新疆鄯善县亚尔沙布拉克地区小热泉子组火山岩构造环境和岩石成因分析
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摘要
小热泉子组位于准噶尔板块的大南湖岛弧带内,分布于调查区康古尔大断裂带以北地区。虽然前人对大南湖岛弧带有较深入的研究,但是就小热泉子组来说,研究程度仍然有限。所以,本文通过对小热泉子组火山岩进行岩相学、同位素年代学、稀土元素和微量元素地球化学等方面的系统研究,科学论证了小热泉子组火山岩的岩浆性质、岩浆演化过程和岩石成因。通过野外调查和室内的研究相结合,取得了以下几点粗浅的认识:
1、小热泉子组火山岩主要岩石类型为:玄武岩、玄武质安山岩、粗面岩、粗面安山岩、粗面英安岩、英安岩、流纹岩,安山质、英安质、流纹质火山角砾岩和凝灰岩,深灰色蚀变含砾中-粗粒岩屑砂岩,深灰色蚀变砂质砾岩。
2、在小热泉子组内采取新鲜流纹岩石样品,经过北京离子探针实验中心SHRIMP锆石U-Pb测年法,测试其形成年龄为325±3.2Ma,属早石炭世德坞阶。
3、小热泉子组火山岩稀土元素总量较高,轻稀土元素富集,重稀土元素亏损,并且重稀土元素分馏程度较弱,轻稀土元素分馏程度较强。富集大离子亲石元素,高场强元素尤其是Nb,Ta强烈亏损,相容元素V、Cr、Ni强烈亏损。表现为岛弧环境下的钙碱性火山岩特征。
4、小热泉子组火山岩从基性到酸性都有分布。基性火山岩为岛弧环境下典型的钙碱性玄武岩,由被俯冲板片脱水反应形成富LILE和LREE的流体交代的上覆地幔楔橄榄岩部分熔融而形成。中性火山岩为基性火山岩经过自身的分离结晶演化而形成。酸性岩则是由俯冲的洋壳上覆楔形地幔的部分熔融形成的幔源岩浆发生底侵作用,加热导致莫霍面附近地壳部分熔融而形成。
5、小热泉子组火山岩分离结晶的主要矿物为单斜辉石,斜长石的分离结晶在岩浆演化过程中作用较弱。中基性岩浆在上升侵位过程中受到一定程度的同化混染,但仍以源区富集为主。
Xiaorequanzi Formation lies in Dananhu island-arc belt in Junggar plate. It is located in the north of Kanggul Fault belt in the investigation area. Although predecessors have in-depth research for Dananhu island-arc belt,to Xiaorequanzi Formation,it still in relatively low limitation.So,this paper scientifically demonstrates the nature,process and cause of formation of Xiaorequanzi Formation igneous rocks according to systematically research in petrography, geochronology,rare earth elements and trace elements geochemistry. Through the integration of wild investigation and study-in-door,we get some initial understanding as follows:
1 .The main volcanic rock types of Xiaorequanzi Formation are basalt, basaltic andesite, trachyte, trachytic andesite, trachytic dacite, dacite, rhyolite;andesitic, dacitic, rhyolitic volcanic breccia and tuff; dark gray alteration in gravel - coarse-grained lithic sandstone, dark gray sandy breccia.
2.Rhylite samples are collected from Xiaorequanzi Formation volcanic rocks,its formation age is 325±3.2Ma by SHRIMP U-Pb zircon determination in the centre of Beijing Ion probe,belonging to Germany-Docking stage of Early Carboniferous.
3. Xiaorequanzi Formation volcanic rocks have characters of high volume of REE, LREE enrichment, LREE enrichment , HREE loss, and week degree of REE fractionation, strong degree of LREE fractionation. It was LILE enrichment and correspondingly HFSE depletion,especially Nb,Ta. Compatible elements such as V,Co,Ni are strongly depleted. It has the characteristics of volcanic rocks calc-alkaline volcanic rocks in the island arc tectonic environment.
