Elsevier

Ore Geology Reviews

Volume 126, November 2020, 103792
Ore Geology Reviews

Tracing mineralization history from the compositional textures of sulfide association: A case study of the Zhenzigou stratiform Zn-Pb deposit, NE China

https://doi.org/10.1016/j.oregeorev.2020.103792Get rights and content

Highlights

  • LA-ICPMS reveals complex pyrite-arsenopyrite-sphalerite-galena compositional texture.

  • The information is applied to constrain ore genesis and fluid evolution.

  • Sedimentary, metamorphic, and magmatic-hydrothermal fluids were inferred and involved.

  • Metals from distinct fluids are fractionationed, entering in distinct sulfide phases.

  • This defines the genesis of Zhenzigou stratiform Zn-Pb deposit, NE China.

Abstract

The Qingchengzi Orefield located in northeastern China hosts more than ten Pb-Zn deposits and several Au-Ag deposits. Among those, the Zhenzigou Zn-Pb deposit displays a typical stratiform morphology, comprising ore bodies in layers and lenses. The ore minerals are simply composed of sphalerite, galena, pyrite, and pyrrhotite, together with minor arsenopyrite, marcasite, and argentite. A sulfide association of sphalerite-galena-pyrite-arsenopyrite was selected for this study; the interior compositional texture of the sulfide association was investigated by means of LA-ICPMS spot and mapping analysis, with the aim of constraining the ore genesis, fluid evolution history and element partitioning behavior. The results show that three distinct fluids were involved in the mineralization, namely an episode of sedimentary fluids at ∼2052 Ma which is responsible for the precipitation of pyrite core (Py0), an episode of metamorphic fluids at ∼1800 Ma which formed an overgrowth of pyrite (Py 1) and new crystallization of sphalerite (Sph1) and arsenopyrite (Aspy1), and a final episode of hydrothermal fluids related to the Triassic magmatism, forming another overgrowth of pyrite (Py2), sphalerite (Sph2) and arsenopyrite (Aspy2), together with minor precipitation of galena (Ga). The sedimentary fluids are relatively low in temperature (<150 °C), enriched in Cu, Pb, Zn, Ag, and depleted in Co, Ni, and As. Pyrite is the main precipitated sulfide mineral, scavenging most of the available trace elements. The late metamorphic and magmatic fluids are high in temperature (>300 °C) and have remobilized As, Co and Ni but only at mineral grain scale. The late metamorphic and magmatic fluids are enriched in In, Cd, Au, As, Ag, Cu, Pb, Sb, Sn, Co and Ni, and depleted in Bi, W, Mo, Te, and Se. The partitioning of most of the metals from the fluids into the sulfide minerals was controlled by the metals’ availability in the fluids and by the compatibility with crystal structure through direct or coupled substitutions. Pyrite acts as the main host of Co, Ni, Pb, and As; arsenopyrite hosts a major amount of Sb and Pb, and a minor amount of Au; sphalerite is the primary host of Cd, In, Cu, and the secondary host of Ag and Sn; galena is the primary host of Ag, Sb, Sn, and subordinately hosts Cd, In and As. In particular, a remarkable amount of In and Cd was carried by the hydrothermal fluids associated with the Triassic magmatism, indicating that the contribution of magmatic hydrothermal fluids to the mineralization is significant. In conclusion, our in-situ geochemical evidence of sulfide minerals reinforces a sedimentation-metamorphism-magmatic-hydrothermal reworking model for the Zhenzigou stratiform Zn-Pb mineralization. This case study underlines the significance of compositional textures of coexisting sulfide minerals when assessing the ore genesis. Overall, our study demonstrates that, by integrating trace element mapping and spot analysis on coexisting sulfide minerals, it is possible to re-construct the fluid evolution history, resolve the metal behaviors associated with fluids evolution, and review the contribution of individual fluids to mineralization.

Graphical abstract

Mineral record of the fluid property and evolution of the Zhenzigou Zn-Pb deposit. A primary fluid with origin of marine sedimentary process is overprinted by a subsequent metamorphism as well as a magmatic hydrothermal fluid with significant trace element associations; elements from two distinct fluids are fractionationed and incorporated in different sulfide phases.

