北半球72ka BP气候突变事件及其与Toba火山的关系

The Relation between the 72 ka BP Event and the Toba Super-eruption

72 ka BP左右的强降温事件是末次冰期最大的气候突变事件,且同时期发生了第四纪以来最强的火山喷发———Toba火山喷发,后者在此次强降温事件中扮演着什么角色一直是古气候学界研究的热点。对此进行深入的研究,有助于全面评价火山喷发的环境效应,进一步完善末次冰期突变事件的成因机制。系统回顾深海岩芯、极地冰芯、洞穴石笋、黄土、湖泊等古气候载体的研究成果,这些记录对72 ka BP左右的强降温事件和/或Toba火山喷发进行了不同程度的描述,并从不同的角度分析二者的关系。从72 ka BP左右的强降温事件和Toba火山喷发的时间上,以及火山喷发对气候变化影响的机理上看,Toba火山喷发确实对这次强降温事件产生了实质性影响。这个影响在格陵兰冰芯记录中表现得尤为明显,并得到了气候模拟的进一步支持。然而,部分低纬海洋记录研究表明,Toba火山喷发前后气候没有发生显著变化,至少低纬地区的气候不如高纬地区变化明显。古生物研究同时显示出Toba火山喷发并未对其生存环境产生灾难性的影响,由此可见,72 kaBP左右的强降温事件驱动机制及其对Toba火山喷发的响应程度尚存争议。今后的研究应重视提高气候记录分辨率和探测Toba火山喷发证据的研究,从解剖事件的内部结构特征入手,进而建立气候模式与火山效应之间的联系,以此来明确"72 ka事件"驱动机制及其对Toba火山喷发的响应关系。

The abrupt cooling event occurred about 72（the 72 ka Event） is the largest climate change during the last glacial period.At the same time a super-eruption of Toba volcano,the largest explosive eruption over the past two million years,erupted in northern Sumatra,with a Volcanic Explosivity Index of magnitude 8.It always deserves special attention for the relation between the 72 ka Event and the Toba Super-eruption.Therefore,an in-depth study of the 72 ka Event should be useful for further evaluating the environment effect of the eruption and refining the mechanism of the abrupt events during the last glacial period.Here,we make a systematic rewiew about the research achievements from different fields such as marine cores,ice cores,stalagmites,loess,lakes and so on.These records showed different expressions on the cold event occurred about 72 ka BP and/or the Toba eruption and their relations.Based on the timing of this cold event and the Toba eruption,and the operating mechanism of the volcanic eruption on climate,the eruption has substantial impact on climate.This impact is well documented by Greenland ice core records,and further supported by climate models.Nevertheless,marine core records in low latitudes did not exhibit an obvious climate change around the super eruption,and,at least,the amplitude of the variation is not strong as one in the high latitude.Also,paleontological evidences show that the Toba eruption did not make a catastrophic effect on the living environment.So,the relation between the 72 ka Event and the Toba Super-eruption is still being hotly debated.The further progress depends not only on developing resolution and chronological precision of climate records,but also on detecting the evidence of volcanic eruptions as well.