Characteristic and essence of rubefication in wall rock alteration of Anjiayingzi gold deposit in Harqin banner, Inner Mongolia.
-
摘要: 安家营子金矿普遍出现红化蚀变，过去一直被认为是钾长石化，并将其看做一种找矿标志，但是效果甚微。经野外地质及室内镜下观察结合电子探针、扫描电镜和主量元素分析确定红化并非钾长石化，而是由绢云母、钠长石、绿帘石和铁的氧化物以及少量钾长石的矿物组合分布在斜长石内部造成的。其过程可能是早期含Na流体通过斜长石内部的显微孔隙，交代形成钠长石，释放出Al和Ca，然后结合流体中的其他成分形成绢云母和绿帘石。随着绢云母的大量生成，ａK+/ａH+变大，再生成钾长石，便形成了钠长石、绢云母、绿帘石和钾长石的组合。而变红的直接原因是由于在钠长石化过程，花岗岩中斜长石或云母中的铁被释放出来，或者流体中带来的Fe，以氧化物的形式充填在显微孔隙中，形成了肉眼所见到的红色。在蚀变较弱的区域，红化蚀变只出现在核部，边部几乎没有蚀变，形成明显的净边结构。这是由于斜长石的核部存在大量的显微孔隙造成的。斜长石在形成过程中核部结晶速率非常快，所以容易捕获周围的熔体或流体形成显微孔隙，而边部生长速度相对较慢，几乎没有孔隙出现，这些孔隙的分布控制了后来的红化蚀变的分布。所以，红化蚀变并非简单的钾长石化，而是斜长石和流体发生的一系列生成钠长石、绢云母、绿帘石和钾长石的相对复杂的蚀变。而这种蚀变在花岗岩地区分布较为普遍，并不一定与成矿作用有关，且其分布范围有限，同流体的物质交换较少，对找矿和成矿作用的意义有限。Abstract: The widespread rubefication in the wall rock alteration of the Anjiayingzi gold deposit was considered to be potassic alteration. Rubefication is a not effective clue for prespecting. However, through geologic studies in the field and microscopic morphology and optics as well as EPMA, SEM, major elements in laboratory, it is found that rubefication is mainly caused by a assembly of sericite, albite, epidote, Fe-oxide and bits of potassium feldspar presenting in plagioclase, not separate potassic alteration. The early Na-bearing fluid through microscopic pores reacted with plagioclase to form albite, releasing Al and Ca, and then combined other component in fluid to form sericite and epidote. As the reaction proceeded, a lot of sericite appear, which leds to increase ａK+/ａH+, then form K-feldspar to constitute the assembly of albite, sericite, epidote and K-feldspar. During this process, iron in plagioclase or mica is released, then precipitate in the pores of plagioclase in the form of oxides, which turned the granite to red. In the weak altered zone, rubefication only appears in the core of plagioclase, which forms pure rim. This is controlled by the distribution of microscopic pores. During crystallization of plagioclase, the speed of formation the core is too fast, so it is able to capture the melt or fluid to form microscopic pores, conversely, the growth rate of the rim is relatively slow, almost no pore appears. These pores directly control the distribution of alteration. Since microscopic pores are distributed in core of plagioclase, so the rubefication is located in the core, and the rim keeps fresh. Based on the results of analyzing, the rubefication is not a solo potash feldspathization. The essence of rubefication was a complex action between plagioclase and fluid. The distribution of this alteration is very common in granite, and not necessarily related to the mineralization. Its distribution is limited, with less material exchange with fluid, so makes little sense to prospecting and mineralization.
