Fault and intrusion control on copper mineralization in the Dexing porphyry copper deposit in Jiangxi, China: A perspective from stress deformation-heat transfer-fluid flow coupled numerical modeling

doi:10.13745/j.esf.sf.2021.1.14

Abstract

Abstract:

The metallogenic mechanism of porphyry deposit is a typical multiphysics magmatic-hydrothermal process affected by stress deformation, heat transfer and fluid flow. Therefore, it is important to study the metallogenic process of porphyry deposits from the perspective of numerical modeling of metallogenic dynamics to understand the dynamic evolutionary mechanism of porphyry magmatic-hydrothermal system and its ore-forming response. The Dexing porphyry copper deposit, including the Zhushahong, Tongchang and Fujiawu orebodies, is the largest porphyry copper deposit in South China and considered to be a critically important case for studying the mineralization process of large or/and super-large porphyry deposits. Previous studies mainly addressed the ore geology, geochemistry, geochronology, isotope and ore-forming fluids of the Dexing porphyry deposit; however, only a few studies investigated the mineralization processes by numerical modeling of metallogenic dynamics. Therefore, the aim of this study was to explore the fault and intrusion controlls on mineralization in the Dexing porphyry copper deposit through numerical metallogenic modeling. Firstly, based on a geological conceptual model of copper mineralization, a geometric model characterizing the magmatic-hydrothermal system was constructed, which contains variables of shape (lengths of long and short axes) and dip angle of porphyry intrusion as well as dip angle and width of ore controlling fault. Next, based on the analysis of the coupling relationships among stress, fluidic and thermal fields affecting porphyry copper mineralization, the corresponding mathematical-physical equations were derived and a metallogenic dynamic computing model was constructed. Then, a numerical model simulating the metallogenic dynamic process was established by finite element numerical simulation. Finally, by constraining rock properties, boundary and initial conditions, stress deformation-heat transfer-fluid flow coupled numerical simulation was carried out to investigate fault and intrusion control on the copper mineralization. The main conclusions are: (1) small fault width is more likely to result in localized fractures, thereby facilitating fluid dispersion and formation of disseminated or micro-vein porphyry mineralization. (2) Larger volume and smaller dip angle of porphyry intrusion are beneficial to porphyry mineralization. (3) Compared with the Tongchang and Fujiawu orebodies, the smaller Zhushahong orebody has greater ore-forming depth but smaller mineral reserve, as its large dip angle led to faster post-magmatic cooling (therefore limiting its surface expansion), and porphyry intrusion of the nearby Zhushahong orebody limited its expansion space. This study revealed the ore-controlling mechanism of porphyry intrusion and fault structure in the Dexing porphyry copper deposit, helping to further our understanding of its genesis and ore controlling factors.

Key words: numerical modeling, multi-field coupled model, porphyry copper deposit, intrusion, fault, Dexing, Jiangxi

CLC Number:

P611.5

XIAO Fan, WANG Kaiqi. Fault and intrusion control on copper mineralization in the Dexing porphyry copper deposit in Jiangxi, China: A perspective from stress deformation-heat transfer-fluid flow coupled numerical modeling[J]. Earth Science Frontiers, 2021, 28(3): 190-207.

Figures/Tables 20

Fig.1 (A) Tectonic sketch map showing the temporal-spatial distribution of the Late Mesozoic magmatic rocks in the South China Craton (modified from [51]) and (B) geological map of the Dexing mineralization district (modified from [42])

Fig.2 (A) Geological and tectonic map of the Dexing orefield (modified from [43]) and (B-D) sketch map showing the attitude and morphology of copper orebodies in each deposit (modified from [40])

Table 1 Geometric parameters of the Fujiawu, Tongchang and Zhushahong intrusions

岩体	地表形态	规模			产状
岩体	地表形态	长度/m	宽度/m	面积/km²	倾伏向/(°)	倾伏角/(°)
富家坞	梯形	650	300	0.2	310	40
铜厂	三角形	1 300	300~800	0.7	320	45~50
朱砂红	岩枝和岩脉群	≤450	≤80	0.06	340	60~70

