湘东北石炭系石英砂岩矿物组成、地球化学特征及沉积环境分析OA北大核心CSTPCD

In order to understand the mineral composition,ore-forming sedimentary environment and ore-forming process of carboniferous quartz sandstone,this paper classifies the quartz sandstone from Pukou-Litian district in Northeast Hunan Province and analyzes its mineral composition and quartz inclusion characteristics,CM pattern and Sahu function method are used to analyze the particle gradation.The geochemical characteristics of quartz sandstone are illustrated by major elements.The results show that the average contents of SiO2,Al2O3 and Fe2O3 are 98.54％,0.905％and 0.147％.The impurity elements of Al and Fe are mainly muscovite,clay,hematite,limonite and ilmenite,occasionally seen other minerals such as monazite and rutile.Fluid inclusions in quartz sandstone are very few with sizes of 0.8～2.5 μm.The depositional environment is river delta,the particle transport method in quartz sandstone is mainly rolling with partial suspension,and the hydrodynamic conditions are general.According to the geochemical characteristics of quartz sandstone,the sandstone in this area belongs to typical quartz sandstone.The siliceous composition of the medium-fine quartz sandstone is high in purity and the impurity minerals are few.The quartz sandstone may be derived from the clastic material in the passive continental margin environment and the quartz-rich sedimentary rock source area.The metamorphic sandstones and Devonian quartz sandstones of Lengjiaxi Group in Mesoproterozoic have provided abundant quartz sand and gravel in this area.The quartz sandstone in this area is a multi-cycle sediment with high maturity.