-
Key words:
- Rubefication /
- Microscopic pore /
- Pure rim /
- Anjiayingzi /
- Chifeng-Chaoyang gold belt
-
-
[1] Chardon ES, Livens FR and Vaughan DJ. 2006. Reactions of feldspar surfaces with aqueous solutions. Earth-Science Reviews, 78(1-2): 1-26
[2] Chen GY, Sun DS and Shao W. 1997. Essence of reddenization in wall alteration of Jiaodong gold deposits and its genetic and prospecting significance. In: The Editorial Team of Selected Works of Chen Guangyuan. Selected Works of Chen Guangyuan 2010. Beijing: Geological Publishing House, 263-270 (in Chinese)
[3] Chen WJ and Liu HT. 2006. Major types and geological features of gold mineralization occurred in the Chifeng-Chaoyang gold concentration region. Gold Science and Technology, 14(5): 1-7 (in Chinese with English abstract)
[4] Chen XD, Ye HS and Wang H. 2012. Alteration characteristic of K-feldspar in Leimengou porphyry Mo deposit in western Henan Province: An its insight into metallogenetic process. Geoscience, 26(3): 478-488 (in Chinese with English abstract)
[5] Chen YJ, Ni P, Fan HR, Pirajno F, Lai Y, Su WC and Zhang H. 2007. Diagnostic fluid inclusions of different types hydrothermal gold deposits. Acta Petrologica Sinica, 23(9): 2085-2108 (in Chinese with English abstract)
[6] David F, Walker FDL, Lee MR and Parsons I. 1995. Micropores and micropermeable texture in alkali feldspars-geochemical and geophysical implications. Mineralogical Magazine, 59(396): 505-534
[7] Engvik AK, Putnis A, Gerald JDF and Austrheim H. 2008. Albitization of granitic rocks: The mechanism of replacement of oligoclase by albite. Canadian Mineralogist, 46: 1401-1415
[8] Farquhar ML, Wogelius RA and Tang CC. 1999. In situ synchrotron X-ray reflectivity study of the oligoclase feldspar mineral-fluid interface. Geochimica et Cosmochimica Acta, 63(10): 1587-1594
[9] Grant JA. 1986. The isocon diagram: A simple solution to Gresens' equation for metasomatic alteration. Economic Geology, 81(8): 1976-1982
[10] Grant JA. 2005. Isocon analysis: A brief review of the method and applications. Physics and Chemistry of the Earth, 30(17-18): 997-1004
[11] Groves DI, Goldfarb RJ, Gebre-Mariam M, Hagemann SG and Robert F. 1998. Orogenic gold deposits: A proposed classification in the context of their crustal distribution and relationship to other gold deposit types. Ore Geology Reviews, 13(1-5): 7-27
[12] Hovelmann J, Putnis A, Geisler T, Schmidt BC and Golla-Schindler U. 2010. The replacement of plagioclase feldspars by albite: Observations from hydrothermal experiments. Contributions to Mineralogy and Petrology, 159(1): 43-59
[13] Hu SX, Ye Y and Fang CQ. 2004. Petrology of the Metasomatically Altered Rocks and Its Signigicance in Prospecting. Beijing: Geological Publishing House, 1-264 (in Chinese)
[14] Jia YF, Kerrich R and Goldfarb R. 2003. Metamorphic origin of ore-forming fluids for orogenic gold-bearing quartz vein systems in the North American Cordillera: Constraints from a reconnaissance study of delta N-15, delta D, and delta O-18. Economic Geology and the Bulletin of the Society of Economic Geologists, 98(1): 109-123
