勉略带关帝坪角闪岩岩石地球化学特征及LA-ICP-MS锆石U-Pb定年
Geochemistry and LA-ICP-MS Zircon U-Pb Dating of the Guandiping Amphibolite in the Mian-Lue Structure Zone
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摘要: 关帝坪蛇绿岩位于勉县关帝坪地区，具典型的堆晶结构，是勉略蛇绿岩带的重要组成部分。对其中的角闪岩进行了岩石地球化学和LA-ICP-MS 锆石U-Pb测年分析。结果表明角闪岩具高MgO、CaO，低K2O的特征，为钙碱性系列，TiO2含量与活动大陆边缘及岛弧区火山岩相似，富集大离子亲石元素Ba、Th、U，显著亏损Nb、Ta，略微富集轻稀土元素，轻重稀土元素分馏不明显，具有岛弧玄武岩的地球化学特征，与勉略带印支期花岗岩可能具有一定的同源性，可能是印支期勉略洋盆向北俯冲的产物，并受到了大陆壳的混染。LA-ICP-MS锆石U-Pb测年结果，表明角闪岩的成岩年龄为（222.5±2.1）Ma，表明其形成于晚三叠世。该年龄略早于研究区花岗岩的成岩年龄，二者的成对性关系说明在勉略古洋壳向北的俯冲一直持续到晚三叠世岛弧火山岩的形成或者更晚时期，之后才进入了碰撞造山阶段。Abstract: Located in Mianxian County and with a typical heap crystal structure, the Guandipin ophiolite is an important part of the Mian-lue ophiolite structure zone. In this study, rock geochemistry and LA-ICP-MS zircon U-Pb dating are applied to analyze the intrusive environment and period of the amphibolite. The result shows that the amphibolite belongs to Calc-alkaline series with typically high content of MgO and CaO but low K2O. The TiO2 content is similar to that of active continental margin and island arc volcanic rocks. Besides, it is rich in LILE such as Ba, Th, U and LREE, while low in HFSE of Nb and Ta. Moreover, the fractionation of light and heavy REE is not obvious. These features indicate that it is probably the product of the northward subduction of the Mian-lüe oceanic basin under island arc environment. Its geochemistry characteristics are similar to the Indosinian granites, suggesting that they may derive from the same source, and are contaminated by the continental crust. LA-ICP-MS zircon U-Pb dating result shows that the diagenetic age of the amphibolite is 222.5±2.1 Ma, which indicates that it was formed in the Late Triassic Epoch. This age is a bit earlier than the granites in the study area, implying that the ancient Mian-lüe was formed in the Late Triassic Epoch. This age is a bit earlier than the granites in the study area, implying that the ancient Mian-lüe oceanic crust continued northward subduction until the forming of island arc volcanic rocks in Late Triassic or later, and then entered the collision orogenic stage.
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Key words:
- geochemistry /
- Zircon U-Pb dating /
- amphibolite /
- Guandiping /
- Mian-lue structure Zone
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冯庆来,杜远生,殷鸿福,等. 南秦岭勉略蛇绿混杂岩带中放射虫的发现及其意义[J]. 中国科学(D辑:地球科学), 1996,26(S1): 78-82.
Feng Qinglai, Du Yuansheng, Yin Hongfu, et al. Carboniferous radiolaria fauna firstly discovered in Mian-Lüe ophiolitic melange belt of South Qinling Mountains[J]. Science in China Series D: Earth Sciences, 1996,26(S1): 78-82.
赖绍聪. 秦岭造山带勉略缝合带超镁铁质岩的地球化学特征[J]. 西北地质, 1997,18(03): 36-45.
Lai Shaocong. Geochemical features of the ultramafic rocks in Mianlue suture zone, Qingling orogenic belt. Northwest Geology, 1997,18(03): 36-45.
赖绍聪. 南秦岭勉略蛇绿构造混杂带辉长辉绿岩类微量-稀土元素地球化学. 地球科学与环境学报, 2005,27(3): 5-9.
Lai Shaocong. Geochemical features of trace and rare earth elements of gabbro-diabase in Mianlue ophiolitic melange zone, South Qinling[J]. Journal of Earth Sciences and Environment, 2005,27(3): 5-9.
赖绍聪,秦江锋. 南秦岭勉略缝合带蛇绿岩与火山岩[M]. 北京: 科学出版社: 2010.
