Petrogenesis of the Quanzigou porphyry Mo deposit at the northern margin of the North China Craton: Constrains from geochronology, geochemistry, and Sr–Nd–Hf isotopes characteristics

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Highlights

  • The Quanzigou Mo deposit fills the early Yanshanian mineralization gap in the region.

  • The mineralization-related granites have high magma oxygen fugacity.

  • The granites were mainly sourced from the lower continent crust.

  • The preexisting high-fO2 sediments of the paleo-Asian oceanic crust is the key for mineralization.

Abstract

The Quanzigou Mo deposit is located in the western portion of the northern margin of the North China Craton (NCC). The results of molybdenite Re–Os isotopes indicate that the mineralization occurred at 170.8 ± 2.0 Ma. It is coeval with the mineralization-related porphyritic biotite granite pluton and granite porphyry dykes of respectively 170.3 ± 1.1 Ma and 169.3 ± 1.0 Ma (zircon U–Pb ages). Thus, the Quanzigou deposit is confirmed to fill the gap of the regional early Yanshanian (i.e., Early–Middle Jurassic) porphyry Mo deposits in this study. Whole-rock εNd(t) (−12.09 to −9.72; mean = −10.80) and zircon εHf(t) values (−16.28 to −9.23; mean = −12.01) of the Quanzigou granites indicate that they originated from the lower continent crust involving some depleted mantle material. Zircon oxygen fugacity results (fO2) show that the mineralization-related granites are high magma fO2 with an average ΔFMQZr (departure from the fayalite–magnetite–quartz oxygen buffer) of +1.1 in the porphyritic biotite granite pluton and an average ΔFMQZr of +1.0 in the granite porphyry dykes, respectively. Because of the relative low-fO2 of the ancient lower continent crust, the high-fO2 source might be associated with continuously metasomatic fluids/melts from the high-fO2 lithospheric mantle, which was metasomatized by the fluids/melts of the preexisting high-fO2 sediments during the closure of the paleo-Asian Ocean. Therefore, the high-fO2 granites are formed during the tectonic setting of the post-collisional compression-to-extension transition caused by the continental collision between the Siberian plate and the NCC. Their high-fO2 characteristics were inherited from the early oceanic crust sediments during the closure of the paleo-Asian Ocean.

Introduction

The Jining Region (Inner Mongolia, China) is located at the northern margin of the North China Craton (northern NCC), notably within the eastern segment of the Central Asian Orogenic Belt (CAOB). The northern NCC is one of the most important Mo ore districts in China, containing at least 30 Mo (Mo-bearing) deposits with most of them relating to continental collision orogenies, including syn- to post-collision tectonism (Chen et al., 2017). So far, many Mo deposits have been discovered already in the middle and eastern parts of the northern margin of the NCC. However, the Jining Region, belonging to the western part, was still at a nearly “Greenfield” level of exploration until the early 2000s, when the discovery of the world-class Caosiyao porphyry-type Mo deposit with a Mo reserve of 1.78 Mt (average Mo 0.075%) and the Dasuji porphyry-type Mo deposit with a Mo reserve of 0.15 Mt (average Mo 0.135%) has made the region the focus for Mo deposit exploration (Nie et al., 2013).

Located between Paleo-Asian and Paleo-Pacific tectonic domains, the Jining Region has the mineralization potential during Indosinian (Triassic) and Yanshanian (i.e., Jurassic-Cretaceous). The Dasuji deposit was associated with the emplacement of a Triassic granite porphyry intrusion (Zhang et al., 2009, Zhang et al., 2019; Wu et al., 2014, Wu et al., 2018; Wu, 2015; Chen et al., 2018, Chen et al., 2019a, Chen et al., 2019b). The world-class Caosiyao deposit was recently dated at 130–150 Ma (molybdenite Re–Os method), relating to the Late Jurassic to Early Cretaceous granite porphyry intrusions (Nie et al., 2013; Wu et al., 2016, Wu et al., 2017; Wang et al., 2017; Zhou et al., 2019).

The Quanzigou Mo deposit is one of the newly discovered Mo deposits in the Jining Region. It was discovered and subject to further exploration in 2009 by the Inner Mongolia Nonferrous Geological Exploration Bureau (IMNGEB). Zhang et al. (2018) have reported a new molybdenite Re–Os age of 161.7 ± 3.1 Ma (n = 5, MSWD = 1.4) for the Quanzigou deposit, suggesting that it is the first early Yanshanian (i.e., early Jurassic) Mo deposit found in the western portion of the northern NCC. The origin of the magmatism and the related Mo mineralization in the Quanzigou deposit have not been adequately established. It is of vital importance to study the Quanzigou deposit to better understand the tectonic evolution of the northern NCC and to assist in the development of methods for exploration for similar deposits and mineral systems in the region. In this study, the petrology, geochemistry, geochronology and isotope systematics of the mineralization-related granites in the Quanzigou deposit are used to constrain the ages of Mo mineralization and to interpret the genesis and magma evolution of the Quanzigou Mo deposit.

