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Shanghua-Yunpan Sulphide Belt - Shanghua, Yunpan, Helan, Motianling |
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Liaoning, China |
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Cu S
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The arcuate, generally east-west trending, ~100 km long Shanghua-Yunpan Sulphide Belt is located in southern Liaoning Province of north-eastern China. It includes a number of stratabound Cu-Fe deposits, such as Shanghua and Yunpan which are ~60 km apart and located towards the opposite ends of the belt, as well as Helan and Motianling 15 km NNE of Shanghua and 25 km NW of Yunpan respectively.
The 400 to 700 m thick host Palaeoproterozoic Northern Liaohe Group comprises tuff dominated meta-volcanics and meta-sediments (arkoses and dolostones) which have been metamorphosed to greenschist to amphibolite facies. The ore sequence comprises in ascending order, pyroclastics, terriginous clastics and carbonates. Extensive albite rich breccias are found at the base of the sequence and as pipes cutting a variety of lithologies and are interpreted to represent original transgressive salt domes. Fe and Cu sulphides and sulphates occur at the transition from tuffs to dolomitic carbonates and are predominantly at two sites, namely i). around proximal venting centres as breccias, lenses and veins, and ii). as stratabound pyrite-chalcopyrite associated with anhydrite that is distal to the salt domes. Proximal ores are accompanied by brecciated albite and tourmaline rich rocks while the distal ores are associated with sulphates. This overview is expanded below with more detail.
The deposits of this district contain around 15 Mt of 35% pyrite, 4 Mt of chalcopyrite and 0.1 Mt of anhydrite (Wang et al., 1998).
The Shanghua, Yunpan and related deposits lie within the Palaeoproterozoic Jiao-Liao-Ji Belt which separates the Archaean cratonic Longgang and Nangrim blocks to the north and south respectively. The sequence within the Jiao-Liao-Ji Belt is divided by a major fault into the Northern and Southern Liaohe groups that were deposited in the Liaodong Rift Zone. The Northern Liaohe Group is much thicker and contains fewer volcanic units. It has undergone greenschist to amphibolite facies metamorphism, whilst the Southern Group is areally much more extensive, has been uniformly metamorphosed to amphibolite grade, and is accompanied by granitoids that are coeval with that metamorphism. Geochronological dating has yielded ages of 2.3 and 1.9 Ga for both groups, interpreted to represent deposition and metamorphism respectively (Wang et al., 1998).
The Northern Liaohe Group has been divided from base upward into the:
• Langzishan Formation - a thick pile of clastic sedimentary rocks with a basal conglomerate unconformably overlying Archaean granitoids. Unconformity style uranium mineralisation is found at the base of this sequence;
• Lieryu Formation - composed of metamorphosed tuffs, clastic sedimentary rocks and carbonates, as described below. It hosts an east-west striking belt on stratabound pyrite mineralisation that occurs over a strike length of up to 100 km;
• Gaojiayu Formation - which comprises organic rich sedimentary rocks;
• Dashqiao Formation - dominantly carbonate rocks, and
• Gaixian Formation - mainly composed of clastic sedimentary rocks.
The Southern Liaohe Group has a basal meta-evaporitic sequence in its basal sections that is correlated with the sulphide hosting sequence of the Northern Liaohe Group. These meta-evaporites are Mg-rich carbonates that host large borate deposits which have been metamorphosed to tourmaline rich rocks. Mesozoic granites intrude the sulphide bearing sequence in the west and resulted in silicification and hornfelsing of the country rock and the formation on local sulphide veinlets (Wang et al., 1998).