Fig.3 Flowchart of the numerical modeling method for fault and intrusion controls on copper mineralization in the Dexing porphyry copper deposit

Fig.4 The geometric conceptual model of the Dexing porphyry copper deposit

Table 2 Rock parameters applied in the numerical models

模型单元	密度/ (kg·m^-3)	杨氏模量/ (10¹⁰ Pa)	泊松比	孔隙率	渗透率/ (10^-12 m²)	导热系数/ (W·m^-1·K^-1)	恒压热容/ (J·kg^-1·K^-1)
地层	2 650	7.0	0.25	0.25	0.40	3.1	880
侵入体	2 850	8.0	0.25	0.21	0.45	2.9	680
断裂	1 800	0.28	0.35	0.40	40.0	2.8	820

Fig.5 Diagram showing the initial and boundary conditions of the numerical model

Table 3 List of numerical models with model parameters

模型	a/m	b/m	c/m	α/(°)	β/(°)	d/m
M1	650	300	1 556	40	70	1
M2	650	300	1 556	40	70	2
M3	650	300	1 556	40	70	5
M4	650	300	1 556	40	70	10
M5	650	300	1 556	50	70	1
M6	650	300	1 556	50	70	2
M7	650	300	1 556	50	70	5
M8	650	300	1 556	50	70	10
M9	650	300	1 556	60	70	1
M10	650	300	1 556	60	70	2
M11	650	300	1 556	60	70	5
M12	650	300	1 556	60	70	10
M13	1 300	800	1 556	40	70	1
M14	1 300	800	1 556	40	70	2
M15	1 300	800	1 556	40	70	5
M16	1 300	800	1 556	40	70	10
M17	1 300	800	1 556	50	70	1
M18	1 300	800	1 556	50	70	2
M19	1 300	800	1 556	50	70	5
M20	1 300	800	1 556	50	70	10
M21	1 300	800	1 556	60	70	1
M22	1 300	800	1 556	60	70	2
M23	1 300	800	1 556	60	70	5
M24	1 300	800	1 556	60	70	10
M25	450	80	1 556	40	70	1
M26	450	80	1 556	40	70	2
M27	450	80	1 556	40	70	5
M28	450	80	1 556	40	70	10
M29	450	80	1 556	50	70	1
M30	450	80	1 556	50	70	2
M31	450	80	1 556	50	70	5
M32	450	80	1 556	50	70	10
M33	450	80	1 556	60	70	1
M34	450	80	1 556	60	70	2
M35	450	80	1 556	60	70	5
M36	450	80	1 556	60	70	10

Fig.6 3D contour plots of von Mises stress simulation results for variable fault width using models M1-4 (a-d)

Fig.7 3D contour plots of bulk strain simulation results for variable fault width using models M1-4 (a-d)

Fig.8 3D contour plots of Darcy’s velocity in fault plane simulated for variable fault width using models M1-4 (a-d)

Fig.9 3D contour plots of temperature simulation results for variable fault width using models M1-4 (a-d)

Fig.10 3D contour plots of von Mises stress simulation results for variable dip angle of porphyry intrusion using models M1,5,9 (a-c)

Fig.11 3D contour plots of bulk strain simulation results for variable dip angle of porphyry intrusion using models M1,5,9 (a-c)

Fig.12 3D contour plots of Darcy’s velocity in fracture plane simulated for variable dip angle of porphyry intrusion using models M1,5,9 (a-c)

Fig.13 3D contour plots of temperature simulation results for variable dip angle of porphyry intrusion using models M1,5,9 (a-c)

Fig.14 3D contour plots of von Mises stress simulation results for variable intrusion shape using models M2,14,26 (a-c)

Fig.15 3D contour plots of bulk strain simulation results for variable intrusion shape using models M2,14,26 (a-c)

Fig.16 3D contour plots of Darcy’s velocity in fracture plane simulated for variable intrusion shape using models M2,14,26 (a-c)

Fig.17 3D contour plots of temperature simulation result for variable intrusion shape using models M2,14,26 (a-c)

