Precambrian metamorphic crustal basement cannot provide much gold to form giant gold deposits in the Jiaodong Peninsula, China
Introduction
The gold province in the Jiaodong Peninsula, eastern North China Craton (NCC) is renowned worldwide for its large resource of >5000 t gold. Much effort has been made to understand the sources of such large-scale gold endowment (e.g., Deng et al., 2020b, Feng et al., 2020, Goldfarb and Santosh, 2014, Groves and Santosh, 2016, Li et al., 2015). The Jiaodong gold deposits formed in a short peak period of around 120 ± 5 Ma and occur in the Precambrian crustal basement which underwent high-grade metamorphism of amphibolite-facies to granulite-facies at 1.9–1.8 Ga (e.g., Deng et al., 2020a, Feng et al., 2020, Liu et al., 2013, Yang and Zhou, 2001, Zhai and Santosh, 2013, Zhang et al., 2020, Zhu et al., 2015). The early-stage metamorphism would have removed much gold and other mobile elements (e.g., Goldfarb and Santosh, 2014, Patten et al., 2020, Pitcairn et al., 2015a, Pitcairn et al., 2015b, Zhong et al., 2015). Theoretically, the Jiaodong Precambrian crustal basement thus should have been so depleted in gold and other ore-forming components that cannot be the main source for the later Mesozoic giant gold deposits (Goldfarb and Groves, 2015, Goldfarb and Santosh, 2014, Zhai et al., 2004). Therefore, recent models increasingly emphasize the key contribution from other reservoirs such as the metasomatized lithosphere mantle (Deng et al., 2020c, Goldfarb and Santosh, 2014, Groves et al., 2020, Li and Santosh, 2014, Wang et al., 2020).
However, for rocks from the Precambrian crustal basement, the gold contents reported in 1980s–1990s overall showed high values of a few ppb and even up to tens of ppb (Fig. 1). Besides, radiogenic Pb isotopes of gold ores generally overlap those of the Precambrian metamorphic rocks (Yang et al., 2014a). The Precambrian crustal basement thus was often inferred as the main gold source, that is, the remobilization of gold from the Jiaodong Precambrian crustal basement for the Mesozoic gold deposits (e.g., Yang et al., 2014a, Zhai and Santosh, 2013). Recently, Chen et al (2019) reported much lower gold contents with a mean of 0.8 ppb for drill cores of the Precambrian crustal rocks, but still followed the model of scavenging gold from Precambrian crustal basement for gold mineralization. Such low gold contents were interpreted to be the residual results after strong extraction from the presumably gold-rich crustal basement to form the gold deposits (Chen et al., 2019). This model is difficult to reconcile with the well-constrained mobile behavior of gold during high-grade metamorphism (e.g., Goldfarb and Santosh, 2014, Patten et al., 2020, Pitcairn et al., 2014, Pitcairn et al., 2006, Wang et al., 2019, Zhong et al., 2015).
The previously reported gold contents of Precambrian crustal basement show a large range which could be ascribed to several reasons: 1) the variable uncertainty of employed analytical methods at different times; 2) the overprint by ore-forming hydrothermal fluids that led to gold enrichment for analyzed rocks (Chen et al., 2019, Taylor et al., 1994); and 3) the heterogenous distribution of gold in crust rocks. Therefore, it is very necessary to apply high-precision analytical methods for well-characterized samples, particularly those without hydrothermal overprint, to better constrain the exact role of Precambrian metamorphic crustal basement for the giant gold deposits. If the high-grade Precambrian metamorphic crustal basement was confirmed to show high gold contents for giant gold mineralization, it would be crucial to revisit the classic orogenic gold deposit model (Goldfarb et al., 2001, Groves et al., 1998). If not, alternative sources would be the main contributor.
In this study, we use high-precision methods to systematically analyze the contents of Au, S and other relevant elements on the typical rock types of the Precambrian metamorphic crustal basement in the Jiaobei terrane. The studied samples include both surface outcrops and crustal xenoliths. In particular, the crustal xenoliths were not overprinted by ore-forming hydrothermal fluids and thus better reflect the pre-gold mineralization, pristine features of the metamorphic crustal rocks. Based on careful field sampling and petrological observation, we will display the strong depletion of gold contents in the Precambrian metamorphic crustal rocks and discuss its limited capability to provide gold for the Jiaodong gold deposits.
