摘要
义敦岛弧南段的格咱火山-岩浆弧的东西斑岩带在成矿期次、成矿作用等方面存在较大差异性,二者之间是否有大型构造单元的存在,与东部代表洋壳消减的甘孜-理塘主蛇绿混杂岩带关系如何等一直是悬而未决问题。研究发现,区内存在由断续出露镁铁-超镁铁堆积杂岩,以及尼汝组玄武岩、硅质板岩和复理石、灰岩等岩片组成的红山-属都蛇绿混杂岩带,属于甘孜-理塘洋壳早期俯冲残留次级蛇绿混杂岩带,与主蛇绿混杂岩带及格咱火山-岩浆弧构成了本区构造格架。其中,红山-属都蛇绿混杂岩带将格咱弧分为东西两个斑岩成矿带。本蛇绿混杂岩带的厘定,为进一步研究甘孜-理塘洋范围、俯冲时限、构造演化、甘孜-理塘洋是否存在两次俯冲,及格咱弧东西斑岩带成矿规律提供了基础资料,并对指导区域找矿具有一定意义。
Geza volcanic-magmatic arc is divided into two porphyry metallogenic belts,east belt and west belt,in the southern part of Yidun island arc. The two belts differ greatly in metallogenic epoch and metallogeny,issues about whether a large structural unit exists between them and how they relate Ganzi-Litang ophiolite mélange were remain undecided. It was found that mafic-ultramafic cumulates discontinuously exposed,together with basalt,siliceous slate,flysch and limestone of Niru Formation. They form Hongshan-Shudu ophiolite mélange which formed in early subduction of Ganzi-Litang oceanic crust and subordinated to Ganzi-Litang mélange belt. The two ophiolite mélange belts and Geza volcanic-magmatic arc have delineated the tectonic sketch of southern Yidun arc. Hongshan-Shudu ophiolite mélange belt is a boundary of the two metallogenic belts above-mentioned. The recognition of Hongshan-Shudu ophiolite mélange has great significance in further approaching the range and tectonic evolution of Ganzi-Litang Ocean,metallogenic regularity of porphyry belts of Geza volcanic-magmatic arc and regional prospecting.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第6期1661-1671,共11页
Acta Petrologica Sinica
基金
国家重点基础研究发展规划("973"项目)(2009CB421007)
国家科技支撑计划项目(2006BAB01A07)资助
关键词
红山-属都
火山-岩浆弧
构造格架
蛇绿混杂岩
斑岩成矿带
成矿规律
Hongshan-Shudu
Volcanic-magmatic arc
Tectonic sketch
Ophiolite mélange
Porphyry metallogenic belt
Metallogenic regularity
