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

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.