[15] Li XC, Fan HR, Santosh M, Hu FF, Yang KF and Lan TG. 2013. Hydrothermal alteration associated with Mesozoic granite-hosted gold mineralization at the Sanshandao deposit, Jiaodong gold province, China. Ore Geology Reviews, 53: 403-421
[16] Li YG, Zhai MG, Miao LC, Zhu JW and Xue LW. 2003a. Relationship between intrusive rocks and gold mineralization of the Anjiayingzi gold deposit, Inner Mongolia and its implications for geodynamics. Acta Petrologica Sinica, 19(4): 808-816 (in Chinese with English abstract)
[17] Li YG, Zhai MG, Yang JH, Miao LC and Guan H. 2003b. Gold mineralization age of the Anjiayingzi gold deposit in Chifeng County, inner Monolia: Implications for Mesozoic metallogenic explosion in North China. Science in China (Ser. D), 33(10): 960-966 (in Chinese)
[18] Li YG, Zhai MG, Miao LC, Xue LW, Zhu JW and Guan H. 2004. Ore-forming fluids of the Anjiayingzi gold deposit in Chifeng region, Inner Mongolia. Acta Petrologica Sinica, 20(4): 961-968 (in Chinese with English abstract)
[19] Miao LC, Fan WM, Zhai MG, Qiu YM, McNaughton NJ and Groves DI. 2003. Zircon SHRIMP U-Pb geochronology of the granitoid intrusions from Jinchanggouliang-Erdaogou gold orefield and its significance. Acta Petrologica Sinica, 19(1): 71-80 (in Chinese with English abstract)
[20] Montgomery CW and Brace WF. 1975. Micropores in plagioclase. Contributions to Mineralogy and Petrology, 52(1): 17-28
[21] Nie FJ, Jiang SH and Liu Y. 2004. Intrusion-related gold deposits of North China craton, People's Republic of China. Resource Geology, 54(3): 299-324
[22] Orville PM. 1963. Alkali ion exchange between vapor and feldspar phases. American Journal of Science, 261(3): 201-237
[23] Parsons I. 1978. Feldspars and fluids in cooling plutons. Mineralogical Magazine, 42(321): 1-17
[24] Parsons I and Lee MR. 2009. Mutual replacement reactions in alkali feldspars I: Microtextures and mechanisms. Contributions to Mineralogy and Petrology, 157(5): 641-661
[25] Pearce TH and Kolisnik AM. 1990. Observations of plagioclase zoning using interference imaging. Earth-Science Reviews, 29(1-4): 9-26
[26] Phillips GN and Powell R. 2009. Formation of gold deposits: Review and evaluation of the continuum model. Earth-Science Reviews, 94(1-4): 1-21
[27] Pluemper O and Putnis A. 2009. The complex hydrothermal history of granitic rocks: Multiple feldspar replacement reactions under subsolidus conditions. Journal of Petrology, 50(5): 967-987
[28] Putnis A, Hinrichs R, Putnis CV, Golla-Schindler U and Collins LG. 2007. Hematite in porous red-clouded feldspars: Evidence of large-scale crustal fluid-rock interaction. Lithos, 95(1-2): 10-18
[29] Putnis A. 2009. Mineral replacement reactions. Reviews in Mineralogy and Geochemistry, 70(1): 87-124
[30] Qiu YM, Groves DI, McNaughton NJ, Wang LG and Zhou TH. 2002. Nature, age, and tectonic setting of granitoid-hosted, orogenic gold deposits of the Jiaodong Peninsula, eastern North China Craton, China. Mineralium Deposita, 37(3-4): 283-305
[31] Que M and Allen AR. 1996. Sericitization of plagioclase in the Rosses Granite Complex, Co Donegal, Ireland. Mineralogical Magazine, 60(403): 927-936
[32] Ramseyer K, Boles JR and Lichtner PC. 1992. Mechanism of plagioclase albitization. Journal of Sedimentary Petrology, 62(3): 349-356
