Petrologic and Geochemical Characteristics of Carbonatites in Huayangchuan U-Nb-Pb Deposit, Shaanxi Province

Abstract

Abstract:

The Huayangchuan U-Nb-Pb deposit is a unique metallogenic type in the Xiaoqinling mineralization belt. The broken belt of carbonatite vein is important ore-forming space. The minerals in unmineralized carbonatites are mainly calcite, and there are few other minerals. Uranium mineralized carbonatites include a variety of minerals, major minerals of which are calcite; and minor minerals of which are amphibole, biotite,sphene,allanite,batafite,barite,apatite,quartz,magnetite,alkali feldspar. Carbonatites are characterized by high REE contents, whose δ¹³C_V-PDB and δ¹⁸O_V-SMOWvalues show the typical characteristics of igneous carbonatite. Based on the diagrams showing ⁸⁷Sr/⁸⁶Sr vs. ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb vs. ²⁰⁶Pb/²⁰⁴Pb and ¹⁴³Nd/¹⁴⁴Nd vs. ⁸⁷Sr/⁸⁶Sr of carbonatite veins, the authors consider that these carbonatite veins are crystal-fractionational products of alkaline silicate-carbonate melt-solution originated from the EMI.

Key words: carbonate vein, petrology, REE, isotopic geochemistry, Huayangchuan U-Nb-Pb deposit, Shaanxi Province

CLC Number:

P618
P588

HUI Xiaochao, CAI Yuqi, HE Sheng, FENG Zhangsheng. Petrologic and Geochemical Characteristics of Carbonatites in Huayangchuan U-Nb-Pb Deposit, Shaanxi Province[J]. Geoscience, 2017, 31(02): 246-257.