4. Xiaorequanzi Formation volcanic rocks vary from mafic volcanic rocks to acid volcanic rocks. Mafic volcanic rocks are typical calc-alkaline basalts in island arc environment. They are formed by partially melting from the mantle wedge peridotites which had metasomatism with LILE and LREE-rich fluid released by underlying subduction slab. Intermediate volcanic rocks of Xiaorequanzi Formation are formed by fraction and crystallization evolvement of its own basic volcanic rocks. Acid volcanic rocks are formed by partially melting from earth's crust rocks near the Moho which were heated by underplating of mantle magma melt by mantle wedge overlying the subduction slab.
The main fractional and crystallizational mineral are clinopyroxene, the fraction and crysrallization of plagioclase get minor effection in the process of magmatic evolution. Intermediate and mafic volcanic rocks are contaminated and assimilated at certain degree in the process of magma rise emplacement.
1、小热泉子组火山岩主要岩石类型为:玄武岩、玄武质安山岩、粗面岩、粗面安山岩、粗面英安岩、英安岩、流纹岩,安山质、英安质、流纹质火山角砾岩和凝灰岩,深灰色蚀变含砾中-粗粒岩屑砂岩,深灰色蚀变砂质砾岩。
2、在小热泉子组内采取新鲜流纹岩石样品,经过北京离子探针实验中心SHRIMP锆石U-Pb测年法,测试其形成年龄为325±3.2Ma,属早石炭世德坞阶。
3、小热泉子组火山岩稀土元素总量较高,轻稀土元素富集,重稀土元素亏损,并且重稀土元素分馏程度较弱,轻稀土元素分馏程度较强。富集大离子亲石元素,高场强元素尤其是Nb,Ta强烈亏损,相容元素V、Cr、Ni强烈亏损。表现为岛弧环境下的钙碱性火山岩特征。
4、小热泉子组火山岩从基性到酸性都有分布。基性火山岩为岛弧环境下典型的钙碱性玄武岩,由被俯冲板片脱水反应形成富LILE和LREE的流体交代的上覆地幔楔橄榄岩部分熔融而形成。中性火山岩为基性火山岩经过自身的分离结晶演化而形成。酸性岩则是由俯冲的洋壳上覆楔形地幔的部分熔融形成的幔源岩浆发生底侵作用,加热导致莫霍面附近地壳部分熔融而形成。
5、小热泉子组火山岩分离结晶的主要矿物为单斜辉石,斜长石的分离结晶在岩浆演化过程中作用较弱。中基性岩浆在上升侵位过程中受到一定程度的同化混染,但仍以源区富集为主。
Xiaorequanzi Formation lies in Dananhu island-arc belt in Junggar plate. It is located in the north of Kanggul Fault belt in the investigation area. Although predecessors have in-depth research for Dananhu island-arc belt,to Xiaorequanzi Formation,it still in relatively low limitation.So,this paper scientifically demonstrates the nature,process and cause of formation of Xiaorequanzi Formation igneous rocks according to systematically research in petrography, geochronology,rare earth elements and trace elements geochemistry. Through the integration of wild investigation and study-in-door,we get some initial understanding as follows:
1 .The main volcanic rock types of Xiaorequanzi Formation are basalt, basaltic andesite, trachyte, trachytic andesite, trachytic dacite, dacite, rhyolite;andesitic, dacitic, rhyolitic volcanic breccia and tuff; dark gray alteration in gravel - coarse-grained lithic sandstone, dark gray sandy breccia.
2.Rhylite samples are collected from Xiaorequanzi Formation volcanic rocks,its formation age is 325±3.2Ma by SHRIMP U-Pb zircon determination in the centre of Beijing Ion probe,belonging to Germany-Docking stage of Early Carboniferous.
3. Xiaorequanzi Formation volcanic rocks have characters of high volume of REE, LREE enrichment, LREE enrichment , HREE loss, and week degree of REE fractionation, strong degree of LREE fractionation. It was LILE enrichment and correspondingly HFSE depletion,especially Nb,Ta. Compatible elements such as V,Co,Ni are strongly depleted. It has the characteristics of volcanic rocks calc-alkaline volcanic rocks in the island arc tectonic environment.
