大兴安岭北段雅尔根楚I型花岗岩年代学、岩石地球化学及其地球动力学意义

对内蒙古大兴安岭北段雅尔根楚花岗岩岩体岩相学研究表明,该花岗岩岩体主要岩性组合为正长花岗岩和花岗质糜棱岩,应用锆石U-Pb LA-ICP-MS测年方法,测得的3组年龄为226.8±2.2Ma、230.2±1.3Ma和233.6±1.5Ma,表明其岩体侵位时代为晚三叠世.岩石主量元素(XRF)具有富硅、富钾的特征,A/CNK值为0.81～1.10,显示铝弱饱和,相对富集轻稀土元素、亏损重稀土元素,具有Eu负异常,微量元素相对富集大离子亲石元素,亏损高场强元素,显示岛弧性质的花岗岩特征,微量元素特征显示其为Ⅰ型花岗岩.经过综合研究认为该Ⅰ型花岗岩可能是在整个伸展环境下,岩石圈地幔压力降低导致地幔上涌,残余的洋壳熔融提供流体注入,从而该岩体发生侵位.     

福州复式岩体的成因:锆石U-Pb年代学、地球化学及Hf同位素约束

福州复式岩体Ⅰ-A型复合花岗岩的岩石成因与源区性质目前尚未得到很好认识.本文对福州复式岩体花岗岩进行了岩石学、锆石U-Pb年代学、主量和微量元素地球化学及锆石Hf同位素研究.该复式岩体花岗岩可分为钙碱性和碱性系列.LA-ICP-MS锆石U-Pb定年结果表明,钙碱性系列花岗岩形成年龄为111 ～ 101Ma,是早白垩世多...     

黑龙江霍龙门地区早石炭世花岗岩的锆石U-Pb年龄、地球化学特征及构造意义

黑龙江霍龙门地区位于兴蒙造山带东部的兴安地块和松嫩地块接触带上,区内花岗岩类以晚古生代花岗岩为主,岩性主要为二长花岗岩、正长花岗岩、碱长花岗岩.研究区二长花岗岩SHRIMP锆石U-Pb定年结果为(351.5±3.5)Ma,表明其形成于早石炭世.该时代岩石的主量元素具有高硅、略富铝、富碱质、低镁和贫钙的特征;微量元素表现出Th、Zr、Nd、Rb、K明显富集,而Ba、Sr、Nb、P、Ti明显亏损;稀土元素具有明显的轻稀土元素富集、重稀土元素相对亏损的特征,有明显的负Eu异常,轻重稀土元素分馏程度较强.岩石总体上属于高钾钙碱性系列花岗岩.花岗岩的R1-R2构造环境判别图解与微量元素Rb-(Yb+Nb)、Rb-(Yb+Ta)构造环境判别图解显示,该期发育的早石炭世花岗岩为同碰撞与造山期后的环境,结合本区所处的构造环境推测研究区内早石炭世花岗岩应为兴安地块与松嫩地块北东向拼合挤压过程由碰撞俯冲阶段向后造山阶段构造转换过程的产物.     

辽宁弓长岭矿区混合花岗岩地球化学特征及成因

经分析辽宁弓长岭二矿区混合花岗岩的主量元素、微量元素和稀土元素特征,对混合花岗岩的成因研究表明: 主量元素中Fe2O3、FeO、MgO 和CaO 含量较低,K2O 和Na2O 含量较高; 微量元素分配曲线属右倾型,强不相容元素富集; 轻稀土元素分馏明显,呈明显的Eu 负异常,但Ce 的正异常不明显,为典型壳型花岗岩稀土特征。弓长岭二矿区混合花岗岩原岩为富铝的沉积岩,混合花岗岩为部分熔融成因。     

四川大水沟碲矿床微量元素地球化学特征

大水沟碲矿床产出于大渡河韧性剪切带中段热穹窿体北端,以Te为主成矿元素的Te,Bi,Se,Ag和Cu等多元素组合型矿床.通过对研究区碲矿床矿体和花岗岩体微量元素对比研究,对碲矿体样品、花岗岩体样品和成矿围岩火山岩微量元素进行R型聚类分析,结果发现,碲矿床成矿物质来源于附近花岗岩体,矿床成因可能与花岗岩关系密切,碲矿床成矿物质来源具多源性.     

