Tracing the source of ancient reworked organic matter delivered to the North Atlantic Ocean during Heinrich Events
Tracing the source of ancient reworked organic matter delivered to the North Atlantic Ocean during Heinrich Events
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DOI：
10.1016/j.gca.2017.02.008
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发表时间：
2017-05-15
影响因子：
5
通讯作者：
Zhang, Shunxin
中科院分区：
文献类型：
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作者：
Hefter, Jens;Naafs, B. David A.;Zhang, Shunxin
地球化学和古气候学界的一项主要工作是确定海因里希层（HLs）中浮冰碎屑（IRD）的具体来源。虽然普遍的共识是，大多数IRD起源于加拿大北部的哈德逊地区，但具体来源并没有得到很好的限制。在这里，我们将HLs的诊断性有机地球化学特征与Laurentide冰盖前边缘的许多古生代露头的有机地球化学特征进行了比较。结果表明，南安普敦和巴芬岛上奥陶统地层的生物标志物特征与拉布拉多海和北大西洋的HLs相一致，而Laurentide冰盖前边缘的其他古生代地层的生物标志物特征则不一致。除了生物标志物特征外，南安普敦和巴芬岛这些地层的关键无机特征（δ O-18、ε (Nd)和Sr-87/Sr-86比值）与HLs报告的结果一致。这些地层在哈德逊海峡内和周围的位置与穿过哈德逊海峡的古冰流状态相容，允许容易的夹带和快速的运输到海洋。基于这些结果，我们认为这些特殊的上奥陶统地层是高陆事件中IRD的主要来源，并由此推断哈德逊海峡古冰流在这些事件中发挥了积极作用。(C) 2017 Elsevier Ltd.版权所有。
A major effort of the geochemical and paleoclimate community has been to identify the specific sources of the ice- rafted debris (IRD) in Heinrich Layers (HLs). Although the general consensus is that the majority of the IRD originated from the Hudson area of northern Canada, the specific sources are not well constrained. Here we compare the diagnostic organic geochemical signature of HLs to that of a number of Paleozoic outcrops across the former margin of the Laurentide ice sheet.We show that the biomarker signature of Upper Ordovician strata from Southampton and Baffin Island is compatible with that found in HLs in the Labrador Sea and North Atlantic, while the biomarker signature of other Paleozoic formations from the former margin of the Laurentide ice sheet is not. In addition to the biomarker signature, key- inorganic characteristics (delta O-18, epsilon(Nd), and Sr-87/Sr-86 ratios) of these formations from Southampton and Baffin Island are consistent with those reported from HLs. The location of these formations in and around the Hudson Strait is compatible with palaeo-ice flow regimes through the Hudson Strait, allowing for easy entrainment and rapid transport to the ocean. Based on these results we propose that these specific Upper Ordovician formations form a main source of IRD in HLs and hence infer an active role of the Hudson Strait paleo-ice flow in these events. (C) 2017 Elsevier Ltd. All rights reserved.