Younger Dryas "black mats" and the Rancholabrean termination in North America
Younger Dryas "black mats" and the Rancholabrean termination in North America
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DOI：
10.1073/pnas.0800560105
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发表时间：
2008-05-06
影响因子：
11.1
通讯作者：
Haynes, C. Vance, Jr.
中科院分区：
文献类型：
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作者：
Haynes, C. Vance, Jr.
在本研究的97个连接更新世-全新世过渡时期的地质考古遗址中，（末次冰消期），大约三分之二的化石具有黑色的富含有机物的层或“黑垫”，其形式为软质古土壤、水螅、藻席或藻类垫，放射性碳年龄表明它们是新仙女木冷却期10，900 B. P.至9，800 B. P.（放射性碳年）的地层表现。这一层或垫覆盖了克洛维斯时代的景观或表面，在其上记录了晚期更新世巨型动物的最后遗迹。从地层学和年代学上看，这次灭绝似乎是灾难性的，似乎太突然和广泛，无论是人类捕食还是气候变化都不是主要原因。这突然终止Rancholabrean在10，900 50 B. P.似乎已经与突然的气候切换从Allerod变暖到新仙女木冷却。最近关于地外撞击的证据，虽然还不令人信服，但需要进一步的测试，因为在10，900 B. P.发生了一个值得注意的重大扰动，需要解释。
Of the 97 geoarchaeological sites of this study that bridge the Pleistocene-Holocene transition (last deglaciation), approximately two thirds have a black organic-rich layer or "black mat" in the form of mollic paleosols, aquolls, diatomites, or algal mats with radiocarbon ages suggesting they are stratigraphic manifestations of the Younger Dryas cooling episode 10,900 B.P. to 9,800 B.P. (radiocarbon years). This layer or mat covers the Clovis-age landscape or surface on which the last remnants of the terminal Pleistocene megafauna are recorded. Stratigraphically and chronologically the extinction appears to have been catastrophic, seemingly too sudden and extensive for either human predation or climate change to have been the primary cause. This sudden Rancholabrean termination at 10,900 50 B.P. appears to have coincided with the sudden climatic switch from Allerod warming to Younger Dryas cooling. Recent evidence for extraterrestrial impact, although not yet compelling, needs further testing because a remarkable major perturbation occurred at 10,900 B.P. that needs to be explained.