Continental aridification and the vanishing of Australia's megalakes
Continental aridification and the vanishing of Australia's megalakes
复制标题
DOI：
10.1130/g31518.1
复制
发表时间：
2011-02-01
期刊：
影响因子：
5.8
通讯作者：
Hellstrom, John C.
中科院分区：
文献类型：
--
作者：
Cohen, Tim J.;Nanson, Gerald C.;Hellstrom, John C.
澳大利亚气候的性质在快速巨型动物灭绝和人类到达澳大利亚的时间是知之甚少，是一个重要因素，在有争议的辩论，是否人类或气候造成的灭绝。在这里，我们提出了一个新的古海岸线年表，在过去的100 k. y延伸。对于Mega-弗罗姆湖来说，这是澳大利亚中部南纬度地区的弗罗姆湖、布兰奇湖、卡拉博纳湖和格雷戈里湖的合并。我们发现，Mega-Frome湖最后一次连接到相邻的湖在50-47万年，形成了最大的古湖泊在澳大利亚大陆上剩余的相互连接的系统。最后的断开和Mega-Frome湖水位的逐步下降代表着气候向干旱化的重大转变，这与人类的到来和巨型动物的灭绝相吻合。在第四纪的不同时期，澳大利亚大陆的水分供应通常被归因于季风的增强。这项研究，结合其他古气候数据，提供了可靠的证据，在最后一个完整的冰期周期的不同时间，增强热带和增强南大洋的水填充这些湖泊的来源。
The nature of the Australian climate at about the time of rapid megafaunal extinctions and humans arriving in Australia is poorly understood and is an important element in the contentious debate as to whether humans or climate caused the extinctions. Here we present a new paleoshoreline chronology that extends over the past 100 k.y. for Lake Mega-Frome, the coalescence of Lakes Frome, Blanche, Callabonna and Gregory, in the southern latitudes of central Australia. We show that Lake Mega-Frome was connected for the last time to adjacent Lake Eyre at 50-47 ka, forming the largest remaining interconnected system of paleolakes on the Australian continent. The final disconnection and a progressive drop in the level of Lake Mega-Frome represents a major climate shift to aridification that coincided with the arrival of humans and the demise of the megafauna. The supply of moisture to the Australian continent at various times in the Quaternary has commonly been ascribed to an enhanced monsoon. This study, in combination with other paleoclimate data, provides reliable evidence for periods of enhanced tropical and enhanced Southern Ocean sources of water filling these lakes at different times during the last full glacial cycle.