  1. Download : Download high-res image (47KB)
  2. Download : Download full-size image

Introduction

Globally, stratiform Pb-Zn deposits supply significant non-ferrous metal resources (Carne and Cathro, 1982). Such sulfide-rich and massive sulfide Pb-Zn-Cu-Ag-Au deposits commonly form sheet-like layers, which are interbedded with chert, shale, carbonate, and barite (Gustafson and Williams, 1981). Examples include those in the Selwyn Basin of Canada, the Copperbelt of central Africa, McArthur Basin in Northern Australia, the North Korean Jiande deposit, and several deposits in the Qingchengzi Orefield such as the Zhenzigou and Diannan deposits, NE China (Okita and Shanks, 1992, Goodfellow, 1987, McClay, 1991, Turner, 1992, Zhang and Yang, 1988).

The Qingchengzi Orefield is one of the major Pb-Zn polymetallic ore fields in China. More than fifty years of exploration have resulted in the discovery of over ten Pb-Zn deposits, one silver deposit and four gold deposits containing ca. 1.5 Mt of Pb and Zn metals, 2000 ton of Ag metal, and 100 ton of Au metal (103GT, 1976). A large body of research has been carried out discussing aspects of the geology, geochronology, and geochemistry of Zn-Pb mineralization in this area, aiming to determine the ore genesis. Despite such extensive work, controversies still persist on a genetic model. At an early stage both a magmatic-hydrothermal origin (103GT, 1976) and a metamorphic origin (Zhang, 1984) were proposed for the mineralizing fluids. Subsequently, a Proterozoic sea floor exhalation model (Wang et al., 1994) and a sedimentation-metamorphism-hydrothermal reworking model (Jiang, 1987, Jiang, 1988, Jiang and Wei, 1989, Ding et al., 1992) were considered to account for the mineralization. More recently, the role of Mesozoic hydrothermal fluids in mineralization has been highlighted (Liu and Ai, 2002, Xue et al., 2003). The development of in-situ isotopic analysis has been further advancing the understanding of the mineralization age (Yu et al., 2009, Duan et al., 2014, Ma et al., 2016, Xu et al., 2020) and the sources of metals and sulphur (Yu et al., 2009, Duan et al., 2017) of the Qingchengzi Orefield, providing vital knowledge to constrain the genesis of the ore field. In particular, what the findings consistently suggest is that the Pb-Zn mineralization system in the Qingchengzi Orefield, including the Zhenzigou Zn-Pb deposit, represents a distal hydrothermal mineralization type related to the Triassic magmatic activity (Duan et al., 2017). In this study, we applied a novel Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) elemental mapping technique on an association of sulfide minerals (galena, sphalerite, pyrite, and arsenopyrite) from the Zhenzigou stratiform Zn-Pb deposit, in combination with in-situ spot analysis data, to reveal their elemental composition and distribution pattern. The compositional texture of the sulfide association carries crucial information regarding the nature and sequence of multi-stage mineralization events that are responsible for their precipitation.

The LA-ICPMS elemental mapping technique has been extensively applied on individual sulfide minerals such as sphalerite (e.g. Cave et al., 2020) and pyrite (e.g. Large et al., 2009, Zhou et al., 2019) for the discussion of ore genesis. The trace element maps of sulfide association have also been reported but not frequently, including for example, an arsenopyrite-pyrite association from an orogenic gold deposit in Australia (Cook et al., 2013), a galena-sphalerite-pyrite-chalcopyrite association from Pb-Zn deposits (George et al., 2015), and a sphalerite-pyrite-chalcopyrite association from the Sulitjelma Cu-Zn ore field (Lockington et al., 2014). Our examination of the full range of coexisting sulphide minerals (galena-sphalerite-pyrite-arsenopyrite) for the Zhenzigou Zn-Pb deposit allows a comprehensive understanding of the mineralization history in the stratiform Pb-Zn ore system. The trace element maps of the sulfide association provide key in-situ evidence reinforcing a sedimentation-metamorphism-magmatic-hydrothermal reworking model for the Zhenzigou Zn-Pb mineralization. Furthermore, by integrating the results of LA-ICPMS spot analysis, we present a full consideration of the metal partitioning behaviors among the coexisting sulfide minerals in the proposed model, which enables detailed characterization of metal paragenesis. Ultimately, our findings provide an insight into the behaviors of precious metals such as Au and energy critical metals such as In and Sn, among coexisting sulfide minerals. The approaches that we applied for this case study are applicable to address the relationship of fluid evolution and metal partitioning in a broad range of ore deposits, and the case study of the Zhenzigou Zn-Pb deposit can provides a suitable example for studying many other stratiform Pb-Zn deposits worldwide.