Section snippets

Regional geology

The NCC is surrounded by the Qinling–Dabie Orogen to the south and east, and bounded on its northern and western sides by the late Paleozoic to the late Mesozoic Mongolian–Great Hinggan and the early Paleozoic Qilianshan orogens, respectively (Zhao et al., 2001). Two major blocks of the Eastern (Yanliao) and the Western (Ordos and Yinshan) are separated by the Central Orogenic Belt (Trans-North China Orogen), which was formed during the collision between the Eastern and Western Blocks at ca.

Granite major and trace element analyses

Eleven representative and fresh samples, including seven granite porphyry and four porphyritic biotite granite samples, were collected from the Quanzigou deposit district for major and trace elemental and Sr–Nd isotopic analyses (Fig. 3). Major elements were determined by an Axios X-ray fluorescence spectrometer. Trace elements, including rare earth elements (REEs), were obtained using a Thermo X-Series2 ICP-MS. Major and trace element analyses with precision being better than 5% relative error

Granite major and trace elements

The major and trace element contents of granite porphyry and porphyritic biotite granites are listed in Table 1. All samples with the loss on ignition (LOI) < 1 wt% are relatively fresh and unaltered.

These granitic samples have similar geochemical characteristics. All samples fall into the high-K calc-alkaline field in the plot of SiO2 versus K2O (Fig. 5a) and they exhibit peraluminous characteristics in the A/NK (molar Al2O3/Na2O + K2O) versus A/CNK (molar Al2O3/CaO + Na2O + K2O) diagram (Fig.

Magmatic and mineralization ages

As mentioned above, the Jining Region, located between the Paleo-Asian and Paleo-Pacific tectonic domains, was subject to several generations of mineralization during the Indosinian and Yanshanian. Zhang et al. (2009), Wu et al. (2014), Chen et al. (2018) and Zhang et al. (2019) reported weighted mean molybdenite Re–Os ages of 223.1 ± 1.6 Ma (2σ; n = 4), 223.9 ± 1.4 Ma (2σ; n = 5), 224.3 ± 1.5 Ma (2σ; n = 5) and 218.9 ± 1.6 Ma (2σ; n = 5) for the Dasuji Mo deposit. Nie et al. (2013), Wang et

Conclusions

  • (1)

    The molybdenite Re–Os isotopic analytic results indicate that the Mo mineralization of the Quanzigou deposit occurred at 170.8 ± 2.0 Ma, which is coeval with the mineralization-related porphyritic biotite granites and the granite porphyry dykes.

  • (2)

    The mineralization-related granites exhibit relative high-fO2 values, which is favorable for Mo mineralization and is consistent with the mineralization-related granites in other porphyry type Cu/Mo deposits.

  • (3)

    The whole-rock εNd(t), zircon εHf(t), and high-

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This research has been jointly supported by National Key Research and Development Program of China (2016YFC0600501), National Natural Science Foundation of China (41702075), a Chinese Geological Survey project (DD20190459), and Fundamental Research Funds for the Central Universities (2652018132). We appreciate the editors and three anonymous reviewers for constructive comments and suggestions.

References (75)

  • T.H. Green et al.

    Proton microprobe-determined partitioning of Nb, Ta, Zr, Sr and Y between garnet, clinopyroxene and basaltic magma at high pressure and temperature

    Chem. Geol.

    (1989)
  • W.L. Griffin et al.

    The Hf isotope composition of cratonic mantle: LAM-MC-ICPMS analysis of zircon megacrysts in kimberlites

    Geochim. Cosmochim. Acta

    (2000)
  • C. Han et al.

    A Re–Os study of molybdenites from the Lanjiagou Mo deposit of North China Craton and its geological significance

    Gondwana Res.

    (2009)
  • G.N. Hanson

    The application of trace elements to the petrogenesis of igneous rocks of granitic composition

    Earth Planet. Sci. Lett.

    (1978)
  • S.B. Jacobsen et al.

    Sm-Nd isotopic evolution of chondrites

    Earth Planet. Sci. Lett.

    (1980)
  • P.J. Jugo et al.

