【作者】 李敏；

【导师】 梁一鸿；

【作者基本信息】 吉林大学 ， 构造地质学， 2012， 硕士

【摘要】 盆地形成的地球动力学背景是地质学研究中的一个热点领域，是研究油气、金属矿床等方面的最为重要的基础研究课题之一。孙吴-嘉荫盆地位于松嫩地块北部，东部与佳木斯地块之间隔着嘉荫—牡丹江缝合带；西部以二连—黑河缝合带为界与兴安地块相邻；西南隔小兴安岭造山带与松辽盆地相接；和俄罗斯境内的布列亚-结雅盆地连为一体。孙吴—嘉荫盆地早白垩世发育一套火山岩建造，火山岩岩性主要为玄武岩、玄武粗安岩、安山岩、粗面英安岩，基本属于高钾钙碱性系列，上白垩统福民河组发育一套碱性流纹岩，属于钾玄岩系列。通过火山岩样品地球化学特征，结合区域地质资料及野外地质调查，分析火山岩喷发的构造环境，进一步讨论盆地形成的地球动力学背景。早白垩世火山岩SiO₂含量为51.86%～64.24%，全碱K₂O+Na₂O（4.25%～7.50%）含量较高，K₂O/Na₂O值为0.39～0.73, TiO₂（21.06%～1.37%）含量偏低，AR值为1.41～2.21，为活动大陆大陆边缘产出。玄武质粗面安山岩和安山岩均为低镁安山岩，与活动大陆边缘靠内陆一侧的火成岩弧内带常发育低镁安山岩相一致。稀土元素总量∑REE(65.54×10^-6～126.06×10^-6)含量中等，球粒陨石标准化稀土元素配分曲线表现为LREE相对于HREE富集，（La/Yb）N变化范围为4.71～9.67，轻重稀土分馏明显。早白垩世样品的Eu和大部分样品的Ce均表现为弱的负异常。富集大离子亲石元素（LILE）Rb、Ba、K、Th、U，富集Pb，亏损高场强元素（HFSE）Nb、Ta、Y、Yb、Lu，亏损Sr、Ti、P、Ti。钙碱性玄武岩Th/Hf、Ta/Hf、La/Nb、Nb/Zr值分别为0.28～1.52、0.12～0.27、8.76～10.33、0.06～0.07，显示为板内玄武岩和钙碱性玄武岩的共同特征。钙碱性玄武岩富集大离子亲石元素（LILE），与洋壳俯冲时大洋沉积物组分的加入有关，而Sr的负异常与岩浆上升过程中陆壳的混染作用有关，Nb、Ta、Ti、P负异常与CAB部分熔融时洋壳物质的加入有关。上白垩统福民河组（K1f）碱性流纹岩SiO₂的变化范围为71.54%～72.4%，全碱K₂O+Na₂O（11.77%～12.2%）含量高，属高钾系列（K₂O的变化范围为5.15%～5.36%），AR为9.34～10.38。稀土元素总量ΣREE(198.27×10^-6～336.01×10^-6)较高；LREE/HREE为5.44～6.82；（La/Yb）N为4.14～6.23，负Eu异常明显。富集大离子亲石元素（LILE）K、Rb、Ba、Tu、U,轻微富集高场强元素（HFSE）Nb、Ta、Zr、Hf，强烈亏损Sr、P、Ti，存在Rb、K、Pb、Zr、Hf正异常和Sr、P、Ti负异常。上地壳强烈富集Th、U、Rb，并伴有Sr亏损和明显的Eu负异常。说明岩浆在上升过程中可能遭受过上地壳混染。相比于下白垩统火山岩，盆地上白垩统福民河组碱性流纹岩具有更高的K₂O含量，显示了“时间极性”，暗示了从盆地从早白垩世至晚白垩世，陆壳纵向加厚，陆壳成分的增加，表明盆地火山岩具有弧火山的性质。上述分析表明孙吴-嘉荫盆地早白垩世火山岩兼具陆内和汇聚边缘火山岩的特点，是一套在活动大陆边缘靠内陆一侧裂谷环境中形成火山岩系列。孙吴-嘉荫盆地在形成过程中，受到同期多重构造事件的影响，其形成的主要动力源来自于早白垩世太平洋板块向NW方向俯冲，研究区地幔底辟，使研究区处于拉张应力场中，形成了NEE向断陷盆地。孙吴-嘉荫盆地是早白垩世泛太平洋板块俯冲形成的活动大陆边缘裂陷。盆地内浅成低温热液矿床较多，断裂较为发育，是主要的控矿条件之一。本文以高松山金矿为研究对象，选取高松山金矿床12件矿石样品，围岩样品12件，围岩上覆地层样品60件，利用SPSS软件，通过相关分析、因子分析、系统聚类分析，分析了Au、 Ag、Cu、Pb、Zn、Co、As、Bi、Hg、W、Mo、Sn12种元素。高松山金矿床矿石元素组合可以分为三组：（Au、Ag、Pb、Mo、Hg），（W、Zn、Co、Cu），（Sn、Bi），As。矿石样品和下白垩统地层样品元素组合特点不一样，且与围岩元素组合不同。板子房组火山角砾岩是矿脉围岩之一，Au含量比上覆地层各岩石高2个数量级。盆地由于伸展作用不均匀产生的简单剪切所形成的NW向断裂是主要的导矿构造。其半生的EW、NNE、NNW向断裂是主要的容矿构造。更多还原

