Iron fertilisation and biogeochemical cycles in the sub-Arctic northwest Pacific during the late Pliocene intensification of northern hemisphere glaciation
Iron fertilisation and biogeochemical cycles in the sub-Arctic northwest Pacific during the late Pliocene intensification of northern hemisphere glaciation
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DOI：
10.1016/j.epsl.2011.05.029
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发表时间：
2011-07-15
影响因子：
5.3
通讯作者：
Roberts, Andrew P.
中科院分区：
文献类型：
--
作者：
Bailey, Ian;Liu, Qingsong;Roberts, Andrew P.
在低场质量特定的磁化率（chi），dropstones和陆源沉积物成分从大洋钻探计划（ODP）网站882（类似于45度N）的增加已被解释为表明一个主要的发病冰漂流到亚北极西北太平洋在海洋同位素阶段（MIS）G6（从类似于2.75 Ma）。相比之下，对ODP 882号站点下风处取芯沉积物中陆源物质含量的研究表明，在MIS G6期间，亚北极太平洋的灰尘和弥散性火山灰沉积显著增加。为了调查尘埃，火山灰和冰筏上新世chi增加的相对贡献，我们提出了新的高分辨率的环境磁性和冰筏碎片记录ODP网站882和885。我们的研究结果表明，在MIS G6的两个站点的chi增加主要是由以前被忽视的风尘和火山灰的混合物控制。我们的研究结果质疑气作为北太平洋冰筏漂流的代表的可靠性。他们还强调了一个以前没有记录的铁施肥和地球化学循环之间的联系，在一个关键阶段，在晚上新世北方半球冰川作用的加剧。(C)2011 Elsevier B.V.保留所有权利。
Increases in the low-field mass-specific magnetic susceptibility (chi), dropstones and the terrigenous sediment component from Ocean Drilling Program (ODP) Site 882 (similar to 45 degrees N) have been interpreted to indicate a major onset of ice-rafting to the sub-Arctic northwest Pacific Ocean during marine isotope stage (MIS) G6 (from similar to 2.75 Ma). In contrast, studies of the terrigenous content of sediments cored downwind of ODP Site 882 indicate that dust and disseminated volcanic ash deposition in the sub-Arctic Pacific increased markedly during MIS G6. To investigate the relative contribution of dust, volcanic ash and ice rafting to the Pliocene chi increase, we present new high-resolution environmental magnetic and ice-rafted debris records from ODP Sites 882 and 885. Our results demonstrate that the chi increase at both sites across MIS G6 is predominantly controlled by a previously overlooked mixture of aeolian dust and volcanic ash. Our findings call into question the reliability of chi as a proxy for ice-rafting to the North Pacific. They also highlight a previously undocumented link between iron fertilisation and biogeochemical cycling in the North Pacific at a key stage during intensification of late Pliocene northern hemisphere glaciation. (C) 2011 Elsevier B.V. All rights reserved.