摘要
通过对广西感仙洞洞穴堆积物粘土矿物和元素丰度的分析,探讨了其垂向变化的古气候环境意义。结果表明,根据粘土矿物组成变化大致可将洞穴堆积物划分为以较高含量蛭石为特征的无分层的上部层段、以高岭石含量较高为特征且有较明显分层的下部层段以及底部砾石段。堆积物元素丰度存在剖面变化,但微量元素和稀土元素配分模式显示洞穴堆积物(除砾石层外)物源基本一致。堆积物化学蚀变指数垂向变化不大,平均值为95.56,显示物源区风化强烈。总体来看该洞穴堆积物代表了古老基地形成的风化壳经侵蚀并在洞穴中再堆积的产物,这些堆积物主要形成于3个时间段,即700 ka底部砾石沉积阶段、700—500 ka间多期次堆积阶段和500—150 ka间快速堆积阶段。最后,粘土矿物与元素含量垂向变化不同步应与物源区剥蚀再堆积及洞穴风化淋滤等有关。
This study has conducted analysis on the clay mineral and elemental composition of karst cave deposits from Bubing Basin of Ganxian,aiming at investigate their regional climate significance.The results shown that the deposits could be divided into the upper layer,lower layer,and bottom gravel three sections.The elemental abundance of cave deposits also shows profile changes,but composition of the trace metal and rare elements is consistent through the whole profile and suggest that these deposits(except the gravel layer)are likely single source sediments.While the CIA index display consistent through the profile with an average of 96.6,suggesting the whole profile of deposits have experienced similar but relative strong weathering processes and the deposits have a single source.In general,the cave deposits were formed in three major period of time,that is a rapid deposit from 150 to 350 ka,and a multi-stage deposit periods of 500-700 ka and the bottom gravel deposits formed 700 ka.Finally,the inconsistency in the profile variation between the clay mineral and elemental composition and contents may reflect the discrepancy in erosion redeposit order and cave leaching-weathering.
作者
黄胜敏
李国山
洪汉烈
郝秀东
欧阳褚红
宋之光
Huang Shengmin;Li Guoshan;Hong Hanlie;Hao Xiudong;Ouyang Chuhong;Song Zhiguang(Key Laboratory of Environment Change and Resource Use in Beibu Gulf(Nanning Normal University),Ministry of Education,Nanning 530001,Guangxi,China;Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation,Nanning Normal University,Nanning 530001,Guangxi,China;School of Earth Science,China University of Geosciences,Wuhan 430074,Hubei,China)
出处
《地理科学》
CSSCI
CSCD
北大核心
2022年第12期2198-2206,共9页
Scientia Geographica Sinica
基金
国家自然科学基金项目(41962003,41861020,42001076,U20A2048)
广西科研基地和人才专项(AD22035046)
广西科技计划项目(AD19245018,AD20159025)资助。