A better-ventilated ocean triggered by Late Cretaceous changes in continental configuration.
A better-ventilated ocean triggered by Late Cretaceous changes in continental configuration.
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DOI：
10.1038/ncomms10316
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发表时间：
2016-01-18
影响因子：
16.6
通讯作者：
Deconinck JF
中科院分区：
文献类型：
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作者：
Donnadieu Y;Pucéat E;Moiroud M;Guillocheau F;Deconinck JF
海洋缺氧事件（OAEs）是发生在前新生代极端温暖时期的大规模深海缺氧事件。在这里，主要大陆配置变化发生在晚白垩世的海洋环流模式，这反过来又影响深海的氧化水平的作用进行评估，我们使用一个耦合的海洋大气气候模型。我们模拟海洋动力学在两个不同的时间片，并比较这些与现有的钕同位素数据（钕钕）。虽然北太平洋的深水生产是连续的，但94和71 Ma的模拟显示，南部深水生产地点从南太平洋转移到南大西洋和印度洋。我们的模拟结果支持这一假设，即加强南大西洋深水生产和逆转的深水通量通过加勒比海航道的主要原因是减少记录在大西洋和印度深水沃茨值在晚白垩世。 在地球历史上，海洋大规模氧气耗尽事件的时间仍然知之甚少。在这里，作者表明，古地理是白垩纪期间的一个主要预处理因素，这意味着目前转向全球缺氧的阈值可能要高得多。
Oceanic anoxic events (OAEs) are large-scale events of oxygen depletion in the deep ocean that happened during pre-Cenozoic periods of extreme warmth. Here, to assess the role of major continental configuration changes occurring during the Late Cretaceous on oceanic circulation modes, which in turn influence the oxygenation level of the deep ocean, we use a coupled ocean atmosphere climate model. We simulate ocean dynamics during two different time slices and compare these with existing neodymium isotope data (ɛNd). Although deep-water production in the North Pacific is continuous, the simulations at 94 and 71 Ma show a shift in southern deep-water production sites from South Pacific to South Atlantic and Indian Ocean locations. Our modelling results support the hypothesis that an intensification of southern Atlantic deep-water production and a reversal of deep-water fluxes through the Caribbean Seaway were the main causes of the decrease in ɛNd values recorded in the Atlantic and Indian deep waters during the Late Cretaceous. In the Earth's history, the timing of oceanic large-scale events of oxygen depletion remains poorly understood. Here, the authors show that palaeogeography was a major preconditioning factor during the Cretaceous, implying that thresholds to shift toward a global anoxia are likely to be much higher at present.