Characteristics of fluid inclusions and their geological significance: A case study of the Jiling uranium deposit in Gansu Province
-
摘要:
为确定芨岭铀矿成矿流体的性质，对成矿期碳酸盐脉开展了详细的流体包裹体研究。包裹体岩相学和显微测温结果表明，碳酸盐脉主要发育气相包裹体、液相包裹体和纯液相包裹体；包裹体均一温度为141~295℃（峰值分别为170~180℃、240~250℃），盐度为2.09%~7.69% NaCleqv（峰值5%~6% NaCleqv），属于低-中温、低盐度铀矿床。激光拉曼和群体包裹体成分分析结果显示：成矿流体气相成分以CH4、H2为主，H2S、N2、CO2次之，液相成分富H2O和CH4，成矿流体属于NaCl-H2O±CH4±CO2体系。结合C、O同位素组成，δ13CVPDB值在-1.50‰~-6.33‰之间，δ18OSMOW值为-2.577‰~5.051‰，成矿热液的水源主要为岩浆热液与大气降水混合特征，且以大气降水形成为主。结合成矿流体特征，流体不混溶或沸腾作用导致相分离产生铀沉淀，以及流体脱气（CO2）作用导致铀矿质沉淀、富集，是芨岭铀成矿的主要成因。
Abstract:Detailed study of fluid inclusions in metallogenic period carbonate veins was conducted to reveal the ore-forming fluid features. Petrographic and microthermometric studies of fluid inclusions suggest that the main types of fluid inclusions of the Jiling uranium deposit are gaseous, liquid and pure liquid inclusions. Temperature test shows that the homogenization temperature and salinity of fluid inclusions vary from 141℃ to 295℃ (mostly in the ranges of 170~180℃ and 240~250℃) and 2.09%~7.69% NaCleqv (with the peak values varying in the range of 5%~6%Na Cleqv) respectively. Based on these results, the authors have reached the conclusion that the ore-forming fluids of the Jiling uranium deposit should be of low temperature and salinity. Laser Raman and group fluid inclusions content studies indicate that gas composition of the ore-forming fluids are mainly CH 4 and H2 with some H2S, N2, and CO2. The ore-forming fluids are then defined to be of the NaCl-H2O±CH4±CO2 system. The results show that δ13C values relative to the VPDB scale range from-1.50‰ to-6.33‰, and δ18O values fall between-2.577‰ and 5.051‰. The features of ore-forming fluids show that hydrothermal fluids are characterized by a mixture of magmatic fluids and atmospheric water, dominated by the latter. Further research suggests that the mineralized ∑CO2 mainly came from mantle degassing related to regional deep faults with minor contribution of marine carbonate rocks. It is concluded that uranium deposition in the Jiling area was related to the phase separation.
-
Keywords:
- Jiling uranium deposit /
- fluid inclusion /
- geological significance /
- Gansu Province
-
致谢: 成文过程中得到核工业二〇三研究所权志高研究员、东华理工大学巫建华教授的大力帮助，审稿专家也提出了宝贵的建议，在此一并表示衷心的感谢。
-
![]()
图 1 甘肃省芨岭地区地质图（据参考文献[4]修改）
1—全新统；2—中新统；3—新元古界孩母山岩群；4—古元古界龙首山岩群；5—加里东期花岗岩；6—钠交代型铀矿床；7—断层及运动方向；8—逆断层；Ⅰ—阿拉善地块；Ⅰ1—龙首山断隆带；Ⅱ—祁连地块；Ⅱ1—河西走廊
Figure 1. Geological map of the Jiling area, Gansu Province
![]()
图 2 芨岭铀矿碳酸盐脉流体包裹体均一温度直方图
Figure 2. Histogram showing microthermometric measurements of fluid inclusions in carbonate from the Jiling uranium deposit
![]()
图版Ⅰ
a~c.铀矿石岩心（U含量1255×10-6~1366×10-6）；d~f.铀矿石显微照片，正交偏光。Cal—方解石；Hem—赤铁矿；Chl—绿泥石；Kfs (Ab)—钾长石钠长石化；Pl (Ab)—斜长石钠长石化；Ab—钠长石
图版Ⅰ.
