文章摘要
刘 芳.海拉尔盆地上库力组两类流纹岩的球粒对比研究[J].地质与勘探,2020,56(2):337-345
海拉尔盆地上库力组两类流纹岩的球粒对比研究
Comparative study of two kinds spherulites from rhyolite in the Shangkuli Formation of the Hailaer Basin
投稿时间:2019-05-23  修订日期:2019-12-03
DOI:10.12134/j.dzykt.2020.02.009
中文关键词: 球粒 柱状节理 流纹岩 熔浆冷却 海拉尔盆地
英文关键词: spherulite, columnar joint, rhyolite, magma cooling, Hailaer Basin
基金项目:宁夏第三批青年科技人才托举工程(编号:TJGC2018024)资助
作者单位E-mail
刘 芳 中国地质大学(北京)地球科学与资源学院, 北京
宁夏回族自治区地质局
宁夏银川 宁夏回族自治区地质调查院宁夏银川 宁夏回族自治区地质矿产勘查院 宁夏银川 
834414859@qq.com 
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中文摘要:
      通过野外观察,结合薄片、铸体薄片等手段研究,发现海拉尔盆地呼伦湖凹陷西界上库力组火山通道相次火山亚相的柱状节理流纹岩和喷溢相上部亚相的球粒流纹岩中发育两种不同结构的球粒,两种球粒均形成于高的过冷却动力学效应下。柱状节理流纹岩中的球粒肉眼不可见,球粒直径小于0.2 mm,球粒中心发育结晶核,组成球粒的纤维体多为隐晶质。条带状球粒流纹岩中的球粒在野外露头上醒目,圆形、椭圆形特征明显,球粒直径在0.5~2 mm之间,均匀分布,结晶核不明显,组成球粒的纤维体为霏细质。本文认为导致这两种球粒结构差异性的主要原因受熔浆过冷度大小的影响,柱状节理流纹岩过冷度较条带状球粒流纹岩大,因此成核速率高,成核密度大,球粒直径小,排列紧密,条带状球粒流纹岩较之相反。同时流纹质熔浆的均质性程度影响了球粒间孔的充填特征。此外研究发现,球粒间孔的发育程度和球粒形态直接相关。柱状节理流纹岩基质中的球粒结构紧密排列,球粒受相互生长制约呈不规则状,由于柱状节理本身由十分致密的球粒构成,储集空间不发育,因此不含油。条带状球粒流纹岩由于球粒排列相对疏松,孔隙大量发育,可能含有丰富的油气,储集空间主要类型为球粒间孔和球粒溶蚀孔。
英文摘要:
      Observations in the field and to thin sections and casting sections reveal two different spherulites textures in columnar joint rhyolite and pyromeride in the Shangkuli Formation, west boundary of the Hulunhu depression, Hailarer Basin. Both of two kinds spherulites were formed by high dynamic effects of supercooling. The spherulites in column joint rhyolite are invisible, with diameter less than 0.2 mm and nucleus in the center. The spherulites in strip-like rhyolite are remarkable in outcrops, with round or ellipse shapes and diameter 0.5~2 mm, distributed homogeneously, with little nucleus of crystallization. These phenomena indicate that nuclear density, rates and the growth conditions of crystallization of these two spherulite textures are different. In addition, the development of inter- spherulite pores is related with spherulite forms. In column joint rhyolite, the spherulites are tightly arranged and irregular due to limited growth, thus with little reservoir space for oil and gas. While the spherulites in strip-like rhyolite are relatively loosely arranged with lots of pores, likely containing much oil and gas in inter-spherulite and solution pores.
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