Li—F花岗岩液态分离和稀土地球化学标志

华南和其他国家典型Ｌｉ－Ｆ花岗岩的１１８个稀土分析研究表明,随Ｌｉ－Ｆ花岗岩由早至晚阶段或自下而上不同岩相演化,稀土模式曲线有三种变化类型;（１）降低变化。（２）升高变化;（３）突然变化等类型。（４）称为正向演化类型,是结晶分异结果;（２０称为反向演化类型,代表气液分馏为主的液态分离;（３）称为演变突变类型,是不混为主的液态分离形成。     

Li—F花岗岩液态分离的同位素地球化学标志

Li-F花岗岩液态分离包括不混溶为主和气液分馏为主两种液态分离作用。Li-F花岗岩不混溶为主液态分离的同位素标志是：在复式Li-F花岗岩体中，随由早至晚阶段Li-F花岗岩侵入变化，岩石中δ^18O、ISr有先降低后突然升高的变化趋势；在典型Li-F花岗岩体中，由下部岩相成分相当翁岗岩（纳长花岗岩）向上至顶部岩相成分相当香花岭岩（云英岩、似伟晶岩）的全岩和石英δ^18O突然升高。Li-F花岗岩气液分馏为主液态分离的同位素标志是：典型Li-F花岗岩体的中、深部岩相向上至浅部岩相，岩石有δ^18O降低和δD升高的变化趋势。     

Li-F花岗岩液态分离的稀土地球化学标志

华南和其他国家典型Ｌｉ－Ｆ花岗岩的１１８个稀土分析研究表明,随Ｌｉ－Ｆ花岗岩由早至晚阶段或自下而上不同岩相演化,稀土模式曲线有三种变化类型：①降低变化,②升高变化,③突然变化等类型。①称为正向演化类型,是结晶分异结果;②称为反向演化类型,代表气液分馏为主的液态分离;③称为演化突变类型,是不混溶为主的液态分离形成。因此,不混溶为主的液态分离标志是稀土模式演化突变类型和Ｌｉ－Ｆ花岗岩在ＲＥＥ－（Ｌａ／Ｙｂ）ｎ、Ｌａ／Ｓｍ－Ｌａ（μｇ／ｇ）图解中主演化方向线与次演化方向线或与成分点呈分离特点。气液分馏为主的液态分离标志是稀土模式反向演化类型和Ｌｉ－Ｆ花岗岩在ＲＥＥ－（Ｌａ／Ｙｂ）ｎ、Ｌａ／Ｓｍ－Ｌａ（μｇ／ｇ）图解中主演化方向线,指向图解的右上方等     

个旧花岗岩的微量元素和稀土元素地球化学演化特征

个旧花岗岩，从斑状黑云母二长花岗岩→中粗粒黑云母钾长花岗岩→二云母碱长花岗岩构成了较完整的同源多阶段演化系列，岩浆是以分离结晶方式演化的。不同类型花岗岩的lg(Rb/Sr)-lgSn,lg(Rb/Ba)-lgSn,lgLa-lgSr,lgCe-lgSr,lgEu-lgSr等具有很好的线性关系，REE分布模式的演化也反映了岩浆分异特征。晚期二云母碱长花岗岩是强烈分异的锡多金属矿化花岗岩，其以高Rb／Sr，Rb/Ba比值和低K／Rb、∑Ce/∑Y比值以及Eu强烈亏损为特征。     

广东阳春盆地花岗岩类同位素,微量元素地球化学研究

对阳春盆地３个花岗岩类岩体进行了年龄测定,岗尾岩体和锡山岩体的黑云母Ｋ－Ａｒ稀释法年龄平均值分别为１５６×１０＾６和７６×１０＾６ａ,石录岩体花岗闪长岩中黑云母,钾长石和斜长石等单矿物＾４０Ａｒ／＾３９Ａｒ坪年龄平均值为１００×１０＾６ａ,马山岩体,岗尾央体和石录岩体的锶同位素初始比值分别为０．７０４０,０．７０６４和０．７０８９,它们均属于壳幔混合型花岗岩类,根据微量元素判别,锡山岩体花岗岩是壳     

稀有元素花岗岩液态分离与实验研究

稀有元素花岗岩液态分离与实验研究王联魁，卢家烂，饶冰（中国科学院广州地质新技术研究所，广州５１０６４０）关键词稀有元素花岗岩、液态分离、富Ｌｉ、Ｆ花岗岩化学成分、结构构造研究发现，浅源南岭系列（系列１）花岗岩演化到晚期，常出现富含钠锂氟的酸性或超酸性...     