Section snippets

Regional geology

The Qingchengzi Orefield is located in the eastern Liaoning Province and it is tectonically situated in the Paleoproterozoic Liaodong Rift Zone (Fig. 1). This paleo rift is located on the northeastern segment of the North China Craton and extends for ca. 700 km trending NNE. It is bounded by the Tanlu fault to the west and extends to the Sea of Japan to the east. The development of the Liaodong Rift is the product of a series of tectonic events during the Palaeoproterozoic, including crustal

Deposit geology

The stratiform Zhenzigou Zn-Pb deposit is located in the east of the Qingchengzi Orefield (Fig. 2). The orebodies occur as conformable layers and lenses in interbedded fractures which are strictly restrained to the folded bedding (Fig. 3). Two stratigraphic intervals host the majority of ore bodies: the lower Dashiqiao Formation composed of graphite-bearing marble and the lower Langzishan Formation which is a graphite-bearing marble interbedded with amphibolite, and biotite schist bands.

Sampling and analysis

In order to distinguish the role of different fluids in assisting grain-scale redistribution of metals, we selected ore samples from the modified near-layer mineralization, which is the most common type of mineralization in the Zhenzigou Zn-Pb deposit. On the basis of microscopy observation, we further chose an association of sulfide phases of sphalerite-galena-arsenopyrite-pyrite from an individual thin section that represents the main mineralization stage. Due to the limited occurrence of

Mineral paragenesis

In our study of the Zhenzigou stratiform Zn-Pb deposit, evidence of macro- and micro-observation of ore texture demonstrates evident paragenesis of the sulfide association. The sharp grain boundaries between a euhedral arsenopyrite and a subhedral sphalerite, and between a euhedral pyrite and a subhedral sphalerite (Fig. 4f, g), suggest that sphalerite was precipitated at a later stage than euhedral pyrite and arsenopyrite. The penetration of mutual boundaries indicates that the fluids that

Multi-stage enrichment process

Pyrite is the most abundant of all sulfide minerals. It is commonly found in mineral deposits, in igneous and sedimentary rocks and their metamorphic equivalents. In addition, pyrite present in any given environment may have formed through more than one process at one or more separate times, and post-depositional effects may alter the composition of pyrite (e.g. Large et al., 2009). In the Zhenzigou Zn-Pb deposit, the irregular and rounded pyrite core (Py 0, Fig. 7) revealed in the trace

Conclusions and remarks

The compositional textures of a pyrite-sphalerite-galena-arsenopyrite association in the Zhenzigou stratiform Zn-Pb deposit suggest that three distinct fluids were responsible for the mineralization (Fig. 11). The earliest episode of fluids was released in an exhalative tectonic setting initiating at ca. 2052 Ma, resulting from de-watering of the Dashiqiao Formation. The fluid is low-temperature (<150 °C) and sedimentary in origin, corresponding to the formation of an early pyrite core (Py0).

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.

Acknowledgements

This research was funded by the National Natural Science Foundation of China (grant no. 41702090), the National Key R&D Program of China (Grant no. 2016YFC0600109), and National Key R&D Program of China (2016YFC0600108-03). Part of the article was written during the first author’s postdoctoral fellowship funded by the Geological Survey of Ireland. The analyses were carried out as a part of collaborative project between the Institute of Geology and Geophysics, the Chinese Academy of Sciences,

References (60)

  • P.M. Okita et al.

    Origin of stratiform sediment-hosted manganese carbonate ore deposits: examples from Molango, Mexico, and TaoJiang, China

    Chem. Geol.

    (1992)
  • O.V. Parasyuk et al.

    Phase diagram of the CuInS2–ZnS system and some physical properties of solid solutions phases

    J. Alloy. Compd.

    (2003)
  • R.L. Rudnick et al.

    Composition of the continental crust

    The crust

    (2003)
  • C. Sombuthawee et al.

    Phase equilibria in the systems ZnS-MnS, ZnS-CuInS2, and MnS-CuInS2

    J. Solid State Chem.

    (1978)
  • R.J. Turner

    Formation of Phanerozoic stratiform sediment-hosted zinc-lead deposits: evidence for the critical role of ocean anoxia

    Chem. Geol.

    (1992)
  • T. Van Acker et al.

    High-resolution laser ablation-inductively coupled plasma-mass spectrometry imaging of cisplatin-induced nephrotoxic side effects

    Anal. Chim. Acta

    (2016)
  • F.Y. Wu et al.

