北祁连大岔-大坂一带海相火山岩化学成分图解及地质意义
The Geological Significance for Geochemical Composition Analysis of Marine Volcanic Rock from Dacha-Daban Areain North Qilian Mountains
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摘要: 北祁连地区早古生代海相火山岩十分发育。笔者对大岔-大坂一带奥陶纪海相火山岩中细碧-角斑岩化过程Na元素的来源与地质意义进行了研究。认为细碧-角斑岩比正常火山岩富Na2O,是海水参与的结果;判别角斑质岩石的原始岩浆系列及构造环境类型时不宜采用涉及Na的图解作为判别依据,应选取惰性元素作为判别依据;同时提出采用Na2O-SiO2图解展示岩石细碧角斑岩化。细碧-角斑岩类与正常海相火山岩界线为一条微上凸的曲线,该界线Na2O含量为3.5%~4%;大岔-大坂一带海相火山岩的成分点多落在该界线之上的细碧-角斑岩类分布区,可反映该区奥陶纪弧后和岛弧扩张脊火山喷发间歇期,海底热卤水对流循环活动强烈,成矿条件非常有利。Abstract: Early Paleozoic marine volcanic rocks were well developed in the North Qilian Mountains. The paper focuses on discussing the formation process and origin of Na element for Ordovician marine volcanic rocks during the process of spilite-keratophyre alteration. There is more Na2O in spilite-keratophyre than normal volcanic rock,because of the basaltic magma react with seawater. Therefore, the discrimination diagram involved with Na element cannot be used as the discrimination criteria for distinguishing the original magma series of keratophyre and related geotectonic setting, but the immobile elements can be used as distinguishing basis. Meanwhile, the Na2O-SiO2 diagram is proposed for reflecting the degree of spilite-keratophyre alteration. In this graphic, the boundary line for the percentage of Na element between spilite-keratophyre and normal volcanic rock is a slightly up-convex, which is stand for the content of Na element ranging from 3.5% to 4%. For the marine volcanic rocks in Dacha-Daban area, most of them fall into the distribution region of spilite-keratophyre, suggesting that the convection of seafloor hot brine was very strong at Ordovician back-arc and island-arc spreading ridge during intervolcanic eruption stage, and this area provides very favorableconditions for mineralization.
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宋志高.北祁连山早古生代细碧岩-角斑岩系及其与蛇绿岩套的关系[J].西安地质矿产研究所所刊.1980,1(1):14-24.
SONG Zhigao. Lower paleozoic spilite-keratophyre suite of N. Qilian Range(Nan Shan) and i-ts bearing on ophiolite suite[J].Northwestern Geology.1980,1(1):14-24(in Chinese with English abstract).
冯益民,何世平.祁连山大地构造与造山作用[M].北京:地质出版社,1996:1-135.
FENG Yimin, HE Shiping. Geotectonics and Orogeny of the Qilian Mountains, China[M].Beijing:Geological Public House,1996:1-135(in Chinese).
宋述光.北祁连山俯冲杂岩带的构造演化[J].地球科学进展,1997,12(4):351-365.
SONG Shuguang.Tectonic evolution of subductive complex belts in the North Qilian Mounta-ins[J]. Advances in Earth Science,1997,12(4):351-365(in Chinese with English abstract).
李文渊.祁连山岩浆作用有关硫化金属矿床成矿与找矿[D].西安:西北大学地质系,2004.
LI Wenyuan.Metallogenic Process and Exploration of Magmatic-association Metallic Sufide Deposits of Qilian Mountain,North west China[D].Xi'an:Northwest University,2004(in Chinese wit-h English abstract).
赵东宏,杨合群,宋忠宝,等.甘肃北祁连山错沟-寺大隆铜(锌)成矿带区域地质背景及找矿方向[J].地质与资源,2003,12(4):215-220.
