全新世中国东部亚热带地区气候变迁的古生物学证据

Paleontological Evidence of the Changes of the North Boundary of Southern Mid-Subtropical Zone in Eastern China during Holocene

中国东部亚热带地区全新世期间的气候波动频繁,引起哺乳动物群的多次迁徙。该时期哺乳动物群的常见种属多见于亚热带地区,仅少数种属如貘、犀、长臂猿和亚洲象等在自然状态下主要分布于热带―中亚热带南部地区,指示了具热带气候性质的中亚热带南部的森林环境。文章在确定中国东部全新世不同阶段此类动物群的种属构成与分布特征的基础上,主要根据热带种的迁徙和分布特征,初步推断各阶段亚热带地区的气候变迁状况如下：盛冰期之后的冰消期,温度逐渐回升,14 000―12 000 a BP时,热带种分布北界大致南移2°,指示1月平均气温较今低3~5℃;12 000―8 500 a BP为升温期,气候转暖,热带种分布北界达中亚热带南部,逐渐类似于现今气候;8 500―5 000 a BP为大暖期,热带种分布北界抵秦岭―淮河一线,北移约6°,指示1月气温较今高约7~9℃;5 000―3 000 a BP为降温期,热带种分布北界位于秦岭―淮河以南的长江流域,北移约4°,指示1月气温较今高约5~6℃;3 000 a BP以来,气候逐渐变冷。这些变化体现了中国东部亚热带地区在全新世时期发生了多次较大的气候和生物气候带变迁事件。

The climate changed frequently in eastern China during Holocene, that caused significant migration of the mammals for several times. The common species of the mammalian fauna mainly lived in subtropical zone, only a few tropical species such as Hylobates, Elephas maximus, Megatapirus augustus and Rhinoceros sinensis, were mainly distributed in tropical zone and south-subtropical zone, indicating a forest environment with tropical climate features in the south of mid-subtropical zone. Studying the faunal composition and geographic distribution characteristics in different phases of Holocene in South China, this paper inferred the climate variation in different phases of Holocene according to the distribution of the tropical species and their far-north living boundary. The results were as follows： the climate gradually turned warmer after the last glacial epoch in Holocene, the north boundary of the southern mid-subtropical zone moved southwards by nearly 2 latitude degrees during 14 000-12 000 a BP, the mean temperature of January in this period was about 3-5 ℃lower than that today. The transitionally warm period was 12 000-8 500 a BP, when the climate was approaximately similar to that of today. The Megathermal period was from 8 500-5 000 a BP. With the north boundary at Qinling-Huaihe, and the mean temperature was about 7-9℃ higher than today＇s in January. The transitionally cold period was 5 000-3 000 a BP, the north boundary reached the Yangtze River Basin, and the temperature was about 5-6℃ higher than today＇s in January. Then from 3 000 a BP, the climate was getting colder, and the north boundary of the zone retreated southwards. Those phenomena suggested the significant changes of the climatic zone and the bio-climate variations in Holocene.