东昆仑那陵格勒河南上三叠统鄂拉山组火山岩地球化学特征及构造环境
|
摘要
东昆仑那陵格勒河南地区发育上三叠统鄂拉山组(T_3e)火山岩,岩石类型主要以英安质玻屑晶屑凝灰岩和英安质熔结凝灰岩为主,具有高碱、高钾、高铝的特征;岩石的二氧化硅含量w(SiO_2)=69.12%~74.52%,全碱含量w(Na_2O+K_2O)=6.42%~7.33%,里特曼指数σ=1.39~2.01,岩石的铝过饱和指数ASI介于1.02~1.17之间,属典型的过铝质高钾钙碱性系列。岩石的稀土元素w(LREE)/w(HREE)=11.02~15.99,δEu=0.54~0.67,铕具中等亏损,属轻稀土富集型;微量元素K、Rb、Ba和Th较强的富集,Sr、Ti、Sc、Cr明显亏损,具有后碰撞下地壳重熔产物的特征。在鄂拉山组玄武质晶屑凝灰熔岩中获U-Pb同位素年龄值为231 Ma±1 Ma,形成时代为晚三叠世。通过综合分析认为,鄂拉山组火山岩可能形成于以侧向挤压为主的陆—陆后碰撞过程中加厚地壳物质部分熔融的产物,属于印支期后碰撞火山盆地岩石建造。
Volcanics of Late Triassic Elashan formation(T_3e)in south Nalinggele river,East Kunlun are mainly dacitic glassy,crystal fragmental tuff and dacitic ignimbrite with high alkaline,high potassium and high aluminum.w(SiO_2)=69.12%~74.52%,w(Na_2O+K_2O)=6.42%~7.33%,Rittmann coefficientδEu=0.54~0.67,aluminum saturation index ASI 1.02~1.17 belonging to paraluminal high-K calc-alkaline rock series.Analysis of w(LREE)/w(HREE)=11.02~15.99andδEu=0.54~0.67 are of LREE enrichment and medium Eu depletion.Trace element analysis shows stronger enrichment of K,Rb,Ba and Th and evident depletion of Sr,Ti,Sc,Cr.The data mentioned above are characteristic of post collision crust remelting products.Sample from basaltic crystal fragmental tuff of Elashan formation dated at U-Pb age of 246.8 Ma±1.7 Ma thus the formation is formed in Late Triassic Epoch.According to comprehensive analysis volcanics of Elashan formation may be the product of the partially remelted thickening crust during the post lateral compression dominant continent-continent collision thus is a post Indosinian period rock formation in collisional volcanic basin.
Volcanics of Late Triassic Elashan formation(T_3e)in south Nalinggele river,East Kunlun are mainly dacitic glassy,crystal fragmental tuff and dacitic ignimbrite with high alkaline,high potassium and high aluminum.w(SiO_2)=69.12%~74.52%,w(Na_2O+K_2O)=6.42%~7.33%,Rittmann coefficientδEu=0.54~0.67,aluminum saturation index ASI 1.02~1.17 belonging to paraluminal high-K calc-alkaline rock series.Analysis of w(LREE)/w(HREE)=11.02~15.99andδEu=0.54~0.67 are of LREE enrichment and medium Eu depletion.Trace element analysis shows stronger enrichment of K,Rb,Ba and Th and evident depletion of Sr,Ti,Sc,Cr.The data mentioned above are characteristic of post collision crust remelting products.Sample from basaltic crystal fragmental tuff of Elashan formation dated at U-Pb age of 246.8 Ma±1.7 Ma thus the formation is formed in Late Triassic Epoch.According to comprehensive analysis volcanics of Elashan formation may be the product of the partially remelted thickening crust during the post lateral compression dominant continent-continent collision thus is a post Indosinian period rock formation in collisional volcanic basin.
引文
[1]詹发余,舒泽民,庄永成.青海省柴南缘与晚三叠世陆相火山活动有关的铜钴等多金属矿产资源潜力调查研究[R].青海省地质调查院,2005.
[2]丰成友.青海东昆仑地区的复合造山过程及造山型金矿床成矿作用[D].中国地质科学院矿产资源研究所,2002.
[3]李运东,刘小玉.青海热水地区晚三叠世火山岩地球化学特征及构造环境[J].西北地质,2014,47(3):14-25.
[4]芦文泉,童海奎,仓索南尖措,等.鄂拉山查查香卡地区晚三叠世火山岩产出环境分析[J].西北地质,2012,45(1):48-55.
[5]童海奎,王树林,宋生春,等.青海省查查香卡地区晚三叠世火山岩岩石学及其构造环境[J].高原地震,2004,16(2):38-48.
[6]李永祥,李善平,王树林,等.青海鄂拉山地区陆相火山岩地球化学特征及构造环境[J].西北地质,2011,44(4):23-32.
[7]张洪美,李海平,冯乔,等.柴达木盆地东南缘晚三叠世火山岩地球化学特征及构造环境分析[J].西北地质,2011,44(4):15-22.
[8]夏楚林,任二峰,高莉,等.青海喀雅克登塔晚三叠世鄂拉山组火山熔岩地球化学特征及构造环境探析[J].青海大学学报(自然科学版),2011,29(6):48-53.
[9]刘洪涛.祁漫塔格陆相火山岩:塔里木陆块南缘印支期活动大陆边缘的岩石学证据[J].岩石学报,2001,17(3):337-351.
[10]张德全,朱华平,闫升好,等.东昆仑古生代复合造山过程及金属成矿作用[J].矿床地质,2002(增刊):293-296.
[11]李怀坤,耿建珍,郝爽,等.用激光烧蚀多接收器等离子会质谱仪(LA-MC-ICPMS)锆石U-Pb同位素年龄的研究[J].矿物学报,2009(增刊):600-601.
[12]吴芳,张续教,张永清,等.东昆仑闹仓坚沟组流纹质凝灰岩锆石U-Pb年龄及其地质意义[J].地质力学学报,2010,16(1):44-50.
[13]张玉清,张长明.X射线荧光光谱测定矿样中主元素及微量元素[J].矿产与地质,1990,4(3):63-96.
[14]邱家骧.岩浆岩岩石学[M].北京:地质出版社,1986.
[15]亨德森.稀土元素地球化学[M].北京:地质出版社,1989.
[16]李昌年.火成岩微量元素岩石学[M].武汉:中国地质大学出版社,1992.
[2]丰成友.青海东昆仑地区的复合造山过程及造山型金矿床成矿作用[D].中国地质科学院矿产资源研究所,2002.
[3]李运东,刘小玉.青海热水地区晚三叠世火山岩地球化学特征及构造环境[J].西北地质,2014,47(3):14-25.
[4]芦文泉,童海奎,仓索南尖措,等.鄂拉山查查香卡地区晚三叠世火山岩产出环境分析[J].西北地质,2012,45(1):48-55.
[5]童海奎,王树林,宋生春,等.青海省查查香卡地区晚三叠世火山岩岩石学及其构造环境[J].高原地震,2004,16(2):38-48.
[6]李永祥,李善平,王树林,等.青海鄂拉山地区陆相火山岩地球化学特征及构造环境[J].西北地质,2011,44(4):23-32.
[7]张洪美,李海平,冯乔,等.柴达木盆地东南缘晚三叠世火山岩地球化学特征及构造环境分析[J].西北地质,2011,44(4):15-22.
[8]夏楚林,任二峰,高莉,等.青海喀雅克登塔晚三叠世鄂拉山组火山熔岩地球化学特征及构造环境探析[J].青海大学学报(自然科学版),2011,29(6):48-53.
[9]刘洪涛.祁漫塔格陆相火山岩:塔里木陆块南缘印支期活动大陆边缘的岩石学证据[J].岩石学报,2001,17(3):337-351.
[10]张德全,朱华平,闫升好,等.东昆仑古生代复合造山过程及金属成矿作用[J].矿床地质,2002(增刊):293-296.
[11]李怀坤,耿建珍,郝爽,等.用激光烧蚀多接收器等离子会质谱仪(LA-MC-ICPMS)锆石U-Pb同位素年龄的研究[J].矿物学报,2009(增刊):600-601.
[12]吴芳,张续教,张永清,等.东昆仑闹仓坚沟组流纹质凝灰岩锆石U-Pb年龄及其地质意义[J].地质力学学报,2010,16(1):44-50.
[13]张玉清,张长明.X射线荧光光谱测定矿样中主元素及微量元素[J].矿产与地质,1990,4(3):63-96.
[14]邱家骧.岩浆岩岩石学[M].北京:地质出版社,1986.
[15]亨德森.稀土元素地球化学[M].北京:地质出版社,1989.
[16]李昌年.火成岩微量元素岩石学[M].武汉:中国地质大学出版社,1992.