关键词: ck₄孔, 湖相地层, 古地理环境, 沉积速率

Abstract: The bore No. 4 is 153. 66m in depth, is located at terrac I of north bank Heihe River nearby Qing-Kang Haighway. After analysing lithological characters and radiocarbon C¹⁴ datings of the bore profile, the conclusions could be stated as follows：The strigraphy at the depth of 0-4.15 m is a stream-swamp stream facies deposit in the late of Holocene；at the depth of 4.15-51.9 m is an alluvial-pluvial deposit and at the depth of 51.95-67.5 m is a transition phase of alluvial-pluvial and lakeshore deposit in the Holocene；at the depth of 67.5-153.66 m is a stationary lacustrine deposit in the Pleistocene. The glaciation did not develop, but the palaeogeographical environment of glacial period and interglacial period appeard alternately could be reflected in the Pleistocene, and the periglcial climate was arid and cold in the Holocene in the Heihe Rever basin. The depositional rate of the sediment was 1.5 mm per year in the late of Pleistocene（40000-10000 B. P. Y. ）, and 6.5 mm per year in the Holocene nearby the bore No. 4 .