Hydrogen index and carbon isotopes of lacustrine organic matter as lake level indicators
Hydrogen index and carbon isotopes of lacustrine organic matter as lake level indicators
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DOI：
10.1016/0031-0182(89)90084-9
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发表时间：
1989-04
期刊：
影响因子：
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通讯作者：
Michael R. Talbot;Daniel A. Livingstone
中科院分区：
文献类型：
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作者：
Michael R. Talbot;Daniel A. Livingstone
应用光学和地球化学技术对东非维多利亚湖和鲁夸河晚第四纪沉积物中的有机质进行了研究。总有机碳（TOC）和氢含量（表示为氢指数，HI）的变化可以与已知的湖泊水位的变化，并用于确定非常低的水或陆上暴露在盆地序列的时期。TOC和HI均随着暴露表面的接近而下降，这主要是由于细菌呼吸和无机氧化选择性地去除了不稳定组分。HI极低的惰性有机物质通常集中在上覆海侵面。在与暴露面相关的沉积物中，颗粒有机物的碳同位素组成往往不那么负。虽然风化可能是部分原因，同位素的变化主要是由于使用C4光合作用的植物，如草和莎草，生长在海岸周围和暴露的湖泥，以及从水生藻类和陆生C3植物的材料的相对重要性的变化。
Optical and geochemical techniques were applied to organic matter of Late Quaternary sediments from Lakes Victoria and Rukwa, East Africa. Variations in total organic carbon (TOC) and hydrogen content (expressed as Hydrogen Index, HI) can be related to known changes in lake level and used to identify periods of very low water or subaerial exposure in basinal sequences. TOC and HI both decline as an exposure surface is approached, mainly due to the selective removal of unstable components by bacterial respiration and inorganic oxidation. Inert organic material of very low HI is typically concentrated at the overlying transgression surface. The carbon isotopic composition of the particulate organic matter tends to be less negative in sediments associated with exposure surfaces. Although weathering may be partially responsible, isotopic variations are mainly due to changes in the relative importance of material from plants using C4 photosynthesis, such as grasses and sedges, growing around the shore and on the exposed lake muds, and of material from planktonic algae and terrestrial C3 plants.