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1.
博格达造山带东段萨尔乔克地区出露大量早石炭世晚期双峰式火山岩组合,其岩石类型主要有亚碱性玄武岩、英安岩和流纹岩,主体属拉斑系列。玄武岩w(SiO2)为48.69%~52.09%,w(TiO2)(1.16%~1.34%)略高于N型大洋中脊玄武岩,w(Al2O3)高(17.44%~20.86%)、w(MgO)低(3.05%~4.98%)、富钠贫钾(Na2O/K2O=1.82~3.04),表明其原始岩浆发生过明显的橄榄石和辉石的分离结晶作用;玄武岩具有近于平坦的稀土元素配分模式,Eu异常不明显(δEu=0.87~1.06),相对富集Rb、Ba、P,亏损Nb、Ta、Th等不相容元素。火山岩地球化学特征表明研究区玄武质岩浆来自于亏损石榴石地幔橄榄岩在一定深度(约75km深度)情况下发生10%~20%的部分熔融,且受到一定程度的地壳物质混染,显示了板内玄武岩的地球化学特征,形成于陆内裂谷环境。中酸性火山岩具有较高的w(SiO2)(70.29%~75.46%)和全碱[w(Na2O+K2O)=5.13%~9.90%],以及较低的w(TiO2)(0.25%~0.30%)、w(Al2O3)(12.85%~15.88%)和w(MgO)(0.36%~1.01%);显示右倾负斜率稀土元素配分模式,铕负异常明显(δEu为0.36~0.86,平均为0.64),富集Rb、Ba、Th等大离子亲石元素,亏损Nb、Ta、Ti、P等高场强元素,指示中酸性火山岩起源于地壳物质的部分熔融,源区有斜长石残留。萨尔乔克地区双峰式火山岩的地球化学特征表明该套火山岩应形成于大陆裂谷环境,同时获得中酸性火山岩中锆石的U-Pb年龄为(320.3±1.1)Ma,表明该套火山岩形成于早石炭世末期。结合进一步的地壳w(Rb)-w(Sr)和Zr/Y-w(Zr)判别图解,表明早石炭世早期开始的博格达初始裂谷在早石炭世晚期进一步快速拉张,发展到成熟阶段。这一发现进一步证实了博格达造山带在石炭纪处于大陆裂谷演化的观点,为进一步理解博格达地区晚古生代构造格局及板块构造体制提供了重要的地质依据。 相似文献
2.
燕山期是华南地区最主要的成矿阶段。近年,越来越多的学者认为该时期形成的众多金属矿床与基性岩脉关系密切。赣中南城地区Au-U等多金属矿化异常明显,区域范围内辉绿岩脉发育。本文针对地表辉绿岩样品进行岩石地球化学和年代学等方面研究。分析结果表明,研究区内岩石主量元素表现相对富铝(w(Al2O3)=12.07%~13.71%),富镁和富钙(w(MgO)=8.77%~10.86%;w(CaO)=10.77%~12.21%),低钛和低碱(w(TiO2)=1.18%~1.58%;w(Na2O+K2O)=3.09%~4.01%),Mg^#=8.91~55.78,w(FeO^T)=14.41%~16.87%,表明研究区内辉绿岩的基性程度较高,初始岩浆演化程度不高,早期没有发生明显的分离结晶作用,岩浆来源具有壳幔混合特征。样品整体富集Rb,Ba,Th,La,Sm等元素,亏损K,Hf,Ti,Yb,Lu等元素。REE配分曲线呈平缓的右倾轻稀土元素富集型,样品(La/Yb)N值在41.25~71.73之间且Ce,Eu无异常。其成岩年龄为158.0 Ma±3.4 Ma,形成于晚侏罗世,辉绿岩的成岩时间与该时期赣中南古陆大部分辉绿岩形成大地构造背景差异性较大,说明赣中南古陆在该时期大地构造背景复杂,推测当时研究区辉绿岩形成于华南和华北地块碰撞引起的多阶段岩石圈伸展拉张的构造环境。 相似文献
3.