Section snippets
Geological settings
Jiaodong giant gold province, the most important region for gold reserves and production in China, is located at the Jiaodong Peninsula, eastern NCC (e.g., Deng et al., 2020c, Qiu et al., 2002, Song et al., 2018, Zhu et al., 2015). The Jiaodong Peninsula lies to the east of the trans-lithospheric Tanlu fault zones and comprises the Jiaobei terrane in the north and Sulu ultrahigh-pressure metamorphic belt in the south, separated by the Wulian-Yantai fault (e.g., Song et al., 2019, Zhao et al.,
Sampling
In this study, we mainly sampled the Precambrian basement crustal rocks from the Jiaobei terrane that hosts the predominant gold reserves of the Jiaodong Peninsula. The collected samples were mainly from surface outcrops in the Zhaoyuan and Qixia districts and also included the crustal xenoliths hosted in Guojialing granodiorites (Fig. 2, Fig. 3 and see details in Supplementary Table S1).
If the preexisting metamorphosed rocks had been affected by later ore-forming hydrothermal fluids, their
Sample preparation and analytical methods
Considering the possible low gold contents in high-grade metamorphic rocks, careful sample preparation was carried out. Visibly altered surfaces of outcrop samples were removed with a rock saw. A few crustal xenoliths were also cut in that they showed scratch of hammer formed during sampling. Each cut surface was abraded with silica emery paper and washed with 18.2 Ω Milli-Q (Nanopure) water, and subsequently dried overnight. Rock pieces of about 100 g were crushed into small chips and
Main results
Major elements, trace elements and other metal contents of the studied Precambrian samples are listed in Table S1. They show a large range of compositions (n = 41), coving typical mafic and felsic crustal metamorphic rocks in the Jiaobei terrane (Fig. 4). The Archean and Paleoproterozoic mafic rocks display similar major compositions of SiO2 and MgO, different from those of TTG gneisses and pelitic granulites. The crustal xenoliths are mostly amphibolites, and their compositions are close to
Low gold abundances in the Precambrian metamorphic basement
The outcrop samples measured in this study include typical rock types from high-grade Precambrian basement, such as Archean TTG gneisses and the Jiaodong Group, and the Paleoproterozoic Fengzishan Group and Jingshan Group. During early Cretaceous (about 120 ± 5 Ma), large-scale hydrothermal gold mineralization occurred in the Jiaobei terrane and may have affected the outcrops and even deep rocks around gold deposits or fault series. For example, the drill cores of 4 km depth which were affected
Conclusions
Agreement was not achieved about whether the Precambrian metamorphic crustal basement as the main source contributed to the gold reserves (>5000 t) of Jiaodong giant gold deposits, eastern NCC. Based on the well-constrained geological settings and field conditions, we have obtained the abundances of Au, S and other associated metals in the representative rocks (n = 40) of Precambrian crustal basement in the Jiaobei terrane. The metamorphic crustal rocks of surface outcrops were sampled far from
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
We thank Haihong Chen, Xiang Wang and Kang Chen for kind support in the lab, and Yan Wang, Xinfu Zhao and Jianwei Li for insightful discussion. We also appreciate the great help from the colleague of Linglong gold mine during fieldwork. The editor Dr. Guochun Zhao and two anonymous reviewers are thanked for their constructive comments which greatly improve the quality of the manuscript. This study was supported by National Key R&D Program of China (No. 2016YFC0600103) and National Natural
Author contributions
Z. Wang, J. Yang and K. Zong designed the project. Z. Wang, Z. Xu, H. Cheng, Y. Zou, J. Guo and L. Xiong collected the samples. Z. Wang, Z. Xu, H. Cheng, Y. Liu and Z. Hu performed the measurements. Z. Wang and Z. Xu wrote the manuscript, and all authors contributed to the data interpretation and revised the manuscript.
References (78)
- et al.
Decratonic gold mineralization: evidence from the Shangzhuang gold deposit, eastern North China Craton
Gondwana Res.
(2018) - et al.
Gold mineralization in China: Metallogenic provinces, deposit types and tectonic framework
Gondwana Res.
(2016) - et al.
Orogenic gold: Common or evolving fluid and metal sources through time
Lithos
(2015) - et al.
Orogenic gold and geologic time: a global synthesis
Ore Geol. Rev.
(2001) - et al.
The dilemma of the Jiaodong gold deposits: are they unique?
Geosci. Front.
(2014) - et al.
Orogenic gold deposits: a proposed classification in the context of their crustal distribution and relationship to other gold deposit types
Ore Geol. Rev.
(1998) - et al.
The giant Jiaodong gold province: the key to a unified model for orogenic gold deposits?
Geosci. Front.
(2016) - et al.
Titanite-scale insights into multi-stage magma mixing in Early Cretaceous of NW Jiaodong terrane, North China Craton
Lithos
(2016) - et al.
The ‘Jiaodong type’ gold deposits: characteristics, origin and prospecting
Ore Geol. Rev.
