尚义葛令夭高铬花岗岩(Closepet-like)——新太古代古缝合带的新证据  

Gelingyao high-Cr granite(Closepet-like) in Shangyi:New evidence of Late-Archean suture zone

作　　者：王仁民[1] 李孟江[2,3] 程素华[4] 

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]中国科学院广州地球化学研究所矿物学与成矿学重点实验室,广州510640 [3]中国科学院研究生院,北京100049 [4]中国地质大学地球科学与资源学院,北京100083

出　　处：《岩石学报》2012年第4期1037-1043,共7页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(40972125)资助

摘　　要：在华北克拉通北部,太古代麻粒岩古陆核与陆外沉积盆地(红旗营子群)之间已经厘定出一个晚太古代的古洋壳残片(Wang et al.,2009)。此残片南北两侧又发现了低Al2O3型TTG岩体(2512±19Ma)、富钾高铬的深熔花岗岩(Closepet-like),含Cr97×10-6～308×10-6,以及含大量密集的煌斑岩脉的含石英的二长岩(Sanukitoid-like)等三类在成因上与俯冲带密切相关的岩体。低Al2O3型TTG是在角闪麻粒岩亚相条件下由俯冲中的滑片部分熔融所生成。深熔花岗岩是TTG再熔融的产物,而它们的基性化演化和Cr的增高是幔源岩浆与富钾深熔花岗岩经复杂的岩浆混合和交代改造的结果。At northern of North China Craton, between Archean granulite nucleus and extra-continental sedimentary basin （hongqiyingzi Group）, a Neoachaean ancient oceanic crust relict has been recognized （Wang et al. , 2009）. The low A1203 TFG rocks （2512 ± 19Ma）, the anateetic granites （Closepet-like） with rich K and high Cr （97 × 10-6 -308 × 10-6）, and quartz monzonites （Sanukitoid-like） with a large number of lamprophyre dykes have been discovered on both sides of the relict, they are closely related to subduetion. The low A1203 TTG rocks were generated by partial melting of subducting slab under an amphibole-granulite subfacies condition. Anatectic granites were products of remelting of the TI＇G rocks and their basic development with increase in Cr were the results of complex mixed and metasomatism between mantle-derived magma and K-enriched anatectic granites.

关 键 词：新太古代 低Al2O3 TTG 高Cr花岗岩(Closepet-like) 古缝合带 华北克拉通 

分 类 号：P541[天文地球—构造地质学] P588.121[天文地球—地质学]