State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Science, University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Science, University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Bull (Beijing). 2023 Mar 30;68(6):637-644. doi: 10.1016/j.scib.2023.03.007. Epub 2023 Mar 7.
Volcanic arc degassing contributes significantly to atmospheric CO levels and therefore has a pivotal impact on paleoclimate changes. The Neo-Tethyan decarbonation subduction is thought to have played a major role in Cenozoic climate changes, although there are still no quantifiable restrictions. Here we build past subduction scenarios using an improved seismic tomography reconstruction method and calculate the subducted slab flux in the India-Eurasia collision region. We find remarkable synchronicity between calculated slab flux and paleoclimate parameters in the Cenozoic, indicating a causal link between these processes. The closure of the Neo-Tethyan intra-oceanic subduction resulted in more carbon-rich sediments subducting along the Eurasia margin, as well as continental arc volcanoes, which further triggered global warming up to the Early Eocene Climatic Optimum. The abrupt termination of the Neo-Tethyan subduction due to the India-Eurasia collision could be the primary tectonic cause of the ∼50-40 Ma CO drop. The gradual decrease in atmospheric CO concentration after 40 Ma may be attributed to enhance continental weathering due to the growth of the Tibetan Plateau. Our results contribute to a better understanding of the dynamic implications of Neo-Tethyan Ocean evolution and may provide new constraints for future carbon cycle models.
火山弧排气对大气 CO 水平有重要贡献，因此对古气候变化有重大影响。新特提斯脱碳俯冲被认为在新生代气候变化中起了主要作用，尽管目前还没有可量化的限制。在这里，我们使用改进的地震层析成像重建方法构建过去的俯冲场景，并计算印度-欧亚碰撞区俯冲板块的通量。我们发现计算出的板块通量与新生代古气候参数之间存在显著的同步性，表明这些过程之间存在因果关系。新特提斯洋内俯冲的关闭导致更多富碳沉积物沿欧亚大陆边缘俯冲，以及大陆弧火山，这进一步引发了全球变暖，直至早始新世气候最优期。印度-欧亚碰撞导致的新特提斯俯冲的突然终止，可能是约 50-40Ma CO 下降的主要构造原因。40Ma 后大气 CO 浓度的逐渐下降可能归因于由于青藏高原的增长而增强的大陆风化作用。我们的研究结果有助于更好地理解新特提斯洋演化的动力学意义，并可能为未来的碳循环模型提供新的约束。
