福建南安向阳绢云母矿地质特征及成因探讨

Discussion on the Geologic Characteristics and Genesis of Xiangyang Sericite Deposit in Nan'an County,Fujian Province

南安五台山火山喷发中心位于闽东火山断坳带福安—南靖火山喷发带中段,晚侏罗—早白垩世火山活动频繁而强烈。各类断裂构造及火山喷发不整合面发育。中或中低温火山热液通过断裂或不整合面渗透交代酸性、中酸性火山岩形成绢云母化、绿帘石化及硅化等,在南园组第二段顶部富含化学性质不稳定的火山玻璃质的熔岩、碎屑岩中绢云化强烈而形成了绢云母矿。

The Wutaishan volcanic outbreak center in Nan＇an County is situated on the intermediate section of the Fu＇an-Nanjing volcanic eruption belt which exists in the Southern Fujian volcanic and fault depression zone.The volcanic activity in the surveyed area occurs violently and frequently during Late Jurassic and Early Cretaceous.There are different kinds of well-developed unconformable surfaces caused by faulted structures and volcanic eruption.The moderate or medium-to-low temperature volcanic hydrothermal solution along fractures or unconformable surfaces forms itself into sericitization,epidotization and silicification after infiltration and replacement of acidic,intermediate acidic volcanics.There exists the violent sericitization in the lava and clastic rocks which are rich in unstable volcanic glass in the second segment of Upper Jurassic Nanyuan Formation and it finally shapes up the sericite deposit.