4. Xiaorequanzi Formation volcanic rocks vary from mafic volcanic rocks to acid volcanic rocks. Mafic volcanic rocks are typical calc-alkaline basalts in island arc environment. They are formed by partially melting from the mantle wedge peridotites which had metasomatism with LILE and LREE-rich fluid released by underlying subduction slab. Intermediate volcanic rocks of Xiaorequanzi Formation are formed by fraction and crystallization evolvement of its own basic volcanic rocks. Acid volcanic rocks are formed by partially melting from earth's crust rocks near the Moho which were heated by underplating of mantle magma melt by mantle wedge overlying the subduction slab.
The main fractional and crystallizational mineral are clinopyroxene, the fraction and crysrallization of plagioclase get minor effection in the process of magmatic evolution. Intermediate and mafic volcanic rocks are contaminated and assimilated at certain degree in the process of magma rise emplacement.
引文
[1]Arturo Gomez-Tuena,Charles H.Langmuir,Steven L.Goldstein.Geochemical evidence for slab melting in the Trans-Mexican volcanic belt[J]..2006,18(1):131-159.
[2]Allegree C J,Minster J F.Quantitative method of trace element behavior in magmatic process[J].Earth Planet Sci.Lett.1978,38:1-25.
[3]C.Annen,J.D.Blundy,R.S.J.Spark.The genesis of intermediate and silicic magmas in deep crustal hot zones.Journal of Pertology[J].2005,48:537-562.
[4]Kogiso T,Hirschmann MM and Pertermann M.High-pressure partial melting of mafic lithologies in the mantle.Journal of petrology[J].2004,45(12):2406-2421.
[5]Rapp R P,Watson E B,Miller C F.Partialmelting of amphibo2lite / eclogite and the origin of Arehaean trondhjemites and tonalities[J].Precam brian Research,1991,51:1-25.
[6]Ewart A,Baxter K,Ross JA.The petrology and petrogenesis of the Tertiary anorogenic marie lavas of Southern and Central Queensland,Australia-possible implications for curstal thickening[J].Mineral Petrol.1980,75:129-152.
[7]Rollinson HR.Using geochemical data:evalution,presentation,interpretation.Longman Scientific and technical[J].1993:1-352.
[8]张海祥,张伯友,牛贺才.富铌玄武岩:板片熔体交代的地幔楔橄榄岩部分熔融的产物.地球科学进展[J].2005,20(11):1234-1232.
[9]姜常义,程松林,叶书锋,等.新疆北山地区中坡山北镁铁质岩体岩石地球化学与岩石成因[J].岩石学报.2006,22(1):115-125.
[10]孙书勤,张成江,黄润秋.板块会聚边缘玄武岩大地构造环境的Th,Nb,Zr判别[J].地球科学进展.2006,22(6):593-598.
[11]姜常义,钱壮志,姜寒冰,唐冬梅,张蓬勃,朱士飞.云南宾川.永胜.丽江地区低钛玄武岩和苦橄岩的岩石成因与源区性质[J].岩石学报.2007,23(4):777-792.
[12]李伍平,李献华.燕山造山带中段中晚侏罗世中酸性火山岩的成因及其意义[J].岩石学报.2004,20(3):501-510.
[13]闫峻,陈江峰.鲁东青山组中性火山岩的地球化学特征、岩石成因和地质意义[J].地球化学.2007,36(1):1-10.
[14]李向民,夏林圻,夏祖春,徐学义,马中平,王立社.东天山石炭纪企鹅山群火山岩岩 石成因[J].吉林大学学报.2006,36(3):336-340.
[15]朱弟成,段丽萍,廖忠礼,潘桂棠。两类埃达克岩的判别[J]。矿物岩石。2002,(3):5-9.
