北山矿区岩溶系统的划分及岩溶发育期的厘定

KARST SYSTEM IN BEISHAN MINE DISTRICT AND ITS STAGES OF KARSTIFICATION

矿区内存在着中更新世岩溶与现代岩溶二个发育期。现代岩溶发育期详分为三个岩溶子系统。现代矿区溶蚀量为603m^3/a,近期地壳上升速度为0.57mm/a。

Field survey, speleological investigation, drilling and radiometric age of cave deposits suggest that: 1.There are at least two stages of karstification during the development of the Beishan Karst system, the Laohudong stage of Middle Pleistocene( 158 -227ka) and the modern stage of karstification. 2.In the modern stage of karstification, 36.3m3 of dolomite, 556.7m3 of calcite and 10m3 of pyrite can be dissolved yearly. The volume of pure dissolution, except corrosion and transportation, is 603m3/a. Three karst subsystems of the modern stage are recognized as peak-cluster moutainous area, peak-cluster valley and Caixiu River Valley. 3.A karst system developed under the control of the same discharge baselevel can be a complex multilayer structure. 4.In general, a transitional zone weakly karstified may exist between two subsystems, located at the front side of the opening of a ksrst subsystem with a deep conduit in a shape of inverted siphon. 5.The rate of the crustal uplift has been 0.57mm/a since the Middle Pleistocene in Beishan area.