摘要
盘县大洞是一个形态和成因复杂的大型喀斯特洞穴系统。本文通过对喀斯特作用与坡立谷结构、古水系变迁与洞穴形成等动力地貌－洞穴过程分析，探讨区域喀斯特及洞穴形成演化的水动力成因，结合岩相古地理环境推测指出：关牛洞形成于早更新世和中更新世早期，大洞洞厅、阴河坡、消洞和水洞形成于中更新世早期至中更新世中期。十里坪坡立谷的形成始于中更新世早期，并经历后来反复积水－消水。
The Panxian Dadong, with a mapped passage of 1660m long is a large karst cave system complicated by multi genesis of morphology. The main passage, 250m×40m×26m in volume, contains much relics of human activities in the Paleolithic Age. Based on analysis of some dynamic geomorphical and speleogenetic processes in the cave area, including karstification and polje structure, fossil drainage and speleogenesis, this paper deals with hydraulic genetic relations on development and evolution between karst and caves. It suggested a evolutional model of the karst landforms and caves in the area, supplemented by paleo geographic environment data and U series dating. Early Pleistocene: The limestone areas around the peak cluster depression on the Dadong Hill anticline were still covered by basalt, sandstone, shale and coal formations with an active erosion transportation process. The Shiliping River, as a surface stream at an elevation of 1710 1750m above sea level, flowed along the fault in the northern part of the Dadong Hill via the Dadong Col to the west. With the strong uplift of neotectonics and the active downcutting of rivers, limestione on the river bed was exposed by erosion and the river disappeared underground, through joints in the fault zone, and captured by underground water of the Mabie River System to the south, which gives rise to a sinking stream and hence underground river of the Guanniudong Cave. Beginning of the Middle Pleistocene: As upstream river bed of the Shiliping further seeped and water of the underground river then decreased, the underground river became a dry cave, the Guanniudong Cave at present. At the same time, the river water found a new way to disappear underground on the eastern slope of the Dadong Hill. One of stream sinks along bedding plan joints, as a former foot cave at 1685m above sea level, collected much upstream water from allogenic area of classic rocks. The water drained into the Xiaodong via Yinhepo passage and into the Loushuidong via Shuidong passage. The flow path gradually became a main underground river with phreatic features, the early Dadong Cave. Mid of the Middle Pleistocene: With the further uplift of neotectoincs and a lowering of base level, the water passage was enlarged by downcutting in dry season and undercutting at the level of the Shiliping polje lake during wet season. Later, water in the passage was captured by lower leveled rivers and disappeared underground again, a seasonal flooded passage of the Dadong Cave was then formed. With alternating changes of cold warm, dry humid climate before 300ka, a set of debris by frost weathering and loess by wind process and breakdowns by collapse were acumulated at the passage entrance to form a natural dam. The water in the polje lake had to drained along the Huashiban Fault to the southe which gives rise to a lowering of the polje bottom, about 30cm. Late of the Middle Pleistocene: With frequent changes of surface water and underground water, caves in the Dadong Hill developed well and the Shiliping River in the polje disappeared underground again at the hill base to form the lowest water passage 20m below the polje floor. Since then onward, the passage was dry, stable and large. The Dadong Cave underwent a long time alternation of speleothem deposition and classic accumulation up to the Holocence.
出处
《人类学学报》
CSCD
北大核心
1997年第3期239-246,共8页
Acta Anthropologica Sinica
