从洞穴碎屑堆积物特征探讨洞穴发育及古环境

本文通过对岩溶洞穴碎屑沉积物结构特征及其矿物、化学成分的研究,探讨岩溶洞穴的发育和形成的古环境.对洞穴石英砂表面微结构作扫描电镜观察研究,表明贵州构皮滩早期洞穴碎屑是在水动力较强的条件下形成的;对洞穴湖相沉积物作了地球化学特征的对比,从而获得不同的古气候环境.如洛塔洞穴堆积物的地球化学特征反映早中更新世时为温暖湿润的气候,而晚更新世时为较干旱气候;通过洞穴砂的矿物成分分析,探索了洞穴本身的展布,为四川彭水岩溶区东西向洞穴系统的存在提供了证据.

Study on Karst Development and Paleo-Environment From the Characteristics of Clastic Sediments in Caves

In this paper the characteristics of the texture of clastic sediments and their chemical and mineral compositions formed in running water in several caves are discussed, on the basis of which the karst cave development and the influence of paleo-environment upon it are studied. The quartz sand surface textures are studied with scanning electron microscope and the results show that the sediments of early caves in Goupitan, Guizhou Province were formed under the strong hydrodynamic condition. The geochemical characteristics of harfour deposits in the caves are compared and the paleoclimate environment is obtained. The geochemical characteristics of deposits in Luota, Hunan Province indicate that during the early-middle pleistoncene the climate was warm and moist and at the end of pleistoncene it was arid. The mineral composition of the sand deposit can be used to study the system of the caves. A karst cave system of E-W direction is found in pengshui, Sichuan Province.