天山北缘硫磺沟地区侏罗系烧变岩特征及其地质意义  

Characteristics and geological significance of burnt rocks in Liuhuanggou area,along northern margin of Tianshan Mountains in Xinjiang,China

作　　者：董燕 陈彬 王美玲 于茜 时志强[1] Dong Yan;Chen Bin;Wang Meiling;Yu Qian;Shi Zhiqiang(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;College of Geography and Environment,Liaocheng University,Liaocheng 252000,China)

机构地区：[1]成都理工大学沉积地质研究院,成都610059 [2]聊城大学地理与环境学院,山东聊城252000

出　　处：《成都理工大学学报（自然科学版）》2024年第5期854-866,879,共14页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家自然科学基金项目(42201006)。

摘　　要：烧变岩在中国北方分布广泛,可能与砂岩型铀矿有成因联系,但一直以来研究者对其关注较少。新疆硫磺沟地区侏罗系煤系地层中广泛发育烧变岩。通过野外观察和岩石显微薄片、扫描电镜及电子探针分析,描述了硫磺沟地区烧变岩的颜色、结构构造及矿物学特征,认为高温变质程度不同的烧变岩在颜色上有差异,以鲜艳的红色(如砖红、赭红、紫红色)、黑色、钢灰色为主,烧变岩的结构构造主要有瓷化构造、渣状构造、角砾状构造等。电子探针测试结果表明,西山白土窑剖面烧变岩的主要化学成分为SiO_(2),其质量分数介于35.43%~99.83%之间,平均为75.73%,次要化学成分有Al_(2)O_(3),CaO,Na_(2)O,K_(2)O,FeO,MgO,MnO,BaO等,推测其是与原岩成分有关的铝硅酸盐矿物。微观测试显示,原岩结构、构造遭受不同程度破坏。经历不同程度高温变质作用部分矿物发生变质,形成堇青石、铁堇青石、莫来石等新矿物,且矿物形态发生不同程度的改变,如出现冷凝边、石英塑性流变、蠕虫状构造、压缩拉伸构造等,矿物充填(微)裂缝形成方解石脉或铁质脉。硫磺沟地区烧变岩形成年龄与区域构造隆升时代具耦合关系。在研究区,烧变岩附近常有铀矿点发育。研究认为,表生热液型砂岩铀矿成矿模式适合于硫磺沟地区铀矿富集解释。Burnt rocks(combustion metamorphic rocks)are widely distributed in northern China,and may be associated with the genesis of sandstone-type uranium deposits.However,few studies have considered the microscopic mineralogical characteristics of burnt rocks,and their geological significance has often been ignored in the relevant research.Highly developed burnt rocks are widely available in the Jurassic coal seam strata in the Liuhuanggou area of Xinjiang,China.This study investigates the color,structure,petrology,and mineralogy of burnt rocks in the region by using field observations and analyses of thin petrographic sections of samples based on scanning electron microscopy and electronic probes.We found that the degree of high-temperature metamorphosis of different kinds of burnt rocks led to them having different colors,ranging from bright red(such as brick red,red ochre,and purple-red)to black and steel gray.The burnt rock predominantly had porcelain,slag,and brecate structures.The results of microscopic examinations showed that the structure of the original rock had been damaged to varying degrees.We analyzed samples collected from Xishan Baituyao in the wild by using an electronic probe.The results showed that SiO_(2)was the main component of the burnt rock,with content in the range of 35.43%~99.83%,with an average of 75.73%.The secondary ingredients included Al_(2)O_(3),CaO,Na_(2)O,K_(2)O,FeO,MgO,MnO,and BaO,and were presumed to be aluminosilicate minerals related to the composition of the original rock.The original rocks had undergone different degrees of high-temperature metamorphism such that part of minerals in them had recombined to produce new types of minerals,including cordierite,iron iolite,mullite,and mica.The morphology of the minerals had also changed by varying degrees,and included condensation edge,rheology of quartz plastic,and a worm-like structure.The pyrothermal sandstone mode of mineralization of uranium ore may be suitable for its enrichment in the Liuhuanggou area,and needs to be researcher

关 键 词：准噶尔盆地 烧变岩 砂岩型铀矿 天山造山带 硫磺沟 

分 类 号：P534[天文地球—古生物学与地层学] P575[天文地球—地质学]