Source, timing, frequency and flux of ice-rafted detritus to the Northeast Atlantic margin, 30-12 ka: testing the Heinrich precursor hypothesis
Source, timing, frequency and flux of ice-rafted detritus to the Northeast Atlantic margin, 30-12 ka: testing the Heinrich precursor hypothesis
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30-12 ka 期间冰筏碎屑流入东北大西洋边缘的来源、时间、频率和通量：检验海因里希前驱假说
DOI：
10.1111/j.1502-3885.2010.00141.x
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发表时间：
2010
期刊：
影响因子：
2.2
通讯作者：
HAAPANIEMI A
中科院分区：
文献类型：
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作者：
HAAPANIEMI A
海洋放射性碳弹脉冲时间历史的每年解决档案从温带地区一直未充分利用。我们在这里展示了来自北大西洋沿海4个地点（北海德国湾;挪威北部特特罗姆; Siglufjordur，北冰岛大陆架;格里姆西，北冰岛大陆架）的长寿双壳类软体动物Arctica islandica已知年龄年增量的Δ 14 C过量，结合乔治浅滩和黑貂浅滩（西北大西洋）以及牡蛎地（北海）发布的系列。大气炸弹脉冲被证明是一个阶跃函数，其在海洋环境中的响应是即时的，但幅度较小，并且由于海洋碳库大得多，因此具有较长的衰减时间。衰减是由区域水文环境的网站，垂直混合，控制14 C的同位素交换过程在空气-海洋边界，14 C含量的淡水通量，初级生产力，和沉积物混合层中的有机物质的停留时间。这些星表形成了一个从高震级-早高峰（German Bight）到低震级-晚高峰（Grimsey）的序列。所有系列都显示出对大气Δ 14 C过量增加的快速响应，但对随后的下降的缓慢响应，这是由于快速的同位素海气交换的连续性，以及由于海洋碳库的变化和来自沉积物混合层的有机碳的掺入而导致的混合层中更渐进的同位素平衡。这些数据构成了使用炸弹脉冲作为海洋环境中高分辨率测年工具和作为沿海海洋水团示踪剂的校准序列。
Marine radiocarbon bomb-pulse time histories of annually resolved archives from temperate regions have been underexploited. We present here series of Δ14C excess from known-age annual increments of the long-lived bivalve mollusk Arctica islandica from 4 sites across the coastal North Atlantic (German Bight, North Sea; Troms⊘, north Norway; Siglufjordur, north Icelandic shelf; Grimsey, north Icelandic shelf) combined with published series from Georges Bank and Sable Bank (NW Atlantic) and the Oyster Ground (North Sea). The atmospheric bomb pulse is shown to be a step-function whose response in the marine environment is immediate but of smaller amplitude and which has a longer decay time as a result of the much larger marine carbon reservoir. Attenuation is determined by the regional hydrographic setting of the sites, vertical mixing, processes controlling the isotopic exchange of 14C at the air-sea boundary, 14C content of the freshwater flux, primary productivity, and the residence time of organic matter in the sediment mixed layer. The inventories form a sequence from high magnitude-early peak (German Bight) to low magnitude-late peak (Grimsey). All series show a rapid response to the increase in atmospheric Δ14C excess but a slow response to the subsequent decline resulting from the succession of rapid isotopic air-sea exchange followed by the more gradual isotopic equilibration in the mixed layer due to the variable marine carbon reservoir and incorporation of organic carbon from the sediment mixed layer. The data constitute calibration scries for the use of the bomb pulse as a high-resolution dating tool in the marine environment and as a tracer of coastal ocean water masses.