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干旱区地理 ›› 2012, Vol. 35 ›› Issue (01): 99-108.

• 地表过程研究 • 上一篇    下一篇

六盘山地区寺口子剖面早白垩世晚期的孢粉组合及其环境意义

张明震1,戴霜1,张永全1,苗运法2,刘俊伟1,黄永波1,赵杰1,刘学1   

  1. 1兰州大学西部环境教育部重点实验室&西部环境研究院, 甘肃兰州730000; 2中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室, 甘肃兰州730000
  • 收稿日期:2011-06-13 修回日期:2011-08-11 出版日期:2012-01-25
  • 通讯作者: 张明震
  • 作者简介:张明震(1984-),男,在读硕士研究生,主要从事中生代气候变化和古孢粉研究
  • 基金资助:

    国家自然科学基金(40972025,40721061,40571017);教育部新世纪人才计划(NCET-07);高等学校学科创新引智计划(B06026)联合资助

Early Cretaceous palynological assemblage and its environmental  significance in the sediments of Liupanshan Group(Sikouzi section), Liupanshan Region,central China

ZHANG Mingzhen1,DAI Shuang1,ZHANG Yongquan1,MIAO Yunfa2,LIU Junwei1, HUANG Yongbo1,ZHAO Jie1,LIU Xue1   

  1. 1 Key Laboratory of Western China’s Environmental Systems with the Ministry of Education,Lanzhou University,Lanzhou730000,Gansu,China; 2 Cold and arid regions environmental and engineering research institute,CAS,Lanzhou,730000,Gansu,China
  • Received:2011-06-13 Revised:2011-08-11 Online:2012-01-25
  • Contact: ZHANG Mingzhen

摘要: 研究白垩纪植物演替与气候变化对认识现今生态环境形成过程与演变具有重要意义。基于在我国六盘山地区下白垩统六盘山群中发现的45 属孢粉化石,探讨了孢粉组合、古生态与古气候变化特征。孢粉组合以裸子植物为主,蕨类植物次之,前者以松柏纲松杉目占优势,以掌鳞杉(Cheirolepidiaceae)科最为繁盛,尼藤目麻黄科(Ephedraceae)和苏铁目或银杏目占有很大比例;后者以真蕨目包括海金沙科(Lygodiaceae)、莎草蕨科(Schizaeaceae)为主。表明当时植物具有比较明显的多样性,既有生长于远处高山的松杉类高大植物,又有近湖低山及湖岸一带的掌鳞杉科及蕨类植物,湖泊水体中生长着淡水藻类。孢粉植物群的这种特征揭示出该地区在早白垩世晚期气候炎热干燥,并且可以划分为116~112 Ma的气温相对较低和112~103 Ma的气温波动升高两个阶段,这种变化与全球古气候的变化趋势一致,说明寺口子剖面孢粉记录的气候变化与对全球气候变化是响应的。

关键词: 孢粉, 古生态, 古气候, 早白垩世, 六盘山盆地

Abstract: The research on the Cretaceous climate and vegetation is fundamental to understand the formation of present environment. The palynological study of 11 samplles from Lower Cretaceous Liupanshan Group on the Sikouzi section(spanning 116-103 Ma),Liupanshan basin was carried out. 55 species(45 genera) of spore and pollen are detected. The palynoassemblages are diverse,with gymnosperms dominant and ferns abundant but angiosperms rare. the gymnosperms are predominated by Cheirolepidiaceae of Coniferales,and the ferns are dominant of Lygodiaceae and Schizaeaceae. The palynological data show that the Early Cretaceous floras are derived from various settings,i.e. the Coniferales plants on the high elevation mountain,the Cheirolepidiaceae plants along the low hill near the lake,the fern grow marsh wetland,and algae in the fresh water of the lake. The palynoflora indicates that the climate in the Liupanshan area is hot and dry ,and the palaeogeography is characterized by complex and various outlook during the late Early Cretaceous Furthermore,the climate evolution revealed by the vegetation can be divided into two stages in this time window. From 116 Ma to 112 Ma,the concentration of Cheirolepidiaceae and Schizaeaceae which developed in the environment of hot and dry are relatively low,and the concentration of conifers are significantly increased,as well as the concentration of ferns is not varied. All those indicate that the climate is humid and cold during this period. From 112 Ma to 103 Ma,the concentration of Cheirolepidiaceae and Schizaeaceae which developed in the environment of hot and dry are relatively high,and the concentration of conifers are significantly decreased. Compared to the upper stage,the total percentage of Lygodiaceae spores were relatively lower. the vegetation change during this period may indicate an increased trend of the dry and hot degree in this regionThe trend of climate change recorded by the pollen assemblages coincide with the global sea surface temperature fluctuation,thus indicates that the climate change recorded by the palynological assemblage in the Sikouzi section has the good response to the global climate change.

Key words: palynology, palaeoecology, palaeoclimate, early Cretaceous, Liupanshan Basin

中图分类号: 

  • P532