Global perturbation of the carbon cycle at the onset of the Miocene Climatic Optimum
Global perturbation of the carbon cycle at the onset of the Miocene Climatic Optimum
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DOI：
10.1130/g36317.1
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发表时间：
2015-02-01
期刊：
影响因子：
5.8
通讯作者：
Meier, K. J. Sebastian
中科院分区：
文献类型：
--
作者：
Holbourn, Ann;Kuhnt, Wolfgang;Meier, K. J. Sebastian
中新世最佳气候（MCO）17-14.7 Ma）代表了过去5000万年长期冷却趋势中的几个主要中断之一。到目前为止，在这一显着的间隔期间，驱动高振幅气候变率和维持全球变暖的过程仍然非常神秘。我们提出了高分辨率的底栖有孔虫和散装碳酸盐稳定同位素记录在一个特殊的，连续的，富含碳酸盐的沉积档案（综合大洋钻探计划网站U1337，东赤道太平洋），这提供了一个新的观点的气候演变的开始MCO。δ O-18和δ C-13在约100 ℃时急剧下降。16.9马，同时大量增加碳酸盐溶解，表明突然变暖耦合到碳循环的强烈扰动。δ C-13的快速恢复在大约。16.7马，类似于250 k.y.在MCO开始之后，标志着在长期的“蒙特利漂移”中第一个碳同位素最大值的开始。“这些结果支持了大气pCO（2）变化通过MCO驱动全球碳库发生深刻变化的观点，这意味着变化的CO2通量，硅酸盐风化率和全球碳封存之间存在微妙的平衡。与跨越白垩纪海洋缺氧事件1a（类似于1.2亿年）开始的高分辨率三角洲C-13记录进行比较。前）揭示了共同的强迫因素和气候响应，提供了一个长期的角度来了解气候碳循环反馈在地球气候变暖时期与大气CO2浓度显着不同。
The Miocene Climatic Optimum (MCO; ca. 17-14.7 Ma) represents one of several major interruptions in the long-term cooling trend of the past 50 m.y. To date, the processes driving high-amplitude climate variability and sustaining global warmth during this remarkable interval remain highly enigmatic. We present high-resolution benthic foraminiferal and bulk carbonate stable isotope records in an exceptional, continuous, carbonate-rich sedimentary archive (Integrated Ocean Drilling Program Site U1337, eastern equatorial Pacific Ocean), which offer a new view of climate evolution over the onset of the MCO. A sharp decline in delta O-18 and delta C-13 at ca. 16.9 Ma, contemporaneous with a massive increase in carbonate dissolution, demonstrates that abrupt warming was coupled to an intense perturbation of the carbon cycle. The rapid recovery in delta C-13 at ca. 16.7 Ma, similar to 250 k.y. after the beginning of the MCO, marks the onset of the first carbon isotope maximum within the long-lasting "Monterey Excursion." These results lend support to the notion that atmospheric pCO(2) variations drove profound changes in the global carbon reservoir through the MCO, implying a delicate balance between changing CO2 fluxes, rates of silicate weathering, and global carbon sequestration. Comparison with a high-resolution delta C-13 record spanning the onset of the Cretaceous Oceanic Anoxic Event 1a (similar to 120 m.y. ago) reveals common forcing factors and climatic responses, providing a long-term perspective to understand climate-carbon cycle feedbacks during warmer periods of Earth's climate with markedly different atmospheric CO2 concentrations.