《矿物岩石》2017,(4)
滨南钼矿位于大兴安岭成矿带,为近年来发现的燕山期中型斑岩型钼矿床。为探讨矿区赋矿岩体的成因,岩体构造环境及成岩成矿关系,对赋矿围岩花岗岩进行了岩石地球化学分析。该花岗岩的锆石U-Pb年龄为155 Ma±1.5 Ma,表明该花岗岩的侵位年龄为晚侏罗世。在地球化学组成上,该花岗岩具有高w(SiO_2)(70.79%~73.35%)、高w(K_2O)(3.23%~4.79%)、低w(P_2O_5)(0.08%~0.11%)、低w(TiO_2)(0.24%~0.30%)的特征,TFeO/MgO比值介于4.98~8.80,分异指数(DI)介于81.98~86.64均较高,经历了高度的结晶分异,属高分异的I型花岗岩。花岗岩的稀土元素总量较低(ΣREE=94.63×10~(-6)~124.94×10~(-6)),轻重稀土分异程度极高[(La/Yb)N=19.88~26.01],并具有中等—弱的负铕异常(δEu=0.69~0.87);具有大离子亲石元素(K,Ba,Rb)富集和高场强元素(Nb,Ta,Ti)亏损的特征,表明赋矿花岗岩具有岛弧花岗岩的特征。成矿与成岩在时间、空间及成分上的一致性,指示成岩与成矿产生于同一地质事件,即形成于中生代蒙古-鄂霍次克洋向东北板块俯冲的构造环境。 相似文献
4.
针对黔西普安铅锌矿区内的辉绿岩脉进行锆石U-Pb年代学与地球化学研究,结果表明其主量元素以高w(TiO2)(4.12%~4.18%)、高w(CaO)(7.46%~8.63%)和低w(MgO)(4.59%~5.02%)、低碱且Na2OK2O为特征,ΣREE总量较高,LREE明显富集。与原始地幔相比,明显富集Rb,Ba,Th等大离子亲石元素,而高场强元素(HFSE)Nb,Zr,Hf等略为亏损,并出现K,Sr和P亏损。主量元素特征和微量元素标准化图解显示,普安辉绿岩属于拉斑玄武岩系列,具有洋岛玄武岩(OIB)的特征,与峨眉山玄武岩为同源产物,具有密切的成因关系。微量元素示踪表明,岩浆来源于富集地幔,具有地幔柱成因特征。LA-ICP-MS锆石U-Pb定年结果表明辉绿岩形成年龄为263 Ma±10 Ma,代表了峨眉山地幔柱的启动时间。 相似文献
5.
西准噶尔早泥盆世马拉苏组主要分布于吾尔喀什尔山西部,整体为一套火山—沉积地层。对其中火山岩进行地球化学研究表明,w(SiO2)49.51%~59.04%,w(TiO2)(0.80%~1.12%)、w(K2O+Na2O)=3.09%~5.28%,富钠贫钾(Na2O/K2O=2.41~24.25)。高w(A12O3)(17.66%~21.19%)、w(MgO)(3.18%~7.00%,Mg#=47~56),属于亚碱性系列。稀土元素总量高(ΣREE=30.40×10-6~93.65×10-6),轻、重稀土分馏较强((La/Yb)N=2.58~11.38),Eu轻微负异常到正异常(Eu/Eu*=0.71~1.35)。相对富集LILE(Rb,Ba,Th和K),亏损HFSE(Zr,Hf),Nb和Ta强烈亏损,Ti轻微亏损。岩石源自轻微交代的亏损地幔部分熔融,具有岛弧火山岩的地球化学特征,这为进一步认识西准噶尔博什库尔-成吉斯岩浆弧的性质及构造演化提供了证据。 相似文献
6.