【Abstract】 Dynamics setting of basin is a hot area in geology research,and it’s one of the most importantbasic research subject in petroleum，rock gas and mineral deposit. Sunwu-Jiayin basin lies in northof Songnen landmass.The east border of the basin is the Jiayin-Mudanjiang fault and adjacent toJiamusi landmass. The west border of the basin is the Erlian-Heihe suture zone and adjacent toHinggan landmass. South-Southwest of the basin and the Song liao basin are divided by the XiaoHinggan Mountains.The basin is linked together with Jeya-Breya basin. volcanic formationdeveloped in Early Cretaceous Epoch in Sunwu-jiayin basin. The volcanic rocks mainly composeof basalt, basaltic trachy andesite,andesites,trachy dacite.Most of they belong to high kaliumcalc-alkalic series. Alkalic rhyolite developed in Later Cretaceous Epoch in Fu minhe formation，and it belonged to potassium kuroiwa series.Analyzing the tectonic setting through geochemical characteristics,information of areageology and field research. SiO₂occupy51.86%～64.24%in oxide in volcanic rock. Volcanicrock samples have relatively high alkali（4.25%～7.50%）contents, relatively low TiO₂2（0.26%～1.3%）contents.The value of K₂O/Na₂O is0.39～0.73,and the value AR variation range from1.4to2.21,it implys that the volcanic rocks has formed in active continental margin. basaltic trachyandesite and andesite both belong to low magnesium andesite which always appears on inland sideof active continental margin. Volcanic rock samples have medium rare earth elements(65.54×10^-6～126.06×10^-6)，and the value of（La/Yb）Nvariation range from0.39to0.73, withweak Eu anomalies and Ce anomalies. These samples are enriched in LILE（Rb、Ba、K、Th、U）and Pb but relatively depleted in HFSE（Nb、Ta、Y、Yb、Lu）and Ti、P、Sr.The value of Th/Hf、Ta/Hf、La/Nb、Nb/Zr of calc-alkalic basalt respectively range from0.28～1.52、0.12～0.27、8.76～10.33、0.06～0.07，which imply the trait of both within plate basalt and calc-alkalicbasalt.The calc-alkalic basalt are enriched in LILE，which is related to the accession of oceansedimentary contents on subducted oceanic crust. Strontium anomalies is related to hybridizationof magma and continental crust in the process of the rise of magma.Anomalies of Nb、Ta、Ti、P isrelated to the accession of oceanic lithosphere contents during partial melting of calc-alkalicbasalt. SiO₂of Alkaline rhyolit occupy71.54%～72.4%in Fu minhe formation in Later CretaceousEpoch，the samples have high alkali（11.77%～12.2%）content，belong to high kalium series（K₂O occupy5.15%～5.36%）. The value AR variation range from9.34to10.38. Alkalinerhyolit samples have high rare earth elements(198.27×10^-6～336.01×10^-6)，and the value ofLREE/HREE variation range from5.44to6.82.The value of（La/Yb）Nvariation range from4.14to6.23, with weak Eu anomalies. Alkaline rhyolit are enriched in LILE （K、Rb、Ba、Tu、U），and a little enriched in HFSE（Nb、Ta、Zr、Hf）but relatively depleted in Sr、P、Ti,with Rb、K、Pb、Zr、Hf positive anomalies and Sr、P、Ti negative anomalies,which implicated that themagma had being infected by upper crust during ascending. Alkaline rhyolit in Later CretaceousEpoch have high K₂O than volcanic rocks in Early Cretaceous Epoch，what shows timepolarity,and it implicate that the continental crust are thicker and have more contents ofcontinental crust in Later Cretaceous Epoch than Early Cretaceous Epoch.These traits show thatvolcanic rock in Sun wu-jia yin Basin have the same character of arc volcanic.The proposed analysis indicates that the volcanic rocks in Early Cretaceous Epoch areprovided with the traits of volcanic rocks in both continental and active continental margin,andthey are volcanic rock seriels which on the inland side of the active continental margin.Sunwu-jiayin Bsin suffered multiple tectonic events during formation in the same period.Pacific plate subducted in NW were major dynamic source of the formation of Sunwu-jiayin Bsinin Early Cretaceous Epoch.It coursed mantle diapir of the study area，and made it in tension stressfield,which formed graben basin along NNE.Sun wu-jia yin Basin was formed on the activecontinental margin，which induced by subduction of the Pacific plate in Early Cretaceous Epoch.There are many epithermal gold deposits in the basin，and there are many faults whichcontrol the mineralization in each deposits.The author have investigated Gaosongshan golddeposit in this paper，and chosen12ore samples，12country rocks samples，60samples in upperlayers.12elements（Au、 Ag、Cu、Pb、Zn、Co、As、Bi、Hg、W、Mo、Sn）havebeing analyzed by correlation analysis, factor analysis and cluster analysis with the help ofSPSS.The ore element assembly in Gaosongshan deposit can be divided into3groups：（Au、Ag、Pb、Mo、Hg）,（W、Zn、Co、Cu）,（Sn、Bi）,As.The elements assembly of ore samples aredifferent from elements assembly of samples in upper layers and country rocks samples.Volcanicbreccias in Banzifang formation is one of the country rocks，which are contained200times moregold than samples in upper layers.The main ore conducting structure are faults along NE whichproced by simple shear what is the result of asymmetry extend.Faults along EW、NNE and NNWassociated with faults along NE are main ore-bearing structure.更多还原