摘要
中国出露从太古代-中生代各个时期的O型埃达克岩。中国太古代TTG大多类似喜马拉雅型花岗岩的特征,少数是埃达克岩,主要是加厚下地壳熔融形成的。中国新元古代埃达克岩大多分布于扬子板块的西缘和北缘,古生代埃达克岩主要分布于中亚造山带和秦祁昆造山带。中亚造山带早古生代和部分晚古生代的O型埃达克岩可能产于板块消减带环境,晚古生代晚期的O型埃达克岩可能与碰撞有关。冈底斯晚白垩世的O型埃达克岩可能产于活动陆缘环境。O型埃达克岩最重要的意义在于其与金铜成矿作用的密切关系。埃达克岩很难判断其形成的构造环境,即使是O型埃达克岩。O型埃达克岩贫钾,说明它来源于贫钾的玄武质源岩,可以产于板块消减带,也可来自下地壳底部;但是,那些富Mg#且Mg#变化大的埃达克岩很可能来自板块俯冲带。
The O-type adakite outcrops in China from the Archean to Mesozoic. The TTG of Archean in China is mostly of characteristics of the Himalaya-type granite, a few of them are adakite mainly formed by the melting of the low thicken crust. The adakites in China during late Proterozoic mostly distributes on the western and northern margin of the Yangtze plate, otherwise the adakites from the Palaeozoic mainly distributes in the Central Asia orogenic belt and Qiling-Qinlian-Kunlun orogenic belt. The O-type adakite in the Central Asia orogenic belt may be origina- ted in the subduction plate during early Palaeozoic, and some of them may be formed during late Palaeozoic, which may relate to the plate collision. The O-type adakite in the Gangdese may be originated in an active continental margin during late Cretaceous period. The O-type adakite is of the most important implication due to the close relation to the gold and copper mineralizations. It is very difficult for the adakite, even O type adakite to be judged its tectonic environment. The O-type adakite with low potassium is proved that it originates from the basalt of the low potassium content, may originate in a subduction plate or the bottom of lower crust. However, the adakite with high Mg# and various Mg# contents will likely come from a plate subduction zone.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2009年第3期432-447,共16页
Geotectonica et Metallogenia
基金
国家自然科学基金重大研究计划(90714011)资助的项目
关键词
O型埃达克岩
TTG
地球化学
构造环境
成矿
O-type adakite
TTG
geochemistry
tectonic environment
mineralization