甘禅口基性辉绿岩脉产于北祁连弧盆系中,岩性为深灰色辉绿岩。脉体主要侵位于古元古代托赖岩群中。利用LA-ICP-MS锆石U-Pb定年方法对该基性辉绿岩脉测年,获得(293.0±1.8)Ma,表明测区在早二叠世有一次伸展事件发生。岩石化学A/CNK值为0.60~0.76,A/NK为2.40~4.35,Al2O3含量为11.60%~18.36%,TiO2含量为0.66%~2.85%,属拉斑玄武岩系列;微量元素K、Rb、Ba、Th富集强烈,Hf、Zr明显亏损,而Y、Yb具有略亏损的特点。脉体具有明显富集的微弱分馏的轻稀土元素,重稀土元素分馏不明显,同时具Eu弱负异常特征。根据区域构造背景及岩石学、地球化学特征,可以认为甘禅口基性辉绿岩脉是祁连山造山带进入造山后陆壳加厚底侵-岩浆混合作用形成的。 相似文献
7.
华北陆块北部燕山地区广泛发育侵位于下马岭组的一套辉绿岩岩床。其岩石地球化学特征表明,燕山地区辉绿岩以高TiO2(1.70%~4.29%),低Al2O3(11.33%~14.98%)和低MgO(4.17%~5.86%),以及Na2OK2O为特征,属大陆拉斑玄武岩系列。稀土元素特征显示,∑REE总量较高,LREE明显富集,轻重稀土分馏不明显;配分曲线右倾,无明显Eu异常。结合Zr-Y、Zr-Nd、Zr/Y-Zr、Ti/100-Zr-Y×3、Ta/Hf-Th/Hf及Nb/Zr-Th/Zr等图解综合分析认为:该辉绿岩岩浆源自过渡性地幔,形成于华北陆块北部中元古代晚期的板内伸展构造背景。 相似文献
8.
基于砂岩岩心样品元素地球化学资料对莺歌海盆地东方区上中新统黄流组一段海底扇砂体的源岩类型、风化程度及构造背景进行了分析。以平均大陆上地壳(UCC)对主量元素做标准化处理,结果显示SiO2略显示富集,CaO和TiO2仅4个样品相对富集,其他大部分样品主量元素均显示相对亏损特征。稀土元素配分模式呈现轻稀土元素富集、重稀土元素亏损特征,轻稀土元素与重稀土元素比值介于7.58~11.12之间(平均9.28),(La/Yb)N介于7.15~13.55之间(平均11.04),(Gd/Yb)N介于1.34~2.07之间(平均1.81),Eu元素显示负异常,δEu介于0.48~0.70之间(平均0.64),且样品的配分模式与UCC相似,Al_2O_3/TiO_2=11.03~17.02(平均14.48),以及w(K_2O)-w(Rb)和w(TiO_2)-w(Zr)图解均表明源岩为中性-长英质火山岩。化学蚀变指数(CIA)值(56.48~68.97)、长石蚀变指数(PIA)值(58.90~75.78)、A-CN-K图解表明黄流组砂岩经历了中等强度的风化作用。Th-Sc-Zr/10三角图、w(TiO_2)-w(Fe_2O_3+MgO)判别图解以及主量元素判别图解均显示源区具有碰撞环境特征(主动大陆边缘或大陆岛弧),且稀土元素配分模式与越南物源相似。综合可知,西部昆嵩隆起的中性-长英质火山岩为研究区主要物质来源。 相似文献
9.