    Experimental data on the speciation of sulfur as a function of oxygen fugacity in basaltic melts

    Geochim. Cosmochim. Acta

    (2005)
  • S.R. Li et al.

    Geodynamics of heterogeneous gold mineralization in the North China Craton and its relationship to lithospheric destruction

    Gondwana Res.

    (2017)
  • W. Li et al.

    U–Pb and Re–Os geochronology of the Bainaimiao Cu–Mo–Au deposit, on the northern margin of the North China Craton, Central Asia Orogenic Belt: implications for ore genesis and geodynamic setting

    Ore Geol. Rev.

    (2012)
  • S.-R. Li et al.

    Inhomogeneous lithospheric thinning in the central North China Craton: zircon U–Pb and S–He–Ar isotopic record from magmatism and metallogeny in the Taihang Mountains

    Gondwana Res.

    (2013)
  • Y. Liu et al.

    U–Pb zircon ages and Nd, Sr, and Pb isotopes of lower crustal xenoliths from North China Craton: insights on evolution of lower continental crust

    Chem. Geol.

    (2004)
  • G. Mahood et al.

    Large partition coefficients for trace elements in high-silica rhyolites

    Geochim. Cosmochim. Acta

    (1983)
  • M.J. Mengason et al.

    Molybdenum, tungsten and manganese partitioning in the system pyrrhotite–Fe–S–O melt–rhyolite melt: impact of sulfide segregation on arc magma evolution

    Geochim. Cosmochim. Acta

    (2011)
  • M. Santosh

    Assembling North China Craton within the Columbia supercontinent: the role of double-sided subduction

    Precambrian Res.

    (2010)
  • Q. Shu et al.

    Zircon U-Pb geochronology and Sr-Nd-Pb-Hf isotopic constraints on the timing and origin of Mesozoic granitoids hosting the Mo deposits in northern Xilamulun district, NE China

    Lithos

    (2015)
  • D.J. Smythe et al.

    Cerium oxidation state in silicate melts: combined fO2, temperature and compositional effects

    Geochim. Cosmochim. Acta

    (2015)
  • D. Trail et al.

    Ce and Eu anomalies in zircon as proxies for the oxidation state of magmas

    Geochim. Cosmochim. Acta

    (2012)
  • G. Wang et al.

    Molybdenite Re–Os age, H–O–C–S–Pb isotopes, and fluid inclusion study of the Caosiyao porphyry Mo deposit in Inner Mongolia, China

    Ore Geol. Rev.

    (2017)
  • H. Wu et al.

    The Mesozoic Caosiyao giant porphyry Mo deposit in Inner Mongolia, North China and Paleo-Pacific subduction-related magmatism in the northern North China Craton

    J. Asian Earth Sci.

    (2016)
  • G. Wu et al.

    Age, geochemistry, and Sr–Nd–Hf–Pb isotopes of the Caosiyao porphyry Mo deposit in Inner Mongolia, China

    Ore Geol. Rev.

    (2017)
  • H. Wu et al.

    U–Pb geochronology, isotope systematics, and geochemical characteristics of the Triassic Dasuji porphyry Mo deposit, Inner Mongolia, North China: implications for tectonic evolution and constraints on the origin of ore-related granitoids

    J. Asian Earth Sci.

    (2018)
  • X. Xia et al.

    U–Pb and Hf isotopic study of detrital zircons from the Wulashan khondalites: constraints on the evolution of the Ordos Terrane, Western Block of the North China Craton

    Earth Planet. Sci. Lett.

    (2006)
  • C. Yin et al.

    U–Pb and Hf isotopic study of zircons of the Helanshan complex: constrains on the evolution of the Khondalite Belt in the Western Block of the North China Craton

    Lithos

    (2011)
  • H. Yurimoto et al.

    Are discontinuous chondrite-normalized REE patterns in pegmatitic granite systems the results of monazite fractionation?

    Geochim. Cosmochim. Acta

    (1990)
  • H.-F. Zhang et al.

    Construction and destruction of cratons: preface

    Gondwana Res.

    (2013)
  • C.C. Zhang et al.

    Oxygen fugacity and porphyry mineralization: a zircon perspective of Dexing porphyry Cu deposit, China

    Geochim. Cosmochim. Acta

    (2017)
  • Y. Zhang et al.

    Geochronology and geochemistry of the Dasuji Mo deposit in the northern margin of the North China Block: implications for ore genesis and tectonic setting

    Ore Geol. Rev.

    (2019)
  • G.C. Zhao et al.

    Archean blocks and their boundaries in the North China Craton: lithological, geochemical, structural and P–T path constraints and tectonic evolution

    Precambrian Res.

    (2001)
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