硅质碎屑砂岩中胶结物来源的新认识

NEW FINDINGS ON SOURCES OF CEMENT IN SILICI-CLASTIC SANDSTONE

分析了浅埋藏砂岩的成岩环境,并从岩石学、矿物学、同位素及质量平衡估算方面论证硅质碎屑砂岩中的胶结物主要来源于砂岩浅埋藏期间的地下水,进而分析浅埋藏带内地下水的流动机制及早期胶结作用对晚期成岩作用的影响。

In many studies an internal source from stratigraphic succession has been implied. This paper tries to focus on an external source of cement driven by groundwater. The diage-netic environment of siliciclastic sand at shallow burial depths is consisdered as an'open system 'involving transfer of chemical constituents over long distances. Petrographic,geochemi-cal,isotopic and mass-balance evidences suggest that cement in siliciclastic sandstone mainly conies from groundwater. Timing of early cementation and groundwater flow mechanism are also discussed. Finally, the paper examines how early cementation controls deep burial diage-nesis.