(2015) - et al.
Metallogeny and craton destruction: Records from the North China Craton
Ore Geol. Rev.
(2014)
Linking lithospheric thinning and magmatic evolution of late Jurassic to early cretaceous granitoids in the Jiaobei Terrane, southeastern North China Craton
Lithos
Thinning and destruction of the lithospheric mantle root beneath the North China Craton: a review
Earth Sci. Rev.
Discovery and geological significance of high-pressure mafic granulites in the Pingdu-Anqiu area of the Jiaobei Terrane, the Jiao–Liao–Ji Belt, the North China Craton
Precambr. Res.
Petrogenesis, P-T–t path, and tectonic significance of high-pressure mafic granulites from the Jiaobei terrane, North China Craton
Precambr. Res.
Lithospheric and asthenospheric sources of lamprophyres in the Jiaodong Peninsula: a consequence of rapid lithospheric thinning beneath the North China Craton?
Geochim. Cosmochim. Acta
Geochronological framework of the Xiadian gold deposit in the Jiaodong province, China: Implications for the timing of gold mineralization
Ore Geol. Rev.
The gold conveyor belt: Large-scale gold mobility in an active orogen
Ore Geol. Rev.
Mobility of gold during metamorphism of the Dalradian in Scotland
Lithos
4.1 – Composition of the Continental Crust
Geochemistry of Archean shoshonitic lamprophyres from the Yilgarn Block, Western Australia: Au abundance and association with gold mineralization
Appl. Geochem.
Windows of metamorphic sulfur liberation in the crust: Implications for gold deposit genesis
Geochim. Cosmochim. Acta
Genesis of two different types of gold mineralization in the Linglong gold field, China: constrains from geology, fluid inclusions and stable isotope
Ore Geol. Rev.
Linking Mesozoic lode gold deposits to metal-fertilized lower continental crust in the North China Craton: Evidence from Pb isotope systematics
Chem. Geol.
Reactivation of the Archean lower crust: implications for zircon geochronology, elemental and Sr–Nd–Hf isotopic geochemistry of late Mesozoic granitoids from northwestern Jiaodong Terrane, the North China Craton
Lithos
Juvenile vs. recycled crust in NE China: Zircon U-Pb geochronology, Hf isotope and an integrated model for Mesozoic gold mineralization in the Jiaodong Peninsula
Gondwana Res.
The early Precambrian odyssey of the North China Craton: a synoptic overview
Gondwana Res.
Metallogeny of the North China Craton: link with secular changes in the evolving Earth
Gondwana Res.
Late Archean to Paleoproterozoic evolution of the North China Craton: key issues revisited
Precambr. Res.
Lithotectonic elements of Precambrian basement in the North China Craton: review and tectonic implications
Gondwana Res.
Indentation-induced tearing of a subducting continent: evidence from the Tan–Lu Fault Zone, East China
Earth Sci. Rev.
Stable isotope geochemistry of ultrahigh pressure metamorphic rocks from the Dabie-Sulu orogen in China: implications for geodynamics and fluid regime
Earth Sci. Rev.
Fate of gold and base metals during metamorphic devolatilization of a pelite
Geochim. Cosmochim. Acta
Carlin-style gold province linked to the extinct Emeishan plume
Earth Planet. Sci. Lett.
Timing of destruction of the North China Craton
Lithos
Discovery of kyanite in typically cordierite/sillimanite-bearing low- to medium-pressure pelitic granulites from the Jiaobei terrain, North China
Craton. Precambr. Res.
Metamorphic evolution and Zircon U-Pb ages of the Nanshankou Mafic high pressure granulites from the Jiaobei Terrane, North China Craton
J. Earth Sci.
The Dabie-Sulu orogenic peridotites: progress and key issues
Sci. China Earth Sci.
Study on Geochemical Background Field of the Gold Deposits in Jiaodong, China
Gold Sci. Technol.
High-precision determination of gold mass fractions in geological reference materials by internal standardisation
Geostand. Geoanal. Res.
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2022, Journal of Asian Earth SciencesCitation Excerpt :The sulfur isotopic signatures of altered wall rocks in Majiayao deposits are thought to be inherited from Jiaodong Precambrian crustal basement, indicating that the basement could provide sulfur for the ore-forming fluids (Feng et al., 2021; Hu et al., 2022). Some Precambrian metamorphic rocks in the Jiaodong Peninsula contain a few sulfides and high S concentrations, but the high-grade metamorphism strongly depleted the Precambrian crustal basement in Au (Goldfarb and Santosh, 2014; Wang et al., 2021b). Thus, the basement cannot be the predominant Au source for the Jiaodong gold deposits.