[33] Seyama H, Kinoshita K and Soma M. 2002. Surface alteration of plagioclase during acid dissolution. Surface and Interface Analysis, 34(1): 289-292
[34] Sun SK, Liu HT and Chu SX. 2012. Origin of the Paishanlou monzogranite in Liaoning Province and its genetic connection with gold mineralization. Acta Petrologica Sinica, 28(2): 607-618 (in Chinese with English abstract)
[35] Sun ZM, Yang XF, Han JB, Jiang X and Zhu B. 2010. Characteristics of ore control fractures in Goldentoad Mountain gold deposit, Harqin Banner, Inner Mongolia. Contributions to Geology and Mineral Resources Research, 25(4): 347-350 (in Chinese with English abstract)
[36] Trumbull RB, Liu H, Lehrberger G, Satir M, Wimbauer T and Morteani G. 1996. Granitoid-hosted gold deposits in the Anjiayingzi District of Inner Mongolia, People's Republic of China. Economic Geology, 91(5): 875-895
[37] Wang YW, Xie XC, Liu XL, Dong WC and LÜ XD. 1997. The type and geological-geochemical features of gold deposits in Anjiayingzi gold minerogenetic field. Gold, 18(11): 3-9 (in Chinese with English abstract)
[38] Wang ZH and Liu R. 2009. Characteristic research of micropores and microcracks in alkali feldspar. Bulletin of Mineralogy Petrology and Geochemistry, 28(2): 143-146 (in Chinese with English abstract)
[39] Worden RH, Walker FDL, Parsons I and Brown WL. 1990. Development of microporosity, diffusion channels and deuteric coarsening in perthitic alkali feldspars. Contributions to Mineralogy and Petrology, 104(5): 507-515
[40] Wu PX, Wu JP, Li CW and Xiao WD. 1998. Crystalline velocity equation and kinetics mechanism of plagioclase oscillatory zoning. Acta Petrologica Sinica, 14(3): 121-127 (in Chinese with English abstract)
[41] Yang JH, Wu FY and Wilde SA. 2003. A review of the geodynamic setting of large-scale Late Mesozoic gold mineralization in the North China Craton: An association with lithospheric thinning. Ore Geology Reviews, 23(3-4): 125-152
[42] 陈光远, 孙岱生, 邵伟. 1997. 胶东金矿红化蚀变的实质与成因及其找矿意义. 见: 《陈光远文选》编辑组. 陈光远文选. 2010. 北京: 地质出版社, 263-270
[43] 陈伟军, 刘红涛. 2006. 赤峰-朝阳金矿化集中区主要金矿类型及地质特征研究. 黄金科学技术, 14(5): 1-7
[44] 陈小丹, 叶会寿, 汪欢. 2012. 豫西雷门沟斑岩钼矿床钾长石化蚀变特征及其成矿意义. 现代地质, 26(3): 478-488
[45] 陈衍景, 倪培, 范宏瑞, Pirajno F, 赖勇, 苏文超, 张辉. 2007. 不同类型热液金矿系统的流体包裹体特征. 岩石学报, 23(9): 2085-2108
[46] 胡受奚, 叶瑛, 方长泉. 2004. 交代蚀变岩岩石学及其找矿意义. 北京: 地质出版社, 1-264
[47] 李永刚, 翟明国, 苗来成, 朱嘉伟, 薛良伟. 2003a. 内蒙古安家营子金矿与侵入岩的关系及其地球动力学意义. 岩石学报, 19(4): 808-816
[48] 李永刚, 翟明国, 杨进辉, 苗来成, 关鸿. 2003b. 内蒙古赤峰安家营子金矿成矿时代以及对华北中生代爆发成矿的意义. 中国科学(D辑), 33(10): 960-966
[49] 李永刚, 翟明国, 苗来成, 薛良伟, 朱嘉伟, 关鸿. 2004. 内蒙古赤峰地区安家营子金矿成矿流体研究. 岩石学报, 20(4): 961-968
[50] 苗来成, 范蔚茗, 翟明国, Qiu YM, McNaughton NJ, Groves DI. 2003. 金厂沟梁-二道沟金矿田内花岗岩类侵入体锆石的离子探针U-Pb年代学及意义. 岩石学报, 19(1): 71-80
[51] 孙守恪, 刘红涛, 褚少雄. 2012. 辽宁省排山楼矿区二长花岗岩成因及其与金矿化的关系. 岩石学报, 28(2): 607-618
[52] 孙志明, 杨秀峰, 韩建栢, 蒋潇, 朱斌. 2010. 内蒙古喀喇沁旗金蟾山金矿床控矿断裂特征. 地质找矿论丛, 25(4): 347-350
[53] 王义文, 谢锡才, 刘晓利, 董万成, 吕晓东. 1997. 安家营子金矿田矿床类型及地质地球化学特征. 黄金, 18(11): 3-9
[54] 王志华, 刘瑞. 2009. 碱性长石中的微孔及微裂隙特征研究. 矿物岩石地球化学通报, 28(2): 143-146
[55] 吴平霄, 吴金平, 李才伟, 肖文丁. 1998. 斜长石韵律环带的结晶速率方程及其动力学机制. 岩石学报, 4(3): 121-127
-
计量
- 文章访问数: 5201
- PDF下载数: 9076
- 施引文献: 0
下载: