青藏高原清水河冻结湖相沉积有机质特征和古湖泊环境变化

The Characteristics of Organic Matter in Frozen Lake Sediments and Palaeoenvironmental Change of Qingshuihe in the Tibetan Plateau

青藏高原清水河冻结湖相沉积有机质以内源为主并保存较好； 钻孔 ５０～４００ ｃｍ 深度样品中有机质组成特征参数具有相同的变化趋势； 可溶有机质／有机碳和烷烃／非烃分别为 ５％ ～１３％ 和 ０２～０５这些比值作为指示水生高等植物和浮游生物对总有机质的贡献大小的指标，可用以指示古湖泊水深的相对变化此外， Ｏ Ｅ Ｐ和 Ｐｒ／ Ｐｈ 分别为 ２４４～７８３ 和１０４～２６５ 之间， 这些参数指示了沉积物表面氧逸度的变化， 从而对湖水深度的相对变化有一定的指示意义

The organic matter in frozen lake sediments of the Tibetan Plateau mainly comes from submerged aquatic plants and plankton and is in a good state of preservation In this work, organic matter in core samples of frozen lacustrine sediments ranging from 50 to 400 cm has been studied systematically In this profile, the concentration of organic matter (Corg), hydrogen index (HI), concentration of soluble organic matter (SOM) and other parameters of the characteristics of organic matter have the same variation tendency The ratios of SOM/Corg and alkane/non hydrocarbon range from 5%～13% and 0 2～0 5 respectively These ratios, which can be regarded as the relative contribution of submerged aquatic plants and plankton, may provide the information of relative water depth of past lake The ratios of OEP and Pr/Ph range from 2 44～7 83 and 1 04～2 65 respectively These ratios indicate the surface of sediments rich in oxygen and are able to reconstruct the relative water depth of past lake