甘肃北山北部红石山地区泥盆系雀儿山群火山岩地球化学特征及构造环境分析
Geochemical Characteristics and Tectonic Settings of Volcanic Rocks from Queershan Group in Hongshishan Area, Gansu
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摘要: 位于北山北部红石山地区雀儿山群的火山岩主要为一套中酸性火山岩,以安山岩、英安岩和流纹岩为主,属钙碱-碱性系列。地球化学研究表明:火山岩SiO2含量较高(62.29%~75.74%),MgO含量较低(<2.15%),全碱含量较高(Na2O+K2O为6.24%~9.2%),且K2O/Na2O<1。轻稀土元素(LREE)相对于重稀土元素(HREE)呈现较强富集[(La/Yb)N=2.94~6.36],轻稀土内部出现较强分馏[(La/Sm)N=1.94~3.33],并且具有相当明显的Eu负异常(0.50~0.90);在微量元素方面,大离子亲石元素(LILE)相对高场强元素(HFSE)富集,具有明显的Nb、Ta、P、Ti相对亏损和Ba、Th、Zr、Ce、Sm相对富集。上述特征表明该火山岩形成于洋壳俯冲作用下的岛弧环境,可能与哈萨克斯坦板块和塔里木板块之间的古洋壳俯冲消减有直接的成因联系,在俯冲过程中洋壳含水流体引起上覆地幔物质的部分熔融,并在岩浆上升中经历了一定的分离结晶作用和上地壳物质的同化混染。Abstract: The volcanic rocks of Queershan Group, located in Hongshishan area, north of Beishan, are mainly composed of intermediate-acid volcanics, andesites, dacite and rhyolite, which belong tocalc-alkaline series. Researches on the geochemistry suggest that, these volcanic rockshave high SiO2 content(62.29%-75.74%, lower MgO content(<2.15%), relatively high alkali content(Na2O+K2O=6.24%-9.2%), and K2O/Na2O<1. These rocksare enrich in LREE relative to HREE((La/Yb)N=2.94-6.36), with a strong fractionation in LREE((La/Sm)N=1.94-3.33), presenting a strong negative anomaly of Eu(0.50-0.90). In the aspect of trace elements, these rocks are enrich in LILE more than HFSE, with relatively depletion of Nb, Ta, P and Ti, as well as the enrichment of Ba, Th, Zr, Ce and Sm. These geochemical characteristics approve that, these volcanic rocks formed in the island arc environment with the effect of oceanic crust subduction, which has a direct genetic relationship with the subduction of ancient oceanic crust between Kazakhstan plate and Tarim plate. During the process of subduction, the partial melting of the overlying mantle material was caused by the hydrous fluids of oceanic crust, and the product created by the rising magma has experienced a certain fractional crystallization and assimilation and contamination of upper crustal material.
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Key words:
- Hongshishan /
- Queershan Group /
- volcanic rocks /
- geochemistry /
- tectonic environment
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何世平,周会武,任秉琛,等.甘肃内蒙古北山地区古生代地壳演化[J].西北地质,2005,38(3):6-15.
HE Shiping, ZHOU Huiwu, REN Bingchen, et al. Crustal evolution of Palaeozoic in Beishan area, Gansu and Inner Mongolia,China[J].Northwestern Geology, 2005, 38(3):6-15.
徐学义,何世平,王洪亮,等.中国西北部地质概论-秦岭、祁连、天山地区[M].北京:科学出版社,2008.
XU Xueyi, HE Shiping, WANG Hongliang, et al.Concise geology of northwest China-Qinling, Qilian and Tianshan area[M].Beijing:Science Press,2008.
左国朝,刘义科,刘春燕.甘新蒙北山地区构造格局及演化[J].甘肃地质学报,2002,12(1):1-15.
ZUO Guochao, LIU Yike, LIU Chunyan. Framework and evolution of the tectonic structure in Beishan area acrossGansu province, Xinjiang Autonomous Region and Inner Mongolia Autonomous Region[J]. Acta Geological Gansu, 2002, 12(1):1-15. 杨合群,李英,李文明,等.北山成矿构造背景概论[J].西北地质,2008,41(1):22-27.
