Ore Types and Genesis of Weathered Deposits in Mianning-Dechang REE Ore Belt, Western Sichuan Province, Southwestern China
-
摘要: 川西冕宁-德昌REE矿带中的风化型矿石研究相对缺乏.根据近几年的野外地质调查，采用电子探针、X光粉晶衍射、全岩分析等对大陆槽、牦牛坪和木落寨矿床中疑似风化矿的样品进行类型和成因分析.结果表明：大陆槽风化型矿石中大量粘土矿物（达40%）和矿石矿物（达60%）发育，风化程度高；相反，牦牛坪和木落寨疑似风化型矿石中几乎没有粘土矿物，风化程度低.通过对牦牛坪和木落寨疑似风化型矿石进行地球化学特征、矿物组成分析并与围岩、矿脉的组成和产状对比，表明疑似风化型矿石主要是由矿脉和围岩在强烈的构造作用下发生机械风化形成.频繁的角砾构造使大陆槽矿石发生强烈的机械风化作用，并加速了矿石发生一定的水岩反应，促进矿石发生中等强度的化学风化作用.目前整个矿带中未发现明显的生物风化作用.整个稀土矿带的风化型矿石比南岭离子吸附型稀土矿石的风化程度低，形成时间较晚（11 Ma），氟碳铈矿大量保存，还没有形成离子吸附型矿床.Abstract: The study of weathered ores is relatively limited in the Mianning-Dechang REE ore belt, western Sichuan. According to the geological survey in recent years, ore types and genesis of suspected weathered ore from Dalucao, Maoniuping and Muluozhai deposits were studied through EPMA, XRD and whole rock analysis. The results show that a large number of clay minerals (up to 40%) and ore minerals (up to 60%) are developed in the weathered ore of the Dalucao deposit, and the weathering degree is relatively high. On the contrary, suspected weathered ore types almost have not developed clay minerals from Maoniuping and Muluozhai deposits, and the weathering degree is relatively low. Through the geochemical characteristics and mineral composition analysis of the suspected weathered ore in Maoniuping and Muluozhai deposits, combining the compositions and occurrences of the wall rock and veins, it is obvious that the suspected weathed ore has been formed by mainly mechanically weathering from the nearby veins and wall rock under the strong tectonic action. Frequent breccia activities promote the strong mechanically weathering of weathered ores, and accelerate the water-rock reaction in Dalucao deposit. At present, there is no obvious biological weathering in the ore belt. The weathered ores in the belt have lower weathering degree than that of the Nanling ion adsorption type rare earth elements ores, and the age of the formation of the belt is younger (11 Ma) and a large amount of bastnaesite preservation, so it has not formed the ion adsorption type deposit.
-
Key words:
- Mianning-Dechang /
- REE deposit /
- weathered deposit /
- ore type /
- ore genesis /
- geochemistry
-
图 1 川西冕宁-德昌稀土成矿带地质构造简图
Fig. 1. Sketch of Mianning-Dechang REE ore belt, Sichuan Province
图 2 川西冕宁-德昌稀土成矿带各矿床地质简图
图a, b据袁忠信等(1995)；图c据杨光明等(1998)著四川省德昌县大陆槽稀土矿床成矿条件研究.a.牦牛坪矿床；b.郑家梁子矿床；c.大陆槽矿床
Fig. 2. Sketches of deposits in Mianning-Dechang REE ore belt, Sichuan Province
图 3 牦牛坪疑似风化型矿石的野外照片
Fig. 3. Field photos of suspected weathered ore from Maoniuping deposit
图 4 木落寨矿床二叠系地层和岩浆岩
据中国地质科学院矿产综合利用研究所(2008)编四川省冕宁县南河乡阴山村方家堡稀土矿区普查报告
Fig. 4. Schematic stratigraphic and magmatic of the Permian in the Muluozhai deposit
图 5 冕宁-德昌REE矿带风化型矿石的背散射照片
a, b.牦牛坪黑色风化型矿石：a.氟碳铈矿沿裂隙分布，钾长石周围分布着一些Fe-Mn氧化物和矿物碎屑；b.块状及长条状的氟碳铈矿.c, d.牦牛坪黄色风化型矿石：c.氟碳铈矿、Fe-Mn氧化物及其他脉石矿物的分布状态；d.氟碳铈矿的分布状态；e~h.大陆槽风化矿：e.长条状的独居石叠加到钠长石中；f.赤铁矿与氟碳铈矿和伊利石共生，表明矿石发生风化作用.g.针状的氟碳铈矿叠加到萤石碎屑中，构成碎屑支撑结构；h.块状的氟碳钙铈矿叠加到萤石碎屑中，构成碎屑支撑结构.Bsn.氟碳铈矿；Par.氟碳钙铈矿；Mnz.独居石；Kfs.钾长石；Chl.绿泥石；Mt.磁铁矿；Phl.金云母；Qtz.石英；Ab.钠长石；Hem.赤铁矿；Ⅲ.伊利石；Fl.萤石.e~g据Liu et al.(2015c)
Fig. 5. BSE images of weathered ores in Mianning-Dechang REE ore belt
图 6 冕宁-德昌REE矿带疑似风化型矿石和主要赋矿围岩(正长岩)的球粒陨石标准化配分模式图
据Sun and McDonough(1989).a.牦牛坪矿床两种疑似风化型矿石的微量元素蛛网图；b.牦牛坪矿床两种疑似风化型矿石的REE配分曲线；c.木落寨矿床疑似风化型矿石的微量元素蛛网图；d.木落寨矿床疑似风化型矿石的REE配分曲线；e.牦牛坪主要赋矿围岩正长岩的微量元素蛛网图；f.牦牛坪主要赋矿围岩正长岩的REE配分曲线；e, f来自Hou et al.(2006)