北阿尔金蛇绿混杂岩带中斜长花岗岩的成因及其地质意义 总被引：6，自引：4，他引：2
北阿尔金蛇绿混杂岩带恰什坎萨依剖面南端的斜长花岗岩,呈不规则脉状和透镜状产出于蚀变辉绿岩之中。该斜长花岗岩具有高的SiO2含量(70.42%~78.29%),Al2O3含量低(9.51%~11.75%),高Na2O低K2O,K2O/Na2O=0.02~0.09,属于低钾准铝质岩石;其∑REE偏低(80.15×10-6~104.1×10-6),具中等Eu异常(δEu=0.68~0.73)以及轻稀土轻微富集的特点,微量元素显示相对富集Th、U而亏损Nb、Ta、Ti的特征。以上特征与产于蛇绿岩中的斜长花岗岩的基本特征相符合。蚀变辉绿岩主量元素显示低SiO2、Al2O3、K2O、TiO2,高CaO、Na2O以及富集Th、U、La、Ce,相对亏损Nb、P、Ti的特征,部分蚀变辉绿岩样品SiO2、Na2O含量的升高应与岩石遭受海水蚀变有关。稀土元素显示弱的Eu异常(δEu=0.86~0.94)以及轻稀土轻微富集的特点。蚀变辉绿岩Mg#=51.3~54.8,Ti/V=11~22,La/Nb=1.67~2.07,Zr/Nb=10.3~27.1的特点与区内蛇绿岩地球化学特征一致,应为区内蛇绿岩的组成部分。斜长花岗岩LA-ICP-MS锆石U-Pb年龄为518.5±4.1Ma,Hf同位素εHf(t)=4.25~9.90。在La-SiO2及TiO2-SiO2图解上,斜长花岗岩均显示部分熔融成因,结合岩石非常低Sr高Yb的特点,认为其应形成于洋壳在运移过程中发生的部分熔融。全岩Sr、Nd、Pb同位素显示蛇绿岩源区具有EMII型富集地幔特征,与前人对区内洋中脊型玄武岩的同位素研究具有一致性,而洋壳源区富集地幔特征暗示此时的洋壳形成于洋盆裂解的早期。结合以上资料分析,本次研究的斜长花岗岩和蚀变辉绿岩可能形成于北阿尔金有限洋盆裂解的早期,形成时代为518.5±4.1Ma。 相似文献
10.
对新疆阿舍勒铜锌矿区潜玄武安山岩进行了岩石学、岩石地球化学和同位素地球化学研究,结果表明:岩石具有中等的SiO_2(51.90%~52.85%)、MgO(4.44%~5.08%)、Al_2O_3(14.94%~16.11%)、TiO_2(0.99%~1.03%)含量,较低的K_2O(0.01%~0.27%)含量,属于低钾拉斑玄武岩系列;岩石具有较低的稀土元素总量,ΣREE=38.07×10~(-6)~41.70×10~(-6),亏损轻稀土元素,LREE/HREE=0.57~0.61,(La/Yb)N=0.84~0.91,具有明显Eu正异常(δEu=1.13~1.23);富集Sr、Ba、Th等大离子亲石元素,亏损Nb、Ta、Zr、Hf等高场强元素,具有洋中脊玄武岩(MORB)和岛弧拉斑玄武岩(IAB)的特征,形成于岛弧(或弧前)环境;具有相对高的εNd(t)值(+6.9~+7.6),表明其原始岩浆来源于俯冲流体交代地幔楔的部分熔融,没有明显深海沉积物加入。结合阿尔泰造山带南缘的区域地质资料及潜玄武安山岩的地球化学特征,认为阿尔泰南缘在晚古生代处于活动大陆边缘,阿舍勒盆地处于岛弧(或弧前)背景。 相似文献
11.
Inter-regional correlation of transgressions and regressions in the Cretaceous period 总被引：1，自引：0，他引：1
T. Matsumoto 《Cretaceous Research》1980,1(4):359-373
Well investigated platforms have been selected in each continent, and the history of Cretaceous transgressions and regressions there is concisely reviewed from the available evidence. The factual records have been summarized into a diagram and the timing of the events correlated between distant as well as adjoining areas.On a global scale, major transgressions were stepwise enlarged in space and time from the Neocomian, via Aptian-Albian, to the Late Cretaceous, and the post-Cretaceous regression was very remarkable. Minor cycles of transgression-regression were not always synchronous between different areas. Some of them were, however, nearly synchronous between the areas facing the same ocean.Tectono-eustasy may have been the main cause of the phenomena of transgression-regression, but certain kinds of other tectonic movements which affected even the so-called stable platforms were also responsible for the phenomena. The combined effects of various causes may have been unusual in the Cretaceous, since it was a period of global tectonic activity. The slowing down of this activity followed by readjustments may have been the cause of the global regression at the end of the Cretaceous. 相似文献
12.
