内蒙古伊盟盐海子YaO2孔氧碳同位素记录的第四纪末次冰期及全新世气候特征

从内蒙古伊盟盐海YaO2孔氧碳同位素资料中可以看到:东亚季风气候在22 000aBP时由第四纪末次冰期气候开始转入末次间冰期气候。东亚季风带第四纪末次冰期时的气候环境是湿冷的淡化期。而末次间冰期的气候环境是热干的成盐期。其次,末次冰期以来,气候由湿冷转变为热干,5400aBP时气候达到热干的大暖期的最热点。之后又逐级降至现代暖趋冷的气候特征。东亚季风气候带的末次间冰期开始界线在22 000aBP左右。δ18O资料告诉我们内蒙古高原第四纪末次冰期曾有过冰川或冰盖地貌景现,在22000aBP以后才消融进入第四纪末次间冰期。

KATAGLACIAL AGE OF QUATERNARY PERIOD AND CLIMATICCHARACTERISTICS OF HOLOCENE EPOCH——A RECORD OFCARBON ISOTOPE FROM YANHAIZI YaO2 BOREHOLE IN YI LEAGUE OF INNER MONGOLIA

A record of carbon isotope from the Yanhaizi YaO2 borehole in Yi League of Inner Mongolia has it that the monsoon climate of East Asia changed 22 000 years ago from the kata-glacial climate of Quaternary periodto the kata-interglacial climate. The former was characteristic of humidness plus coldness, thus the seawater tending to desalination, compared with the latter which was warm and arid, the seawater beginning salination. Beginning with the kata-glacial age, though the wet and cold climate transited a warm and arid one until 5400 years ago when the climate reached the warmest, not long after that, it was taking a present warm to cold turn. The starting limit of the kata-glacial age of East Asia monsoon belt is defined as 22 000 years ago. The δ 18O data indicate that Inner Mongolian plateau was once covered by glaciers or glacial sheets during the kata-glacial age of Quaternary period but soon, 22 000 years ago, the glaciers or glacial sheets started piece by piece melting, meaning the arrival of the kata-interglacial age of Quaternary period.