The dissociation of marine methane hydrates due to the increased ocean temperature may be widespread in the context of global warming. However, direct evidence for this phenomenon is limited. Here, we reported the carbon and oxygen isotopes, mineralogy, elements, and clumped isotopes (Δ) of coring seep carbonates (MIS5e) to explore the influence of temperature changes on gas hydrate stability. The extremely low δC and high δO values of bulk carbonates (average, −48.1‰ and 4.4‰, respectively) indicated the authigenic carbonates formed from the anaerobic oxidation of methane and gas hydrate dissociation. An anaerobic environmental condition with intense methane seepages was confirmed by the dominant aragonite, Mo enrichment (Mo averaged as 312), and positive Ce anomalies (averaged as −0.03). The Δ values ranged from 0.714 to 0.745, indicating a higher bottom-water temperature (averaged at 7.5 °C) during MIS5e compared with the current seafloor temperature (5.4 °C). This study provides direct evidence for the dissociation of gas hydrate triggered by ocean warming, presenting new insights into potential temperature-induced gas hydrate instability due to global climate warming.

中文翻译：

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渗漏碳酸盐团块同位素揭示海洋变暖引起的天然气水合物解离


在全球变暖的背景下，由于海洋温度升高而导致的海洋甲烷水合物的解离可能会普遍存在。然而，这种现象的直接证据有限。在这里，我们报告了取心渗流碳酸盐（MIS5e）的碳和氧同位素、矿物学、元素和团块同位素（Δ），以探讨温度变化对天然气水合物稳定性的影响。块状碳酸盐的极低 δ13C 和高 δ18O 值（平均值分别为-48.1‰和4.4‰）表明自生碳酸盐是由甲烷厌氧氧化和天然气水合物解离形成的。主要文石、Mo 富集（Mo 平均为 312）和 Ce 正异常（平均为 -0.03）证实了具有强烈甲烷渗漏的厌氧环境条件。 Δ 值范围为 0.714 至 0.745，表明 MIS5e 期间海底水温（平均为 7.5 °C）高于当前海底温度（5.4 °C）。这项研究为海洋变暖引发的天然气水合物解离提供了直接证据，为全球气候变暖导致的潜在温度引起的天然气水合物不稳定性提供了新的见解。