珠江三角洲晚第四纪气候波动的新认识

A NEW APPROACH TO THE CLIMATIC FLUCTUATION DURING LATE QUATERNARY IN THE PEARL RIVER DELTA

珠江三角洲中部番禺东涌剖面密取样、高分辨率的磁化率、δ13C、C/N3条曲线相互基本谋合,为判断MIS2以来的气候波动提供了新依据,从中得出了一些新认识:末次冰盛期很不明显,降温不超3℃;有新仙女木冷回返事件的反映;冷回返事件后直至2 500aBP,持续波动升温,难以识别8 500～3 000 a BP的大暖期;晚全新世降温始于2 500aBp,而不是3 000 aBP;最暖期不是在中全新世,而是在晚全新世.

Dongchong profile, 29.8 m in length, is located at Panyu in the central part of the Pearl River Delta. From the profile 583 samples for susceptibility, 61 samples for δ^13C and C/N and 4 samples for AMS dating are obtained. The analysis results show that the three curves of susceptibility, δ^13C and C/N are essentially indentical with each other, providing some new evidences to estimate the climate variation since MIS2 in the Pearl River Delta. From this research some new ideas are presented as follows： 1 ） The appearance of the Maximum of Lastest Glaciation was not obvious, whose amplitude of drop in temperature less than 3℃. 2） The cooling event of Younger Dryas can be recognized. 3 ） It is difficult to recognize the Megathermal of 8500-3000 a BP, because during the period after the cooling event of YD until 2500 a BP the process of rise in temperature with fluctuation continued. 4） The beginning of drop in temperature during Late Holocene was 2500 a BP rather than 3000 a BP. 5 ） The warmest stage was not in Middle Holocene but in Late Holocene.