Super greenhouse temperatures at the onset of the Cenomanian‐Turonian oceanic anoxic event (OAE 2) have been widely linked with large igneous province (LIP) volcanic activity. However, the extent to which volcanism influenced subsequent climate changes throughout OAE 2, such as global cooling during the Plenus Cold Event (PCE) early in the OAE, and the subsequent return to very warm conditions through the second part of the crisis remain less clear. Here, new osmium‐isotope (¹⁸⁷Os/¹⁸⁸Os) data are presented from the northeastern margin of the proto‐North Atlantic Ocean (ODP Leg 174AX Bass River, NJ, USA). The results are consistent with previously published OAE 2 records and are similarly interpreted as documenting LIP activity while further demonstrating the ability to use osmium‐isotope stratigraphy as a global chemostratigraphic marker in open‐ocean records. Correlations of ¹⁸⁷Os/¹⁸⁸Os and sea‐surface temperature trends at Bass River and other sites show that the earliest PCE cooling coincided with intense volcanism, but that LIP activity began to decline during or soon after the cold pulse. These temporal relationships support previous hypotheses that the PCE was regionally diachronous and likely caused by enhanced carbon sequestration via organic‐matter burial and silicate weathering, rather than a period of volcanic quiescence, while the persistently warm conditions later in OAE 2 were linked to reduced silicate weathering rather than sustained volcanism. These findings highlight the complex interactions between LIP emplacement and climate responses during OAE 2, reemphasizing the need for similar correlations between volcanism and paleotemperature proxy data for other major events in Earth's history.

中文翻译：

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大的火成岩的省位与全球温度变化之间的复杂相互作用，在塞诺曼尼亚-土伦的海洋缺氧事件（OAE 2）中

Cenomanian-Turonian海洋缺氧事件（OAE 2）发生时的超级温室温度与大型火成岩省（LIP）火山活动广泛相关。但是，在整个OAE 2中，火山活动对随后的气候变化的影响程度（如在OAE初期的Plenus Cold Event（PCE）期间的全球降温以及在危机的第二部分随后恢复到非常温暖的条件）的程度仍不清楚。在这里，新的iso同位素（¹⁸⁷ Os / ¹⁸⁸Os）数据来自原始北大西洋的东北边缘（ODP Leg 174AX Bass River，美国新泽西州）。结果与先前发表的OAE 2记录一致，并被类似地解释为记录LIP活性，同时进一步证明了在开放海洋记录中使用同位素地层作为全球化学地层标记的能力。¹⁸⁷ Os / ^188的相关性巴斯河和其他站点的Os和海面温度趋势表明，最早的PCE降温与强烈的火山活动同时发生，但是LIP活性在冷脉动期间或之后开始下降。这些时间关系支持先前的假设，即PCE在区域上是不同步的，并且可能是由于有机物埋藏和硅酸盐风化而不是一段时间的火山静止而使碳固存增加，而OAE 2后期的持续温暖条件与减少的硅酸盐有关风化而不是持续的火山作用。这些发现强调了在OAE 2期间LIP进位与气候响应之间的复杂相互作用，再次强调了地球历史上其他重大事件的火山作用与古温度替代数据之间也需要类似的关联。