Three Alkali—Rich Intrusive Rock Belts Bewly Discovered in the Mt.Kunlkun—Mt.Altun Region,Xinjiang,China

The newly discovered three alkali-rich intrusive rock belts in the Mt.Kunlun Mt.Altun region of southern Xinjiang are the Lapeiquan-Yitunbulak alkali-rich intrusive fock belt, the Gez-Taxkorgan alkali-rich intrusive rock belt and the Beeilisai-Abulash alkali-rich intrusive rock belt.The former two belts were formed during the Yanshanian period,and the third one was formed during the Himalayan period,which is the youngest alkali-rich intrusive rock belt in China.The discovery of the alkali-rich intrusive rock belts is of great significance in shedding light on the history of tectono-magmatic activities in this region.     

岚皋金云角闪辉石岩类捕虏体：地幔交代作用的证据

产于陕西岚皋地区碱质基性－超基性潜火山杂岩中的金云角闪辉石岩类捕虏体，主要由透辉石、富钛韭闪石、金云母、磷灰石、榍石、及钛铁矿组成。捕虏体发育三联晶、碎裂边、肯克变形等固相线下变形变质结构，矿物学特征表明，透辉石、富钛韭闪石、金云母为地幔来源，是地幔交代作用的产物；与正常地幔尖晶石二辉橄榄岩相比，捕虏体富ＴｉＯ２、Ｆｅ２Ｏ３、ＣａＯ、Ｎａ２Ｏ、Ｋ２Ｏ，贫ＭｇＯ，其稀土元素具富集特征，尤其富集ＬＲＥＥ；微量元素分配型式显示了富亲石不相容元素的特征。岩相学、矿物学及岩石化学特征表明：该类捕虏体为交代地幔捕虏体，它代表了北大巴山早古生代裂谷作用时期的异常地幔，是地幔交代作用的产物。交代营力可能源于地幔热缕的上升，交代过程推测为深处小范围的流体交代及随后硅酸岩熔体的“弥散”性交代     

The lamprophyres of Afyon stratovolcano,western Anatolia,Turkey: description and genesis

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.     

盐腔内回填碱渣沉降固结特性室内试验研究

碱渣回填到充满卤水的废弃盐腔后,颗粒会自由沉降到盐腔底部形成沉积层,进而在自重作用下固结。为了解盐腔内回填碱渣的沉降固结特性,以江苏淮安地区碱渣为对象,进行了沉降柱试验和固结试验。试验结果表明:(1)碱渣在卤水中的沉降过程可以分为3个阶段:絮凝阶段、沉降阶段和固结阶段。初始浓度对碱渣的沉降曲线和沉降速率有很大的影响。(2)碱渣颗粒分布、密度、含水率和孔隙比均呈现出分层特性,颗粒粒径、密度随深度的增加而增大,含水率、孔隙比随深度的增大而减小。(3)碱渣具有很高的压缩性,压缩系数a1-2为3.36 MPa-1。在压力范围小于100 kPa下,固结系数随固结压力的增加而显著减小。试验结果对了解盐腔内回填碱渣的沉降固结特性提供了参考,有利于指导回填施工工艺和碱渣的后期处理。     

云南个旧塘子凹锡多金属矿床夕卡岩地质地球化学特征

从地质产状、矿物组合和岩石化学成分等方面探讨了个旧塘子凹接触带不同类型夕卡岩的特征。该夕卡岩带从内侧到外侧常具有辉石夕卡岩带和石榴子石夕卡岩带交替出现的现象，其岩石化学成分也相应地发生韵律变化，表现为在辉石夕卡岩带中SiO2和MgO含量较高，而在石榴子石夕卡岩带中CaO、TFe和Al2O3含量较高。认为夕卡岩带中的韵律变化一方面与被交代围岩中存在灰质白云岩和大理岩的互层带有关，另一方面与岩浆期后热液的渗滤交代作用有关。围岩中的灰质白云岩层被交代后形成辉石带，大理岩层被交代后形成石榴子石带。     

阳春盆地锡山钨锡矿床钾长花岗岩的矿物学特征及地质意义

锡山钨锡多金属矿是粤西阳春盆地内一个中型石英脉型矿床,成矿岩体岩性为钾长花岗岩,主要矿物组成为钾长石、斜长石、石英、黑云母,副矿物包括锆石、磷灰石、金红石、钛铁矿和铌铁矿等。文章利用电子探针技术对主要矿物的矿物学特征进行了研究,结果表明花岗岩中斜长石为钠长石,钾长石为透长石,黑云母属于铁叶云母。黑云母化学成分显示其w(Ti)介于0.19~0.39,具有低的氧逸度(log f(O2)Ni-Ni O),指示其有利于钨锡矿床的形成且仍具有较好的找矿潜力。结合已有的区域地质资料,文章认为锡山钨锡多金属矿床是岩石圈伸展背景下的产物。     

系统结构模型在矿产勘查中的应用

系统结构模型是一种描述系统要素之间以及系统与环境之间相互关系的模型 ,是概念模型到定量模型的中介 ,特别是对一些难以量化的系统常采用这种模型加以描述。以往矿产勘查系统模型对系统要素结构分析不够深入。文章在系统结构模型介绍的基础上 ,以滇西北地区喜山期富碱斑岩有关Cu Mo Au矿产勘查为例 ,构建了一个适用于本区该类矿产勘查的系统结构模型 ,对模型要素的矿产勘查意义进行了解释     

白云鄂博矿区交代及成矿作用的成因矿物学研究

通过对白云鄂博矿区碱性角闪石和金云母的成因矿物学研究，证实本区确实有岩浆碳酸岩的活动，活动中心在矿区东部，矿区碱交代作用来源于岩浆碳酸岩的后期热液活动，与白云鄂博铁－铌－稀土矿床中的主斯铁矿化无趋势关系，但与稀土矿化关系密切，作为铁矿化的太物学标志是：标型矿物镁钠闪石和镁钠铁闪石；金云母的特殊反多色性及其低Ｔｉ，高Ｘ＾ｔｅｔｓｉ的成分特征以及特殊的标型矿物组合。     

Fluid-rock interaction in some shear zones from the Pyrenees

Abstract Mylonites from shear zones cutting Hercynian gneisses in the central Pyrenees have been studied in thin section and using the electron microprobe. The shear zones contain retrogressive greenschist facies assemblages implying introduction of an aqueous fluid during deformation in the zones. Textural evidence suggests that fluid-rock interaction occurred throughout the active life of the shear zones.
Whole-rock chemical changes during deformation are documented in a variety of mylonitic lithologies and retrogressed country rocks. The overall effect was to reduce chemical differences between lithologies. Activity diagrams show that this would be expected if a hydrous fluid was circulating between different lithologies during deformation. In most cases fluid/rock ratios were relatively small resulting in gradual chemical changes and repeated recrystallization. 'Open-system'behaviour with reduction in the number of phases is seen in some granite mylonites, suggesting focusing of fluid movement in parts of the shear zones. Continual fluid-rock interaction may have led to reaction-enhanced ductility in the shear zones over a long period of time. The source of fluid is uncertain, but may be related to underthrusting of material beneath the area investigated.