摘要
综合研究得出结论:"甘肃北山红石山断裂带以北的雀儿山—英安山地区为一种与俯冲洋壳板块相关的岛弧带,它记录了古亚洲大洋向南缘东天山古陆系统下俯冲消减的整个地史过程"。主要依据:①该地区缺少古老基底陆壳;②发育于区内的中奥陶世—泥盆纪不同时代地层中的火山岩和石炭—三叠纪的中酸性侵入岩,主要以钙碱性或TTG或埃达克成分系列为主要标志,揭示深部有消减洋壳板片或岩源的存在;③从中奥陶世和志留纪火山岩的玄武岩、安山岩和英安岩组合,到泥盆纪以安山岩、英安岩为主的流纹岩、玄武岩组合,至三叠纪马鞍山、小草湖中酸性侵入岩序列的部分高钾钙碱性岩石类型组合,反映古亚洲大洋在南侧消减带之上从一种不成熟岛弧到成熟岛弧和大陆边缘弧发育演化的过程;文章提出代表古亚洲大洋南缘消减带的实际位置应在雀儿山—英安山一线以北的蒙古境内,而北山岛弧带实属南侧东天山古陆陆缘增生地体的一部分。
Based on the comprehesvie analysis of previsou research results, the study concludes that the Que ershan-Yinganshan area, which is to the north of Hongshishan fault belt in Beishan Mt. , Gansu province is an island arc associated with subduction ocean crust and records the geological process of the subduction of the ancient Asian Ocean crust subducted into the southern margin of East Tianshan old land. The conclusion is based on the facts as follows：① this area is lack of ancient continental crust basement; ② subducted ocean crust relicts are indicated by volcanic rocks contained various age strata ranging from mid-Ordovician to Devonian and Carboniferous Triassic intermediate-acidic intrusions. These rocks are represented by some calc-alkaline rock association or TTG or adakite series; ③the evolution process of ancient Asian Ocean, which began with immature arc island, followed by mature island arc and ended by continental marginal arc, was successively testified by volcanic rock associations such as basalt, andesite and dacite in mid-Ordovician and Silurian, dominated by andesite and dacite interclating rhyolite in Devonian, and parts of high K calc-alkaline rock association of intermediate-acidic intrusions in Maanshan and Xiaocaohu in Triassic. Furthermore, it is suggested that the south subduction zone of ancient Asian Ocean should be really located in Mongolia, and the island arc zone should belong to part of continental margin accretionary terrain of East Tianshan old land.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2009年第11期1584-1600,共17页
Acta Geologica Sinica
基金
"十一五"国家科技支撑计划课题(编号2006BAB01A11)
国土资源大调查项目"甘肃营毛沱地区矿产远景调查"(矿调【2004】8-2号)资助的成果
关键词
甘肃北山
雀儿山
英安山地区
北山岛弧带
陆缘增生地体
Gansu Beishan
Queershan-Yinganshan accretlonary terrain area
island arc zone
continental margin
