川西冕宁—泸沽地区早更新世双桥冰期之证据

THE EVIDENCES OF THE SHUANGQIAO GLACIATION OF THE EARLY PLEISTONCENE, MIANNING-LUGU AREA, WEST SICHUAN PROVINCE

This paper subdivides the Late Cenozoic stratigraphy of the studied area into fifteen formations, including seven terraces. Except for the Shuangqiao Formation which belongs to a till,the others all are nonglacial sediments. We have made a sys-tematic study of the lower gravel bed of the Shuangqiao Formation on the upland which is 1872 meters high in respect of boulder sourceland,relevant geomorphology, sedimentary structure, roundness, matrix size characteristic, and surface texture of quartz sand. Finally, the gravel bed was confirmed to be a till. In view of the above mentioned, we have established the Shuangqiao glaciation of the middle -early stage of the Early Pleistoncene.