[16]付建明,谢才富,张业明,彭松柏,刘云华。湘南西山两江口高钾钙碱性火山岩的成因分析[J]。华南地质与矿产。2003,2:16-25.
[17]刘肇昌.板块构造学[M].四川科学技术出版社.1985:56-71.
[18]杨学明,杨晓勇,陈双喜译。岩石地球化学[M]。中国科技大学出版社。2000.
[19]邱家骧。岩浆岩岩石学[M]。地质出版社.1985:132-138.
[20]姜常义,夏明哲,余旭,逯东霞,魏巍,叶书锋.塔里木板块东北部柳园粗面玄武岩带软流圈地幔减压熔融的产物.岩石学报.2007,23(7):1765-1773.
[21]邓晋福,罗照华,苏尚国,等.岩石成因、构造环境与成矿作用[M].地质出版社.2004,21-77.
[22]张海祥,牛贺才,于学元,等.准噶尔板块东北缘富铌玄武岩的发现及其意义[J].地质找矿论丛。2003,18(1):71-71.
[23]金性春,丁开平.俯冲工厂及大陆物质的俯冲再循环研究[J].地球科学进展.2003,18:737-744.
[24]姜常义,姜寒冰,叶书锋,夏明哲,逯东霞.新疆库鲁克塔格地区二叠纪脉岩群岩石地球化学特征,Nd、Sr、Pb同位素组成与岩石成因[J].地质学报.2005,79(6):823-833.
[25]姜常义,穆艳梅,赵晓宁,白开寅,张虹波.塔里木板块北缘活动陆缘型侵入岩带的岩石学与地球化学[J].中国区域地质.2001,20(2):158-163.
[26]王宝瑜,郎智君,李向东,等。中国西天山地质构造新认识[J]。新疆人民出版社。1995,28-34.
[27]冯益民,朱宝清,杨军录,张开春.东天山大地构造及演化-1:5万东天山大地构造图简要说明[J].新疆地质.2002,20(4):309-314.
[28]成守德,张湘江.新疆大地构造基本格架.新疆地质.2008,18(4):293-296.
[29]赵泽辉,郭召杰,韩宝福,王毅,刘畅.新疆东部-甘肃北山二叠纪玄武岩对比研究及其构造意义[J].岩石学报.2006,22(5):1279-1293.
[30]新疆维吾尔地质矿产局.新疆维吾尔自治区区域地质志[M].地质出版社.1993,657-71.
[31]肖渊甫,王道永,吴德超,邓江红,何政伟.新疆北山构造带西段地质演化[J].四川 科学出版社、新疆:新疆科技卫生出版社.2000,113-139.
[32]姜常义,贾承造,李良辰,张蓬勃,卢登蓉,白开寅.新疆麻扎尔塔格地区铁富集型高镁岩浆的源区[J].地质学报.2004.(b),78(6):770-780.
[2]Allegree C J,Minster J F.Quantitative method of trace element behavior in magmatic process[J].Earth Planet Sci.Lett.1978,38:1-25.
[3]C.Annen,J.D.Blundy,R.S.J.Spark.The genesis of intermediate and silicic magmas in deep crustal hot zones.Journal of Pertology[J].2005,48:537-562.
[4]Kogiso T,Hirschmann MM and Pertermann M.High-pressure partial melting of mafic lithologies in the mantle.Journal of petrology[J].2004,45(12):2406-2421.
[5]Rapp R P,Watson E B,Miller C F.Partialmelting of amphibo2lite / eclogite and the origin of Arehaean trondhjemites and tonalities[J].Precam brian Research,1991,51:1-25.
[6]Ewart A,Baxter K,Ross JA.The petrology and petrogenesis of the Tertiary anorogenic marie lavas of Southern and Central Queensland,Australia-possible implications for curstal thickening[J].Mineral Petrol.1980,75:129-152.
[7]Rollinson HR.Using geochemical data:evalution,presentation,interpretation.Longman Scientific and technical[J].1993:1-352.
