Geochronology and geochemistry of the Shilu Cu–Mo deposit in the Yunkai area, Guangdong Province, South China and its implication

Abstract Shilu is a large porphyry–skarn deposit in the Yunkai district in Guangdong Province, South China. The Shilu granitic intrusion in the mine area is a granodiorite which is genetically related to Cu mineralization. Plagioclase in the granodiorite has a zoned texture and is mainly andesine with minor amounts of labradorite, whereas the K-feldspars exhibit Carlsbad twins and some are also characterized by a zonal texture. K-feldspars from the granodiorite show high contents of Or (87–92 wt.%) with minor Ab (8–13 wt.%) and negligible An value of 0–0.3 wt.%. Biotite can be classified as magnesio-biotite, and is characterized by Mg-rich [Mg/(Mg + Fe) = 0.54–0.60] and AlVI-low (average values = 0.11). Hornblende is chiefly magnesiohornblende and tschermakite. LA-ICP-MS zircon U–Pb age of the Shilu granodiorite is 107 ± 0.7 Ma, which is consistent with molybdenites Re–Os age of 104.1 ± 1.3 Ma. Geochemical data indicate that the Shilu granodiorite is silica-rich (SiO2 = 63.43–65.03 wt.%) and alkali-rich (K2O + Na2O = 5.45–6.05 wt.%), as well as calcium-rich (CaO = 4.76–5.1 wt.%). Trace element geochemistry results show enrichments in large ion lithophile elements (e.g., Rb, K, and Ba) and depletions in some high field strength elements (e.g., Nb, P, Ta, and Ti). The total rare earth element (REE) content of the granodioritic rocks is low (∑ REE   9] and moderately negative Eu anomalies (Eu/Eu* = 0.83–0.90). These mineralogical, geochronological, and geochemical results suggest that the Shilu granodiorite has a mixed crust–mantle source with a geochemical affinity to I-type granitoids. Hornblende thermobarometry yielded magmatic crystallization temperatures of 686–785 °C and crystallization pressures between 1.0 and 2.34 kbar, which is converted to depths in a range of 3.31 to 7.71 km. Biotite thermobarometry yielded similar temperatures and lower pressures of 680–780 °C and 0.8–2 kbar (depth 2.64–6.6 km), respectively. The parent magma had a high oxygen fugacity. The Shilu granodiorite has a relatively low eNd/t–t value and high (87Sr/86Sr)i value, and Nd isotopes yield two-stage depleted mantle Nd model ages of 969–1590 Ma. Our new data, combined with previous studies, imply that the granodiorite and the associated Shilu Cu–Mo deposit was formed in an extensional environment, closely related to remelting of residual subducted slab fragments in the Jurassic.

[1]  S. Taylor,et al.  The geochemical evolution of the continental crust , 1995 .

[2]  Z. Tian,et al.  Laser ablation-MC-ICP-MS technique for Hf isotope microanalysis of zircon and its geological applications. , 2007 .

[3]  D. Henry,et al.  The Ti-saturation surface for low-to-medium pressure metapelitic biotites: Implications for geothermometry and Ti-substitution mechanisms , 2005 .

[4]  Dongliang Zhang,et al.  A precise U–Pb age on cassiterite from the Xianghualing tin-polymetallic deposit (Hunan, South China) , 2008 .

[5]  K. Ludwig User's Manual for Isoplot 3.00 - A Geochronological Toolkit for Microsoft Excel , 2003 .

[6]  Mao Jingwen,et al.  Major types and time–space distribution of Mesozoic ore deposits in South China and their geodynamic settings , 2013, Mineralium Deposita.

[7]  F. Guo,et al.  K-Ar dating of late Mesozoic volcanism and geochemistry of volcanic gravels in the North Huaiyang Belt, Dabie orogen: Constraints on the stratigraphic framework and exhumation of the northern Dabie orthogneiss complex , 2002 .

[8]  Huichao Rui Some problems concerning relationship between Mesozoic-Cenozoic lithospheric extension and uranium metallogenesis in South China , 2007 .

