青海湖底沉积物的矿物物相及有机质保存研究

盐湖沉积环境是烃源岩发育的重要地质环境。本文以青海湖湖底沉积物为例，根据有机质与粘土矿物含最及矿物表面积的关系，分析了矿物学因素对盐湖相富有机质沉积物中有机质保存的影响。研究发现：湖底沉积物中有机质丰富，为上层水中的浮游生物和南河流携带束的陆地高等植物两种来源。矿物物相分析发现沉积物中粘土矿物含量达到32．4％，以伊利石为主。沉积物经密度分离后测试发现，有机碳含量与粘土矿物含量及矿物表面积之间具有很好的正相关性，说明粘土矿物吸附是青海湖底沉积物中有机质的主要赋存形式。

The mineralogical phase and sediments of preservation of organic matter in the Qinghai Lake

The saline lake is one of the most favorable environments for developing hydrocarbon source rocks. In this paper, a sample core from the Qinghai Lake was studied. Based on the relationship of the organic matter content and clay mineral content to the mineral surface area, the authors used the mineral component (or mineralogical phase) to analyze the preservation of organic matter in sediments. Organic matters from abundant terrigenous plants around the lake area composed mainly of microbes and algaes are very rich in the lake. The mineralogical phase indicates that clay minerals are up to 32.4% in sediments at the bottom of the Qinghai Lake, with illite being the main component part. Density fractionation reveals that organic matter content is closely relevant to clay mineral content and mineral surface area in the salified Lake, suggesting that clay mineral adsorption is the major mechanism in the preservation of organic matter in sediments of the Qinghai Lake.