![]()
图 3 芨岭铀矿床主成矿阶段碳酸盐流体包裹体气相和液相激光拉曼图
Figure 3. Raman spectrograms of fluid inclusions in carbonate from the Jiling uranium deposit
![]()
图 4 芨岭铀矿碳酸盐脉流体包裹体盐度直方图
Figure 4. Histogram showing salinity of fluid inclusions in carbonate from the Jiling uranium deposit
![]()
图 5 芨岭铀矿床成矿压力直方图
Figure 5. Histogram showing ore-forming pressures from the Jiling uranium deposit
![]()
图 6 岌岭铀矿床C-O同位素相关图解
（据参考文献[6]修改）
Figure 6. Diagram showing δ18O and δ13C from the Jiling uranium deposit
表 1 芨岭铀矿碳酸盐脉流体包裹体显微测温数据及参数
Table 1 Microthermometric data and estimated parameters of fluid inclusions in carbonate from the Jiling uranium deposit
样号 测试数 均一相态 Ti/℃ Tht/℃ NaCleqv/% p1/MPa h1/km ρ/(g· m-3) ZKJ9-2-6 6 液相 -0.7~-1.8 172.0~187.6 1.2~3.1 7.6~22.8 0.3 ~0.8 0.81~0.91 5 气相 -2.2~-4.1 193.5~200.0 3.6~6.6 27.9~59.1 0.9 ~2.0 0.83~0.92 ZKJ9-2-7 5 液相 -2.5~-3.4 188.5~195.4 4.2~5.6 33.1~47.9 1.1 ~1.6 0.93~0.95 6 气相 -2.0~-2.4 165.2~180.6 3.4~4.0 25.7 ~31.6 0.9 ~1.1 0.85~0.93 ZKJ9-2-8 5 液相 -3.1~-3.5 171.7~173.4 5.1~5.7 43.1~49.5 1.4 ~1.6 0.87~0.95 6 气相 -1.7~-2.6 141.1~171.3 2.8~4.4 20.7 ~35.4 0.7~1.2 0.92~0.93 ZKJ9-2-9 4 液相 -4.0~-4.3 182.4~185.5 6.4~6.8 56.6~61.5 1.9~2.0 0.83~0.88 5 气相 -2.6~-3.4 168.8~174.2 4.3~5.6 34.6 ~47.9 1.2 ~1.6 0.93~0.97 ZKJ9-2-10 5 液相 -1.2~-1.7 195.4~214.0 2.1~2.9 14.6 ~21.4 0.5~0.7 0.92~0.95 5 气相 -3.2~-3.7 180.5~192.1 5.2~5.9 43.9~51.8 1.5 ~1.7 0.86~0.89 ZKJ9-2-11 4 液相 -2.1~-2.7 279.8~287.8 3.5~4.5 27.2 ~36.9 0.9 ~1.2 0.93~0.97 5 气相 -4.0~-4.6 245.0~246.8 6.4~7.3 57.4 ~67.9 1.9 ~2.3 0.85~0.93 ZKJ9-2-12 4 液相 -1.8~-2.0 291.2~294.5 3.0~3.3 22.1 ~25.0 0.7 ~0.8 0.92~1.07 4 气相 -4.6~-5.0 205.1~226.6 7.2~7.7 67.1~72.7 2.2~2.4 0.97~1.03 ZKJ9-2-13 4 液相 -1.7~-2.5 245.3~256.6 2.8~4.2 20.7 ~33.1 0.7~1.1 0.92~0.93 5 气相 -3.7~-4.5 217.3~223.4 6.0~7.0 52.6 ~64.7 1.8~2.2 0.94~0.97 注：Ti为冰点下降温度；Tht为均一温度；NaCl为盐度；p1为成矿压力；h1为成矿深度；ρ为密度 
下载: 导出CSV
-
柴保民.龙首山花岗岩与铀矿化的关系[J].地质科研, 1987, 1/2:39-48. http://www.cnki.com.cn/Article/CJFDTOTAL-DZKT201506008.htm 胡能高.甘肃东大山地区龙首山岩群地球化学特征及其构造环境[J].长安大学学报, 2003, 25(4):32-39. http://www.cnki.com.cn/Article/CJFDTOTAL-XAGX200304008.htm 孙圭, 赵致和.中国北西部铀矿地质志 (下)[M].西安:核工业西北地质局, 1988:375-380. 陈云杰, 赵如意, 李涛.甘肃省铀边寺铀矿床铀化特征及成矿条件分析[J].甘肃地质, 2011, 20(3):46-50. http://www.cnki.com.cn/Article/CJFDTotal-GSDZ201103007.htm 陈云杰, 赵如意, 武彬.甘肃龙首山地区芨岭铀矿床隐爆角砾岩发现及成因探讨[J].地质与勘探, 2012, 48(6):1-8. http://www.cnki.com.cn/Article/CJFDTOTAL-DZKT201206007.htm 陈云杰, 傅成铭, 王刚, 等.花岗岩型热液铀矿床C、O同位素研究——以甘肃省龙首山芨岭矿区为例[J].地质与勘探, 2011, 50(4):641-648. http://www.cnki.com.cn/Article/CJFDTOTAL-DZKT201404004.htm 赵如意, 陈云杰, 武彬, 等.甘肃龙首山芨岭地区钠交代型铀矿成矿模式研究[J].地质与勘探, 2013, 49(1):67-74. http://www.cnki.com.cn/Article/CJFDTOTAL-DZKT201301009.htm 张朋, 杨宏智, 孙景贵, 等.黑龙江省马连金矿床流体包裹体特征及其地质意义[J].中国地质, 2015, 42(1):265-274. http://www.cnki.com.cn/Article/CJFDTOTAL-DIZI201501020.htm 周慧, 郗爱华, 熊益学, 等.流体包裹体的研究进展[J].矿物学报, 2013, 33(1):92-100. http://www.cnki.com.cn/Article/CJFDTOTAL-KYDH201401001.htm 卢焕章, 范宏瑞, 倪培, 等.流体包裹体[M].北京:科学技术出版社, 2004:1-487. 刘斌, 沈昆.流体包裹体热力学基础[M].北京:地质出版社, 1999:1-290. 孙晓明, 王敏, 薛婷, 等.流体包裹体中微量气体组成及其成矿示踪体系研究新进展[J].地学前缘, 2004, 11(2):471-478. http://www.cnki.com.cn/Article/CJFDTOTAL-DXQY200402024.htm 陈勇, 周瑶琪, 查明, 等. CH4-H2O体系流体包裹体拉曼光谱定量分析和计算方法[J].地质论评, 2007, 53(6):814-823. http://www.cnki.com.cn/Article/CJFDTotal-DZLP200706018.htm 王蕾.流体包裹体分析法在铀矿床研究中的应用——以相山铀矿田邹家山、沙洲矿床为例[J].铀矿地质, 2011, 27(6):331-336. http://www.cnki.com.cn/Article/CJFDTOTAL-YKDZ201106003.htm 苟学明, 李万华, 姬海军, 等.巴丹吉林盆地沙枣泉铀矿床成矿特征与成矿模式[J].铀矿地质, 2014, 30(1):7-13. http://www.cnki.com.cn/Article/CJFDTOTAL-YKDZ201401002.htm Vapnik Y, Moroz I. Compositions and formation conditions of flu-id inclusions in emerald from the Maria deposit[J]. Mineralogical Magazine, 2002, 66(1):201-213. doi: 10.1180/0026461026610023
Bruke E A J. Raman micro-spectrometry of fluid inclusion[J]. Lith-os, 2001, 55(1/4):139-158. http://www.sciencedirect.com/science/article/pii/0375674291900653
卢焕章.地幔岩中流体包裹体研究[J].岩石学报, 2008, 24(9):1954-1960 http://www.cnki.com.cn/Article/CJFDTOTAL-YSXB200809002.htm Potter R W Ⅱ, Clynne M A, Brown D L. Freezing pointdepres-sion of aqueous sodium chloride solutions[J]. Econ. Geol., 1978, 73:284-285. doi: 10.2113/gsecongeo.73.2.284
Hall D L, Sterner S M, Bodnar R J. Freeing point depression of Na-Cl-KCl-H2O solutions[J]. Econ. Geol., 1988, 83:197-202. doi: 10.2113/gsecongeo.83.1.197
刘斌.中高盐度NaCl-H2O包裹体的密度式和等容式及其应用[J].地质论评, 2001, 47(6):617-622. http://www.cnki.com.cn/Article/CJFDTotal-DZLP200106014.htm 邵洁涟, 梅建明.浙江火山岩区金矿床的矿物包裹体标型特征研究及其成因找矿意义[J].矿物岩石, 1986, 6(3):103-111. http://www.cnki.com.cn/Article/CJFDTOTAL-KWYS198603012.htm 邵洁连.金矿找矿矿物学[M].武汉:中国地质大学出版社, 1999:1-150. 张德会, 周圣华, 万天丰, 等.矿床形成深度与深部成矿预测[J].地质通报, 2007, 26(12):1509-1518. doi: 10.3969/j.issn.1671-2552.2007.12.002
计量
- 文章访问数: 2257
- HTML全文浏览量: 240
- PDF下载量: 215
