研究团队展示了一份东印度洋海水化学和沉积物来源800万年的记录，该记录位于印尼贯穿流水域的出口附近。通过对有孔虫壳和粒度特定的碎屑组分进行地球化学分析，研究人员发现，蛇绿岩的侵蚀和化学风化在400万年(Ma) 之后显著增加，这与广泛岛屿的出现和太平洋纬向海洋表面温度梯度逐步加强相一致。结合对海水87sr / 86sr曲线的重新分析，得出当时镁铁质风化增强的支持性证据，这一发现强调，西太平洋岛屿隆起和水文气候变化有助于在整个晚第三纪维持较高的大气CO2的消耗量。
据介绍，新近纪东南亚的弧-陆碰撞可能通过新暴露的蛇绿岩的化学风化作用，将大气中的CO2去除，从而驱动全球冷却。然而，人们对侵蚀该地区构造和气候的长期演变之间的因果关系知之甚少。
附：英文原文
Title: Accelerated mafic weathering in Southeast Asia linked to late Neogene cooling
Author: Germain Bayon, Martin Patriat, Yves Godderis, Anne Trinquier, Patrick De Deckker, Denise K. Kulhanek, Ann Holbourn, Yair Rosenthal
Issue&Volume: 2023-03-29
Abstract: Arc-continent collision in Southeast Asia during the Neogene may have driven global cooling through chemical weathering of freshly exposed ophiolites resulting in atmospheric CO2 removal. Yet, little is known about the cause-and-effect relationships between erosion and the long-term evolution of tectonics and climate in this region. Here, we present an 8-million-year record of seawater chemistry and sediment provenance from the eastern Indian Ocean, near the outflow of Indonesian Throughflow waters. Using geochemical analyses of foraminiferal shells and grain size–specific detrital fractions, we show that erosion and chemical weathering of ophiolitic rocks markedly increased after 4 million years (Ma), coincident with widespread island emergence and gradual strengthening of Pacific zonal sea-surface temperature gradients. Together with supportive evidence for enhanced mafic weathering at that time from re-analysis of the seawater 87Sr/86Sr curve, this finding suggests that island uplift and hydroclimate change in the western Pacific contributed to maintaining high atmospheric CO2 consumption throughout the late Neogene.
DOI: adf3141
