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首页> 外文期刊>Paleoceanography >Millennial-scale variability to 735 ka: High-resolution climate records from Santa Barbara Basin, CA
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Millennial-scale variability to 735 ka: High-resolution climate records from Santa Barbara Basin, CA

机译：千年尺度变化至735 ka：加利福尼亚州圣巴巴拉盆地的高分辨率气候记录

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Determining the ultimate cause and effect of millennial-scale climate variability remains an outstanding problem in paleoceanography, partly due to the lack of high-resolution records predating the last glaciation. Recent cores from Santa Barbara Basin provide ～2500-5700 year "windows" of climate with ～10-50 year resolution. Ages for three cores, determined by seismic stratigraphic correlation, oxygen isotope stratigraphy, and biostratigraphy, date to ～293 ka (MIS 8), ～450 ka (MIS 12), and ～735 ka (MIS 18). These records sample the Late Pleistocene, during which the 100 kyr cycle strengthened and the magnitude of glacial-interglacial cyclicity increased. Thus, these records provide a test of the dependence of millennial-scale behavior on variations in glacial-interglacial cyclicity. The stable isotopic (δ~(18)O) composition of planktonic foraminifera shows millennial-scale variability in all three intervals, with similar characteristics (duration, cyclicity) to those previously documented during MIS 3 at this site. Stadial G. bulloides δ~(18)O values are 2.75-1.75‰ (average 2.25‰) and interstadial values are 1.75-0.5‰ (average 1‰), with rapid (decadal-scale) interstadial and stadial initiations of 1-2‰, as in MIS 3. Interstadials lasted ～250-1600 years and occurred every ～650-1900 years. Stadial paleotemperatures were 3.5-9.5°C and interstadial paleotemperatures were 7.5-13°C. Upwelling, evidenced by planktonic foraminiferal assemblages and δ~(13)C, increased during interstadials, similar to MIS 3; high productivity during some stadials was reminiscent of the Last Glacial Maximum. This study builds upon previous records in showing that millennial-scale shifts were an inherent feature of Northern Hemisphere glacial climates since 735 ka, and they remained remarkably constant in the details of their amplitude, cyclicity, and temperature variability. Key Points Discrete intervals in Santa Barbara Basin cores show D/O-like shifts to 735 kaCores have ～10-50 year resolutionMillennial-scale climate shifts in all cores are similar to those during MIS 3
机译：确定千年尺度气候变化的最终原因和影响仍然是古海洋学中的一个突出问题，部分原因是最后一次冰川消融之前缺乏高分辨率记录。来自圣塔芭芭拉盆地的最新岩心提供了〜2500-5700年的“窗口”，分辨率约为10-50年。由地震地层相关性，氧同位素地层学和生物地层学确定的三个岩心的年龄可追溯至〜293 ka（MIS 8），〜450 ka（MIS 12）和〜735 ka（MIS 18）。这些记录对晚更新世进行了采样，在此期间，100 kyr周期加强，冰川-冰川间的周期性增加。因此，这些记录提供了对千年尺度行为对冰川-冰川间周期性变化的依赖性的检验。浮游有孔虫的稳定同位素（δ〜（18）O）成分在所有三个间隔中均表现出千年尺度的变化，其特征（持续时间，周期性）与以前在该站点的MIS 3记录的相似。 Sta.ial G. Bulloidesδ〜（18）O值为2.75-1.75‰（平均2.25‰），际值是1.75-0.5‰（平均1‰），快速（年代际尺度）的stadial和stadial初始化为1-2 ‰，如MIS 3中所示。间断持续〜250-1600年，每〜650-1900年发生一次。球场古温度为3.5-9.5°C，球场间古温度为7.5-13°C。上升期，由浮游有孔虫的组合和δ〜（13）C证实，在上升期增加，类似于MIS 3。在某些休耕期的高生产率让人联想到上次冰川期最高峰。这项研究建立在以前的记录的基础之上，表明千禧年尺度的变化是自735 ka以来北半球冰川气候的固有特征，并且在幅度，周期性和温度变化方面，它们都保持了非常稳定的状态。关键点圣塔芭芭拉盆地岩心的离散间隔显示D / O样变化到735 ka岩心具有〜10-50年的分辨率所有核心的千年尺度气候变化与MIS 3期间的相似

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