References 78

[1]	SILLITOE R H. Porphyry copper systems[J]. Economic Geology, 2010, 105(1):3-41. DOI URL
[2]	WILKINSON J J. Triggers for the formation of porphyry ore deposits in magmatic arcs[J]. Nature Geoscience, 2013, 6:917-925. DOI URL
[3]	侯增谦. 斑岩Cu-Mo-Au矿床: 新认识与新进展[J]. 地学前缘, 2004, 11(1):131-144.
[4]	芮宗瑶, 张洪涛, 陈仁义, 等. 斑岩铜矿研究中若干问题探讨[J]. 矿床地质, 2006, 25(4):491-500.
[5]	SILLITOE R H. A plate tectonic model for the origin of porphyry copper deposits[J]. Economic Geology, 1972, 67:184-197. DOI URL
[6]	RICHARDS J P, BOYCE A J, PRINGLE M S. Geological evolution of the Escondida area, northern Chile: a model for spatial and temporal localization of porphyry Cu mineralization[J]. Economic Geology, 2001, 96:271-305. DOI URL
[7]	RICHARDS J P. Tectonic-magmatic precursors for porphyry Cu-(Mo-Au) deposit formation[J]. Economic Geology, 2003, 98(8):1515-1533. DOI URL
[8]	COOKE D R, HOLLINGS P, WALSHE J L. Giant porphyry deposits: characteristics, distribution, and tectonic controls[J]. Economic Geology, 2005, 100(5):801-818. DOI URL
[9]	侯增谦, 潘小菲, 杨志明, 等. 初论大陆环境斑岩铜矿[J]. 现代地质, 2007, 21(2):332-351.
[10]	侯增谦, 杨志明, 王端, 等. 再论中国大陆斑岩Cu-Mo-Au矿床成矿作用[J]. 地学前缘, 2020, 27(2):20-44.
[11]	杨志明, 侯增谦. 初论碰撞造山环境斑岩矿成矿模型[J]. 矿床地质, 2009, 28(5):515-538.
[12]	HOU Z Q, ZHOU Y, WANG R, et al. Recycling of metal-fertilized lower crust: origin of non-arc Au-rich porphyry deposits at cratonic edges[J]. Geology, 2017, 45(6):563-566. DOI URL
[13]	SHINOHARA H, KAZAHAYA K, LOWENSTERN J B. Volatile transport in a convecting magma column: implications for porphyry Mo mineralization[J]. Geology, 1995, 23:1091-1094. DOI URL
[14]	BLUNDY J, MAVROGENES J, TATTITCH B, et al. Generation of porphyry copper deposits by gas-brine reaction in volcanic arcs[J]. Nature Geoscience, 2015, 8:235-240. DOI URL
[15]	於崇文, 岑况, 鲍征宇, 等. 成矿作用动力学[M]. 北京: 地质出版社, 1998.
[16]	PHILLIPS O M. Flow and reactions in permeable rocks[M]. Cambridge, UK: Cambridge University Press, 1991.
[17]	ZHAO C B, HOBBS B E, ORD A. Fundamentals of computational geosciences: numerical methods and algorithms[M]. Berlin: Springer, 2009.
[18]	刘亮明. 浅成岩体引发的流体超压与岩石破裂及其对成矿的制约[J]. 地学前缘, 2011, 18(5):78-89.
[19]	池国祥, 薛春纪. 成矿流体动力学的原理、研究方法及应用[J]. 地学前缘, 2011, 18(5):1-18.
[20]	ZHANG Y H, ROBINSON J, SCHAUBS P M. Numerical modelling of structural controls on fluid flow and mineralization[J]. Geoscience Frontiers, 2011, 2(3):449-461. DOI URL
[21]	贾蔡, 袁峰, 张明明, 等. 宁芜盆地白象山铁矿床成矿作用过程数值模拟[J]. 岩石学报, 2014, 30(4):1031-1040.
[22]	林舸, ZHAO C B, 王岳军, 等. 含矿流体混合反应与成矿作用的动力平衡模拟研究[J]. 岩石学报, 2003, 19(2):275-282.
[23]	朱江建, 陈广浩, 龚贵伦, 等. 广东河台金矿糜棱岩化过程构造-流体成矿研究[J]. 地学前缘, 2011, 18(5):67-77.
[24]	赵崇斌, HOBBS B E, ORD A. 用计算地球科学研究方法探讨地质现象的动力学机制: 以断层中等距成矿分布为例[J]. 中国科学: D辑, 2008, 38(5):646-652.