辽宁本溪地区关门山岩体地球化学特征及构造环境

对辽宁本溪地区关门山岩体正长花岗岩主量元素特征的研究表明,其属于高钾钙碱性系列.球粒陨石标准化稀土元素分配模式显示LREE相对富集,HREE相对亏损,具有中等亏损的负Eu异常,模式图总体呈“海鸥式”分布.微量元素蛛网图显示富集大离子亲石元素（LILE）Rb、Th、K,贫高场强元素（HFSE）Ta、P、Ti.正长花岗岩微量元素组成表明本区的花岗岩岩浆形成压力小于1.0 GPa,源区物质存在于30~40 km的地壳深处,属于减薄型地壳.正长花岗岩的形成时代为早白垩世,当时辽东陆块处于陆内伸展环境.     

东北地区花岗岩地质图(1∶1500000)编图及其说明

在收集前人资料和最新区调及科研成果文献的基础上,梳理厘定公开发表文献的花岗岩岩体同位素年龄数据1093个,硅酸盐数据772套,微量元素数据627套,稀土元素数据653套.依据这些数据及最新调查成果编制东北地区花岗岩地质图(1∶1 500 000).该图突出了构造-花岗岩区划作用.此次研究将前中生代构造-花岗岩类划分为2个构造花岗岩域、2个构造花岗岩省和7个构造花岗岩区(带),将中新生代构造-花岗岩类划分为2个构造花岗岩域、3个构造花岗岩省和7个构造花岗岩区(带),使得花岗岩类的时空演化特征更加明显.     

西昆仑阿克萨依铁矿二长花岗岩岩石成因及动力学背景:年代学、地球化学及Sr-Nd-Pb-Hf同位素约束

对甜水海地块东北部阿克萨依矽卡岩型铁矿区内与矿化有关的二长花岗岩开展LA-ICP-MS锆石U-Pb年代学、全岩主微量元素、Sr-Nd-Pb同位素及锆石Lu-Hf同位素研究,旨在厘定花岗岩的形成时代、岩石成因及成矿动力学背景.LA-ICP-MS锆石U-Pb定年结果表明,二长花岗岩侵位年龄为12.37±0.18 Ma(中新...     

贵东岩体地质地球化学特征及其形成的构造环境识别

本文在研究贵东花岗岩岩体岩石矿物组合、结构构造等地质特征的基础上 ,运用花岗岩的岩石化学、微量元素和同位素等分析数据 ,采用目前广泛应用的几种岩石化学图解、微量元素和同位素图解等方法 ,判别了贵东岩体形成的构造环境为造山带后碰撞型     

吉林省西南部地区花岗岩类微量元素特征研究及成因探讨

本文对吉林省西南部地区花岗岩类的微量元素特征进行了系统的研究,并利用微量元素的某些特征值对区内花岗岩成因进行了探讨。     

Stable W Isotope Measurements of Geological Reference Materials and Tungsten Ore Minerals by Double Spike MC-ICP-MS

