吉林蛟河橄榄石的岩石学及宝石学特征

发布时间：2018-06-16 21:37

本文选题：吉林蛟河 + 橄榄玄武岩　；参考：《成都理工大学》2017年硕士论文

【摘要】：吉林蛟河橄榄石是我国除河北汉诺坝之外的第二大橄榄石产出矿区,是重要的有色宝石矿区之一。笔者以吉林蛟河橄榄石作为研究对象,吉林蛟河大石河矿物为主要研究矿区,通过手标本特征、显微特征、X射线荧光光谱分析、X射线粉晶衍射分析、傅里叶红外光谱测试等方法,获得本区橄榄玄武岩及橄榄岩包体的化学成分、矿物组成及结构信息;通过宝石显微镜、折射仪、二色镜等常规宝石学测试获得吉林蛟河橄榄石的宝石学特征信息,补充吉林蛟河橄榄石矿床研究领域的不足。吉林蛟河橄榄岩矿床主要受敦化-密山断裂带的影响,为船底山期碱性粗面玄武岩。矿体内含大量橄榄岩包体,呈粒状结构产出,矿床呈似层状。橄榄玄武岩呈灰黑色角砾状隐晶质结构,可见气孔构造。玄武岩基质为斑状结构,含长石、橄榄石、辉石等矿物。玄武岩基质中橄榄石呈浑圆粒状结构,为地幔橄榄岩的破碎产物捕虏晶而非斑晶。可见橄榄石、辉石外围多发生蚀变,常见双晶及扭折带,出现成分环带。具环带的矿物边部成分接近玄武岩,核部成分又保留地幔的成分信息。寄主岩浆与捕虏晶之间有着元素转移的关系。橄榄岩包体呈不等粒状结构,含橄榄石、顽火辉石、透辉石、铬铁矿及尖晶石,为尖晶石二辉橄榄岩。橄榄石及顽火辉石多见双晶及变形纹,透辉石呈艳绿色粒状结构。橄榄石根据颜色分为两种,推测为两个不同时期形成。吉林蛟河产出的宝石级橄榄石颜色绿色至黄绿色,透明-半透明,内部含有暗色包体,睡莲状包体、负晶及裂隙,多色性很弱,相对硬度为6.52 Kg/mm2、相对密度为3.37g/cm3,折射率处于橄榄石范围内的中间部分,蓝绿、红橙区域有吸收光谱。玄武岩中的橄榄岩包体为幔源包体,在岩浆喷发前早已存在,经历过部分熔融。随着船底山期火山活动频繁,地幔流体交代熔融汇聚成的玄武岩岩浆携带橄榄岩包体喷出,形成吉林蛟河橄榄玄武岩矿床。
[Abstract]:Jiaohe olivine in Jilin Province is the second largest olivine producing area in China besides Hanoba in Hebei Province. It is one of the important non-ferrous gemstone mining areas. The author takes Jiaohe olivine as the research object and Jiaohe Dashihe mineral as the main mining area. Through the characteristics of hand specimens and microscopic features, the X-ray powder diffraction analysis is carried out by X-ray fluorescence spectroscopy. The chemical composition, mineral composition and structure of olivine basalt and peridotite inclusions were obtained by Fourier transform infrared spectroscopy. Conventional gemological tests such as dichromatic mirror have obtained the information of gemological characteristics of olivine in Jiaohe, Jilin Province, which complements the deficiency in the research field of Jiaohe olivine deposit in Jilin Province. The Jiaohe peridotite deposit in Jilin Province is mainly influenced by Dunhua-Mishan fault zone and belongs to basalt of basalt. There are a lot of peridotite inclusions in the ore body, and the ore deposit is stratiform. Olivine basalts have a gray-black breccia cryptic structure and a stomatal structure. Basalt matrix is porphyry structure, containing feldspar, olivine, pyroxene and other minerals. Olivine in basalt matrix has a round granular structure, which is a cataclastic product of mantle peridotite rather than porphyry. Olivine, pyroxene periphery of the alteration, common double crystal and torsion band, the composition of the ring zone. The mineral edge of the annular belt is close to basalt, and the nuclear component retains the information of mantle composition. There is an element transfer relationship between host magma and xenocryst. The peridotite xenoliths, which contain olivine, enstatite, diopside, chromite and spinel, are spinel peridotite. Olivine and enstatite are mostly dicrystalline and deformed, diopside is green granular structure. Olivine is divided into two types according to color, presumably formed in two different periods. Jilin Jiaohe produced gemstone grade olivine color green to yellowish green, transparent-translucent, inside contain dark color inclusion, water lily shape inclusion, negative crystal and fissure, multicolor is very weak, The relative hardness is 6.52 kg / mm ~ (-2), the relative density is 3.37 g / cm ~ (-3), the refractive index is in the middle part of the range of olivine, blue and green, red orange region have absorption spectrum. The peridotite xenoliths in basalt are mantle xenoliths which existed long before magma eruption and experienced partial melting. With the frequent volcanic activity in the Chuandishan period, the mantle fluid metasomatism and melt converging basalt magma exhaled peridotite inclusions and formed the Jiaohe olivine basalt deposit in Jilin province.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P588.125;P619.28

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