Evidence for a rapid release of carbon at the Paleocene-Eocene thermal maximum
Evidence for a rapid release of carbon at the Paleocene-Eocene thermal maximum
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古新世-始新世热最大值时碳快速释放的证据
DOI：
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发表时间：
2013
影响因子：
11.1
通讯作者：
M. Schaller
中科院分区：
文献类型：
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作者：
J. Wright;M. Schaller
PETM - CIE开始时期沉积的万宝路黏土的碳酸钙和碳同位素记录表明，轻质碳的大量释放是瞬时的，为碳释放的大小和可能的机制提供了重要的约束条件。古新世/始新世热最大值（PETM）和相关的碳同位素偏移（CIE）通常被认为是当前人为co2浓度升高的最佳地质模拟。然而，由于CIE开始的持续时间存在很大的不确定性，PETM CIE的因果机制仍未确定。在这里，我们报道了一系列由古新世/始新世万宝路粘土（索尔兹伯里海湾）组成的有节奏的沉积对联。这些对联具有相应的δ18O旋回，暗示了气候的起源。季节性日照是唯一能合理解释δ18O振幅和层数的规律气候周期。高分辨率稳定同位素记录显示，在13对中δ13C下降了3.5‰，这定义了CIE的开始，这需要大量的13c耗尽碳的瞬时释放。在CIE期间，陆架上形成了一个明显的δ13C梯度，最浅水域的偏移最大，表明大气δ13C下降了~ 20‰。我们的观测和修正后的释放速率与大气扰动3,000亿吨碳（GtC）一致。
Significance Calcium carbonate and carbon isotope records from the rhythmically bedded Marlboro Clay, deposited during the onset of the PETM CIE, show that the massive release of isotopically light carbon was instantaneous, providing important constraints for the magnitude of carbon released and potential mechanisms. The Paleocene/Eocene thermal maximum (PETM) and associated carbon isotope excursion (CIE) are often touted as the best geologic analog for the current anthropogenic rise in pCO2. However, a causal mechanism for the PETM CIE remains unidentified because of large uncertainties in the duration of the CIE’s onset. Here, we report on a sequence of rhythmic sedimentary couplets comprising the Paleocene/Eocene Marlboro Clay (Salisbury Embayment). These couplets have corresponding δ18O cycles that imply a climatic origin. Seasonal insolation is the only regular climate cycle that can plausibly account for δ18O amplitudes and layer counts. High-resolution stable isotope records show 3.5‰ δ13C decrease over 13 couplets defining the CIE onset, which requires a large, instantaneous release of 13C-depleted carbon. During the CIE, a clear δ13C gradient developed on the shelf with the largest excursions in shallowest waters, indicating atmospheric δ13C decreased by ∼20‰. Our observations and revised release rate are consistent with an atmospheric perturbation of 3,000-gigatons of carbon (GtC).
影响因子：
18.3
作者：
Cui, Ying;Kump, Lee R.;Harding, Ian C.
通讯作者：
Harding, Ian C.