A型花岗岩的微量元素地球化学

本文总结和评述了A型花岗岩典型的微量元素特征,如富集Ga、稀土元素（除Eu外）和高场强元素,亏损Ba、Sr和明显的Eu负异常。分别讨论了影响微量元素特征的多种制约因素,主要包括源区性质、岩浆的物理化学条件、岩浆作用过程和络合作用。通过对比世界范围内几个地区相伴生的碱性A型花岗岩和铝质A型花岗岩的微量元素地球化学特征,发现前者Ga、F含量更高,而轻重稀土比值小,Eu、Ba、Sr等元素含量更低,显示了前者的岩浆分异作用更强,同时说明了碱性A型花岗岩可以由与之伴生的铝质A型花岗岩分异而来。     

REE Geochemical Indicatrices of Li—F Granite Liquid Segregation

The results of 118 REE analyses of Li-F granites from South China and other countries indicate that there are three variation types of REE pattern curves with different evolution trends from early to late stages of Li-F granite complex of from lower to upper petrofacies of the Li-F granite body;(1) the decreasing,(2) the increasing,and (3) the saltatory variation types.The first variation type is called the positive evolution type,attributed to crystallization differentiation.The second is called the reversion evolution type.which represents liquid segreation dominated by vapor-liquid distillation.The third is called the saltatory variation type,which is formed from liquid segregation dominated by immiscibilty,Therefore,the indicatices of liquid segregation dominated by immiscibility are the saltatory variation type of REE pattern evolution and the separation of the main evolution trend lines either from the sub-evolution trend lines or from the composition points of Li-F granites in the diagrams of REE-(La-Yb)N and La/Sm-La,The indicatrices of liquid segregation dominated by vapor-liquid fractional distillation are the reverstion evolution type of REE pattern curves and the main evolution trend lines of Li-F granites directing to the upper right-hand on the REE-La/Yb)N and La/Sm-La diagrams.     

The three end members of Li-F granites and their origin of liquid segregation

Li-F granites all over the world can be represented by three end members, i. e., the Na-rich ongonite (O), the K-rich xianghualingite (X) and the Si-rich topazite (T). Characters and criteria are presented for these end-member rocks. Vertical zoning in Li-F granites, as reflected by increasing normative Q and C (corundum) and decreasing ALK (K₂O+ Na₂O) with increasing content of fluorine, can be explained using the three-end-member scheme in terms of petrochemistry and norms. Considering the difference in melt structure, viscosity and density between the end members, in couple with the regularities that govern the Na-K and SiALK segregation known from field evidence and experiments, it is suggested that the three end members may have resulted from liquid segregation (immiscibility) rather than from crystal fractionation as commonly believed.     

Experimental investigations of superliquidus phase separation in phosphorus-rich melts of Li-F granite cupolas

Experiments at a temperature of 800°C and a pressure of H-C-O fluid of 200 MPa under moderately reducing conditions (magnetite stability field) revealed the occurrence of superliquidus nanocluster cryptic and contrasting phase separation of a quartz-feldspar type in Li-F granite melts of the Podlesi cupolas (Czech Republic) with F, P, and H₂O contents approaching the natural values. Similar to natural observations, ore components (W and Sn) were accumulated in the experimental samples in melts enriched in P and F.     

中国花岗岩型铀矿区域地球化学指示元素特征及异常模式

我国铀矿床主要划分为四大类型,包括花岗岩型铀矿床、火山岩型铀矿床、砂岩型铀矿床和碳硅泥岩型铀矿床。花岗岩型铀矿约占我国已探明铀矿总资源储量的三分之一以上,是我国重要的铀矿化类型。地球化学勘探方法对花岗岩型铀矿床勘查具有良好的效果。根据全国铀矿资源潜力评价项目研究成果,在大量研究中国花岗岩型铀矿化水系沉积物地球化学异常特征基础上,总结了一套对花岗岩型铀矿化勘查稳定的、行之有效的指示元素及其组合,确定了花岗岩型铀矿化地球化学异常模式,并以实例说明典型花岗岩型铀矿化异常模式。水柰沉积物地球化学异常是进行铀矿产预测评价的有效手段,对铀矿资源的潜力评价发挥了重要作用。     

不同来源两个系列Li-F花岗岩的同位素组成区别

根据地质和地球化学特点,特别是同位素组成,将Li-F花岗岩划分为浅源南岭系列(系列Ⅰ)和深源长江系列(系列Ⅱ).系列Ⅰ的δO18＞10‰,ISr＞0.7100,εNd(t)＜-6,在207Pb/204Pb-206Pb204Pb铅同位素构造图上位于上地壳线附近;系列Ⅱ的δ18O＜10‰,ISr＜0.7100,εNd(t)＞-6,在207Pb/204Pb-206Pb/204铅同位素构造图上位于地幔线与造山带线之间.说明浅源南岭系列Li-F花岗岩物质来源比较浅,以上地壳(再循环地壳)物质为主,而深源长江系列Li-F花岗岩物质来源比较深,以地幔、下地壳和造山带(原生地壳)物质为主.     