The Afyon stratovolcano exhibits lamprophyric rocks, emplaced as hydrovolcanic products, aphanitic lava flows and dyke intrusions, during the final stages of volcanic activity. Most of the Afyon volcanics belong to the silica-saturated alkaline suite, as potassic trachyandesites and trachytes, while the products of the latest activity are lamproitic lamprophyres (jumillite, orendite, verite, fitztroyite) and alkaline lamprophyres (campto-sannaite, sannaite, hyalo-monchiquite, analcime–monchiquite). Afyon lamprophyres exhibit LILE and Zr enrichments, related to mantle metasomatism. 相似文献
13.
K.Naganjaneyulu 《地学前缘(英文版)》2014,5(1):1-2
正The Precambrian shields and associated suture zones of the globe preserve important records of continental growth and destruction,the formation and closure of ocean basins,and the early evolution of the Earth in terms of tectonics,resources,and environment.They also offer critical clues on the nature and style 相似文献
14.
Daniel Harlov 《地学前缘(英文版)》2014,5(5):621-625
正1.Introduction This special issue of Geoscience Frontiers is a tribute volume honoring the life and career of Jacques Touret.A set of research papers has been assembled,which broadly reflect his research interests over his 50 plus year career.These papers focus on the role that fluids play during the formation and evolution of the Earth's crust.Below I provide a brief summary of the life of Jacques Touret,along with a select bibliography of his more important papers.This is then followed by a brief introduction to the papers assembled for this special issue. 相似文献
15.
《地学前缘(英文版)》2014,(1):139-141
正1 AIM AND SCOPE GEOSCIENCE FRONTIERS(GSF)is a bi-monthly international journal that publishes in English high quality original research articles and timely reviews in interdisciplinary fields of Earth and Planetary Sciences.GSF aims to bridge innovative,provocative and challenging concepts and models related to various fields of research including petrology and geochemistry in understanding lithospheric architecture and mantle dynamics,global tectonics,economic geology and fuel exploration,geophysics,stratigraphy and paleontology with new 相似文献
16.
正The world petroleum exploration suggests that,about70%of the world’s potash resources were discovered during oil and gas exploration(Zheng et al.,2007).The Kuqa depression in the Tarim basin is abundant with petroleum exploration data,and 相似文献
17.
正Qarhan Salt Lake is located in the eastern part of the Qaidam Basin,which is first discovered the large potash deposit in the late 1950s.The Bieletan section is located in the west of Qarhan Salt Lake,where saline sediment 相似文献
18.
正With the approach of the 45th World Earth Day,China’s Ministry of Land and Resources issued the status of the Chinese geological survey and environments on 22nd April 2013.Regional geological survey in 2013 achieved new results—(why was oceanic in twice?)polar and oceanic expedition were fully completed,a national census of geography was begun,and 相似文献
19.
正1 Introduction The Lop Nor playa,located in the eastern end of the Tarim Basin,capped with a thick salt crust covering an area of approximately 5,500 km2(Ma 2007)that closely resembles a"Great Ear"in satellite images.Understanding the formation of the salt crust can provide important 相似文献
20.
In Liaoning, Hunan, Guangxi, Guizhou, Gansu, Sichuan, Anhui, Jilin and other provinces in China, there is a wide occurrence of metal quantity over 1000 tons of refractory gold ores, principally because of low gold recoveries and become ＂stay mine＂. Features of refi＇actory gold ores are： gold in micro-particles or a microscopic state that is wrapped in pyrite, presence of arsenopyrite and other sulfide minerals or disseminated in the crystal lattice of sulfide minerals; harmful impurity elements such as arsenic, carbon, mercury, antimony, copper with high content are closely related with the gold, and these elements affect the contact reaction between the gold and solvent extraction, making the recovery of the gold extraction process low. In the past 20 years, overseas countries have developed the application of the roasting oxidation method, hot acid （alkali） oxidation, bacterial oxidation and flash chlorination oxidation technology to solve this problem.Among these, biological oxidation has developed rapidly in the domestic market and gold enterprises abroad because of its low investment in infrastructure, low production costs, less environmental pollution, simple process and easy control, etc. 相似文献