    Nature and significance of the early Cretaceous giant igneous event in eastern China

    Earth Planet. Sci. Lett.

    (2005)
  • L. Xu et al.

    Pyrite Rb-Sr, Sm-Nd and Fe isotopic constraints on the age and genesis of Pb-Zn deposits in Qingchengzi, northeastern China

    Ore Geol. Rev.

    (2020)
  • L. Ye et al.

    Trace and minor elements in sphalerite from base metal deposits in South China: a LA-ICPMS study

    Ore Geol. Rev.

    (2011)
  • G. Yu et al.

    Geochronological framework and Pb, Sr isotope geochemistry of the Qingchengzi Pb–Zn–Ag–Au orefield, Northeastern China

    Ore Geol. Rev.

    (2009)
  • L. Zhou et al.

    LA-ICP-MS elemental mapping of pyrite: an application to the Palaeoproterozoic atmosphere

    Precambr. Res.

    (2017)
  • 103GT (103 Geological Team and Research Group on Geology of Qingchengzi Pb Deposits), 1976. General Report of Geology...
  • E.A.J. Burke et al.

    Roquesite and Cu-In-bearing sphalerite from Långban, Bergslagen, Sweden

    Canad. Mineral.

    (1980)
  • Carne, R.C. and Cathro, R.J., 1982. Sedimentary exhalative (SEDEX) zinclead deposits, northern Canadian Cordillera:...
  • B. Cave et al.

    The effect of co-crystallising sulphides and precipitation mechanisms on sphalerite geochemistry: a case study from the Hilton Zn-Pb (Ag) Deposit, Australia

    Minerals

    (2020)
  • J.F. Chen et al.

    Pb isotope geochemistry of lead, zinc, gold and silver deposit clustered region, Liaodong rift zone, northeastern China

    Sci. China Series D

    (2005)
  • N.J. Cook et al.

    Arsenopyrite-pyrite association in an orogenic gold ore: tracing mineralization history from textures and trace elements

    Econ. Geol.

    (2013)
  • N.J. Cook et al.

    Distribution and substitution mechanism of Ge in a Ge-(Fe)-bearing sphalerite

    Minerals

    (2015)
  • T.P. Ding et al.

    Stable Isotope Studies on the Proterozoic Pb–Zn Mineral Belt of Northern China

    (1992)
  • X.X. Duan

    Integrated Research on Metallogenic Characteristics and Ore Genesis of Qingchengzi Polymetallic Orefield, Liaoning Province (Doctoral dissertation)

    (2015)
  • Cited by (13)

    • Mineralogical distribution and genetic aspects of cobalt at the active Fåvne and Loki's Castle seafloor massive sulfide deposits, Arctic Mid-Ocean Ridges

      2023, Ore Geology Reviews
      Citation Excerpt :

      Helium was used as carrier gas in the ablation cell and Ar and N2 were added at the ICP-MS interface to enhance signal sensitivity. Sets of parallel and overlapping line rasters were ablated sequentially across rectangular map areas and the laser beam size, fluence, repetition frequency, scan speed and dwell time were set according to the target sulfide grain sizes in each map (Zhou et al., 2020). The external standards MASS-1 and UQAC were measured at the beginning and at the end of each run to correct for mass bias and instrument drift.

    • Trace element compositions of galena in an MVT deposit from the Sichuan-Yunnan-Guizhou metallogenic province, SW China: Constraints from LA-ICP-MS spot analysis and elemental mapping

      2022, Ore Geology Reviews
      Citation Excerpt :

      Generally, Sb, Bi, Ag, Se, Tl, and Te are preferentially incorporated into galena, while Cd, Fe, Mn, Ge, Ga, Cu, and In are primarily concentrated in coexisting sphalerite (George et al., 2016, 2017; Wei et al., 2021; Zhou et al., 2020). The element partitioning between galena and associated sulfides has been attributed to intrinsic factors of the focused trace element and the host base metal sulfides (e.g., valence state, ionic radius, the availability of this element in the hydrothermal fluid, and the maximum capacity of the host mineral lattice), rather than external factors, such as physicochemical parameters (temperature, pressure, and redox conditions) during sulfide precipitation and the sources of base metals (George et al., 2016, 2017; Wei et al., 2021; Zhou et al., 2020). Trace element signatures of base metal sulfide minerals, especially sphalerite, have been widely employed to identify the genetic types of ore deposits (Frenzel et al., 2016; Yang et al., 2021; Ye et al., 2011).

    View all citing articles on Scopus
    View full text