陆相碎屑岩中粘土矿物的形成机理及蚀变规律—以济阳坳陷始新统孔店组为例Formation Mechanism and Alteration of Clay Minerals in Clastic Rocks—Take the Kongdian Fm. of Paleogene in Jiyang Depression for Example
刘志波, 谭先锋, 王杰, 冉天, 沈杰, 徐小斐, 姜芳
粘土矿物, 形成机理, 蚀变规律, 影响因素, 成岩流体Clay Minerals, Formation Mechanism, Alteration Law, Influence Factors, Diagenetic Fluid
《Advances in Geosciences》, Vol.5 No.6, 2015-12-31
Clay minerals are the important fillings in clastic rocks, have important geological significance for oil and gas reservoir. In this paper, the characteristics, formation mechanism, alteration law and influence factors of the clay minerals in the new system of Jiyang Depression are studied by means of X diffraction, scanning electron microscopy, and electron microscopy. The results show: The Eocene Kongdian formation of clay minerals such as illite, kaolinite, chlorite and illite/smectite in Jiyang depression, Illite honeycomb, silk thread and ribbon shaped under the scanning electron microscope, a book like kaolinite, chlorite, wormlike, lobular flake, Illite/smectite irregular gra-nular, flake; The formation mechanism of clay minerals can be divided into mineral terrigenous detrital clay mineral formation mechanism and its mechanism of two kinds of clay. The formation mechanism of terrigenous detrital clay minerals associated with hydrodynamic intensity. The formation mechanism of the in-situ clay minerals is influenced by the temperature and the fluid properties. At a certain temperature, into the rock and fluid in the alkaline range to form mont-morillonite, illite and chlorite in the acidic range is conducive to kaolinite formation; The formation mechanism and alteration process of clay minerals are controlled by the paleo temperature and the formation of the fluid. When the temperature of the local temperature was 70 - 140, the montmorillonite and kaolinite altered to form illite; The local temperature rises to 100 - 140 DEG C, illite/smectite illite alteration; When the diagenetic fluid from acid to alkaline, kaolinite chlorite alteration was formed; When the alkaline diagenetic fluid gradually becomes stronger, montmo-rillonite alteration of illite and chlorite is formed.