[9]  V. Wall,et al.  Origin and evolution of a peraluminous silicic ignimbrite suite: The Violet Town Volcanics , 1984 .

[10]  B. Leake,et al.  Nomenclature of amphiboles; report of the subcommittee on amphiboles of the International Mineralogical Association, Commission on New Minerals and Mineral Names , 1997 .

[11]  D. Günther,et al.  Gold concentrations of magmatic brines and the metal budget of porphyry copper deposits , 1999, Nature.

[12]  J. Lowenstern,et al.  The role of magmas in the formation of hydrothermal ore deposits , 1994, Nature.

[13]  Zheng We Zircon U-Pb geochronological and Hf isotopic constraints on petrogenesis of Yingwuling tungsten polymetallic deposit in Guangdong Province and its geological significance , 2013 .

[14]  P. Hans,et al.  Stability of biotite: experiment, theory, and application , 1965 .

[15]  Mao Jing Large-scale tungsten-tin mineralization in the Nanling region,South China:Metallogenic ages and corresponding geodynamic processes. , 2007 .

[16]  Shou‐ting Zhang,et al.  Geology, geochemistry and geochronology of the Jiaojiguanliangzi Fe-polymetallic deposit, Tengchong County, Western Yunnan (China): Regional tectonic implications , 2014 .

[17]  Mlr Key,et al.  Mineralogy and Sr-Nd-Pb isotopic compositions of quartz diorite in Tonglushan deposit,Hubei Province , 2010 .

[18]  M. Neugebauer,et al.  Reviews of Geophysics , 1988 .

[19]  T. Pettke,et al.  Experimental determination of Au solubility in rhyolite melt and magnetite: Constraints on magmatic Au budgets , 2003 .

[20]  W. McDonough,et al.  Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes , 1989, Geological Society, London, Special Publications.

[21]  J. Walshe,et al.  Giant Porphyry Deposits: Characteristics, Distribution, and Tectonic Controls , 2005 .

[22]  J. Whalen,et al.  A-type granites: geochemical characteristics, discrimination and petrogenesis , 1987 .

[23]  J. Mao,et al.  SHRIMP zircon U-Pb dating for volcanic rocks of the Dasi Formation in southeast Hubei Province, middle-lower reaches of the Yangtze River and its implications , 2006 .

[24]  Wei-dong Sun,et al.  The formation of the Dabaoshan porphyry molybdenum deposit induced by slab rollback , 2012 .

[25]  W. Hildreth,et al.  Crustal contributions to arc magmatism in the Andes of Central Chile , 1988 .

[26]  M. Whitehouse,et al.  Plesovice zircon : A new natural reference material for U-Pb and Hf isotopic microanalysis , 2008 .

[27]  Chen Yu-chuan,et al.  Spatial-Temporal Distribution of Mesozoic Ore Deposits in South China and Their Metallogenic Settings , 2008 .

[28]  Mao Jingwen,et al.  Geology, geochemistry and age constraints on the Mengku skarn iron deposit in Xinjiang Altai, NW China , 2010 .

[29]  T. Holland,et al.  Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer , 1990 .

[30]  Shu Liangshu Principal Geological Features of Nanling Tectonic Belt, South China , 2006 .

[31]  A. Tindle,et al.  Trace Element Discrimination Diagrams for the Tectonic Interpretation of Granitic Rocks , 1984 .

[32]  W. McDonough,et al.  Distribution of titanium and the rare earth elements between peridotitic minerals , 1992 .

[33]  B. Leake,et al.  Nomenclature of the Amphiboles: Report of the Subcommittee on Amphiboles of the International Mineralogical Association Commision on New Minerals , 1997 .

[34]  Cai Ming-hai Geochemical characteristics of basic intrusive rocks in the Yunkai uplift, Guangdong-Guangxi, China, and their tectonic significance. , 2006 .

[35]  Jian-wei Li,et al.  Geochronology, geochemistry, and mineralization of the granodiorite porphyry hosting the Matou Cu–Mo (±W) deposit, Lower Yangtze River metallogenic belt, eastern China , 2014 .

