
Qamdo
Tibet Autonomous Region
