Beijing Natural History Museum, China

Based on the study of the planktonic foraminiferal zones, the stratigraphy of the N22 zone of the Pleistocene, N21 and N20 zone of the late Pliocene, N19-N18 zone of the early Pliocene, N17 zone, N16-N15 zone, N14 zone, N13-N9, zone, N8-N7 zone, N6 zone, N5 zone, and N4 zone of the middle Miocene, and the N3 zone of the late Oligocene at the LH-1 9-4-1 borehole in the neritic province of the northern South China Sea and the ODP site 1148 in the continental slope region of the northern South China Sea are corresponding and can be correlative. The five cooling events (C1-C5) had occurred in the neritic province of the northern South China Sea since the end of the N3 zone of the late Oligocene to the N22 zone of the Pleistocene, they are the C1 in the end of the N3 zone of the late Oligocene, 23.20-23.40 Ma, it is considered the Mi-1 event; the C2 in the N4 zone middle-late stage, the early period of the E. Miocene, 22.50-21.80 Ma, it corresponds to the Mi-1a event and it responds to the C2 in the continental slope region; the C3 in the N7 zone early-middle stage, the late period of the E. Miocene, 17.15-17.10 Ma, it is equal to the Mi-lb event probably; the C4 in the N10 zone late stage, middle period of the M. Miocene, 14.65-14.60 Ma, it could be regarded as the Mi-3 event; the C5 in the N22 zone early stage, E. Pleistocene. The 14.60 Ma is the time limit of the C4 ending, is the time limit of the paleoenvironment changing in long time scale, and is the time limit of the altering settlement velocity from slow to faster in the study area also. It may also be the time limit of the turning uplift speed from slow to faster of the Tibet plateau in the middle period of the M. Miocene. The environment fell into the middle-outer neritic province from the end stage of the late Oligocene to the early period of the Pleistocene in this sea area.