论四川盆地下中三叠统成盐模式及找钾方向

ON POTASH-FORMING MODEL AND ORE-HUNTING DIRECTION OF LOWER-MIDDLE TRIASSIC SERIES IN SICHUAN BASIN

四川盆地下中三叠统盐系发育,是我国海相碳酸盐型找钾的重要地区和层位。研究表明,成盐作用受古构造活动控制,成盐模式为“多通道的巨型浅水盆地蒸发成盐模式”。成钾条件是具备的。广泛分布该下统嘉陵江组T_1j^5—T_2l^1盐系的川东北、川东地区,中统雷口坡组T_2l^4盐系的川西地区是成钾有利地区。而成盐期后的成岩变质、构造形变和淋滤溶蚀作用对盐钾的破坏,不容忽视。可见加强成钾有利地区保存条件和构造条件的研究,是急待研究的课题。

The lower-midd;e Triassic series in Sichuan basin are known for extensively developed saline strata, regarded as important targets for exploration of carbonate-typed, marine potash recourses , Studies indicate that owing to the strong impact of old tectonic movements on saline deposition, the potash-forming model should be worked out such as 'formation of potash salt through evaporation of saline water from a large shallow basin receiving multi-source supplies of potassium'. The model teaches us that the Jialingjiang group T1j5-T2j1 of the lower Triassic series in Northeast Sichuan and East Sichuan and the Leikoupo group T2l4 of middle Triassic series should favor potash formation but the destroy of the developed potash beds by late diagenic metamorphism, tectonic deformation and leaching action should not be ignored. This requires strengthening without delay the studies of the environments and structures needed for potash preservation of prospective areas.