俄罗斯白海活动带中的太古宙榴辉岩  

Archean eclogites from Belomorian Mobile Belt,Russia

作　　者：李小犁[1,2] 张立飞[1,2] 魏春景[1,2] 

机构地区：[1]北京大学地球与空间科学学院 [2]造山带与地壳演化教育部重点实验室,北京100871

出　　处：《地学前缘》2013年第2期172-185,共14页Earth Science Frontiers

基　　金：国家自然科学基金项目(40821002)

摘　　要：在俄罗斯白海活动区发现的迄今为止最古老的太古宙榴辉岩的出露,对整个地质学领域是一次革命性事件。白海活动带位于芬诺斯干地亚地盾东北部太古宙陆核,处于科拉半岛大陆和卡累利阿克拉通之间的太古宙增生碰撞带中,在新太古代和古元古代期间多次受到中高压变质和构造变形作用。榴辉岩出露包括Gridino和Salma两大地区。Gridino榴辉岩区的榴辉岩产状可分为TTG片麻岩围岩中具有复杂成因的太古宙榴辉岩包裹镶体(2.72Ga),组成强烈构造变形的混合混杂岩体(mélange),以及众多古元古代侵入岩墙岩脉状基性榴辉岩。Salma榴辉岩区的榴辉岩年龄应该晚于2.87Ga,其中的Fe-Ti-榴辉岩年龄测定为约2.80Ga。两大榴辉岩区的p-T演化轨迹比较类似,Gridino榴辉岩的峰期变质温压值(T=740～865℃,p=1.4～1.8GPa)比Salma榴辉岩(T≈700℃,p=1.3～1.4GPa)要高。Salma榴辉岩原岩可能与大洋环境有关。The oldest eclogite outcrops with Archean age were found in Belomorian Mobile Belt in Russia, which is a sharp breakthrough in geology. The Beiomorian Mobile Belt is located at the north-east of Archean nucleus of the Fennoscandian shield, in the Belomorian accretionary-collisional orogeny between Kola Peninsula and Karelian craton, which was affected many times by high moderate-pressure metamorphism and structural deformation in Neoarchean and Paleoproterozoic periods. There are two eclogite-bearing areas, Gridino and Salma. Gidino eclogites include polygenetic Archean eclogite fragments （-2.72 Ga） with complicated compo sition, consisting of migmatized and strongly deformed tectonic melange, and various Paleoproterozoic mafic dykes and veins. Salma eclogites were considered to be formed at 2. 87 Ga, and the Fe-Ti-eelogite variety at 2.8 Ga. The two eclogite assemblages have similar FT evolution paths in general, and the FT condition of Oridino eclogite （T=740- 865 ℃, p=1.4- 1.8 GPa） should be higher than that of Salma eclogites （T≈700℃, p=1.3 - 1.4 GPa）. The protolith of Salma eelogite might be related with oceanic environment.

关 键 词：白海活动带 太古宙榴辉岩 Gridino榴辉岩 Salma榴辉岩 

分 类 号：P588.3[天文地球—岩石学]