华北克拉通南缘古元古代早期岩浆作用及构造演化

Early Paleoproterozoic magmatism and tectonic evolutionin the southern section of North China Craton

古元古代早期是地质历史上一段特殊的时期,也称为“静寂期”,在此期间全球只有零星的岩浆记录并伴有重大环境的巨变。传统观点认为这可能与全球性的板块构造运动的停滞有关,俯冲的停滞导致火山作用及大陆地壳生长的暂停。然而,近年来的研究发现2.45~2.2 Ga期间全球构造-岩浆作用并不完全“平静”,在局部地区表现为板块边缘的汇聚作用和新生地壳产生,形成了一定数量的增生造山带。华北克拉通中部带是全球广泛分布“静寂期”岩浆活动的地区之一,记录了活动大陆边缘背景下的地壳增生过程。该文聚焦华北克拉通“静寂期”岩浆活动最为发育的南缘地区,以花岗质片麻岩和钾质片麻岩为主要研究对象,结合辉长-闪长质片麻岩以及辉绿-辉长岩,综述了相关岩石地球化学研究进展,并详细探讨了“静寂期”岩浆岩的成因以及古元古代早期的构造背景。

The period of 2.45~2.20 Ga in the Early Paleoproterozoic era is a special time,which is called"quiet interval"because of decreased significantly magmatic activity and significant environmental changes in the world.According to the traditional view,this may be caused by the stagnation of global plate tectonic,and the stagnation of subduction leads to the suspension of volcanism and continental crust growth.However,recent studies have found that the global tectonic magmatism of 2.45~2.20 Ga was not completely ceased,which had resulted in the converging of plates and the production of new crust in some areas,subsequent formation of accretionary orogenic belts.The central belt of the North China Craton is one of the regions widely distributed in the world during the quiet interval,which records the crustal accretion process under the setting of the active continental margin.In this paper,we focus on the Paleoproterozoic granitic gneiss and potassium gneiss in the southern margin of this craton with the most abundant magmatic activities in the quiet interval.Taking as the main research objects,combined with gabbro-diorite gneiss and diabase-gabbro,we have summarized the research progress of related rock geochemistry and discussed the genesis of 2.45~2.2 Ga magmatic rocks and the tectonic background of Early Paleoproterozoic.