甘肃厂坝地区中—晚泥盆世早期三种不同的海岸沉积类型及其找矿意义

THREE TYPES AND EXPLORATION POTENTIAL OF THE MIDDLE AND EARLY LATE DEVONIAN COASTAL DEPOSITS IN THE CHANGBA REGION,GANSU

现代大陆边缘海岸类型是多姿多态的,但若按照影响海岸类型的古地形和水动力作用过程来划分,大致可以分为三种类型:一种是以波浪作用为主,称为无障壁的海岸;第二种是以潮汐作用为主,称为障壁海岸;第三种是两者兼而有之的以波浪和潮汐共同作用的,称为过渡海岸。这三种海岸类型都有其独特的一套标志,这对于古代已经消失的不同时期众多海岸类型是一种很好识别标志。我国特大型铅锌矿床所在的厂坝地区,就是一个在中一晚泥盆世早期同一地区并存三种海岸类型的地区。尽管它们有许多共同特征。

It is contended that there are three types of the ancient ancient coastal deposits, as revealed by the modern coastal deposits. In this paper, the sedimentary characteristics of each type of the coastal deposits are described with the emphasis on the Middle and early Late Devonian strata in the Changba region, Gansu. Although there are some similarities among these ancient coastal deposits, sedimentary sequences and the associations of sedimentary structures are quite different. It is due to the basic differences that mineralization characteristics and exploration potential of these deposits may vary greatly.