A late Pleistocene–Mid‐Holocene noble gas and stable isotope climate and subglacial record in southern Michigan
A late Pleistocene–Mid‐Holocene noble gas and stable isotope climate and subglacial record in southern Michigan
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密歇根州南部更新世晚期-全新世中期稀有气体和稳定同位素气候和冰下记录
DOI：
10.1029/2012gl053098
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发表时间：
2012
影响因子：
5.2
通讯作者：
K. C. Lohmann
中科院分区：
文献类型：
--
作者：
M. Castro;R. Warrier;C. Hall;K. C. Lohmann
密歇根州南部萨吉诺含水层的稳定同位素(δD，δ18O)和14C测年表明，在最后一次冰盛期之后，晚更新世劳伦蒂德冰盖对冰下融水的贡献高达36%。观测到前几次冰期的贡献率高达74%。连同马歇尔记录[Ma等人，2004年]，稀有气体温度(NGT)和来自萨吉诺含水层的过剩空气(Ea)首次被捕获，年轻仙女木(∼12.9KYR BP)的开始，伴随着∼3.3°C的冷却和更干燥的条件。还发现了中全新世(MH)气候变化，变暖(∼2.9°C)，从∼5.4KYR BP开始干旱加剧，然后在∼4.1KYR BP逆转到更凉爽、更潮湿的条件。除了最后一次MH倒转外，稳定同位素记录与NGT和EA记录相似。δ18O和上一次MH倒转中的重氢过剩显示的对比趋势表明，来自墨西哥湾的水蒸气输送增强。
Stable isotopes (δD, δ18O) and 14C derived ages in the Saginaw aquifer in southern Michigan suggest subglacial meltwater contributions from the Laurentide Ice Sheet of up to 36% in the late Pleistocene, following the Last Glacial Maximum. Contributions of up to 74% from previous glaciation periods are observed. Together with the Marshall record [ Ma et al., 2004 ], noble gas temperatures (NGTs) and excess air (EA) from the Saginaw aquifer capture, for the first time, the onset of the Younger Dryas (∼12.9 kyr BP) with a ∼3.3°C cooling accompanied by drier conditions. Mid‐Holocene (MH) climatic shifts are also identified, with warming (∼2.9°C), increased aridity starting at ∼5.4 kyr BP followed by reversal to cooler, humid conditions at ∼4.1 kyr BP. Except for the last MH reversal, the stable isotope record mimics the NGT and EA records. Contrasting trends displayed byδ18O and deuterium‐excess in the last MH reversal suggests enhanced vapor transport from the Gulf of Mexico.