【作者】 杨梦楚；

【导师】 施光海；

【作者基本信息】 中国地质大学(北京) ， 宝石学， 2012， 硕士

【摘要】 黄龙玉原生矿体产于龙陵县小黑山矿区，原生矿体产于三叠系公养河群板岩与花岗岩接触带上，部分产于花岗岩张性裂隙中，一般呈透镜状、囊状和不规则状产出。原生矿产出山料，主要以洞坑石料为主。次生矿床分布于以小黑山为源头的苏帕河流域，分散于河底、河滩、河流两岸田地中，次生矿产出籽料。组成黄龙玉的硅质种类主要分为，蛋白石、玉髓、微晶石英和粗晶石英。典型的黄龙玉呈现均一或非均一的隐晶及凝胶结构，微晶结构及以上两种结构的镶嵌结构。物相分析显示黄龙玉的主要组成矿物为玉髓及石英，次要矿物为绢云母、铁泥质矿物、高岭石等。X射线粉晶衍射分析中发现的残留白云石提供了成矿硅质流体交代白云质碳酸盐岩的证据。本次首次发现了黄龙玉样品中含有细分散状的高岭石。黄龙玉中的高岭石呈细分散状或者细脉状并呈现出长石假象，其周围常伴有板片状绢云母颗粒，是黄龙玉围岩花岗岩发生高岭石化的产物。高岭石具有很好吸附性，能够在黄龙玉局部富集一定致色成分。是硅质黄龙玉出现类似印章石质感的根本原因，对黄龙玉的品质优越性有着极其重要的贡献。常量元素地球化学特征表明，黄龙玉含有较多的陆源输入物，主要为高岭石。稀土元素的特征分析显示，黄龙玉的δCe及δEu值偏高证实了黄龙玉地下水主导成岩过程的机制。通过对小黑山矿物样品的石英及玉髓的氢氧同位素分析发现，小黑山矿床具有明显偏负的δD值，介于-131‰~-179‰之间，远远低于龙陵地区地热温泉水的δD值范围，与高纬度大气降水特征相符，，进一步证明其成矿流体主要来自大气降水。黄龙玉的原生矿脉形成于浅地表的开放拉张裂隙环境，属于由地下水携带的二氧化硅形成的表生无矿硅质岩。黄龙玉是沉积作用、风化淋滤作用等多种过程协同而成，使原生黄龙玉的外观发生多种变化，丰富了黄龙玉的内涵并极大地扩展了其工艺设计与想象空间。更多还原

【Abstract】 The Huanglong Jade (Chrismatite) of Longling, Yunnan, which has delicate andexquisite texture, and had been honored as Siliceous Tianhuang, is a new type of highquality chert jade appeared lately years in the Chinese jade market. The HuanglongJade occurs mainly in contact zone or tensile cracks of upper granite and slate ofGongyanghe Group (Triassic). Its secondary ores are distributed along the river bed,flood plain and fields of the Supa River.Field observation and modern test technologies have been used in this paper, tomake a systematic study on aspects of geochemical and petrological characteristics ofHuanglong Jade (Chrismatite). Furthermore, coupling analysis is done on the basis ofprevious studies to make a connection between its gemology and mineralogycharacteristics. In this thesis, texture types, group, evolution characteristics have beenstudied under polarizing microscopy. Geochemical characteristics of minor elements,and REE have been detailed studied, and revealed that formation of the HuanglongJade is mainly related to atmospheric precipitation, and hydrothermal fluids also takepart in its formation.The main siliceous mineral constituent of Huanglong Jade, aphanitic quartz，chalcedony, microcrystalline quartz and mega quarz, whose are characterized byvaried crystal form and size, have been showed different texture element features.From the microscope we can tell that the structure of the Huanglong jade is mainlyaphanitic to particulate structure, and it also contains phanerocrystalline, fine-grainedand macrograin type. The analysis of X-ray diffraction and infrared shows that themineral composition of the Huanglong Jade is mainly quartz, and also containing asmall amount of muscovite, dolomite and clay minerals of iron. And for the first timethe author discovered that finely dispersed kaolinites are contained in the HuanglongJade, which contributes greatly to the excellent quality of it. The Jade sample have showed negative anomalies and not clear anomalies ofδCe, even positive anomalies of δCe. The value of δEu is weak positive anomalies,which reveal the genesis of atmospheric precipitation sedimentation. The abovedistribution characteristics of main and REE have been argely controlled by theoriginal depositional environment and the activity grade of ore-forming fluid.Three variables, body colour, structural diversity, types and content of thesecondary minerals are the three major factors related to the quality of the HuanglongJade. The original ore, which resulted in combined actions of sedimentation,weathering and eluviation, formed in the open fracture environment of subsurface.Secondary ore is formed by subsurface effect (including biological weathering,chemical weathering and actions of water), which changed the appearance of theoriginal ore greatly and enriched the variety of the Huanglong Jade.更多还原