自贡地区棋盘格式构造及其对T_1j^（4－4）成盐作用的控制

CHESS-BOARD STRUCTURE AND ITS SALT CONTROL IN T_1j￣(4-4) IN ZIGONG REGION,SICHUAN

自贡地区Ｔ_１ｊ^（４－４）（下三叠统嘉陵江组第四段四层）岩盐体，受控于Ⅲ级棋盘格式“Ｘ”扭断裂之交叉处。据此预测的岩盐体与剖面岩相法预测的岩盐体有惊人的一致性，并陆续被钻井证实。在１２０ｋｍ~２内，已有１００余口井证实在“ｘ”交叉处１ｋｍ~２之外，均无岩盐体存在。“Ｘ”交叉处在ＴＭ遥感图象上几乎都有环形影象的反映，个别已证实为岩盐体引起。棋盘格式构造找矿模式已超出找岩盐的本身，它为重新认识找钾盐和其它矿产开拓了新思路。丰富了地质力学的内容。

Rock salt body in J_1j￣(4-4) in Zigong region is controlled by intersection of X-type shear fractures of the third-order chess-board structure.Rock salt prognostication in view of the above is extremely consistent with that from lithofacies section and has been verified by more than 100 drilling wells within the scope of more than 120 km￣2.There is not any rock salt beyond the scope of 1km￣2 around the intersection. TM images of the intersections are characterized by circular features,that some of which are reflection of rock salt has been verified.Prospecting model of chess-board structure enriches geomechanics and opens up a new path for search not only for rock salt but also for potash salt and other minerals.