Figures/Tables 20

References 30

[1]	MENG Q R, ZHANG G W. Geologic framework and tectonic evolution of the Qinling orogen,central China[J]. Tectonophysics, 2000, 323(3/4):183-196. DOI URL
[2]	赵振华, 涂光炽. 中国超大型矿床(Ⅱ)[M]. 北京: 科学出版社, 2003:523-542.
[3]	张国伟, 张本仁, 袁学诚, 等. 秦岭造山带与大陆动力学[M]. 北京: 科学出版社, 2001:1-729.
[4]	张国伟, 孟庆任, 于在平, 等. 秦岭造山带的造山过程及其动力学特征[J]. 中国科学(D辑), 1996, 26(3):193-200.
[5]	张正伟, 朱炳泉, 常向阳. 东秦岭钼矿带成岩成矿背景及时空统一性[J]. 高校地质学报, 2001, 7(3):307-315.
[6]	李永峰, 毛景文, 胡华斌, 等. 东秦岭钼矿类型、特征、成矿时代及其地球动力学背景[J]. 矿床地质, 2005, 24(3):293-294.
[7]	WOLLEY A R, KEMPE D R C. Carbonatites: Nomenclature, average chemical composition[M]//BELL K. Carbonatites: Genesis and Evolution[J]. London: Unwin Hyman, 1989:1-14.
[8]	CULLER R I, GRAF J I. Rare earth elements in igneous rocks of the continental crust: Predominantly basic and ultra-basic rocks[M]//HENDERSON P. Developments in Geochemistry. Vol.2: Rare Earth Geochemistry. Amsterdam: Elsevier, 1984:237-274.
[9]	JONES J H, WALER D, PICKET D A, et al. Experimental investigations of the partitioning of Nb, Mo, Ba, Ce, Pb, Ra, Th, Pa and U between immiscible carbonate and silicate liquids[J]. Geochimica et Cosmochimica Acta, 1995, 59:1307-1320. DOI URL
[10]	VEKSLER I V, PETIBON C, JENNER G A. Trace element partitioning in immiscibility and silicate liquid: An initial experimental study using a centrifuge autoclave[J]. Journal of Petrology, 1988, 39:2095-2104. DOI URL
[11]	MARAVIC H V, MORTEANI G. Petrology and geochemistry of the carbonatite and syenite complex of Lueshe (N. F. Zaire)[J]. Lithos, 1980, 3(2):159-168.
[12]	MCDONOUGH W F, SUN S S. The composition of the Earth[J]. Chemical Geology, 1995, 120:223-253. DOI URL
[13]	KELLER J, HOEFS J. Stable isotope characteristics of recent natrocarbonatites from Oldoinyo Lengai[M]//BELL K, KELLER J. Carbonatites Volcanism: Oldoinyo Lengai and Petro Genesis of Natrocarbonatites(LAVCEI Proceeding in Volcanology) Berlin: Springer-Verlag, 1995:113-123.
[14]	DEMENY A, AHIJADO A, CASILLAS R L. Crustal contamination and fluid/rock interaction in the carbonatites of Fuerteventura Canary Islands, Spain: A C, O, H isotope study[J]. Lithos, 1998, 44:101-115. DOI URL
[15]	RAY J S, RAMESH R, PANDE K, et al. Isotope and rare earth element chemistry of carbonatite alkaline complexes of Deccan volcanic province: implications to magmatic and alteration processes[J]. Journal of Asian Earth Sciences, 2000, 18:177-194. DOI URL
[16]	POWELL J L, MURLET P M, FAIRBAIRN H W. The Strontium Isotopic Composition and Origin of Carbonatites[M]. Massachusetts: Institute of Technology, 1966: 365-376.
[17]	侯增谦, 田世洪, 谢玉玲, 等. 川西冕宁德昌喜马拉雅期稀土元素成矿带:矿床地质特征与区域成矿模型[J]. 矿床地质, 2008, 27(2):145-176.
[18]	SIMONETTI A, BELL K, VILADKAR S G. Isotopic data from the Amba Dongar carbonatite complex, west central India: evidence for an enriched mantle source[J]. Chemical Geology, 1995, 122: 185-198. DOI URL
[19]	TILTON G R, BRYCE J C, MATEEN A. Pb-Sr-Nd isotope data from 30 and 300 Ma collision zone carbonatites in Northwest Pakistan[J]. Journal of Petrology, 1998, 39(11/12): 1865-1874. DOI URL
[20]	WHITE W M. Isotope Geochemistry[M]. New Jersey: Wiley-Blackwell, 2003: 117-120.
[21]	ZINDLER A, HART S R. Chemical geodynamics[J]. Annual Review of Earth & Planetary Sciences, 1986, 14:493-571.
[22]	杨富全, 吴海, 刘晓文, 等. 冀北甲山正长岩的矿物学、地球化学及Sr-Nd同位素特征[J]. 现代地质, 2005, 19(4): 528-530.
[23]	陈岳龙, 王忠, 罗照华, 等. 康定杂岩Rb-Sr、Sm-Nd同位素系统及其意义[J]. 现代地质, 2008, 22(5): 709-711.
[24]	BELL K, TILTON G R. Nd, Pb and Sr isotopic compositions of East African Carbonatites: evidence for mantle mixing and plume inhomogeneity[J]. Journal of Petrology, 2001, 42 (10):1927-1945. DOI URL
[25]	段士刚, 薛春纪, 冯启伟, 等. 豫西南栾川地区铅锌矿床碳、氧同位素地球化学[J]. 现代地质, 2010, 24(4): 772-774.
[26]	彭义伟, 顾雪祥, 王新利, 等. 新疆伊宁县塔北铅锌矿床地质特征和S、Pb、C、O同位素组成[J]. 现代地质, 2014, 28(4): 682-684.
[27]	HART S R, HAURI E H, OSCHMANN L A, et al. Mantle plumes and entrainment: isotopic evidence[J]. Science, 1992, 256:517-520. PMID
[28]	徐夕生, 邱检生. 火成岩岩石学[M]. 北京: 科学出版社, 2010: 256-257.
[29]	黄典豪, 侯增谦, 杨志明, 等. 东秦岭钼矿带内碳酸岩脉型钼(铅)矿床地质地球化学特征、成矿机制及成矿构造背景[J]. 地质学报, 2009, 83(12):1978-1979.
[30]	XU Cheng, CAMPBELL I H, ALLEN C M, et al. Flat rare earth element patterns as an indicator of cumulate processes in the Lesser Qinling carbonatites, China[J]. Lithos, 2007, 95: 267-278. DOI URL

