Radiocarbon chronology of the last glacial maximum and its termination in northwestern Patagonia
Radiocarbon chronology of the last glacial maximum and its termination in northwestern Patagonia
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DOI：
10.1016/j.quascirev.2015.05.027
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发表时间：
2015-08
影响因子：
4
通讯作者：
P. Moreno;G. Denton;H. Moreno;T. Lowell;A. Putnam;A. Putnam;M. Kaplan
中科院分区：
文献类型：
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作者：
P. Moreno;G. Denton;H. Moreno;T. Lowell;A. Putnam;A. Putnam;M. Kaplan
我们研究了位于南美洲中纬度巴塔哥尼亚西北部末次盛冰期 (LGM) 和末次盛冰期 (LGT) 的时间和强度。我们的数据表明，LGT的主要阶段始于距今17,800和17,100卡的突然暖脉冲，伴随着常绿温带雨林的快速建立和安第斯山脉在1000年内的广泛冰川消融。这一响应表明，南美中纬度地区的气温已接近间冰期平均温度 16,800 卡路里。 BR 巴塔哥尼亚西北部的气温上升，与太平洋对岸的南中纬度地区的新西兰南阿尔卑斯山开始大幅变暖和冰川退缩同时发生。从这一对应关系来看，从距今 17,800 卡路里开始的变暖似乎在南半球中纬度地区广泛存在，至少占从末次盛冰期到全新世总温度恢复的 75%。此外，这种变暖脉冲与北大西洋地区的 Heinrich Stadial 1 (HS1) 的上半部分同时发生。 HS1的特点是北大西洋经向翻转环流减弱，两半球西风带和热带辐合带南移，亚洲季风减弱。除了引发触发因素外，确定两个极地半球这些相反的气候信号相互作用的机制，无论是通过海洋还是大气双极跷跷板，或者两者兼而有之，都是理解 LGT 的核心。
We examine the timing and magnitude of the last glacial maximum (LGM) and the last glacial termination (LGT) in northwestern Patagonia, situated in the middle latitudes of South America. Our data indicate that the main phase of the LGT began with abrupt warm pulses at 17,800 and 17,100 cal yrs BP, accompanied by rapid establishment of evergreen temperate rainforests and extensive deglaciation of the Andes within 1000 years. This response shows that South American middle-latitude temperatures had approached average interglacial values by 16,800 cal yrs BR The temperature rise in northwestern Patagonia coincides with the beginning of major warming and glacier recession in the Southern Alps of New Zealand at southern mid-latitudes on the opposite side of the Pacific Ocean. From this correspondence, the warming that began at 17,800 cal yrs BP appears to have been widespread in middle latitudes of the Southern Hemisphere, accounting for at least 75% of the total temperature recovery from the LGM to the Holocene. Moreover, this warming pulse is coeval with the first half of the Heinrich Stadial 1 (HS1) in the North Atlantic region. HS1 featured a decline of North Atlantic meridional overturning circulation, a southward shift of the westerly wind belt in both hemispheres and of the Inter-tropical Convergence Zone, as well as a weakening of the Asian monsoon. Along with the initiating trigger, identifying the mechanisms whereby these opposing climate signals in the two polar hemispheres interacted whether through an oceanic or an atmospheric bipolar seesaw, or both-lies at the heart of understanding the LGT.