Variability of surface water characteristics and Heinrich-like events in the Pleistocene midlatitude North Atlantic Ocean: Biomarker and XRD records from IODP Site U1313 (MIS 16-9)
Variability of surface water characteristics and Heinrich-like events in the Pleistocene midlatitude North Atlantic Ocean: Biomarker and XRD records from IODP Site U1313 (MIS 16-9)
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DOI：
10.1029/2008pa001639
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发表时间：
2009-06
期刊：
影响因子：
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通讯作者：
R. Stein;J. Hefter;J. Grützner;A. Voelker;B. Naafs
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文献类型：
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作者：
R. Stein;J. Hefter;J. Grützner;A. Voelker;B. Naafs
[1]重建Milankovitch的千年尺度变化的海表温度（SST）和海表生产力在更新世中纬度北大西洋（海洋同位素阶段（MIS）16-9）及其与冰盖不稳定性的关系进行了从综合大洋钻探计划（IODP）站点U1313的沉积物。该重建是基于烯酮和正构烷烃的浓度，U37 K ′指数，总有机碳（TOC）和碳酸盐含量，X射线衍射数据，磁化率和积累速率。增加输入的冰筏碎片发生在MIS 16，12，和10，其特点是高浓度的白云石，石英，晶石和陆源物质的积累率升高。另一方面，确定了MIS 13和11的陆源物质最小输入值。白云岩的峰值，与石英，斜长石，钾长石的峰值和最大值的长链正构烷烃指示陆地植物，被解释为海因里希样的事件有关的突然不稳定的Laurentide冰盖在早期和晚期（冰消）阶段的冰川。增加TOC值的绝对浓度升高的烯酮的巧合表明增加冰川生产力，可能是由于更南部的位置的极锋。基于烯酮的SST在MIS 11.3期间达到约19°C的绝对最大值，并且在MIS 12和10期间达到<10°C的绝对最小值。在MIS 11中，发生了显著的冷却事件（MIS 11.22和11.24）。绝对SST极小值记录直接之前和之后的冰川极大MIS 10.2和12.2有关的海因里希事件融水脉冲，支持的SST极小值和极大值的巧合C37：4烯酮和白云石。这些突然的融水脉冲，特别是在终止IV和V，可能导致浮游植物生产力的崩溃所示的烯酮浓度的明显下降。冰盖解体和随后的冰山和融水排放的激增和爆发可能是由北方高纬度地区日照增加引发的。
[1] A reconstruction of Milankovitch to millennial-scale variability of sea surface temperature (SST) and sea surface productivity in the Pleistocene midlatitude North Atlantic Ocean (marine isotope stage (MIS) 16–9) and its relationship to ice sheet instability was carried out on sediments from Integrated Ocean Drilling Program (IODP) Site U1313. This reconstruction is based on alkenone and n-alkane concentrations, U37K′ index, total organic carbon (TOC) and carbonate contents, X-ray diffraction data, magnetic susceptibility, and accumulation rates. Increased input of ice-rafted debris occurred during MIS 16, 12, and 10, characterized by high concentrations of dolomite, quartz, and feldspars and elevated accumulation rates of terrigenous matter. Minimum input values of terrigenous matter, on the other hand, were determined for MIS 13 and 11. Peak values of dolomite, coinciding with quartz, plagioclase, and kalifeldspar peaks and maxima in long-chain n-alkanes indicative for land plants, are interpreted as Heinrich-like events related to sudden instability of the Laurentide Ice Sheet during early and late (deglacial) phases of the glacials. The coincidence of increased TOC values with elevated absolute concentrations of alkenones suggests increased glacial productivity, probably due to a more southern position of the Polar Front. Alkenone-based SST reached absolute maxima of about 19°C during MIS 11.3 and absolute minima of <10°C during MIS 12 and 10. Within MIS 11, prominent cooling events (MIS 11.22 and 11.24) occurred. The absolute SST minima recorded directly before and after the glacial maxima MIS 10.2 and 12.2 are related to Heinrich-like event meltwater pulses, as supported by the coincidence of SST minima and maxima in C37:4 alkenones and dolomite. These sudden meltwater pulses, especially during terminations IV and V, probably caused a collapse of phytoplankton productivity as indicated by the distinct drop in alkenone concentrations. Ice sheet disintegration and subsequent surges and outbursts of icebergs and meltwater discharge may have been triggered by increased insolation in the northern high latitudes.