YANG Hequn, LI Ying, LI Wenming,et al. General Discussion on Metallogenitic Tectonic Setting of Beishan Mountain, Northwestern China[J]. Northwestern Geology,2008,41(1):22-27.
左国朝,李茂松.甘蒙北山地区早古生代岩石圈形成与演化[M].兰州:甘肃科学技术出版社,1996.
ZUO Guochao,LI Maosong. Formation and Evolution of the Early Paleozoic Lithosphere in the beishan area,gansu-inner mongolia,China[M].Lanzhou:Gansu Science and Technology Press,1996.
左国朝,何国琦.北山板块构造及成矿规律[M].北京:北京大学出版社,1990.
ZUO Guochao, HE Guoqi. Plate Tectonics and Mineralization Rules in Beishan area[M].Beijing:Peking University Press,1990.
左国朝,张淑玲,何国琦,等.北山地区早古生代板块构造特征[J].地质科学,1990,25(4):305-314. ZUO Guochao, ZHANG Shuling, HE Guoqi, et al. Early Paleozoic Plate Tectonics in Beishan Area[J]. Scientia Geologica Sinica, 1990,25(4):305-314.
何世平,任秉琛,姚文光,等.甘肃、内蒙古北山地区构造单元划分[J].西北地质,2002,35(4):30-40.
HE Shiping, REN Bingshen,YAO Wenguang, et al. The division of tectonic units of Beishan area, Gansu-Inner Mongolia[J]. Northwestern Geology, 2002,35(4):30-40. 李向民,余吉远,王国强,等.甘肃北山红柳园地区泥盆系三个井组和墩墩山群LA-ICP-MS锆石U-Pb测年及其意义[J].地质通报,2011,30(10):1501-1507.
LI Xiangmin, YU Jiyuan, WANG Guoqiang, et al. LA-ICP-MS zircon U-Pb dating of Devonian Sangejing Formation and Dundunshan Group in Hongliuyuan, Beishan area, Gansu Province[J]. Geological Bulletin of China, 2011, 30(10):1501-1507.
冯益民,何世平.北祁连山蛇绿岩地质和地球化学研究[J].岩石学报,1995,11:125-146.
FENG Yimin, HE Shiping. Research for Geology and Geochemistry of Several Ophiolites in the North Qilian Mountains, China[J]. Acta Petrologica Sinca, 1995,11:125-146. 左国朝,刘春燕,白万成,等.北山泥盆纪碰撞造山火山-磨拉石地质构造及地球化学特征[J].甘肃地质学报,1995,4(1):35-43.
ZUO Guochao, LIU Chunyan, BAI Wancheng, et al. Volcano-Molasse Geological Structure and Geochemical Signature in Devonian Period Collision Orogenic in Beishan,Gansu-in Mongolia[J]. Acta Geological Gansu, 1995, 4(1):35-43.
周国庆,赵坚信,李献华.内蒙古月牙山蛇绿岩特征及形成的构造背景:地球化学和Sr-Nd同位素制约[J].地球化学,2000,29(2):108-119.
ZHOU Guoqing, ZHAO Jianxin, LI Xianhua. Characteristics of the Yueyashan ophiolite from western Nei Mongol and it tectonic setting:Geochemisrty and Sm-Nd isotopic constraints[J]. Geochimica, 2000, 29(2):108-119.
穆治国, 刘驰, 黄宝玲, 等.甘肃北山古生代造山带地壳演化的同位素和稀土元素地球化学特征[J].北京大学学报(自然科学版),1994,30(2):202-214.
MU Zhiguo, LIU Chi, HUANG Baoling, et al. Isotope and REE Geochemical Characteristics of Crust Evolution in the Paleozoic Orogenic Belt of Beishan Region,Gansu Province[J].Acta Scientiarum Naturalium Universitatis Pekinensis, 1994, 30(2):202-214.
刘明强,党引业,龚全胜.甘肃北山平头山逆冲推覆构造的特征[J].西北地质,2002,35(1):22-27.
