BURIAL OF ORGANIC-CARBON AND PYRITE SULFUR IN SEDIMENTS OVER PHANEROZOIC TIME - A NEW THEORY
BURIAL OF ORGANIC-CARBON AND PYRITE SULFUR IN SEDIMENTS OVER PHANEROZOIC TIME - A NEW THEORY
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DOI：
10.1016/0016-7037(83)90151-5
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发表时间：
1983-01-01
影响因子：
5
通讯作者：
RAISWELL, R
中科院分区：
文献类型：
--
作者：
BERNER, RA;RAISWELL, R
在现今的海洋沉积物中，几乎所有的沉积物都是在正常的含氧海水中沉积的，有机碳（C）和黄铁矿硫（S）的埋藏速率呈正相关，并且彼此具有恒定的比率（C/S = 3）。相反，根据GarrelsandLerman（1981）同位素模型的计算表明，在中生代的不同时期，世界范围内的埋藏率一定与现今的值有很大的不同。这一比例变化是由这样的要求引起的，即全球范围内有机碳质量的增加必须伴随着沉积黄铁矿硫质量的同等减少，以保持大气中O2的大致恒定水平。如果主要有机碳埋藏的地点随着时间的推移从目前的正常海洋环境转移到非海洋淡水环境或过去地质时期的富氧环境，那么这种明显矛盾的行为就可以得到解释。主要是淡水埋藏的转变可以帮助解释预测的高C/S比在石炭-二叠纪沉积物中，和一个转变到富氧环境可以帮助解释预测的低C/S比在早古生代。它表明，这三种环境今天表现出明显不同的平均C/S比。
In present day marine sediments, almost all of which are deposited in normal oxygenated seawater, rates of burial of organic carbon (C) and pyrite sulfur (S) correlate positively and bear a constant ratio to one another (C/S ∼- 3 on a weight basis). By contrast, calculations, based on the isotopic model ofGarrelsandLerman(1981), indicate that at various times during the Phanerozoic the worldwide burial ratio must have been considerably different than the present day value. This ratio change is caused by the requirement that, increases in the worldwide mass of organic carbon must be accompanied by equivalent decreases in the mass of sedimentary pyrite sulfur, in order to maintain a roughly constant level of O2in the atmosphere. Such apparently contradictory behavior can be explained if the locus of major organic carbon burial has shifted over time from normal marine environments, as at present, to non-marine freshwater, or to euxinic environments, in the geologic past. A shift to predominantly freshwater burial can help explain predicted high C/S ratios in Permo-Carboniferous sediments, and a shift to euxinic environments can help explain predicted low C/S ratios during the early Paleozoic. It is demonstrated that the three environments today exhibit distinguishably different average C/S ratios.