Milankovitch‐paced Termination II in a Nevada speleothem?
Milankovitch‐paced Termination II in a Nevada speleothem?
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DOI：
10.1029/2011gl048560
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发表时间：
2011-09
影响因子：
5.2
通讯作者：
J. Shakun;S. Burns;P. Clark;Hai Cheng;R. Edwards
中科院分区：
文献类型：
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作者：
J. Shakun;S. Burns;P. Clark;Hai Cheng;R. Edwards
来自内华达州大盆地的魔鬼洞方解石记录首次提供了晚更新世气候波动的辐射测年时间序列。在此过程中，卫生署提出倒数第二次冰川消融，即终止II(T-II)，发生在142ka±3ka，即夏季日照上升之前的∼10Kyr，这有助于引发米兰科维奇的“因果关系问题”。自那以后，对卫生署记录的解释一直受到相当大的讨论。我们提出了第一次尝试，以来自内华达州雷曼洞穴的石笋为基础，重现大盆地早期T-II的DH记录，雷曼洞穴位于魔鬼洞东北400公里处的∼。我们的洞穴记录至少记录了T-II在∼133ka-129ka生长期的后半部分，这似乎与DH中T-II的早期时间不一致。在过去的两次冰川消融中，dh也显示出与许多其他古气候记录的重要差异，尽管在冰量校正dhδ18O后，这些记录有所减少。我们认为，该记录中的气候信号仍有待充分解释。
The Devils Hole (DH) calcite record from the Great Basin, Nevada, provided the first radiometrically dated time series of late‐Pleistocene climate fluctuations,. In doing so, DH suggested that the penultimate deglaciation, Termination II (T‐II), occurred at 142 ± 3 ka, which is ∼10 kyr before the associated rise in summer insolation, helping to launch the “causality problem” for Milankovitch. The interpretation of the DH record has been subject to considerable discussion ever since. We present the first attempt to reproduce the DH record of an early T‐II in the Great Basin based on a stalagmite from Lehman Caves, Nevada, which is ∼400 km northeast of Devils Hole. Our speleothem records at least the latter part of T‐II over its period of growth from ∼133–129 ka, which appears to disagree with the early timing of T‐II in DH. DH also exhibits important differences from many other paleoclimate records over the past two deglaciations, though these are reduced somewhat after ice‐volume correcting DH δ18O. We suggest that the climatic signal in the DH record remains to be fully explained.