Lai Shaocong, Qin Jiangfeng. Ophiolite and volcanic rocks in Mianlue suture zone, South QinLing[M]. Science press: Beijing,2010.
赖绍聪,张国伟,董云鹏,等. 秦岭-大别勉略构造带蛇绿岩与相关火山岩性质及其时空分布[J]. 中国科学D辑, 2003,33(12): 1174-1183.
Lai Shaocong, Zhang Guowei, Dong Yunpeng, et al. The character and space time distribution of the ophiolite and volcanic rock in the Qinling-Dabie and Mian-Lue tectonic belt. Science in China[J]. Science in China (Series D), 2003,33(12): 1174-1183.
赖绍聪,张国伟,杨永成,等. 南秦岭勉县─略阳结合带蛇绿岩与岛弧火山岩地球化学及其大地构造意义[J]. 地球化学, 1998,27(03): 283-293.
Lai Shaocong, Zhang Guowei, Yang Yongcheng, et al. Geochemistry of the ophiolite and island arc volcanic rock in the Mianxian-Lueyang suture zone,southern Qinling and their tectonic significances[J]. Geochimica, 1998,27(03): 283-293.
李瑞保,裴先治,丁仨平,等. 西秦岭南缘勉略带琵琶寺基性火山岩LA-ICP-MS锆石U-Pb年龄及其构造意义[J]. 地质学报, 2009. 83(11): 1612-1623.
Li Ruibao, Pei Xianzhi, Ding Saping, et al. LA-ICP-MS Zircon U-Pb Dating of the Pipasi Basic Volcanic Rocks Within the Mian-Lue Tectonic Zone in the Southern Margin of West Qinlin and its Geological Implication[J]. Acta Geologica Sinica, 2009,83(11): 1612-1623.
李曙光,侯振辉,杨永成,等. 南秦岭勉略构造带三岔子古岩浆弧的地球化学特征及形成时代[J]. 中国科学D辑, 2003,33(12): 1163-1173.
Li Shuguang, Hou Zhenghui, Yang Yongcheng, et al. Geochemical features and forming age of the Sanchazi palaeo magmaarc in the Mian-Lue tectonic zone[J]. Science in China (Series D), 2003,33(12): 1163-1173.
李曙光,孙卫东,张国伟,等. 南秦岭勉略构造带黑沟峡变质火山岩的年代学和地球化学——古生代洋盆及其闭合时代的证据[J]. 中国科学(D辑:地球科学), 1996,26(03): 223-230.
Li Shuguang, Sun Weidong, Zhang Guowei, et al. Chronology and geochemistry of metavolcanic rocks from Heigouxia Valley in Mianlue tectonic zone,South Qinling: Evidence for a Paleozoic oceanic basin and its close time[J]. Science in China (Series D), 1996,26(03): 223-230.
秦江锋,赖绍聪,李永飞. 南秦岭勉县-略阳缝合带印支期光头山埃达克质花岗岩的成因及其地质意义[J]. 地质通报, 2007,26(4): 466-471.
Qin Jiangfeng, Lai Shaocong, Li Yongfei. Genesis of the Indosinian Guangtoushan adakitic biotite plagiogranite in the Mianxian-Lueyang (Mianlue) suture, South Qinling, China, and its tectonic implications[J]. Geological Bulletin of China, 2007,26(4): 466-471.
邱家骧,林景仟. 岩石化学[M]. 北京: 地质出版社: 1991.
Qiu Jia-xiang, Lin Jingqian. Petrochemistry[M]. Geological publishing house: Beijing,1991.
孙卫东,李曙光,Chen Ya dong,等. 南秦岭花岗岩锆石U-Pb定年及其地质意义[J]. 地球化学, 2000,29(3): 209-216.
Sun Weidong, Li Shuguang, Chen Yadong, et al. Zircon U-Pb dating of granitoids from South Qinling,Central China and their geological significance[J]. Geochimica, 2000,29(3): 209-216.
吴峰辉,刘树文,李秋根,等. 西秦岭光头山花岗岩锆石U-Pb年代学及其地质意义[J]. 北京大学学报(自然科学版), 2009,45(5): 811-818.