[25]	刘亮明, 周瑞超, 赵崇斌. 构造应力环境对浅成岩体成矿系统的制约: 从安庆月山岩体冷却过程动力学计算模拟结果分析[J]. 岩石学报, 2010, 26(9):2869-2878.
[26]	王语, 周永章, 肖凡, 等. 基于成矿条件数值模拟和支持向量机算法的深部成矿预测: 以粤北凡口铅锌矿为例[J]. 大地构造与成矿学, 2020, 44(2):222-230.
[27]	HOBBS B E, ZHANG Y, ORD A. Application of coupled deformation, fluid flow, thermal and chemical modelling to predictive mineral exploration[J]. Journal of Geochemical Exploration, 2000, 69/70:505-509. DOI URL
[28]	LAMY-CHAPPUIS B, HEINRICH C A, DRIESNER T, et al. Mechanisms and patterns of magmatic fluid transport in cooling hydrous intrusions[J]. Earth and Planetary Science Letters, 2020, 535. DOI: 10.1016/j.epsl.2020.116111 DOI
[29]	SUN T, LIU L. Delineating the complexity of Cu-Mo mineralization in a porphyry intrusion by computational and fractal modeling: a case study of the Chehugou deposit in the Chifeng district, Inner Mongolia, China[J]. Journal of Geochemical Exploration, 2014, 144:128-143. DOI URL
[30]	WEIS P, DRIESNER T, HEINRICH C A. Porphyry-copper ore shells form at stable pressure-temperature fronts within dynamic fluid plumes[J]. Science, 2012, 338:1613-1616. DOI URL
[31]	KORGES M, WEIS P, ANDERSEN C. The role of incremental magma chamber growth on ore formation in porphyry copper systems[J]. Earth and Planetary Science Letters, 2020, 552. DOI: 10.1016/j.epsl.2020.116584 DOI
[32]	LI J K, ZHANG D H, WANG D H. Numerical simulations of heat and mass transfer for the Tongchang porphyry copper deposit, Dexing, Jiangxi Province, China[M]//MAO J, BIERLEIN F P. Mineral deposit research: meeting the global challenge, Vols 1 and 2. Berlin, Heidelberg: Springer, 2005: 425-428.
[33]	GOW P A, UPTON P, ZHAO C B, et al. Copper-gold mineralisation in New Guinea: numerical modelling of collision, fluid flow and intrusion-related hydrothermal systems[J]. Australian Journal of Earth Sciences, 2002, 49:753-771. DOI URL
[34]	GUILLOU-FROTTIER L, BUROV E. The development and fracturing of plutonic apexes: implications for porphyry ore deposits[J]. Earth and Planetary Science Letters, 2003, 214:341-356. DOI URL
[35]	LIU L M, LI J F, ZHOU R C, et al. 3D modeling of the porphyry-related Dawangding gold deposit in south China: Implications for ore genesis and resources evaluation[J]. Journal of Geochemical Exploration, 2016, 164:164-185. DOI URL
[36]	HU X Y, LI X H, YUAN F, et al. Numerical modeling of ore-forming processes within the Chating Cu-Au porphyry-type deposit, China: Implications for the longevity of hydrothermal systems and potential uses in mineral exploration[J]. Ore Geology Reviews, 2020, 116. DOI: 10.1016/j.orefeorev.2019.103230 DOI
[37]	毛景文, 张建东, 郭春丽. 斑岩铜矿-浅成低温热液银铅锌-远接触带热液金矿矿床模型: 一个新的矿床模型: 以德兴地区为例[J]. 地球科学与环境学报, 2010, 32(1):1-14.
[38]	王国光, 倪培, 赵超, 等. 德兴大型铜金矿集区的研究进展和成矿模式[J]. 岩石学报, 2019, 35(12):3644-3658.
[39]	周清, 姜耀辉, 廖世勇, 等. 德兴斑岩铜矿床研究新进展[J]. 地质论评, 2013, 59(5):933-940.
