关闭地质碳循环的时间
1Department of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY 14853.
概括
使用经过修订的海洋碳输入的新计算解决了沉积有机碳埋葬流量估计中的差异. 这项研究提供了更准确的现代埋葬流和洞察过去的碳循环动态.
科学领域:
- 地质化学 地质化学
- 地球科学 地球科学 地球科学
- 古气候学 古气候学
背景情况:
- 在估计沉积有机碳埋葬流量的库存和同位素质量平衡方法之间存在差异.
- 以前的模型并没有完全考虑海洋大气碳系统的所有重要输入.
- 了解这些流动对于理解全球碳循环和气候调节至关重要.
研究的目的:
- 解决沉积有机碳埋葬流量估计中的差异.
- 通过纳入对碳输入的修订评估来完善同位素质量平衡模型.
- 研究过去的气候事件和地质过程对碳循环的影响.
主要方法:
- 修订的同位素质量平衡计算包括碳酸盐和旧煤化的气候变化,地质甲氧化,以及火山/变态脱气.
- 对同位素轻碳输入 (OCpetro和CH4) 的分析,以确定总碳输入的平均同位素组成.
- 蒙特卡洛评估,以评估碳酸盐和有机碳的晚凯诺纪储库增长的确定性.
主要成果:
- 经过修订的同位素质量平衡模型产生了 15.9 ± 6.6 Tmol y-1.1 的现代沉积有机碳埋葬流.
- 火山和变态脱气对总碳输入的贡献约为23%.
- 苗代中期的气候最佳同位素异常导致~4.3×106 Tmol的综合过量沉积,超过了主要火山事件的估计.
结论:
- 沉积有机碳埋葬流量估计通过精细的同位素质量平衡方法进行协调.
- 晚凯诺纪可能看到碳酸盐和有机碳水库的净增长,这表明沉积碳质量增加.
- 沉积碳的增加意味着表面环境的氧化和大气氧 (pO2) 的潜在增加.
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