This study presents high-precision W isotopic measurement results using the ¹⁸⁰W-¹⁸³W double spike technique with MC-ICP-MS. The effects of isobaric and polyatomic interferences on W isotopic measurements were evaluated. The δ^186/184W values were not significantly affected when the solution had Hf/W ≤ 3 × 10^-4, Ta/W ≤ 1, Os/W ≤ 0.06, Ce/W ≤ 0.0075, Nd/W ≤ 3.5 and Sm/W ≤ 5. The intermediate measurement precisions of both standard solutions (NIST SRM 3163 and Alfa Aesar W) and geological reference materials (NOD-A-1) were better than ±0.024‰ (2s). We also obtained a precision of 0.026‰ for a minimum sample loading mass of 5 ng, allowing the analysis of samples with low W contents. Replicated measurements of geological reference materials (AGV-2, BCR-2, BHVO-2, GSP-2, RGM-1, SDC-1, NOD-A-1 and NOD-P-1) yielded δ^186/184W values ranging from 0.017‰ to 0.144‰. The δ^186/184W values of two major tungsten ore minerals (scheelite and wolframite) were reported and compared herein. Scheelites had systematically slightly heavier W isotopic compositions than wolframites, which may reflect differences in the crystal structure. The resolvable variations of stable/mass-dependent W isotopic compositions in rocks and ore minerals make W isotopes a novel tool for studying hydrothermal mineralisation processes and the W cycle of geological reservoirs.     

The Earth’s tungsten budget during mantle melting and crust formation

During silicate melting on Earth, W is one of the most incompatible trace elements, similar to Th, Ba or U. As W is also moderately siderophile during metal segregation, ratios of W and the lithophile Th and U in silicate rocks have therefore been used to constrain the W abundance of the Earth’s mantle and the Hf-W age of core formation. This study presents high-precision W concentration data obtained by isotope dilution for samples covering important silicate reservoirs on Earth. The data reveal significant fractionations of W from other highly incompatible lithophile elements such as Th, U, and Ta. Many arc lavas exhibit a selective enrichment of W relative to Th, U, and Nb-Ta, reflecting W enrichment in the sub-arc mantle via fluid-like components derived from subducting plates. In contrast, during enrichment by melt-like subduction components, W is generally slightly depleted relative to Th and U, but is still enriched relative to Ta. Hence, all arc rocks and the continental crust exhibit uniformly low Ta/W (ca. 1), whereas W/Th and W/U may show opposite fractionation trends, depending on the role of fluid- and melt-like subduction components. Further high-precision W data for OIBs and MORBs reveal a systematic depletion of W in both rock types relative to other HFSE, resulting in high Ta/W that are complementary to the low Ta/W observed in arc rocks and the continental crust. Similar to previous interpretations based on Nb/U and Ce/Pb systematics, our Ta/W data confirm a depletion of the depleted upper mantle (DM) in fluid mobile elements relative to the primitive mantle (PRIMA). The abundance of W in the depleted upper mantle relative to other immobile and highly incompatible elements such as Nb and Ta is therefore not representative of the bulk silicate Earth. Based on mass balance calculations using Ta-W systematics in the major silicate reservoirs, the W abundance of the Earth’s primitive mantle can be constrained to 12 ppb, resulting in revised ratios of W-U and W-Th of 0.53 and 0.14, respectively. The newly constrained Hf-W ratio of the silicate Earth is 25.8, significantly higher than previously estimated (18.7) and overlaps within error the Hf-W ratio proposed for the Moon (ca. 24.9). The ¹⁸²Hf-¹⁸²W model age for the formation of the Earth’s core that is inferred from the ¹⁸²W abundance and the Hf/W of the silicate Earth is therefore younger than previously calculated, by up to 5 Myrs after solar system formation depending on the accretion models used. The similar Hf/W ratios and ¹⁸²W compositions of the Earth and the silicate Moon suggest a strong link between the Moon forming giant impact and final metal-silicate equilibration on the Earth.     

异常地热对烃源岩生烃的影响——以三塘湖盆地辉绿岩侵入体为例

为了探讨异常地热对烃源岩沉积有机质热演化的影响,采集了三塘湖盆地大黑山东剖面附近一辉绿岩侵入体南侧石炭系哈尔加乌组上部黑色泥岩层系的8块样品（W008～W015）,其与辉绿岩岩体的距离分别是20 cm、50cm、100 cm、180 cm、300 cm、500 cm、1 000 cm和1 700 cm,通过分析这八块样...     