矿物种类	方解石	黑云母	角闪石	碱性长石	石英	磷灰石	铌钛铀矿	磁铁矿	独居石	重晶石	榍石	褐帘石	其他矿物
矿化碳酸岩	55.19	15.52	5.78	6.69	0.28	0.28	0.79	0.28	0.55	3.50	0.90	0.24	10.00
矿化碳酸岩	62.34	15.97	6.58	0	0.50	0.18	0.37	0.30	0.27	3.16	0.23	0.14	9.96
未矿化碳酸岩	90.19	0.15	0.07	0	0	0.01	0.09	0	0.13	0.02	0	0.04	9.30

矿物种类	方解石	黑云母	角闪石	碱性长石	石英	磷灰石	铌钛铀矿	磁铁矿	独居石	重晶石	榍石	褐帘石	其他矿物
矿化碳酸岩	55.19	15.52	5.78	6.69	0.28	0.28	0.79	0.28	0.55	3.50	0.90	0.24	10.00
矿化碳酸岩	62.34	15.97	6.58	0	0.50	0.18	0.37	0.30	0.27	3.16	0.23	0.14	9.96
未矿化碳酸岩	90.19	0.15	0.07	0	0	0.01	0.09	0	0.13	0.02	0	0.04	9.30

矿物	Fe₂O₃	MgO	CaO	MnO	BaO	SrO	CO₂	H₂O	总量
方解石	0.77	0.47	51.76	1.52	0.22	1.02	42.48	0.08	98.32
方解石	0.62	0.24	52.61	1.23	0.21	1.06	42.71	0.30	98.98
方解石	0.39	0.15	56.05	1.63	0.13	1.01	41.11	0.1	100.57
方解石	0.45	0.33	54.44	0.59	0.22	1.11	42.65	0.07	99.43
平均值	0.56	0.30	53.72	1.24	0.20	1.05	42.24	0.14	99.43

矿物	Fe₂O₃	MgO	CaO	MnO	BaO	SrO	CO₂	H₂O	总量
方解石	0.77	0.47	51.76	1.52	0.22	1.02	42.48	0.08	98.32
方解石	0.62	0.24	52.61	1.23	0.21	1.06	42.71	0.30	98.98
方解石	0.39	0.15	56.05	1.63	0.13	1.01	41.11	0.1	100.57
方解石	0.45	0.33	54.44	0.59	0.22	1.11	42.65	0.07	99.43
平均值	0.56	0.30	53.72	1.24	0.20	1.05	42.24	0.14	99.43

矿物	Na₂O	F	K₂O	P₂O₅	MgO	SiO₂	CaO	TiO₂	Al₂O₃	FeO	MnO	总量
金云母	0.08	3.38	10.18	0.04	18.54	40.22	0.04	0.80	11.51	13.44	0.62	98.85
金云母	0.11	3.38	9.93	-	17.24	40.68	0.01	0.44	10.63	14.96	0.65	98.03
金云母	0.05	3.76	10.26	0.05	19.38	41.08	0.03	0.51	10.94	12.28	0.84	99.18
金云母	0.04	3.05	10.18	-	19.22	41.29	0.07	0.41	11.19	12.75	0.92	99.12
金云母	0.08	4.48	10.79	0.03	23.41	42.74	-	0.43	10.55	7.13	0.49	100.13
平均值	0.07	3.61	10.27	0.04	19.56	41.20	0.04	0.52	10.96	12.11	0.70	99.062