LIU Mingqiang, DANG Yinye, GONG Quansheng. The feature of Pingtoushan thrust-nappe structure inBeishan, Gansu[J]. Northwestern Geology, 2002, 35(1):22-27. 张国英.甘肃北山北部双沟山地区发现泥盆系雀儿山群地层[J]. 地层学杂志,2008,32(1):51-54.
ZHANG Guoying. Discovery of the Devonian Queershan Group in the Shuanggoushan in the North of Beishan,Gansu[J]. Journal of Stratigraphy, 2008, 32(1):51-54. 谢春林,杨建国,王立社,等.甘肃北山地区古亚洲南缘古生代岛弧带位置的讨论[J].地质学报,2009,83(11):1585-1600.
XIE Chunlin, YANG Jianguo, WANG Lishe, et al. Disscussion on the Location of Paleozoic Island Arc Zone on the South Margin of Paleo-Asian Ocean in the Beishan Area of Gansu Province[J]. Acta Geologica Sinca, 2009, 83(11):1585-1600. 甘肃省地质矿产局.甘肃省区域地质志[M].北京:地质出版社, 1989.
Bureau of geology and mineral resources ofgansu province. Regional Geology of Gansu Province[M]. Beijing:Geological Publishing House, 1989.
邱家骧,林景仟.岩石化学[M].北京:地质出版社, 1991.
QIU Jiaxiang, LIN Jingqian. Petrochemistry[M]. Beijing:Geological Publishing House, 1991.
谯文浪,刘凌云,刘贞才.东天山伊吾地区早石炭世火山岩地球化学特征及其构造意义[J].贵州地质,2011,28(106):35-41.
QIAO Wenlang, LIU Lingyun, LIU Zhencai. Geochemical Characteristics and Its Structural Significance of Early Carboniferous Volcanic Rock in Yiwu Area,Eastern Tianshan[J]. Guizhou Geology, 2011, 28(106):35-41.
张旗.蛇绿岩研究中的几个问题[J].岩石学报, 1995, 11(增刊):228-240.
ZHANG Qi. Some Problems Concerning the Ophiolite Study[J].Acta Petrologica Sinca,1995, 11(Suppl.):228-240. DEFANT M J, DRUMMOND M S. Derivation of some modern arc magmas by melting of young subducted lithosphere[J]. Natrue, 1990, 37:662-665.
MIYASHIRO A. Volcanic rock series in island areas and active continental margins[J]. AIS, 1974, 274:321-335.
SAUNDERS A D, NORRY M J,Tarney J. Origin of MORB and chemically-depleted mantle reservoirs:Trace element constraints[J]. Journal of Petrology(Special Lithosphere Issue), 1988, 415-445.
WEAVER B L. The origin of ocean island basalt end-member composition:Trace element and isotopic constraints[J]. Earth and Planetary Science Letters, 1991, 104:381-397.
HERGT J M, PEATE D W,Hawkesworth C J. The petrogenesis of Mesozoic Gondwana low-Ti flood basalts[J]. Earth and Planetary Science Letters, 1991, 105:134-148.
MILLER C, SCHUSTER R, KLOTZLI U,et al. Post-collisional potassic and ultrapotassic magmatism in SW Tibet:Geochemical and Sr-Nd-Pb-O isotopic constraints for mantle source characteristics and petrogenesis[J]. Journal of Petrology, 1999, 40:1399-1424.
BARTH M G, MCDONOUGH W F,RUDNICK R L. Tracking the budget of Nb and Ta in the continental crust[J]. Chemical Geology, 2000, 165:197-213.
JOCHUM K P, PFANDER J, SNOW J E,et al. Nb/Ta in mantle and crust[J]. EOS, 1997, 78:804.
LE Maitre R W. A proposal by the IUGS subcommission on the systematics of igneous rocks for a chemical classification of volcanic rocks based on the total alkali silica(TAS) diagram[J]. Australian Journal of Earth Sciences,1984,31:243-255.
TAYLOR S R, MCLENNAN S M. The Continental Crust:its Composition and Evolution[M]. Oxford:Blackwell, 1985.
SALTERSV T M, HART S R. The mantle sources of ocean ndges, island arcs the Hf-isotope connection[J]. Earth Planet Sci Lett., 1991, 104:364-380.
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