试论皖北奥陶纪豹皮灰岩的古岩溶成因  

A Discussion on the Genesis of the Leopard Fur Limestone of Ordovician Period in Northern Anhui, China

作　　者：李定龙[1] 杨为民[1] 程学丰[1] 汪才会[1] 

机构地区：[1]淮南工业学院资源与环境工程系,安徽淮南232001

出　　处：《地质论评》1999年第5期463-469,共7页Geological Review

基　　金：煤炭科学基金资助项目(编号96地区10708)

摘　　要：本文通过对安徽北部两个奥陶系剖面豹皮灰岩(俗称豹斑)的宏观、微观及地球化学特征研究,认为豹皮灰岩的形成与奥陶纪灰岩沉积过程中的古岩溶作用及其后生改造密切相关。其形成演化模式可概括为4个阶段:①碳酸盐岩沉积间断暴露地表发育裂隙;②各种裂隙淋滤溶蚀形成沉积岩溶洞穴体系;③海侵导致海相沉积物充填岩溶洞穴;④回流渗透或混合作用使充填物白云石化而形成“斑”。The studied Ordovician limestone sections lie in the Huaibei-Suxian region in northern An-hui, China. Like other areas in North China, leopard fur limestones are found all over this region (most in Majiagou Formation at the top of the Ordovician limestone). According to the study of the macro- and micro- features as well as geochemistry of the leopard fur limestone (commonly called ' leopard spats' ) of the two Ordovician sections in northern Anhui , the authors consider that there is a close relationship between the formation of the 'leopard spots' and the paleokars-tifiction of the Ordovician limestone ,and its epigenetic changes. Its model of formation and evolution can be summarized into four stages: ① development of fractures during the exposure of carbonate rocks ; ② the diverse fractures were corroded to form the sedimentary karst cave system; ③ the karst caves were filled by marine sediments; ④ the fillings were dolomitized into 'spots' by seepage flow or mixed flow. The paper draws the following conclusions: ① There is a close relationship between the formation of the leopard fur limestone and the formation and evolution of the depositional karst. The leopard spots are the important macro -marks of the depositional karst, and it belongs to the second stage of the model of sedimentary karst cave system. ② The formation and evolution of the leopard fur limestone consists of four stages; the local exposure and development of fractures, the development of sedimentary karst caves filling of caves caused by transgression and dolomitization of the fillings caused by eustasy. ③ The gypsification in the weathering crust karstification period and hydrothermalism in structural karstification period can all transform the leopard fur limestone formed in the sedimentary karstification period by re-dolomitization and de-dolomitization, etc. As a result,the shapes of spots, mixed-spots and so on are formed.

关 键 词：豹皮灰岩 古岩溶 成因模式 奥陶纪 皖北 

分 类 号：P642.25[天文地球—工程地质学] P534.42[天文地球—地质矿产勘探]