Widespread oceanic anoxia, biological crises, and volcanic activity are associated with the onset of Early Aptian (ca. 120 Ma) Oceanic Anoxic Event 1a (OAE1a). Reconstructions of oceanic deoxygenation and its links to broadly contemporaneous volcanism, however, remain poorly resolved. We use geochemical data, including δ53Cr ratios and rare Earth element abundances, to define the timing and tempo of submarine volcanism and global oceanic deoxygenation across this event. Pacific Ocean sediments deposited in the run up to OAE1a record multiple phases of marine volcanism associated with the emplacement of Ontong Java Plateau lavas. Rapid oceanic deoxygenation followed the initial phases of volcanism and a biocalcification crisis. Large swaths of the oceans likely became anoxic from the Tethys to the Pacific Oceans in <30 k.y. Oceanic anoxia persisted for almost one million years after this and was likely sustained through intensified continental and submarine weathering. These results paint a new picture of OAE1a in which volcanism, biological crisis, and oceanic deoxygenation are separated in time and linked through Earth system responses that operate on time scales of tens of thousands of years.

中文翻译：

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海洋缺氧事件 1a 期间的脉冲火山活动和快速海洋脱氧

广泛的海洋缺氧、生物危机和火山活动与早期阿普提阶（约 120 Ma）海洋缺氧事件 1a (OAE1a) 的发生有关。然而，海洋脱氧的重建及其与广泛同时期火山活动的联系仍未得到很好的解决。我们使用地球化学数据，包括 δ53Cr 比率和稀土元素丰度，来定义整个事件中海底火山活动和全球海洋脱氧的时间和节奏。在 OAE1a 之前沉积的太平洋沉积物记录了与 Ontong Java 高原熔岩侵位相关的多个海洋火山活动阶段。在火山作用和生物钙化危机的初始阶段之后，海洋迅速脱氧。从特提斯到太平洋的大片海洋可能在 <30 ky 内变得缺氧 在此之后，海洋缺氧持续了近一百万年，并且很可能是通过大陆和海底风化加剧而持续的。这些结果描绘了 OAE1a 的新图景，其中火山活动、生物危机和海洋脱氧在时间上是分开的，并通过在数万年时间尺度上运行的地球系统响应而联系起来。