秘鲁南部阿雷基帕段海岸岩基带找矿方向探讨（英文）

New metallogenic approaches to the Coastal Batholith,Arequipa segment between 15° and 16°30' South latitude, Peru

通过详细的岩相学和锆石U-Pb年龄的研究,秘鲁海岸岩基带阿雷基帕段的填图工作得到了补充,该岩基带岩浆活动可分为7个阶段和4个旋回,各阶段都显示出不同的岩浆容量,其地貌主要表现为岩基和岩脉。旋回Ⅰ和旋回Ⅱ代表侏罗纪岩浆活动阶段(201~145Ma),岩浆分异为辉长岩到花岗岩;旋回Ⅲ和旋回Ⅳ代表白垩纪岩浆,岩浆分异为英云闪长岩-二长花岗岩、闪长岩与花岗闪长岩及英云闪长岩-花岗闪长岩。对角闪石和黑云母矿物晶体的数量关系研究表明,旋回Ⅰ的侵入岩有大量辉石和角闪石结晶,并伴随金-铁成矿作用;旋回Ⅱ有大量的群集角闪石晶体和呈定向排列或群集的六边形黑云母,且伴随铜-金-铁成矿作用;旋回Ⅲ侵入岩内发育角闪石和黑云母,伴随着金-铜和铁成矿作用;旋回Ⅳ发育大量角闪石和六边形黑云母,岩石更偏长英质,并伴随铜-锌-金-银-铁和铜-金-钼成矿作用。

The mapping of intrusive rocks from the Arequipa segment of the Coastal Batholith was complemented by detailed petrographic studies and U-Pb zircon ages.The results were analyzed and grouped into seven stages and four cycles.Each stage shows unique magmatic volumes,and the landform finds expression in batholiths and stocks.Cycles I and II represent the stages of Jurassic magmatism(201~145Ma),the magmatic differentiation grades from gabbros to granites.Cycles III and IV represent the stages of Cretaceous magmatism,the magmatic differentiation varies from tonalites to monzogranites,diorites to granodiorites and from tonalites to granodiorites.In relation to the amphibole and biotite crystal population,the intrusives of the Cycle I have abundant pyroxene and amphibole crystals,associated with Au-Fe mineralization;those of Cycle II have abundant clustered amphibole crystals and in some cases are aligned or grouped biotite crystals and eventually hexagonal,associated with Cu-Au-Fe mineralization;those of Cycle III have well developed isolated amphibole and biotites,and the intrusive rocks are associated with Au-Cu and Fe;those of Cycle IV have some amphibole and hexagonal biotite in separated form,and the intrusive rocks are more felsic and are associated with Cu-Zn-Au-Ag-Fe and Cu-Au-Mo mineralization.