山东蓝宝石及其环带研究

【作者】 张战军；

【导师】 赫英；

【作者基本信息】 西北大学 ， 地球化学， 2003， 硕士

【摘要】 本文通过对山东昌乐蓝宝石的地质与地球化学研究，结合对海南等其它蓝宝石特征的比较分析，探讨山东昌乐蓝宝石特别是其环带的形成机制，从而为蓝宝石找矿以及蓝宝石的加工和改色提供指导。 本次研究取得如下主要进展： 1、对山东昌乐、海南岛蓬莱蓝宝石及其环带的特征进行了电子探针研究。研究表明，山东昌乐的蓝宝石普遍发育环带，从外观上讲，蓝宝石中深浅色度的交替出现是出现环带的直接原因，而总Fe含量的近周期性变化是形成蓝宝石环带的根本原因；同一蓝宝石的同一环带，其总Fe的含量几乎相同，所以该环带上的任何一个成分点都可以代表整条环带的成分；同一蓝宝石的不同环带，颜色越深，含Fe越高，颜色越浅，含Fe则越低；凡出现环带的蓝宝石，其核部总是深黑色或者蓝黑色，而其含铁量一般都比其它部位高。 2、对山东昌乐蓝宝石及其环带的拉曼谱特征进行了研究。研究表明，山东蓝宝石中Fe主要是以Fe³⁺的形式存在的；Fe含量的周期性变化主要表现为Fe³⁺含量的周期性变化；而在蓝宝石中，Fe主要是以类质同象的形式替换Al而进入刚玉晶格的，在刚玉晶格中存在着O-Al₄，和O-Fe₄的结构格式，也极有可能存在着二者的几个过渡型分子结构如O-Al₃Fe，O-Al₂Fe₂及O-AlFe₃。 3、观察到了山东、海南蓝宝石普遍存在的反应边，并测试了反应边的成分，证实其以富Fe，Mg，和K为特征；研究了蓝宝石里面的包体，发现蓝宝石里面存在着大小不等的KCl的结晶颗粒，还发现了富K富Si的熔浆包裹体，说明其形成过程中有同化混染的贡献；此外还发现了斜方辉石，磁铁矿，铬铁矿，锆石的包体矿物。 4、在昌乐地区区分出三类主要的玄武岩：a，牛山组含矿的碱性橄榄玄武岩，位于方山，含大量的大小不一的风化蚀变程度不同的地幔岩包体；b，牛山组几乎不含矿的碱性橄榄玄武岩，含少量地幔岩包体，且包体一般比方山小，多数已经遭严重风化而只留下空洞，含有相当数量的钛铁矿，主要位于北岩南部的苍山，桃花山及乔官火山口。c，尧山组橄榄玄武岩，不含任何包体，也不含矿。分别采用XRF和ICP-MS分析了上述三类岩石全岩的主量元素和微量元素，结果发现这三类岩石在主量元素和微量元素方面都有着比较明显的区别。在此基础上讨论了K，Na，Ca等碱质元素对于蓝宝石结晶的控制机理。硕士论文题目:山东蓝宝石及其环带的研究作者:张战军二零零三年五月五日反应和环带的变化情况进行了实验研究。实验表明，尽管温度高达1360吧，但在干系统条件下，在12小时的接触过程中，没有观察到蓝宝石与三类岩石（即上述含矿，不含矿及其过渡类型）的熔浆有明显的交代迹象，且蓝宝石的环带依然清晰可见。在此基础上对蓝宝石的改色提出了一些建议。6、在上述研究基础上，讨论了山东昌乐蓝宝石及其环带形成的岩浆结晶- 同化混染联合作用机制及其与封闭开放条件的关系。更多还原

【Abstract】 We have studied the geological and geochemical characteristics of sapphire from Shandong Changle,comparing this with other sapphire from Hainan ect, researching the mechanism of Shandong sapphire,especially the mechanism of the sapphire bands, and thus gave the instruction for searching sapphire deposits and changing its color.The following results are acquired during this study:1. By the electronic probe analysis and research on sapphire and its bands both from Shandong Changle and Hainan Penglai,we think that the sapphire from Shandong Changle enriched with bands. Speaking from its outline, shallow and deep color existing alternately is the direct reason why the bands emerged, while the periodical change of the total Fe content in the sapphire is the foundmental reason; In the same band of the same sapphire, the total Fe content is nearly the same, so in this sense any spot can respresent the whole band in which the spot lies; In one sapphire, the deep-color band must contain the higher Fe than the shallow one ; The sapphire which exists bands must have a black or a dark blue core, where the Fe content is usually higher than other bands.2. We have also studied the Raman Spectrum of the Shandong sapphire and its bands and find that Fe of the Shandong sapphire is mianly Fe3+,and the periodical change of Fe is mostly the change of Fe3+; Mostly, Fe entered sapphire crystal by replacing Al in the form of isomorphism . Retrahedrons O-Al4 and O-Fe4 exist in the Shandong sapphire, while other Tetrahedrons such as O-Al3Fe, O-Al2Fe2 and O-AlFe3 may also exist.3. Sapphire from Shandon and Hainan commonly have the reaction border, we found out this reaction border enriched with Fe,Mg,and K by testing its components; We also studied the inclusion in the sapphire, and found many KC1 crystal grain with variety of size, a melt inclusion enriched with K,Si, is also found, this may suggest an assimilationary-magmatic course; Besides that, another minerlinclusions such as enstenite, magnetite, chromite, zircon are also found.4. Three type of basalt is recognized in Changle region: a, Sapphire-embodied alkli-olivine-basalt of Niushan group(most distributed in Fangshan),enriched with a large number of mantle-orignated xenoliths with different extent of weathering; b, alkli-olivine-basalt of Niushan group with little sapphire embodied,but contan a few mantle-orignated xenoliths usually samller than that of Fangshan, most of the mantle-orignated xenoliths weathered seriously only lefting with some vacant caves, this kind of rock mostly lies in Cangshan, Taohuashan.and Qiaoguan volcanic vent,contain amount of ilmenite; c, Olivine-basalt of Yaoshan group, contain neither xenoliths nor sapphire. The major and trace elements are tested by XRE and ICP-MS respectively, and we found out that this three type of rock differed obviously both in term of major elements and trace elements. On the basis of this test, we studied the mechanism that the alkli elements (such as K,Na ,Ca )control the crystallization of sapphire.5. Under the condition that is dry system, high temperature, common pressure and air-touched, we experimented to studied the reaction between the sapphire and the basalt meit,as well as the change of the sapphire bands in the basalt melt. The experiment suggested that under the dry condition, during the 12-hour-touched, the reaction between the sapphire and the three type of the basalt melt is not obvious, and the sapphire bands can be seen obviously, although the temperature amounted to 1360癈. On the basis of this experiment ,we would like to give some advice on sapphire-color-changed research.6. On the ground of all these research works, we studied the magma crystallization- assimilationary mechanism that works on the Shandong sapphire and its bands,we also analysed the relationship between this mechanism and the isolated or open condition.更多还原