兰坪-思茅盆地白秧坪-燕子洞地区断裂构造特征及与成矿关系

本文根据白秧坪-燕子洞地区岩石、断裂及矿体特征,结合实测剖面资料,分析断裂构造在盆地演化阶段的性质与成矿的协变关系,确定断裂的控矿作用,并建立了成矿模式。初步认为,四十里箐、华昌山断裂是多期活动的断裂,在三叠纪裂谷形成时,在拉张环境下,断裂活动与沉积过程相伴,表现为正断层性质;侏罗纪-白垩纪,在东西挤压应力作用下,表现为逆断层性质;在新生代,由于东西方向的持续挤压,表现为东西向的对冲推覆构造。在新生代盆山转换阶段,诱发了一系列张性、张扭性断层,是矿体的赋存空间。在三叠纪晚期,成矿流体沿四十里箐、华昌山断裂向上运移,在沉积阶段进入两侧次级盆地,进行第一次喷流沉积成矿;在新生代,成矿流体沿四十里箐、华昌山断裂向上运移进入次级张性、张扭性断裂带中进行第二次热卤水改造(填充交代)成矿。

Relationship Between Fault Structure and Mineralization of Baiyangping-Yanzidong Region in the Lanping-Simao Basin

Abstract: According to the feature of petrology, structure and ore body, combining with the measured section, the covariant relations between faults and mineralization of the basin evolution were analyzed, the ore-controlling role of the fractures were determined and the mineralization model were established. It suggests that the Sishiliqing Fault and the Huachang Mountain Fault experience several active stages.When Triassic rift formed, under the distending condition They were normal faults in which sedimentary process accompanied with fracture movement. In the Jurassic and cretaceous,they became reverse faults which were affected by the E-W extrusion stress caused. In Cenozoic, They were E-W hedge nappe structure brought by E-W continuous press. In the late of Triassic, the ore fluid moved along and migrated upward into both sides of the sub-basin for forming the first time exhalative mineralization in the sediment phase. The ore bodies occur in the series of tension and tension-shear faults in the stage of the Oligocene basin-mountain transition..In Oligocene, the second hot brine mineralization started in the form of Filling metasomatic transforming when the ore-forming fluid in range of conversion phase migrated into the sub-tensile and shear fracture zone of the basin.