Wu Fenghui, Liu Shuwen, Li Qiugen, et al. Zircon U-Pb Geochronology and Geological Significance of Guangtoushan Granitoids from Western Qinling,Central China[J]. Acta Scientiarum Naturalium Universitatis Pekinensis, 2009,45(5): 811-818.
吴美玲,郭永峰,李学军. 陕西勉县地区关帝坪闪长岩体的LA-ICP-MS锆石U-Pb年龄及其地质意义[J]. 西北地质, 2009,42(1): 73-78.
Wu Meiling, Guo Yongfeng, Li Xuejun. Zircon LA-ICP-MS U-Pb Dating of the Guandiping Diorite Pluton from Mianxian,South Qinling,Central China[J]. Northwestern Geology, 2009,42(1): 73-78.
吴元保,郑永飞. 锆石成因矿物学研究及其对U-Pb年龄解释的制约[J]. 科学通报, 2004,49(16): 1589-1604.
Wu Yuanbao, Zhen Yongfei. Genesis of zircon and its constraints on interpretation of U-Pb age[J]. Chinese Science Bulletin, 2004,49(16): 1589-1604.
闫全人,王宗起,闫臻,等. 秦岭勉略构造混杂带康县—勉县段蛇绿岩块—铁镁质岩块的SHRIMP年代及其意义[J]. 地质论评, 2012,53(6): 755-764.
Yan Quanren, Wang Zongqi, Yan Zhen, et al. SHRIMP Analyses for Ophiolitic-Mafic Blocks in the Kangxian-Mianxian Section of the Mianxian-Lueyang elange:Their Geological Implications[J]. Geological Review, 2012,53(6): 755-764.
杨崇辉,魏春景,张寿广,等. 南秦岭佛坪地区麻粒岩相岩石锆石U-Pb年龄[J]. 地质论评, 2012,45(2): 173-179.
Yang Chonghui, Wei Chunjing, Zhang Shouguang, et al. U-Pb Zircon Dating of Granulite Facies Rocks from the Foping Area in the Southern Qinling Mountains. Geological Review, 2012,45(2): 173-179.
张成立,张国伟,晏云翔,等. 南秦岭勉略带北光头山花岗岩体群的成因及其构造意义[J]. 岩石学报, 2005,21(3): 711-720.
Zhang Chengli, Zhang Guowei, Yan Yunxiang, et al. Origin and dynamic significance of Guangtoushan granitic plutons to the north of Mianlue zone in southern Qinling[J]. Acta Petrologica Sinica, 2005,21(3): 711-720.
张国伟,程顺有,郭安林,等. 秦岭-大别中央造山系南缘勉略古缝合带的再认识——兼论中国大陆主体的拼合[J]. 地质通报, 2004,23(9): 846-853.
Zhang Guowei, Cheng Shunyou, Guo Anlin, et al. Mianlue paleo-suture on the southern margin of the Central Orogenic System in Qinling-Dabie with a discussion of the assembly of the main part of the continent of China[J]. Geological Bulletin of China, 2004,23(9): 846-853.
张国伟,董云鹏,赖绍聪,等. 秦岭-大别造山带南缘勉略构造带与勉略缝合带[J]. 中国科学D辑, 2003,33(12): 1121-1135.
Zhang Guowei, Dong Yunpeng, Lai Shaocong, et al. The Mian-Lue suture zone in the South Qinling-Dabie Orogenic Belt[J]. Science In China (Series D), 2003, 33(12): 1121-1135.
张宗清,唐索寒,张国伟,等. 勉县-略阳蛇绿混杂岩带镁铁质-安山质火山岩块年龄和该带构造演化的复杂性[J]. 地质学报, 2005,79(4): 531-539.
Zhang Zongqing, Tang Suohan, Zhang Guowei, et al. Ages of Metamorphic Mafic-Andesitic Volcanic Rock Blocks and Tectonic Evolution Complexity of Mianxian-Lueyang Ophiolitic Melange Belt[J]. Acta Geologica Sinica, 2005,79(4): 531-539.
张宗清,张国伟,唐索寒,等. 秦岭勉略带中安子山麻粒岩的年龄[J]. 科学通报, 2002,47(22): 1751-1755.
Zhang Zongqing, Zhang Guowei, Tang Suohan, et al. Age of the Anzishan granulites in the Mianxian-Lueyang suture zone of the Qingling orogen[J]. Chinese Science Bulletin, 2002,47(22): 1751-1755.
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