Relationship between garnet skarn and W mineralization: A case study from the Tongshankou Cu-Mo-W deposit,Daye, Hubei.SCIEI北大核心CSCD

石榴子石是矽卡岩型矿床的标志性矿物之一,其结构和成分特征被广泛用来示踪早期成矿流体性质的变化,但其生长过程与金属元素富集过程的关系还不清楚。本文对长江中下游成矿带最西端鄂东矿集区内的铜山口铜钼钨矿床中的石榴子石开展了显微结构和电子探针主量元素、LA-ICP-MS微量元素点分析和面扫描分析。结果显示,铜山口矿床中的石榴子石端元成分以钙铁榴石-钙铝榴石为主,普遍含有一定量的W,特别是在钙铁榴石端元比例高的石榴子石中(可达3898×10-6),且W与Mo、As、Sn存在明显的正相关关系、与Ti存在一定的负相关关系,指示W以类质同象的方式进入石榴子石晶格。石榴子石可包裹结构简单的白钨矿或被具复杂结构的白钨矿交代,指示石榴子石记录了白钨矿形成前和形成过程中流体性质(氧逸度和W含量等)的变化。铜山口矿床中钙铁榴石的大量结晶,导致成矿早期W的大量分散,不利于高品位和大规模钨矿的形成,仅在这些钙铁榴石遭受强烈的退化蚀变时,释放的W在一定程度能够提高矿石的品位,这可能是氧化性矽卡岩型钨矿通常比还原性矽卡岩型钨矿品位低、规模小的重要原因。石榴子石的成分特征(如W、Sn等元素含量和W/Sn、W/Mo和W/As等比值)可以作为判断矽卡岩的氧化还原性和钨矿床的品位及规模的依据,并具有成为W、Mo和Sn等矿床的找矿勘查指示矿物的潜力。     

新疆东昆仑白干湖钨地球化学块体的确立及意义

新疆东昆仑是我国西部地质工作程度较低地区之一,白干湖钨地球化学块体的确定及白干湖钨锡矿床的发现成为该区矿产勘查中突破性的进展.文章概述了白干湖钨地球化学块体的地质、矿产及地球化学特征.对该块体与成矿的关系进行了探讨,认为钨地球化学块体为白干湖钨锡矿床的形成提供了丰富的成矿物质,钨的成矿与岩浆的演化有着密切的成因关系.指出白干湖钨锡矿床有望成为超大型矿床,新疆东昆仑地区有望成为我国一个新的钨矿远景区和新的钨矿产区.     

奇异的波至现象

1997年，笔者在水力压裂后砂岩产油井中进行高分辨率VSP工作时，除观测到常规纵波及转换波,还观测到来自产油层的几种奇异的慢速波至。由于该慢速波至的性质不明，按视速度从高到低分别命名为W1，W2，W3，…（W为wave的第1个字母），在顺5井裂隙优势方向，1210m深度上观测到5种反射波；反射纵波，反射转换波，W1，W2，W3波，在裂隙非优势方向上，W2，W3波没有出现，在顺4井1532m深度上观测到4种反射波；反射纵波，反射转换波，还有2种慢速波至，为了区别于顺5井中观测到的慢速波至，将其命名为W4，W5波。结合该区钻井，测井，地面地震，井间地震等资料对观测到的慢速波至进行了详细分析，分析结果表明：该慢速波至既不属于不均匀介质产生的绕射波，侧界面产生的反射波，槽波，管波，斯通利波，也与Biot慢纵波动力学特征相悖，现有波动理论不能解释这种慢速波至现象，这意味着地球内部介质中存在人类还未认识的弹性波传播规律。     

