Enhanced ocean connectivity and volcanism instigated global onset of Cretaceous Oceanic Anoxic Event 2 (OAE2) ∼94.5 million years ago
Enhanced ocean connectivity and volcanism instigated global onset of Cretaceous Oceanic Anoxic Event 2 (OAE2) ∼94.5 million years ago
复制标题
海洋连通性和火山活动的增强导致了 9450 万年前的白垩纪海洋缺氧事件 2 (OAE2) 在全球爆发
DOI：
10.1016/j.epsl.2021.117331
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发表时间：
2022-01-15
影响因子：
5.3
通讯作者：
Li, Xianghui
中科院分区：
文献类型：
--
作者：
Li, Yong-Xiang;Liu, Xinyu;Li, Xianghui
海洋缺氧事件 2 (OAE2) 是白垩纪中期温室中全球海洋和气候变化的一个例证。然而，其全球启动的时间和机制仍然难以捉摸。在这里，我们报告了来自中国西藏南部扩大的 OAE2 区间的高分辨率初始锇同位素（Os-187/Os-188(i)，Os-i）和 delta C-13(org) 记录，该区间沉积在南半球。 Os-i 记录记录了间歇性、加剧的火山活动，其最高强度事件的特征是在大约 94.5 Ma 处发生了一次大的 Os-i 偏移，随后出现了大约 200 kyr 的 Os-i 最小值，并伴随着一段冷却间隔，这与北半球记录的普林斯冷事件 (PCE) 大致同步。此外，大的 Os-i 偏移比 OAE2 的发生滞后了大约 50 kyr，并且发生在基于与其他主要 OAE2 记录的高分辨率相关性的近乎同步的全球海侵期间。这些结果被解释为表明海洋连通性的增强在帮助触发大约 94.5 Ma 的 OAE2 全球爆发方面发挥了关键作用。 (c) 2021 Elsevier B.V. 保留所有权利。
Oceanic Anoxic Event 2 (OAE2) exemplifies an episode of global oceanographic and climatic changes in the mid-Cretaceous greenhouse. However, the timing and mechanism of its global initiation remain elusive. Here we report a high-resolution initial osmium isotope (Os-187/Os-188(i), Os-i) and delta C-13(org) record from an expanded OAE2 interval in southern Tibet, China that was deposited in the Southern Hemisphere. The Os-i record documents episodic, intensifying volcanism with the highest intensity episode marked by a large Os-i excursion at similar to 94.5 Ma and a subsequent similar to 200 kyr Os-i minimum concomitant with a cooling interval, which is broadly synchronous with the Plenus Cold Event (PCE) recorded in the Northern Hemisphere. Also, the large Os-i excursion lags the onset of OAE2 by similar to 50 kyr and occurred during a near synchronous global transgression based on high-resolution correlation with other major OAE2 records. These results are interpreted as indicating that enhanced ocean connectivity played a critical role in helping trigger the global onset of OAE2 at similar to 94.5 Ma. (c) 2021 Elsevier B.V. All rights reserved.