矿泉水中微量元素锶富集的地球化学环境

本文通过对全国566处富含锶(Sr)矿泉水的化学测试数据、所处的地球化学环境、地质背景的分析,重点阐述了微量元素Sr的富集与含水介质岩性的关系,并概括了矿泉水中Sr富集的地球化学特征。认为富含Sr矿泉水的形成与不同含水介质岩性和Sr的丰度等地球化学环境密切相关。矿泉水中Sr富集的最有利的环境是碳酸盐岩地层,其次是碎屑岩地层。研究表明,HCO3-Ca型的矿泉水分布最广,但Sr含量普遍偏低。各种重碳酸型的矿泉水中Sr的平均含量均小于1mg,L;相反,由于Sr^2 和SO4^2-呈正相关关系,各种硫酸型的矿泉水中Sr的平均含量大于1mg/L。地下水中的pH值能影响Sr的迁移能力,含Sr的矿泉水pH值多集中在7∽8．5之间。     

丹东花岗岩的地球化学特征及其成因

新的SHRIMP定年结果表明,原先划归于古元古代的丹东花岗杂岩现在被确定为中生代岩体。其岩浆型环锆石带的年龄代表结晶年龄,为167～157Ma;但是这些锆石的核部年龄主体为古元古代。本文侧重探讨丹东花岗岩体的岩石学和地球化学特征,论证其起源和产生的构造背景。研究结果表明,丹东花岗岩体具铕异常(Eu／Eu=0．59～1．41),轻重稀土分异明显,其微量元素特征与安第斯型构造背景下的花岗岩特征一致,其tDM和εNd(t)变化范围分别为1．93～2．30Ga和-17．95～-21．32。εNd(t)-t图解显示丹东花岗岩的源岩以古元古代中酸性壳源岩石为主。构造环境环境判别结果表明其形成于大陆边缘岩浆弧。结合中生代丹东地区所处的大地构造背景,本文认为丹东花岗岩体的起源和侵位与古太平洋板块向欧亚板块的俯冲有关。     

A review of experimental studies of crystal/liquid trace element partitioning

Available data on silicate/liquid, phosphate/liquid and oxide/liquid trace element partition coefficients from experimental studies show an encouraging degree of consistency, although much more work is required before a set of coefficients of wide-ranging application to planetary problems can be compiled. The complex dependences of most coefficients on bulk chemical composition (and liquid structure) are important aspects which remain to be fully resolved. Further determinations of coefficients for a number of elements for phosphates, zircon, spinels, amphiboles and garnets are especially desirable and investigations into the effects of pressure and volatiles on the magnitudes of partition coefficients are also needed. There is a major discrepancy among existing data regarding the upper concentration limits of Henry's Law dilute solution behavior under different experimental conditions. Data obtained at 1 atmosphere under dry conditions can apparently be reconciled with data from highpressure, H₂O-saturated experiments only if Henry's Law limits are themselves functions of variables such as pressure, temperature, H₂O activity and chemical composition. Further experiments (including studies bearing on the role of defect substitution at very low trace element concentrations) are required to resolve this question.     

Composition of Li-F granite melt and its evolution during the formation of the ore-bearing Orlovka massif in Eastern Transbaikalia

By the example of the Orlovka massif of Li-F granites in Eastern Transbaikalia, the major- and trace-element (Li, Be, B, Ta, Nb, W, REE, Y, Zr, and Hf) compositions of the parental melt and the character of its variations during the formation of the differentiated rock series were quantitatively estimated for the first time on the basis of electron and ion microprobe analysis and Raman spectroscopy of rehomogenized glasses of melt inclusions in quartz. It was shown that the composition of the Orlovka melt corresponded to a strongly evolved alumina-saturated granitoid magma (A/CNK = 1.12–1.55) rich in normative albite, poor in normative quartz, and similar to ongonite melts. This magma was strongly enriched in water (up to 9.9 ± 1.1 wt %) and fluorine (up to 2.8 wt %). Most importantly, this massif provided the first evidence for high B₂O₃ contents in melts (up to 2.09 wt %). The highest contents of trace elements were observed in the melt from pegmatoid bodies in the amazonite granites of the border zone: up to 5077 ppm Li, 6397 ppm Rb, 313 ppm Cs, 62 ppm Ta, 116 ppm Nb, and 62 ppm W. Compared with the daughter rock, the Orlovka melt was depleted at all stages of formation in SiO₂ (by up to 6 wt %), Na₂O (by up to 2.5 wt %), and, to a smaller extent, in Ti, Fe, Mg, Sr, and Ba, but was enriched in Mn, Rb, F, B, and H₂O.