西班牙萨拉戈萨大学L. Alegret团队研究了始新世早期温室西南太平洋底水形成强化。该项研究成果发表在2025年3月27日出版的《地质学》杂志上。

早始新世气候最佳期（EECO；53−49 Ma），即地球经历新生代地表温度峰值时，为海洋环流如何在增强的温室气候条件下运作提供了一个测试案例。该主题处于当前地球科学的前沿，但在此极端气候期间海洋环流的演变仍未得到解决，尤其是在高纬度地区。研究组展示了南部高纬度地区钕同位素值的第一个高分辨率记录（国际海洋发现计划U1510站点），这是一个追踪海底水的替代物。

EECO中部塔斯曼海海水ε_Nd（t）的显著负移可能是由新的底层水团驱动的，太平洋的南极部分是明显的来源。与塔斯曼海其他地点的低分辨率研究相比，表明在EECO期间，一个新的中间水源从塔斯曼海流入太平洋。在温室温度达到峰值期间，南部高纬度地区密集水的形成加剧令人惊讶，但这与最近强调全球温盐环流复杂性的发现是一致的。

附：英文原文

Title: Intensified bottom water formation in the southwest Pacific during the early Eocene greenhouse—Insights from neodymium isotopes

Author: I. Pealver-Clavel, S.J. Batenburg, R. Sutherland, E. Dallanave, G.R. Dickens, T. Westerhold, C. Agnini, L. Alegret

Issue&Volume: 2025-03-27

Abstract: The Early Eocene Climatic Optimum (EECO; 5349 Ma), when Earth experienced peak Cenozoic surface temperatures, provides a test case for how ocean circulation might operate under enhanced greenhouse climate conditions. The topic lies at the forefront of current geoscience, but evolution of ocean circulation during this climatic extreme remains unresolved, critically at high southern latitudes. We present the first highly resolved record of neodymium isotope values at high southern latitudes (International Ocean Discovery Program Site U1510), a proxy that tracks ocean bottom water. A prominent negative shift in seawater εNd(t) in the Tasman Sea in the middle of the EECO was likely driven by a new bottom water mass, with the Antarctic sector of the Pacific Ocean being the obvious source. Comparison with low-resolution studies from other sites in the Tasman Sea suggests that a new intermediate water source flowed farther away from the Tasman Sea and into the Pacific during the EECO. Intensification of dense water formation at high southern latitudes during peak greenhouse warmth is surprising but consistent with recent findings that highlight the complexity of global thermohaline circulation.

DOI: 10.1130/G52974.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G52974.1/653319/Intensified-bottom-water-formation-in-the