广西横县六景古近纪冲积物研究  

Palaeogene alluvial deposits in Liujing,Hengxian,Guangxi

作　　者：刘疆[1] 白志强[1] 

机构地区：[1]北京大学地球与空间科学学院,北京100871

出　　处：《沉积与特提斯地质》2008年第3期89-95,共7页Sedimentary Geology and Tethyan Geology

基　　金：国家自然科学基金(40372018)

摘　　要：广西横县六景火车站南侧,角度不整合覆盖下泥盆统莫丁组和那叫组下段,被新近系大面积覆盖而呈两部分远距离割裂状态的一套"二元结构"特征显著的红色泥砂基底碳酸盐岩粗巨砾岩及其横向相变部分,长期以来未被将其作为一个冲积扇的有机统一体进行研究。经笔者两次实地踏勘,系统采样和分析,以现代山麓冲积扇鉴别特征为主,辅以古冲积扇特征,综合分析认为该套沉积系列相关分割露头分别为一古近系冲积扇所残存扇根、扇中和扇缘。该冲积扇为一典型的古近纪早期干旱气候条件下,母岩区为陡峻碳酸盐岩山体的古山麓冲积扇。There occur the carbonate cobble conglomerates and boulder conglomerates in the northeastern part of Liujing, Hengxian, Guangxi. These deposits including their lateral facies display a kind of distally separated ＂binary structure＂. The synthetic study of field reconnaissance and sampling, in combination with the examination of modem piedmont alluvial fans and ancient alluvial fans, shows that these deposits should be assigned to the residual proximal fan, mid-fan and fan fringe of a Palaeogene alluvial fan. The alluvial fan was initiated under the arid and/or semiarid climatic conditions in the early and middle stages of the Eocene, and the detritus were derived from the ancient piedmont alluvial fan from the steep earbonate rock terraces.

关 键 词：广西 六景 古近系 碳酸盐岩 冲积扇 

分 类 号：P534.611[天文地球—古生物学与地层学]