The Mt Logan Holocene-late Wisconsinan isotope record: Tropical Pacific-Yukon connections
The Mt Logan Holocene-late Wisconsinan isotope record: Tropical Pacific-Yukon connections
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DOI：
10.1177/0959683608092236
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发表时间：
2008-08-01
期刊：
影响因子：
2.4
通讯作者：
Rupper, Summer
中科院分区：
文献类型：
--
作者：
Fisher, David;Osterberg, Erich;Rupper, Summer
在育空地区洛根山（海拔5.4公里）的探矿者罗素科尔（Prospector Russell Col）发现的冰芯跨度超过2万年。这一独特的记录提供了从冰川期到现在的稳定同位素和化学记录的太平洋观点。时间尺度是基于季节性计算年，已知最大的火山酸特征以及新仙女木期末期稳定同位素和化学的主要变化。稳定同位素记录存在与海相和陆相化学序列反相关的大而持续的变化。该地区的氧-18不是古温度的代表，而是源区的代表。最后一次主要同位素转变发生在公元1840年的三角洲（O-18）和化学上，并与Quinn的ENSO记录进行了比较。在拉尼娜现象更频繁的时期（更强的热带东风），有更多的纬向水汽输送到太平洋西北部，三角洲（O-18）值较大，氘过量d较小。这些时期与育空地区南部降水减少的时期相吻合。全新世三角洲（O-18）记录表明经向（强厄尔尼诺）和纬向（拉尼娜）之间有许多大的转变。Logan同位素记录与西北泥炭沼泽开始日期的湿度/温度敏感时间序列的比较显示出很强的相关性（0.36），表明高积累速率与低δ (O-18)和增强的经向流相一致。4200 BP和7000-8000 BP的核心变化表明经向流增强，这与厄尔尼诺和拉尼娜之间平衡的太平洋古记录的大变化相吻合，4200 BP似乎开启了“现代”ENSO世界。
The ice core recovered from Prospector Russell Col on Mt Logan (5.4 km a.s.l.), in the Yukon spans over 20 000 years. This unique record offers a Pacific view of the stable isotope and chemical record from the Lateglacial to the present. The timescale is based on seasonal counted years, the largest known volcanic acid signatures and the major shift in stable isotopes and chemistry at the end of the Younger Dryas. There are large and sustained changes in the stable isotopic record that are anti-correlated with marine and continental chemistry series. The oxygen-18 in this area is not a proxy for palaeotemperature but rather for source region. The last major isotope shift in AD 1840 in delta(O-18) and chemistry is compared with the Quinn's ENSO record. During periods of more frequent La Nina (stronger tropical easterlies) there is more zonal flow of water vapour transport to the Pacific Northwest, delta(O-18) values are larger and the deuterium excess d smaller. These periods coincide with periods of lower accumulation/precipitation in southern Yukon. The Holocene delta(O-18) record indicates many large shifts between the meridional (strong El Nino) and zonal (La Nina). Comparison of the Logan isotopic record and the moisture/temperature-sensitive time series of peat bog inception dates for the Northwest shows a strong correlation (0.36) that points to high accumulation rates coincident with low delta(O-18) and enhanced meridional flow. Major changes in the core at 4200 BP and 7000-8000 BP point to enhanced meridional flow, which coincide with big changes in the Pacific palaeorecords of the balance between El Nino and La Nina. 4200 BP seems to have inaugurated the 'modern' ENSO world.