摘要
钛铀矿由于其特殊的矿物学性质,在自然界中基本均以变生态产出,因此其原始结构数据很难被准确测定。文章通过α粒子径迹蚀刻、扫描电镜背散射图像、能谱分析、元素面扫描等综合手段发现,湘西北地区黑色岩系中的钛铀矿大部分从成矿溶液中直接晶出,自形程度较高,主要呈针状、板条状;少部分以交代金红石、钛铁矿等早先矿物的方式形成,此种方式形成的钛铀矿晶型差,自形程度低,多数情况下还可见被交代矿物的残留晶形;少数钛铀矿以含矿溶液对含铀、钛的氢氧化物或氧化物进行热液改造和重结晶作用的方式形成,此种方式形成的钛铀矿矿物颗粒较为细小,大多呈针状,有时以放射状集合体的形式出现。以上发现不仅能为研究自然条件下的钛铀矿提供较为详实的实物样本,也能为开发利用黑色岩系中铀多金属的采冶工艺提供矿物学方面的依据。统计研究发现鲕粒状磷灰石,平均有机碳含量为21.18%;部分溶蚀磷灰石,平均有机碳含量为11.49%;重结晶磷灰石,大部分不含有机碳。结合黑色岩系矿物学方面的研究认为,海底喷流热水中所携带的矿化元素会通过出溶作用和还原作用在黑色岩系的微孔洞、微裂隙和矿物间隙中沉淀富集,生成钛铀矿、沥青铀矿、辉砷镍矿、方铅矿等不同类型的铀多金属矿物。
Because of its special mineralogical properties,brannerite is basically produced in nature by metamorphosis,so its original structure data is difficult to measure accurately.By the integrated methods ofα-particle track etching,SEM backscatter image,energy spectrum analysis,element mapping and so on,most of the brannerite in the black rock series in northwestern Hunan was found crystallizing directly from the mineralization solution,with a high degree of idiomorphic,mainly in the shape of needles and slats.A small part brannerite was formed by metasomatic rutile,ilmenite and other earlier minerals,the brannerite crystal form formed in this way is poor and the degree of idiomorphic is low,in most cases the residual crystalline form of replaced minerals can be examined.A few brannerite was formed by hydroxides or oxides containing uranium and titanium which hydrothermal transformation and recrystallization by ore-bearing solution,the mineral particles of brannerite formed in this way are small,mostly in the form of needles,sometimes in the form of radial aggregates.The above findings not only provide more detailed physical samples for the study of branneritein natural conditions,but also provide mineralogical basis for the development and utilization of uranium polymetallic mining technology in black rockseries.The statistical research found that the average organic carbon content of oolitic apatite is 21.18%,the average organic carbon content of partially dissolved apatite is 11.49%,and most of the recrystallized apatite does not contain organic carbon.Combining with the mineralogical study of black rock series,it was believed that the mineralized elements carried in the submarine exhalation hot water precipitated and enriched in the micro-voids,micro-cracks and mineral gaps of black rock series through exsolution and reduction,generated different types of uranium polymetallic minerals such as brannerite,pitchblende,gersdorffite and galena.
作者
王健
杨帆
王文全
王振云
李治兴
WANG Jian;YANG Fan;WANG Wenquan;WANG Zhenyun;LI Zhixing(CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology,Beijing Research Institute of Uranium Geology,Beijing 100029,China)
出处
《铀矿地质》
CAS
CSCD
2024年第3期470-479,共10页
Uranium Geology
基金
中国核工业地质局地勘费项目“全国低品位大矿量易开发铀资源远景评价”(编号:地D2346-4)资助。
关键词
钛铀矿
黑色岩系
磷灰石
出溶作用
湘西北
brannerite
black rock series
apatite
exsolution
northwestern Hunan