[36]  Mao Jingwen,et al.  Geodynamic settings of Mesozoic large-scale mineralization in North China and adjacent areas——Implication from the highly precise and accurate ages of metal deposits , 2003 .

[37]  G. Dipple,et al.  World Skarn Deposits , 2005 .

[38]  Mlr Key Geological Characteristics of the Qinhang (or Shihang) Metallogenic Belt in South China and Spatial-Temporal Distribution Regularity of Mineral Deposits , 2011 .

[39]  T. Furman,et al.  Erosion of lithospheric mantle beneath the East African Rift system: geochemical evidence from the Kivu volcanic province , 1999 .

[40]  Mao Jingwen Mineral Deposit Models of Mesozoic Ore Deposits in South China , 2009 .

[41]  Yu Zhang Geological characteristics and ages of granites and related mineralization in the Dajinshan tungsten-tin polymetallic deposit,western Guangdong Province , 2012 .

[42]  Han Wu,et al.  CGDK: An extensible CorelDRAW VBA program for geological drafting , 2013, Comput. Geosci..

[43]  A. Buddington,et al.  Iron-Titanium Oxide Minerals and Synthetic Equivalents , 1964 .

[44]  W. Dickinson Potash-Depth (K-h) Relations in Continental Margin and Intra-Oceanic Magmatic Arcs , 1975 .

[45]  C. Albuquerque Geochemistry of biotites from granitic rocks, Northern Portugal , 1973 .

[46]  Sho Endo,et al.  Relationship Between Solidification Depth of Granitic Rocks and Formation of Hydrothermal Ore Deposits , 2007 .

[47]  Liping Xian Mesozoic shoshonitic intrusives in the Yangchun Basin, western Guangdong, and their tectonic significance:II . Trace elements and Sr- Nd isotopes , 2001 .

[48]  Tian Yun Re-Os dating of molybdenite from the Shilu Cu(Mo) deposit in western Guangdong Province and its geological implications , 2012 .

[49]  F. Pirajno,et al.  Distribution of porphyry deposits in the Eurasian continent and their corresponding tectonic settings , 2014 .

[50]  W. Boynton Cosmochemistry of the rare earth elements: meteorite studies. , 1984 .

[51]  F. Corfu,et al.  Zircon M257 ‐ a Homogeneous Natural Reference Material for the Ion Microprobe U‐Pb Analysis of Zircon , 2008 .

[52]  W. Boynton Geochemistry of the rare earth elements : meteorite studies , 1984 .

[53]  M. D. Foster,et al.  Interpretation of the composition of trioctahedral micas , 1960 .

[54]  Ji Qiang,et al.  Jurassic Tectonic Revolution in China and New Interpretation of the “Yanshan Movement” , 2008 .

[55]  Mao Jingwen,et al.  Mesozoic Large‐scale Mineralization and Multiple Lithospheric Extensions in South China , 2006 .

[56]  Josnpn B. Wrrer Opaque mineralogy and mafic mineral chemistry of I- and S-type granites of the Lachlan fold belt. southeast Australia* , 1988 .

[57]  F. Pirajno,et al.  Mesozoic metallogeny in East China and corresponding geodynamic settings — An introduction to the special issue , 2011 .

[58]  Xixi Zhao,et al.  Isotopic and paleomagnetic constraints on the Mesozoic tectonic evolution of south China , 1996 .

[59]  Jian‐tang Peng,et al.  In situ LA-MC-ICP-MS and ID-TIMS U-Pb geochronology of cassiterite in the giant Furong tin deposit, Hunan Province, South China New constraints on the timing of tin-polymetallic mineralization , 2011 .

[60]  Liping Xian Mesozoic shoshonitic intrusives in the Yangchun Basin, western Guangdong, and their tectonic significance:I . Petrology and isotope geochronology , 2000 .

[61]  J. Mungall Roasting the mantle: Slab melting and the genesis of major Au and Au-rich Cu deposits , 2002 .

