(1. 中南大学 地球科学与信息物理学院，长沙 410083；
2. 中南大学 有色金属成矿预测教育部重点实验室，长沙 410083；
3. 桂林理工大学 地球科学学院，桂林 541004)
摘 要: 对位于厄瓜多尔中新世金属成矿带的Beroen金银矿床不同位置的英云闪长岩和花岗闪长岩进行锆石 U-Pb定年及地球化学研究。结果表明：加权平均年龄分别为(15.92±0.4) Ma和(34.73±0.7) Ma。结合两个岩体的地球化学特征对比，认为由于俯冲洋壳板片脱水后，交代软流圈地幔楔形成相似的母源岩浆在后期演化过程中差异化，渐新世的花岗闪长岩母源岩浆在区域伸展应力背景下上侵，倾向发育斜长石的结晶分异。而英云闪长岩是深层熔浆在上侵过程中受到挤压应力作用影响造成停滞形成的，熔体在中下地壳层进行以角闪石(±榍石)为主的结晶分异作用。构造背景的改变与Beroen绢云母蚀变形成时间都在中新世，成矿作用与中新世岩浆侵位有密切关系。
关键字: 厄瓜多尔；Beroen矿床；锆石U-Pb年龄；埃达克型；成岩；成矿
（1. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
2. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education, Central South University, Changsha 410083, China;
3. College of Earth Science, Guilin University of Technology, Guilin 541004, China）
Abstract:Beroen gold deposit is part of central Andean miocene metallogenic belt. Zircon U-Pb dating of intrusions of Beroen: tonalite, granodiorite, indicates that tonalite has emplaced in middle Miocene, granodiorite had emplaced in early Oligocene, with weighted average age of (15.92±0.4) Ma and (34.73±0.7) Ma, respectively. Combined with their geochemical characteristics, both intrusions melt derived similarly from slab dehydration fluids fluxing mantle wedge partial melting, then experienced different evolution process. The Oligocene granodiorites were emplaced in a crustal domain extension and emplaced through trench-parallel and trench-normal faults and sutures, through a continuous passive ascent process, with undergoing more plagioclase differentiation. The Miocene tonalite emplaced under compressive stress background with trench parallel structures was sealed. The magmas were thus impeded to rise, ponded and undergone mainly amphibole differentiation at lower crust. The sericite in orebody formed prior to emplacement of tonalite. Maybe Beroen mineralization was resulted from the geodynamic transition of extension condition to compression condition induced by subduction zone’s geodynamic changing.
Key words: Ecuador; Beroen deposit; zircon U-Pb; adakite; petrogenesis; metallogeny
