Carbonate ions, orbits and Mg/Ca at ODP 1123
Carbonate ions, orbits and Mg/Ca at ODP 1123
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DOI：
10.1016/j.gca.2018.03.013
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发表时间：
2018-09
影响因子：
5
通讯作者：
S. Crowhurst;H. Pälike;R. Rickaby
中科院分区：
文献类型：
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作者：
S. Crowhurst;H. Pälike;R. Rickaby
镁/钙古温度指标的准确性一直受到质疑，特别是因为有孔虫测试中的镁/钙比可能受到深水碳酸盐离子浓度局部或全球变化的影响。与这项技术有关的一个问题是，它与轨道偏心率的相位关系有问题：中水和深水的镁/钙记录通常显示出相对于轨道偏心率的相位领先。这让人质疑镁/钙古温度指标的有效性，或者轨道偏心率与100KYR气候振荡同步的假设，或者两者兼而有之。本文讨论了这些问题，并提出在ODP1123观测到的这种类型的相铅不太可能是由碳酸盐离子效应产生的，而可能是由于低偏心率事件期间海洋中的热储存。
The accuracy of the magnesium/calcium palaeotemperature proxy has been questioned, in particular because the ratio of magnesium to calcium in foraminiferal tests could be affected by local or global changes in carbonate ion concentrations in deep water. A related question regarding the technique is its problematic phase relationship to orbital eccentricity: Mg/Ca records of intermediate and deep waters typically show a phase lead with respect to orbital eccentricity. This calls into question either the validity of the Mg/Ca palaeotemperature proxy, or the assumption that orbital eccentricity is pacing the 100 kyr climate oscillations, or both. This paper addresses these questions, and suggests that a phase lead of the type observed at ODP 1123 is unlikely to be generated by the operation of the carbonate ion effect, and might be attributable to heat storage in the oceans during low eccentricity episodes.