[40]	朱训, 黄崇轲, 芮宗瑶. 德兴斑岩铜矿[M]. 北京: 地质出版社, 1983.
[41]	芮宗瑶, 黄崇轲, 齐国明. 中国斑岩铜(钼)矿床[M]. 北京: 地质出版社, 1984.
[42]	MAO J W, ZHANG J D, PIRAJNO F, et al. Porphyry Cu-Au-Mo-epithermal Ag-Pb-Zn-distal Hydrothermal Au deposits in the Dexing area, Jiangxi province, East China: a linked ore system[J]. Ore Geology Reviews, 2011, 43(1):203-216. DOI URL
[43]	WANG Q, XU J F, JIAN P, et al. Petrogenesis of adakitic porphyries in an extensional tectonic setting, Dexing, South China: implications for the genesis of porphyry copper mineralization[J]. Journal of Petrology, 2006, 47(1):110-144.
[44]	LIU X, FAN H R, SANTOSH M, et al. Remelting of Neoproterozoic relict volcanic arcs in the Middle Jurassic: implication for the formation of the Dexing porphyry copper deposit, Southeastern China[J]. Lithos, 2012, 150:85-100. DOI URL
[45]	WANG G G, NI P, YAO J, et al. The link between subduction-modified lithosphere and the giant Dexing porphyry copper deposit, South China: constraints from high-Mg adakitic rocks[J]. Ore Geology Reviews, 2015, 67:109-126. DOI URL
[46]	WANG G G, NI P, LI L, et al. Petrogenesis of the Middle Jurassic andesitic dikes in the giant Dexing porphyry copper ore field, South China: implications for mineralization[J]. Journal of Asian Earth Sciences, 2020, 196. DOI: 10.1016/j.jseaes.2020.104375 DOI
[47]	芮宗瑶, 张立生, 陈振宇, 等. 斑岩铜矿的源岩或源区探讨[J]. 岩石学报, 2004, 20(2):229-238.
[48]	於崇文. 成矿作用动力学: 理论体系和方法论[J]. 地学前缘, 1994, 1(3):54-82.
[49]	於崇文. 成矿动力系统在混沌边缘的分形生长: 一种新的成矿理论与方法论[J]. 矿物岩石地球化学通报, 2002, 21(2):31-41.
[50]	朱金初, 金章东, 饶冰, 等. 德兴铜厂斑岩铜矿流体过程[J]. 南京大学学报(自然科学版), 2002, 38(3):418-434.
[51]	HOU Z Q, PAN X F, LI Q Y, et al. The giant Dexing porphyry Cu-Mo-Au deposit in east China: product of melting of juvenile lower crust in an intracontinental setting[J]. Mineralium Deposita, 2013, 48:1019-1045. DOI URL
[52]	ZHANG D H, YU C W, BAO Z Y, et al. Ore zoning and dynamics of ore-forming processes of Yinshan polymetallic deposit in Dexing, Jiangxi[J]. Chinese Journal of Geochemistry, 1997, 16:123-132. DOI URL
[53]	郭国章, 任启江, 方长泉, 等. 德兴斑岩铜矿成矿过程中地下热水运移的动力学模拟[J]. 地球化学, 1994, 1(4):402-410.
[54]	HE W W, BAO Z Y, LI T P. One-dimensional reactive transport models of alteration in the Tongchang porphyry copper deposit, Dexing district, Jiangxi Province, China[J]. Economic Geology and the Bulletin of the Society of Economic Geologists, 1999, 94(3):307-323. DOI URL
[55]	於崇文. 江西德兴斑岩铜矿田成矿作用的流体动力分形弥散机制[J]. 地质论评, 1995, 41(3):211-220.
[56]	ZHOU Q, JIANG Y H, ZHAO P, et al. Origin of the Dexing ore-bearing porphyries, South China: elemental and Sr-Nd-Pb-Hf isotopic constraints[J]. International Geology Review, 2012, 54(5):572-592. DOI URL
[57]	闵康, 高剑峰, 齐有强, 等. LA-ICP-MS/FT方法在矿床保存研究中的应用: 以赣东北德兴铜矿和银山铅锌矿床为例[J]. 大地构造与成矿学, 2020, 44(1):80-91.