ZHAO Donghong, YANG Hequn, SONG Zhongbao, et al. Regional geology and prospecti-ng direction of Cuogou(zinc) metallogentic belt in Gansu province[J]. Geology and Resour-ces, 2003,12(4):215-220(in Chinese with English abstract).
杨合群,宋忠宝,王兴安,等.北祁连山中西段塞浦路斯型铜矿特征、成矿作用及找矿标志[J].西北地质,2002,35(4):66-85.
YANG Hequn, SONG Zhongbao, WANG Xingan, et al. Thecharacteristics, mineralization and prospecting indications of Cyprus-type copper deposits in mid-west section of the North Qilian mountains, China[J]. Northwestern Geology, 2002,35(4):66-85(in Chinese with English abstract).
郭周平,李文渊,贾群子,等.北祁连塞浦路斯型铜矿床地质地球化学特征对比研究[J].地质与勘探,2010,46(1):352-365.
GUO Zhouping, LI Wenyuan, JIA Qunzi, et al. A Contrastive Study on the Geological and Geochemical Characteristics of Cyprus-type Copper Deposits in North Qilian Mountain, China[J]. Geology and Exploration, 2010,46(1):352-365(in Chinese with English abstract).
夏林圻,夏祖春,徐学义.北祁连山海相火山岩岩石成因[M].北京:地质出版社,1996.
XIA Linqi, XIA Zuchun, XU Xueyi. Lithogenesis of Marine Volcanic Rocks from North Qilian Mountains[M]. Beijing:Geological Public House,1996(in Chinese).
杨合群,宋忠宝,王兴安,等.北祁连山大坂大岔地区蛇绿岩含矿性[J].西北地质,2003,36(3):50-56 YANG Hequn, SONG Zhongbao, WANG Xingan, et al. Ore-bearing property of ophiolite in Daban-Dachaarea, North Qilian Mts.[J]. Northwestern Geology,2003,36(3):50-56(in Chinese with English abstract).
夏林圻,夏祖春,任有祥,等.北祁连山构造-火山岩浆-成矿动力学[M].北京:中国大地出版社,2001,10:204-219 XIA Linqi, XIA Zuchun, REN Youxiang. Dynamics of tectono-volcanol magmatic-metallogenic in North Qlian Mountains[M].Beijing:China Land Press,2001,10:204-219(in Chinese).
YODER,H.S.Jr. Spilites and serpentinites, Annual report of cornegieinst[J].Wa-shington, Geophys.lab.,1965-1966:269-278.
VALLANCE,T.G.,Spilite degradation of a cholelithic basalt[J]. Petrol.,1974, 15:79-96.
SEYFRIED,W.E. and BISCHOFF,J.E.Low temperature basalt alteration by seawater:an exper-imental study at 70℃ and 50℃[J]. Geochim. Cosmochim. Acta., 1979,43:1937-1947.
HAJASH.A and ARCHER,P. Experimental seawater/basalt interaction:effects of colling, Con-trib[J]. Mineral.Petrol., 1980,75:1-13.
BISCHOFF, J.L.,and DICKSON, W. E. Seawater-basalt interaction at200℃ and 500℃ bars. Implication for origin of seafloor heavy-metal deposits and regulation of seawater chemis-try[J]. Earth Planet. Sci. Lett. 1975,25:385-397.
MOTTL, M.J.and HOLLAND, H.D.Chemical exchange during hydrothermal alteration of basalt by seawat er-[J]. Geochim. Cosmchim. Acta, 1978,42:1103-1115.
MOTTL, M.J.,Holland. H.D.and CORR, R. F. Chemical exchange during hydrotherm-al alteration of basalt by seawater-Ⅱ.[J]. Geochim. Coschim. Aota,1979,43:869-884.
HAJASH, A. and CHANDLER, G. W. An experimental investigation of high-temperature inter action between seawater and rhyolite, andesite, basalt and peridotite[J]. Contrib.-Mineral. Petrol,1981,78:240-254.
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