Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8564, Japan.
University of Urbino, Carlo Bo, 61029, Urbino, Italy.
Nat Commun. 2022 Jan 11;13(1):239. doi: 10.1038/s41467-021-27817-0.
During the mid-Cretaceous, the Earth experienced several environmental perturbations, including an extremely warm climate and Oceanic Anoxic Events (OAEs). Submarine volcanic episodes associated with formation of large igneous provinces (LIPs) may have triggered these perturbations. The osmium isotopic ratio (Os/Os) is a suitable proxy for tracing hydrothermal activity associated with the LIPs formation, but Os/Os data from the mid-Cretaceous are limited to short time intervals. Here we provide a continuous high-resolution marine Os/Os record covering all mid-Cretaceous OAEs. Several OAEs (OAE1a, Wezel and Fallot events, and OAE2) correspond to unradiogenic Os/Os shifts, suggesting that they were triggered by massive submarine volcanic episodes. However, minor OAEs (OAE1c and OAE1d), which do not show pronounced unradiogenic Os/Os shifts, were likely caused by enhanced monsoonal activity. Because the subaerial LIPs volcanic episodes and Circum-Pacific volcanism correspond to the highest temperature and pCO during the mid-Cretaceous, they may have caused the hot mid-Cretaceous climate.
在白垩纪中期，地球经历了几次环境干扰，包括极其温暖的气候和海洋缺氧事件（OAEs）。与大火成岩省（LIPs）形成相关的海底火山事件可能引发了这些干扰。锇同位素比值（Os/Os）是追踪与 LIPs 形成相关的热液活动的合适示踪剂，但白垩纪中期的 Os/Os 数据仅限于短时间间隔。在这里，我们提供了一个涵盖整个白垩纪中期所有 OAE 的连续高分辨率海洋 Os/Os 记录。几个 OAE（OAE1a、Wezel 和 Fallot 事件以及 OAE2）对应于非放射性 Os/Os 变化，表明它们是由大规模海底火山事件引发的。然而，没有明显非放射性 Os/Os 变化的较小 OAE（OAE1c 和 OAE1d）可能是由增强的季风活动引起的。由于陆上 LIPs 火山事件和环太平洋火山活动与白垩纪中期的最高温度和 pCO 相对应，它们可能导致了白垩纪中期的炎热气候。