[8]张海祥,张伯友,牛贺才.富铌玄武岩:板片熔体交代的地幔楔橄榄岩部分熔融的产物.地球科学进展[J].2005,20(11):1234-1232.
[9]姜常义,程松林,叶书锋,等.新疆北山地区中坡山北镁铁质岩体岩石地球化学与岩石成因[J].岩石学报.2006,22(1):115-125.
[10]孙书勤,张成江,黄润秋.板块会聚边缘玄武岩大地构造环境的Th,Nb,Zr判别[J].地球科学进展.2006,22(6):593-598.
[11]姜常义,钱壮志,姜寒冰,唐冬梅,张蓬勃,朱士飞.云南宾川.永胜.丽江地区低钛玄武岩和苦橄岩的岩石成因与源区性质[J].岩石学报.2007,23(4):777-792.
[12]李伍平,李献华.燕山造山带中段中晚侏罗世中酸性火山岩的成因及其意义[J].岩石学报.2004,20(3):501-510.
[13]闫峻,陈江峰.鲁东青山组中性火山岩的地球化学特征、岩石成因和地质意义[J].地球化学.2007,36(1):1-10.
[14]李向民,夏林圻,夏祖春,徐学义,马中平,王立社.东天山石炭纪企鹅山群火山岩岩 石成因[J].吉林大学学报.2006,36(3):336-340.
[15]朱弟成,段丽萍,廖忠礼,潘桂棠。两类埃达克岩的判别[J]。矿物岩石。2002,(3):5-9.
[16]付建明,谢才富,张业明,彭松柏,刘云华。湘南西山两江口高钾钙碱性火山岩的成因分析[J]。华南地质与矿产。2003,2:16-25.
[17]刘肇昌.板块构造学[M].四川科学技术出版社.1985:56-71.
[18]杨学明,杨晓勇,陈双喜译。岩石地球化学[M]。中国科技大学出版社。2000.
[19]邱家骧。岩浆岩岩石学[M]。地质出版社.1985:132-138.
[20]姜常义,夏明哲,余旭,逯东霞,魏巍,叶书锋.塔里木板块东北部柳园粗面玄武岩带软流圈地幔减压熔融的产物.岩石学报.2007,23(7):1765-1773.
[21]邓晋福,罗照华,苏尚国,等.岩石成因、构造环境与成矿作用[M].地质出版社.2004,21-77.
[22]张海祥,牛贺才,于学元,等.准噶尔板块东北缘富铌玄武岩的发现及其意义[J].地质找矿论丛。2003,18(1):71-71.
[23]金性春,丁开平.俯冲工厂及大陆物质的俯冲再循环研究[J].地球科学进展.2003,18:737-744.
[24]姜常义,姜寒冰,叶书锋,夏明哲,逯东霞.新疆库鲁克塔格地区二叠纪脉岩群岩石地球化学特征,Nd、Sr、Pb同位素组成与岩石成因[J].地质学报.2005,79(6):823-833.
[25]姜常义,穆艳梅,赵晓宁,白开寅,张虹波.塔里木板块北缘活动陆缘型侵入岩带的岩石学与地球化学[J].中国区域地质.2001,20(2):158-163.
[26]王宝瑜,郎智君,李向东,等。中国西天山地质构造新认识[J]。新疆人民出版社。1995,28-34.
[27]冯益民,朱宝清,杨军录,张开春.东天山大地构造及演化-1:5万东天山大地构造图简要说明[J].新疆地质.2002,20(4):309-314.
[28]成守德,张湘江.新疆大地构造基本格架.新疆地质.2008,18(4):293-296.
[29]赵泽辉,郭召杰,韩宝福,王毅,刘畅.新疆东部-甘肃北山二叠纪玄武岩对比研究及其构造意义[J].岩石学报.2006,22(5):1279-1293.
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[31]肖渊甫,王道永,吴德超,邓江红,何政伟.新疆北山构造带西段地质演化[J].四川 科学出版社、新疆:新疆科技卫生出版社.2000,113-139.
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