【作者】 张旗； 王焰； 钱青； 翟明国； 金惟浚； 王元龙； 简平；

【Author】 ZHANG Qi,WANG Yan,QIAN Qing,ZHAI MingGuo,JIN Weijun,WANG YuanLong and JIAN Ping 1.Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China 2.Department of Earth Sciences,The University of Hong Kong,Hong Kong,China 3.Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China

【机构】 中国科学院地质与地球物理研究所； 香港大学地球科学系； 中国地质科学院地质研究所；

【摘要】 Shirey and Hanson(1984)将某些太古代的高镁闪长岩套称为sanukite(赞岐岩),类似于日本中新世(11～15 Ma)Setouchi火山岩带的高镁安山岩。Sanukitoids由闪长岩-二长闪长岩-花岗闪长岩组成,不同于TTG岩套(奥长花岗岩-英云闪长岩-花岗闪长岩)。Sanukitoids具有下列地球化学特征:富Mg,Mg~#>0.60,Nj和Cr>100μg/g,Sr和Ba>500μg/g,LREE富集(大于球粒陨石100倍),无Eu异常。高镁安山岩在太古代很少见,而其相应的侵入岩高镁闪长岩或.sanukitoids,虽然数量也很少,但却是各地晚太古代地体中随处可见的。Sanukitoids的原始岩浆是交代的地幔楔部分熔融形成的,随后可能经历了广泛的分离结晶作用。TTG和sanukitoids岩套可以相伴产出,二者均与板片熔融有关,TTG与其直接有关,sanukitoids可能与其间接有关。全球Sanukitoids主要集中在晚太古代时期,可能暗示板块的消减作用在～3.0 Ga以后才起了重要的作用。更多还原

【Abstract】 Some Archean high-Mg diorites suite originally were recognized and termed sanukitoids by Shirey and Hanson(1984), which are similar to those of high-Mg andesites found in the Setouchi Miocene(11～15 Ma) volcanic belt in Japan.The sanukitoids are composed of diorite-monzodiorites-granodiorite and diffenrt from those of TTG suite(trondhjemite-tonalite-granodiorite). Sanukitoids have the following chemical characteristics:Mg numbers>0.60,Ni and Cr are both>100 ppm,Sr and Ba both typically>500 ppm,and light rare earth elements are strongly enriched(>100 chondritic values ) with no Eu anomaly.High-Mg andesite is rare in the Archaean,but the intrusive equivalent,high-Mg diorite or sanukitoid,forms a minor but widespread component of most late Archaean terrains.The source region for sanukitoid parent magmas is thought to be the melting of the metasomatized mantle wedge, followed by extensive fractional crystallization in the crust.TTG and the sanukitoid suite may be continuous with each other,and both the products of slab melting,either directly(TTG) or indirecdy(sanukitoid).Sanukitoids appear to concentrate in the Late Archaean,suggesting that subduction may have become an important process only after～3.0 Ga.更多还原