[62]  Changqian Ma,et al.  Origin of the Tongshankou porphyry–skarn Cu–Mo deposit, eastern Yangtze craton, Eastern China: geochronological, geochemical, and Sr–Nd–Hf isotopic constraints , 2008 .

[63]  S. Ishihara The Magnetite-series and Ilmenite-series Granitic Rocks , 1977 .

[64]  M. Roberts,et al.  Origin of high-potassium, talc-alkaline, I-type granitoids , 1993 .

[65]  Zhang Zhi Alteration and mineralization zoning in Tongshan skarn-type copper depositin in Guichi,Anhui Province,and its genesis , 2010 .

[66]  I. Campbell,et al.  Relative oxidation states of magmas inferred from Ce(IV)/Ce(III) in zircon: application to porphyry copper deposits of northern Chile , 2002 .

[67]  R. Sillitoe,et al.  Characteristics and controls of the largest porphyry copper‐gold and epithermal gold deposits in the circum‐Pacific region , 1997 .

[68]  R. Binns,et al.  Release of gold-bearing fluids in convergent margin magmas prompted by magnetite crystallization , 2004, Nature.

[69]  Zhang Hong Geochronology and Metallogenesis of the Shapinggou Giant Porphyry Molybdenum Deposit in the Dabie Orogenic Belt , 2011 .

[70]  Mao Jing Mesozoie large-scale metallogenic pulses in North China and corresponding geodynamic settings , 2005 .

[71]  P. Rickwood Boundary lines within petrologic diagrams which use oxides of major and minor elements , 1989 .

[72]  Marie C. Johnson,et al.  Experimental calibration of the aluminum-in-hornblende geobarometer with application , 1989 .

[73]  Yu Shun,et al.  Re-Os dating of molybdenite from the Xintianling giant tungsten-molybdenum deposit in southern Hunan Province,China and its geological implications , 2012 .

[74]  Y. Isozaki,et al.  Paleogeographic maps of the Japanese Islands: Plate tectonic synthesis from 750 Ma to the present , 1997 .

[75]  P. King,et al.  Characterization and Origin of Aluminous A-type Granites from the Lachlan Fold Belt, Southeastern Australia , 1997 .

[76]  Zheng We Re-Os ISOTOPIC DATING OF MOLYBDENITES FROM THE YINGWULING POLYMETALLIC DEPOSIT IN GUANGDONG PROVINCE AND ITS GEOLOGICAL SIGNIFICANCE , 2013 .

[77]  A. Glazner,et al.  Voluminous granitic magmas from common basaltic sources , 2005 .

[78]  W. Griffin,et al.  Igneous zircon: trace element composition as an indicator of source rock type , 2002 .

[79]  Chi-yu Lee,et al.  Shoshonitic intrusive suite in SE Guangxi: Petrology and geochemistry , 2000 .

[80]  J. Liégeois,et al.  Contrasting origin of post-collisional high-K calc-alkaline and shoshonitic versus alkaline and peralkaline granitoids. The use of sliding normalization , 1998 .

[81]  Xian‐Hua Li,et al.  Intraplate crustal remelting as the genesis of Jurassic high-K granites in the coastal region of the Guangdong Province, SE China , 2013 .

[82]  Chen Mao Rb-Sr isochron age of Tiantang Cu-Pb-Zn polymetallic deposit in Guangdong Province and its geological significance , 2013 .

[83]  J. Pasteris MOUNT PINATUBO VOLCANO AND NEGATIVE PORPHYRY COPPER DEPOSITS , 1996 .

[84]  S. Taylor,et al.  Large ion lithophile elements in rocks from high-pressure granulite facies terrains , 1985 .

[85]  D. Groves,et al.  East asian gold: Deciphering the anomaly of phanerozoic gold in precambrian cratons , 2007 .

[86]  Zhi-hui Wang,et al.  Ch4-rich fluid inclusions in the Yushigou mantle peridotite and their implications, North Qilian Mountains, China , 1999 .

[87]  R. Sillitoe Porphyry Copper Systems , 2010 .