[58]	毛景文, 胡瑞忠, 陈毓川, 等. 大规模成矿作用与大型矿集[M]. 北京: 地质出版社, 2006.
[59]	LI L, NI P, WANG G G, et al. Multi-stage fluid boiling and formation of the giant Fujiawu porphyry Cu-Mo deposit in South China[J]. Ore Geology Reviews, 2017(81):898-911.
[60]	李利, 倪培, 王国光, 等. 德兴斑岩铜矿田黄铁矿Re-Os同位素定年及其地质意义[J]. 矿床地质, 2018, 37(6):1168-1178.
[61]	潘小菲, 宋玉财, 王淑贤, 等. 德兴铜厂斑岩型铜金矿床热液演化过程[J]. 地质学报, 2009, 83(12):1929-1950.
[62]	GROTE K, ANTONSSON E. Springer handbook of mechanical engineering[M]. Switzerland: Springer International Publishing, 2009.
[63]	HERTZBERG R. Deformation and fracture mechanics of engineering materials[M]. Hoboken, USA: John Wiley & Sons, 1996.
[64]	BOWER A F. Applied mechanics of solids[M]. Boca Raton, USA: CRC Press, 2009.
[65]	BEAR J. Hydraulics of groundwater[M]. New York: Dover Publications, 1979.
[66]	INGEBRITSEN S E, SANFORD W E. Groundwater in geologic processes[M]. Cambridge, United Kingdom: Cambridge University Press, 1998.
[67]	SLEEP N H, FUJITA K. Principles of geophysics[M]. Oxford, UK: Blackwell Science, 1997.
[68]	TURCOTTE D L, SCHUBERT G. Geodynamics[M]. Cambridge, United Kingdom: Cambridge University Press, 2002.
[69]	BIOT M A. Mechanics of deformation and acoustic propagation in porous media[J]. Journal of Applied Physics, 1962(33):1482-1498.
[70]	BEAR J, BACHMAT Y. Introduction to modeling of transport phenomena in porous media[M]. Dordrecht: Springer, 1990.
[71]	POWERS J M. On the necessity of positive semi-definite conductivity and onsager reciprocity in modeling heat conduction in anisotropic media[J]. Journal of Heat Transfer, 2004, 126(5):670-675. DOI URL
[72]	NIELD D A, BEJAN A. Convection in porous media[M]. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013.
[73]	SCHON J H. Physical properties of rocks: a workbook[M]. Amsterdam, the Netherlands: Elsevier B. V., 2011.
[74]	胡宝群, 吕古贤, 王方正, 等. 岩石圈中热压系数的计算[J]. 地学前缘, 2008, 15(3):123-129.
[75]	LIU L M, SUN T, ZHOU R C. Epigenetic genesis and magmatic intrusion’s control on the Dongguashan stratabound Cu-Au deposit, Tongling, China: evidence from field geology and numerical modeling[J]. Journal of Geochemical Exploration, 2014, 144:97-114. DOI URL
[76]	OSSANDÓN G, FRÉRAUT R, GUSTAFSON L B, et al. Geology of the Chuquicamata mine: a progress report[J]. Economic Geology, 2001, 96:249-270. DOI URL
[77]	FRIKKEN P H, COOKE D R, WALSHE J L, et al. Mineralogical and isotopic zonation in the Sur-Sur tourmaline breccia, Río Blanco-Los Bronces Cu-Mo deposit, Chile: implications for ore genesis[J]. Economic Geology, 2005, 100:935-961. DOI URL
[78]	VARGAS R, GUSTAFSON L B, VUKASOVIC M, et al. Ore breccias in the Rio Blanco-Los Bronces porphyry copper deposit, Chile[J]. Society of Economic Geologists Special Publication, 1999, 7:281-297.