Fig. 6. Chondrite-normalized of suspected weathered ore from Mianning-Dechang REE ore belt
-
Bao, Z.W., Zhao, Z.H., 2008.Geochemistry of Mineralization with Exchangeable REY in the Weathering Crusts of Granitic Rocks in South China.Ore Geology Reviews, 33(3-4):519-535. https://doi.org/10.1016/j.oregeorev.2007.03.005 Chi, R.A., Tian, J., Luo, X.P., et al., 2012.The Basic Research on the Weathered Crust Elution-Deposited Rare Earth Ores.Nonferrous Metals Science and Engineering, 3 (4):1-13 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-JXYS201204003.htm Fu, W., Huang, X.R., Yang, M.L., et al., 2014.REE Geochemistry in the Laterite Crusts Derived from Ultramafic Rocks:Comparative Study of Two Laterite Profiles under Different Climate Condition.Earth Science, 39(6):716-732. http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQKX201406007.htm Guo, Z.F., Hertogen, J., Liu, J.Q., et al., 2005.Potassic Magmatism in Western Sichuan and Yunnan Provinces, SE Tibet, China-Petrological and Geochemical Constraints on Petrogenesis.Journal of Petrology, 46(1):33-78. https://doi.org/10.1093/petrology/egh061 Hou, Z.Q., Liu, Y., Tian, S.H., et al., 2015.Formation of Carbonatite-Related Giant Rare-Earth-Element Deposits by the Recycling of Marine Sediments.Scientific Reports, 5:10231. https://doi.org/10.1038/srep10231 Hou, Z.Q., Ma, H.W., Zaw.K., et al., 2003.The Himalayan Yulong Porphyry Copper Belt-Product of Large-Scale Strike-Slip Faulting in Eastern Tibet.Economic Geology, 98(1):125-145. https://doi.org/10.2113/gsecongeo.98.1.125 Hou, Z.Q., Pan, G.T., Wang, A.J., et al., 2006.Metallogenesis in Tibetan Collisional Orogenic Belt:Ⅱ.Mineralization in Late-Collisional Transformation Setting.Mineral Deposits, 25(5):521-543 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-KCDZ200605000.htm Hou, Z.Q., Tian, S.H., Xie, Y.L., et al., 2009.The Himalayan Mianning-Dechang REE Belt Associated with Carbonatite-Alkaline Complexes, Eastern Indo-Asian Collision Zone, SW China.Ore Geology Reviews, 36(1-3):65-89. https://doi.org/10.1016/j.oregeorev.2009.03.001 Hou, Z.Q., Tian, S.H., Yuan, Z.X., et al., 2006.The Himalayan Collision Zone Carbonatites in Western Sichuan, SW China-Petrogenesis, Mantle Source and Tectonic Implication.Earth and Planetary Science Letters, 244(1-2):234-250. https://doi.org/10.1016/j.epsl.2006.01.052 Hu, W.J., Tian, S.H., Wang, S.P., et al., 2012.Sm-Nd Isochron Age of Carbonatite from the Maoniuping REE Deposit, Sichuan Province and Their Geological Implications.Mineral Resources and Geology, 26(3):237-241 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-KCYD201203011.htm Kynicky, J., Smith, M.P., Xu, C., 2012.Diversity of Rare Earth Deposits:The Key Example of China.Elements, 8(5):361-367. https://doi.org/10.2113/gselements.8.5.361 Ling, X.X., Li, Q.L., Liu, Y., et al., 2016.In Situ SIMS Th-Pb Dating of Bastnaesite:Constraint on the Mineralization Time of the Himalayan Mianning-Dechang Rare Earth Element Deposits.Journal of Analytical Atomic Spectrometry, 31(8):1680-1687. https://doi.org/10.1039/c6ja00093b Liu, Y., Chen, C., Shu, X.C., et al., 2017.The Formation Model of the Carbonatite-Syenite Complex REE Deposits in the East of Tibetan Plateau:A Case Study of Dalucao REE Deposit.Acta Petrologica Sinica, 33(7):1978-2000 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-YSXB201707002.htm Liu, Y., Chen, Z.Y., Yang Z.S., et al., 2015a.Mineralogical and Geochemical Studies of Brecciated Ores in the Dalucao REE Deposit, Sichuan Province, Southwestern China.Ore Geology Reviews, 70:613-636. https://doi.org/10.1016/j.oregeorev.2015.03.006 Liu, Y., Hou, Z.Q., Tian, S.H., et al., 2015b.Zircon U-Pb Ages of the Mianning-Dechang Syenites, Sichuan Province, Southwestern China-Constraints on the Giant REE Mineralization Belt and Its Regional Geological Setting.Ore Geology Reviews, 64:554-568. https://doi.org/10.1016/j.oregeorev.2014.03.017 Liu, Y., Zhu, Z.M., Chen, C., et al., 2015c.Geochemical and Mineralogical Characteristics of Weathered Ore in the Dalucao REE Deposit, Mianning-Dechang REE Belt, Western Sichuan Province, Southwestern China.Ore Geology Reviews, 71:437-456. doi: 10.1016/j.oregeorev.2015.06.009 Liu, Y., Hou, Z.Q., 2017.A Synthesis of Mineralization Styles with an Integrated Genetic Model of Carbonatite-Syenite-Hosted REE Deposits in the Cenozoic Mianning-Dechang REE Metallogenic Belt, the Eastern Tibetan Plateau, Southwestern China.Journal of Asian Earth Sciences, 137:35-79. https://doi.org/10.1016/j.jseaes.2017.01.010 Luo, Y.N., Yu, R.L., Hou, L.W., et al., 1998.Longmenshan-Jinpingshan Intracontinental Orogenic Belt.Sichuan Science and Technology Publishing House, Chengdu (in Chinese). Mo, X.X., Zhao, Z.D., Deng, J.F., et al., 2003.Response of Volcanism to the India-Asia Collision.Earth Science Frontiers, 10(3):135-148 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DXQY200303019.htm Sanematsu, K., Watanabe, Y., 2016.Characteristics and Genesis of Ion Adsorption-Type Rare Earth Element Deposits:Reviews in Economic Geology.Society of Economic Geologists, 18:55-79. Sun, S. S., McDonough, W. F., 1989. Chemical and Isotopic Systematics of Oceanic Basalts: Implications for Mantle Composition and Processes. In: Saunders, A. D., Norry, M. J., eds., Magmatism in the Ocean Basins. Geological Society of London Special Publication, 42: 313-345. Wang, D.H., Chen, Y.C., Wang, R.J., et al., 2013a.Discussion on Some Problems Related to Prospecting Breakthrough in Nanling Region.Mineral Deposits, 32(4):854-863 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-KCDZ201304018.htm Wang, D.H., Zhao, Z., Yu, Y., et al., 2013b.Progress, Problems and Research Orientation of Ion-Adsorption Type Rare Earth Resources.Rock and Mineral Analysis, 32 (5):796-802 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-YKCS201305022.htm Wang, D.H., Yang, J.M., Yan, S.H., et al., 2001.A Special Orogenic-Type Rare Earth Element Deposit in Maoniuping, Sichuan, China-Geology and Geochemistry.Resource Geology, 51:177-188. doi: 10.1111/rge.2001.51.issue-3 Wang, D.H., Zhao, Z., Yu, Y., et al., 2017.A Review of the Achievements in the Survey and Study of Ion-Adsorption Type REE in China.Acta Geoscientica Sinica, 38(3):317-325 (in Chinese with English abstract). http://agris.fao.org/agris-search/export!exportTopEndNoteXML.action?agrovocString=Guangxi&onlyFullText=false Wu, C.Y., 1989.Rare Earth Mineraliztion in Weathering Crust-A Nonequilibrium Process.Mineral Deposits, 8(4):85-90 (in Chinese with English abstract). Xie, Y.L., Li, Y.X., Hou, Z.Q., et al., 2015.A Model for Carbonatite Hosted REE Mineralisation-The Mianning-Dechang REE Belt, Western Sichuan Province, China.Ore Geology Reviews, 70:595-612. https://doi.org/10.1016/j.oregeorev.2014.10.027 Yang, Y.H., Wu, F.Y., Li, Y., et al., 2014.In Situ U-Pb Dating of Bastnaesite by LA-ICP-MS.Journal of Analytical Atomic Spectrometry, 29(6):1017-1023. https://doi.org/10.1039/c4ja00001c Yin, A., Harrison, T.M., 2000.Geologic Evolution of the Himalayan-Tibetan Orogen.Annual Review of Earth and Planetary Sciences, 28:211-280. doi: 10.1146/annurev.earth.28.1.211 Yin, A., Harrison, T.M., 2000.Geologic Evolution of the Himalayan-Tibetan Orogen.Annual Review of Earth and Planetary Sciences, 28:211-280. https://doi.org/10.1146/annurev.earth.28.1.211 Yuan, Z.X., Shi, Z.M., Bai, G., et al., 1995.The Maoniuping Rare Earth Ore Deposit, Mianning County, Sichuan Province.Seismological Press, Beijing (in Chinese). Zhang, Y.X., Luo, Y.N., Yang, C.X., 1988.The Panxi Rift.Geological Publishing House, Beijing, 224-270 (in Chinese). Zhao, Z., Wang, D.H., Pan, H., et al., 2017.REE Geochemistry of a Weathering Profile in Guangxi, Southern China, and Genesis of Ion-Adsorption Type REE Deposit.Earth Science, 42(10):1697-1706 (in Chinese with English abstract). Zhong, D.L., Ding, L., Liu, F.T., et al., 2000.Multi-Direction Layer and Frame Structure of Rock Layers in Orogenic Belt and Its Control on Cenozoic Magmatic Activities-An Example from Sanjiang and Its Neighboring Area.Science in China (Series D), 30(Suppl.):1-8 (in Chinese). 池汝安, 田君, 罗仙平, 等, 2012.风化壳淋积型稀土矿的基础研究.有色金属科学与工程, 3(4):1-13. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=jxys201204003&dbname=CJFD&dbcode=CJFQ 付伟, 黄小荣, 杨梦力, 等, 2014.超基性岩红土风化壳中REE地球化学不同气候风化壳剖面的对比.地球科学, 39(6):716-732. http://www.earth-science.net/WebPage/Article.aspx?id=2878 侯增谦, 潘桂棠, 王安建, 等, 2006.青藏高原碰撞造山带:Ⅱ.晚碰撞转换成矿作用.矿床地质, 25(5):521-543. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=kcdz200605000&dbname=CJFD&dbcode=CJFQ 胡文洁, 田世洪, 王素平, 等, 2012.四川牦牛坪稀土矿床碳酸岩Sm-Nd等时线年龄及其地质意义.矿产与地质, 26(3):237-241. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=kcyd201203011&dbname=CJFD&dbcode=CJFQ 刘琰, 陈超, 舒小超, 等, 2017.青藏高原东部碳酸岩-正长岩杂岩体型REE矿床成矿模式-以大陆槽REE矿床为例.岩石学报, 33(7):1978-2000. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=ysxb201707002&dbname=CJFD&dbcode=CJFQ 骆耀南, 俞如龙, 侯立玮, 等, 1998.龙门山-锦屏山陆内造山带.成都:四川科学技术出版社. 莫宣学, 赵志丹, 邓晋福, 等, 2003.印度-亚洲大陆主碰撞过程的火山作用响应.地学前缘, 10(3):135-148. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=dxqy200303019&dbname=CJFD&dbcode=CJFQ 王登红, 陈毓川, 王瑞江, 等, 2013a.对南岭与找矿有关问题的探讨.矿床地质, 32(4):854-863. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=kcdz201304018&dbname=CJFD&dbcode=CJFQ 王登红, 赵芝, 于扬, 等, 2013b.离子吸附型稀土资源研究进展、存在问题及今后研究方向.岩矿测试, 32(5):796-802. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=ykcs201305022&dbname=CJFD&dbcode=CJFQ 王登红, 赵芝, 于扬, 等, 2017.我国离子吸附型稀土矿产科学研究和调查评价新进展.地球学报, 38(3):317-325. doi: 10.3975/cagsb.2017.03.02 吴澄宇, 1989.风化壳稀土成矿作用——一种不平衡过程.矿床地质, 8(4):85-90. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=kcdz198904011&dbname=CJFD&dbcode=CJFQ 袁忠信, 施泽民, 白鸽, 等, 1995.川西冕宁牦牛坪轻稀土矿床.北京:地震出版社. 张云湘, 骆耀南, 杨崇喜, 1988.攀西裂谷.北京:地质出版社, 224-270. 赵芝, 王登红, 潘华, 等, 2017.广西某地花岗岩风化壳中稀土元素特征与iREE矿床成矿机制.地球科学, 42(10):1697-1706. http://www.earth-science.net/WebPage/Article.aspx?id=3667 钟大赉, 丁林, 刘福田, 等, 2000.造山带岩石层多向层架构造及其对新生代岩浆活动约束——以三江及邻区为例.中国科学(地球科学), 30(增刊):1-8. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=jdxk2000s1000&dbname=CJFD&dbcode=CJFQ -
下载:
点击查看大图
图(6)
计量
- 文章访问数: 3978
- HTML全文浏览量: 2074
- PDF下载量: 44
- 被引次数: 0
