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| 北祁连早古生代花岗质岩浆作用及构造演化 | |
| 引用本文： | 吴才来,徐学义,高前明,李向民,雷敏,郜源红,Ronald B FROST,Joseph L WOODEN.北祁连早古生代花岗质岩浆作用及构造演化[J].岩石学报,2010,26(4):1027-1044. |
| 作者姓名： | 吴才来 徐学义 高前明 李向民 雷敏 郜源红 Ronald B FROST Joseph L WOODEN |
| 作者单位： | 1. 中国地质科学院地质所,北京,100037 2. 中国地质调查局西安地矿所,西安,710054 3. 安徽省地矿局321地质队,铜陵,244033 4. 怀俄明大学,美国怀俄明州 5. 斯坦福大,美国加州 |
| 基金项目： | 国家自然科学基金项目(40672049、40472034)、中国地质调查局地质调查项目(1212010918007、1212010818090、1212010611803、1212010711816)的联合资助 |
| 摘 要： | 北祁连山中段花岗岩锆石SHRIMP定年结果表明,柯柯里岩体的斜长花岗岩和石英闪长岩的年龄分别为512Ma和501 Ma,野马咀和金佛寺花岗岩的年龄分别为508Ma和424Ma。结合区内其它花岗岩体的定年资料,根据花岗岩的岩石地球化学特征及岩体产出的构造位置、区域地质资料等,我们认为,早古生代北祁连洋板块向南俯冲,至少引发了两期花岗质岩浆作用,第一次岩浆作用形成柯柯里斜长花岗岩(512Ma)、野马咀花岗岩(508Ma)和柯柯里石英闪长岩(501 Ma),第二次花岗质岩浆作用形成牛心山花岗岩(477Ma)。由于往南俯冲的板块受到柴达木板块向北俯冲的影响,俯冲受阻,继而俯冲极性发生变化,转向北俯冲,形成了民乐窑沟(463Ma)等花岗岩侵入体。大约440Ma之后,洋盆闭合,柴达木陆块和阿拉善陆块对接碰撞,形成北祁连造山带。由于造山带根部岩石圈发生折沉作用,造山带上不同的块体伸展、滑塌,形成一系列碰撞后花岗岩如金佛寺花岗岩(424Ma)及牛心山岩体的石英闪长岩(435Ma)等。 |
| 关 键 词： | 花岗岩 锆石SHRIMP定年 岩浆作用 构造演化 北祁连 |
| 收稿时间： | 6/9/2009 12:00:00 AM |
| 修稿时间： | 2010/3/26 0:00:00 |
Early Palaezoic grranitoid magmatism and tectonic evolution in North Qilian, NW China |
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| Wu CL,Xu XY,Gao QM,Li XM,Lei M,Gao YH.Early Palaezoic grranitoid magmatism and tectonic evolution in North Qilian, NW China[J].Acta Petrologica Sinica,2010,26(4):1027-1044. | |
| Authors: | Wu CL Xu XY Gao QM Li XM Lei M Gao YH |
| Affiliation: | Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Xi'an Institute of Geological and Ore Deposits, CGS, Xi'an 710054, China;321 Geological Party, Anhui Bureau of Geology and Mineral Resources, Tongling 244033, China;Xi'an Institute of Geological and Ore Deposits, CGS, Xi'an 710054, China;Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;University of Wyoming, Laramie 82071, WY, USA;Stanford University, CA 94305, USA |
| Abstract: | Zircon SHRIMP dating of granitoids from the middle segment of North Qilian showed that they are 512 Ma and 501 Ma for plagiogranite and quartz diorite from Kokoli, 508Ma for Yemazhui granite, and 424Ma for Jinfusi granite, respectively. Based on petrogeochemistry of granites and occurrence in tectonics, combined with the dating of other granites and regional geological data, we think that North Qilian oceanic plate was subducted southward under the Middle Qilian terrane, which caused two episodes of magmatism, one was forming Kokoli plagiogranite (512Ma), Yemazui granite (508Ma) and Kokoli quartz diorite (501Ma), another forming Niuxinshan granite (477Ma). Lately, subduction polarity for the North Qilian basin changed from southward to northward because it was blocked by the deep subduction of Qaidam continental plate northward on the south of Qilian, which formed Minleyaogou granite (463Ma). After about 440 Ma, the Qilian Ocean was closed because of collision between Qaidam and Alax terrane, forming the North Qilian orogen. The post-collision granites such as Jinfusi granite (424Ma) and Niuxinshan quartz diorite (435Ma), and so on, were formed in the North Qilian Orogen where different blocks stretched and collapsed because of lithosphere delamination below the orogen. |
| Keywords: | Granite Zircon SHRIMP dating Magmatism Tectonic evolution North Qilian |
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