W同位素高精度负离子热电离质谱(NTIMS)测定方法

W同位素的高精度测定对于研究地球、月球和太阳系其他行星的起源和早期演化、核幔相互作用等领域具有重要意义。本文开展了负离子热电离质谱(NTIMS)高精度W同位素测定方法研究(测定WO_3~-)。采用多接收动态跳扫方式对W同位素进行测定,实时在线测定~(18)O/~(16)O,并利用实验室实时在线氧校正NTIMS Os同位素分析时获得的~(17)O/~(16)O-~(18)O/~(16)O同位素分馏趋势线计算~(17)O/~(16)O,进行氧校正计算。对多接收动态和多接收静态数据处理方式及不同的同位素分馏校正方法进行了详细对比研究。在上述工作基础上,最终建立了以~(186)W/~(184)W=0.92767进行标准化,采用多接收动态方法进行数据处理的在线氧校正W同位素NTIMS测定方法。~(182)W/~(184)W测定结果的外部精度(2RSD)可达3×10~(-6)～6×10~(-6),基本满足地球、月球和行星早期演化等W同位素研究工作的需要。     

江西省小龙钨矿深部地球化学找矿远景预测

运用岩石地球化学找矿方法预测了小龙钨矿区深部Ｃｕ、Ａｇ、Ｗ矿化富集规律及其找矿远景。认为矿区南涪７、１１勘探线八中段以下存在Ｃｕ、Ａｇ、Ｗ矿体可能;北部０勘探线六中段Ｃｕ、Ａｇ晕已收敛,深部存在Ｃｕ、Ａｇ矿体可能性不大,而Ｗ的强度和规模在八中段以下呈显著增大趋势,深部可能存在Ｗ矿体,为矿区深部部署坑道工程提供了准确的地球化学依据。     

Molybdenum and tungsten in volcanic rocks and in surface and <100 °C ground waters in Iceland

The concentrations of Mo and W in tholeiite series basaltic to silicic volcanics in Iceland increase with the concentrations of incompatible magmatic elements. In normal Mid Ocean Ridge Basalt (MORB), Mo and W levels are as low as 0.03 and 0.01 ppm but in rhyolites they are up to 4 and 1.3 ppm, respectively. In the slightly evolved Tertiary tholeiites of the main study area of Skagafjördur, northern Iceland, Mo and W concentrations are 1.01 and 0.32 ppm, respectively, on average. Surface waters in this area typically contain <0.5 ppb Mo and <0.1 ppb W. Concentrations are higher in ground waters and, on the whole, they increase with increasing temperature and increasing age of these waters, being as high as ∼100 ppb for Mo and ∼10 ppb for W in the hottest (∼90 °C) and oldest (>10,000 years) waters. In river and ground waters, the average Mo/W ratio is the same as that of the basalt host rock. On the other hand, in peat soil waters, the average Mo/W ratio is higher due to adsorption processes involving W. In river and ground waters, both Mo and W display conservative behavior. Progressive water-rock interaction leads to successively lower aquatic B/Mo and B/W ratios. However, the B/Mo and B/W ratios of the most reacted waters are considerably higher than those of the basalt due to non-stoichiometric rock dissolution: B is dissolved preferentially to both Mo and W because B is largely present in a soluble form, but Mo and W are concentrated in the Fe-Ti-oxides. These minerals are stable, under both surface and sub-surface conditions, i.e. the waters are over-saturated with respect to these minerals. The main supply of Mo and W to surface waters is from dissolution of plagioclase and pyroxene, as well as volcanic glass. Olivine is not an important source due to its scarcity in the basalts. In <30 °C ground waters, the dominant supply of Mo and W is plagioclase. At higher temperatures pyroxene also contributes, with its contribution increasing with increasing temperature, as deduced from its decreasing stability at higher temperature. Dissolution of basaltic glass produces lower B/Mo and B/W aqueous ratios than dissolution of crystalline basalt.     

赣南合龙钨矿矿床地质、成岩成矿时代与成矿模式

合龙钨矿床位于南岭东西向构造岩浆带与北-北东向于山构造带交汇部位,是南岭东段于都-赣县矿集区的重要组成.合龙钨矿床是赣南地区近年在石英脉型钨矿勘查取得最重要突破的矿区,新发现钨多金属矿体达48条,新探明黑钨矿资源量3.5万余吨,WO3平均品位2.189％,深部具有大型以上资源潜力.合龙钨矿床以外带石英大脉型矿体与岩体内...