Stable carbon isotopes of amorphous kerogens from Phanerozoic sedimentary rocks
Stable carbon isotopes of amorphous kerogens from Phanerozoic sedimentary rocks
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DOI：
10.1016/0016-7037(86)90121-3
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发表时间：
1986-08
影响因子：
5
通讯作者：
M. Lewan
中科院分区：
文献类型：
--
作者：
M. Lewan
显生宙沉积岩的非晶态干酪根根据其δ 13c值可分为两组，h-非晶态干酪根的同位素值在- 24 ~ - 20 / mil之间，l-非晶态干酪根的同位素值在- 35 ~ - 26 / mil之间，其中一个岩石单元的非晶态干酪根出现在中间同位素范围，说明这两组之间可能存在弱连续体。浮游植物，在较小程度上，浮游动物和细菌被认为是这两种干酪根类型的前体。对这种两分法的合理解释可以从浮游植物利用的二氧化碳的来源中找到，它被认为是由环境因素控制的。h-非晶干酪根预计会出现在被膨胀的良好循环深水（> 500 m）覆盖的盆地中，在这些盆地中，光区的主要碳来源是大气衍生的二氧化碳。相反，l-非晶态干酪根预计会出现在被层状浅水（< 200米）覆盖的受限盆地中，在这些盆地中，光区的主要碳源可能是有机来源的CO2。
Amorphous kerogens from Phanerozoic sedimentary rocks may be divided into two groups on the basis of theirδ13C values.h-amorphous kerogens have isotopic values in the range of −24 to −20 per mil, andl-amorphous kerogens have isotopic values in the range of −35 to −26 per mil. The occurrence of amorphous kerogens in the intermediate isotopic range from one rock unit in the data set suggests a weak continuum may exist between these two groups. Phytoplankton and, to a lesser extent, zooplankton and bacteria are considered to be the precursors for both kerogen types. A plausible explanation for this dichotomy may be found in the source of CO2utilized by phytoplankton, which is considered to be controlled by environmental factors.h-amorphous kerogens are expected to occur in silled basins that are overlain by expansive well-circulated deep (> 500 m) water, where the prevailing source of carbon in the photic zone is atmospheric-derived CO2. Conversely,l-amorphous kerogens are expected to occur in restricted basins that are overlain by stratified shallow (< 200 m) water, where the prevailing source of carbon in the photic zone may be organic-derived CO2.