略论古岩溶不整合──以广西阳朔白沙堡晚白垩世岩溶为例

PRELIMINARY DISCUSSION ON PALAEOKARST UNCONFORMITY──Illustrated by Late Cretaceous Karst in Baishabao,Yangshuo County, Guangxi

本文综述了岩溶不整合的内涵和研究意义，系统总结了古岩溶不整合的鉴别依据，把组成岩溶体系的改造形态（体）和建造作为主要标志：认为岩溶改造形态（体）有古个体形态标志和组合形态（体）──地形地貌标志，这些形态（体）应有岩溶建造充填或覆盖才有鉴定意义；还认为岩溶建造是确定岩溶不整合的主要依据，与建造同时形成的生物化石及同位素年龄是直接的关键证据：岩溶建造底部建造层中的溶积钙砾岩和溶积钙屑灰岩，两岩石系列中的岩石成因类型、结构构造、层面构造是确定古岩溶不整合面产状、古岩溶水流向的决定性标志；此外，古构造对岩溶和岩溶建造都有一定控制作用，有建造充填、覆盖，也是确定岩溶不整合的标志。

he paper expounds the intension and rescarch significance of karst unconformity,systematically summarizes identification criteria for the palaeokarst unconformity, considers thedeformational form (body) and formation constituting karst system as major marks. Karstdeformational form (body) should have got individual form marks──land-form andgeomorphological marks and must be filleil or covered by karst formation. The karst formation,faseils and isotopic age are the direct and key marks for determining karst unconformity. Thepetrogenetic typo, structure and bedding plane structure of dissolved-depoited calcareousconglomerate and calcareous-fragment limestone at the bottom of the karst formation are the decisivemarks for determining the occurence of palaeokarst planes and the flowing direction of palaeokarstwater. In addition, palaeostructure, to some extent, had influenced over karst and karst formation;The fillings and coverings of formation are also the marks for deciding karst unconformity.