中国埃达克岩的时空分布及其形成背景 附:《国内关于埃达克岩的争论》

ON THE SPACE-TIME DISTRIBUTION AND GEODYNAMIC ENVIRONMENTS OF ADAKITES IN CHINA ANNEX: CONTROVERSIES OVER DIFFERING OPINIONS FOR ADAKITES IN CHINA

中国的埃达克岩出露很广,几乎遍及全国各地(除两广和湘黔4省区外),主要集中在古亚洲洋造山带、吉林—黑龙江东部以及中国东部地区,其次为秦祁昆造山带、新特提斯造山带以及青藏高原,在中国南方仅有零星的分布。中国最早的埃达克岩位于赣东北蛇绿岩中(1000 Ma),最年轻的第三纪埃达克岩产于青藏高原(60～10 Ma)。中国各地的埃达克岩可大体分为O型和C型埃达克岩两类,主要反映了板块俯冲和地壳加厚2个不同的地球动力学背景。文中还讨论了不同地质时期由埃达克岩所指示的板块消减事件和陆壳加厚事件及其地球动力学意义。

Adakites occur widely in most area of China except for Guangdong, Guangxi, Hunan and Guizhou Provinces, and concentrate mainly on the Paleo-Asian erogenic belt, east of Jinlin and Hei-longjiang and east China, as well as on the Qin-Qi-Kun orogenic belt, Neo-Tethyan erogenic belt and Tibet Plateau, but sporadically in south China. The oldest adakite (about 1 000 Ma) in China occurs associated with ophiolite in NE Jiangxi, while the youngest adakite (60-10 Ma) in China is the Tertiary adakite in Tibet Plateau. All the adakites in China can be divided into two groups: one is Otype adakite, the other is C-type adakite, which are formed by plate subduction and crust thickening, respectively. It is also discussed in the paper that the events of subduction and continental crust thickening in different geological ages and their geodynamic implications which are indexed by the adakites.