The Shanghua and Yunpan deposits are hosted by the Palaeoproterozoic Lieryu Formation of the Northern Liaohe Group. This formation is principally composed of metamorphosed tuffs, clastic sedimentary rocks and carbonates that total 400 to 700 m in thickness. Tuffaceous rocks predominate in the lower section whilst clastics and carbonates make up the upper portion of the sequence. Brecciated sodic-albitic volcanic rocks form a marker horizon at the base of the tuffs, but also occur as pipes crosscutting the Lieryu Formation. These pipes cut tuffs and clastic rocks of the formation, but do not reach the upper carbonate units. Bedded, fine grained, quartzo-feldspathic rocks with well preserved pyroclastic textures comprise >50% of the host sequence. Their mineralogy is dominantly quartz (up to 30%), albite and biotite with lesser augite, scapolite, actinolite and magnetite. They are locally enriched in tourmaline (up to 10%), occurring as layers parallel to bedding. Albite enrichment is associated with the brecciation, forming a proximal zone, whilst microcline is the dominant feldspar distal to the breccias. The thickness of the sedimentary rocks and tuffs on the flanks of the domes is greatest (>200 m) adjacent to the breccias. The clasts in the breccia are similar to the surrounding lithologies, in a matrix of coarse grained albite and quartz, whilst the breccia margins are cemented by carbonates, talc or pyrite, commonly containing tourmaline. Sedimentary structures in the tuffs surrounding the breccias suggest the breccias are associated with synsedimentary domal uplift, surrounded by rim sinks. Clastic sedimentary rocks account for ~10% of the ore bearing sequence and are located between the tuffs and overlying carbonates and as intercalations within those lithofacies. They comprise up to 90% microcline, 10 to 70% quartz, minor albite, carbonates and biotite-sericite with up to 5% iron oxides and a similar amounts of graphite. These metamorphosed sedimentary rocks are interpreted to represent red-bed arkoses, and may contain up to 10 µm native copper grains. Carbonates account for 20 to 40% of the host sequence. They are banded and vary from dolostone to limestone, with the former being associated with sulphide mineralisation distal to the breccias, and the latter being found adjacent to the breccias. These rocks are frequently associated with substantial amounts of anhydrite and actinolite (Ca2Si8O22(OH)2) and are gradational with anhydrite bodies. Minor biotite and quartz grains enclosed within either carbonates or anhydrite form a texture interpreted to indicate a detrital origin. Actinolite-albite rich volcanic and actinolitic rocks are the immediate host to stratabound sulphide-sulphate mineralisation. Actinolite also characterises the transition between the albitic tuffs and the overlying carbonates, and is interpreted to represent protoliths of impure tuffaceous carbonates or marls (Wang et al., 1998).
The sulphide belt has been deformed by clusters of folds, each composed of numerous anticlines and synclines with large variations in thickness and lithology across the folds. Albite-rich breccias occur as pipes or domes in the cores of the anticlines, whilst carbonates and clastics thicken away from the cores. The variation of thickness cannot be solely accounted for by deformation and is suggested to reflect the mobilisation and dissolution of evaporites and introduction of salt domes. The same pattern is not observed in the formations above and below (Wang et al., 1998).
Sulphide mineralisation has a close association with breccia centres, with all ores restricted to zones surrounding the breccias, with the thickness of s and sulphate being rocks being greatest in depressions surrounding the breccias. Sulphides occur in three modes: i). as veins or stockworks within the breccias, which are only of minor economic importance; ii). lenses and adjacent to the breccias; or iii). stratabound to sub-stratabound bodies distal to the breccias, accounting for >90% of the sulphide mineralisation in the deposits. The first two types are hosted in breccias, or in metamorphosed tuffs or clastic sedimentary rocks close to breccia pipes, whilst the third type are hosted in metamorphosed tuffaceous dolostone immediately overlying the metatuffs (Wang et al., 1998).
The main sulphides in the deposits are pyrite and chalcopyrite, with minor pyrrhotite. Pyrite dominates to the east, and chalcopyrite to the west. In the Yunpan district, >95% of the sulphides are pyrite, whilst at Shanghua, chalcopyrite is dominant. Within the ore bearing sequence, chalcopyrite and pyrite are concentrated in the lower and upper parts on the section respectively. Three mineralogic categories have been recognised within the ores of the pyrite belt; i). sulphide-silicate, closer to the breccias; ii). sulphide-carbonate; and iii). sulphide-sulphate distal to the breccias. The gangue mineralogy of the ores is intimately related to the host lithology. In addition to the sulphides, the gangue is dominantly composed of albite and quartz with varying biotite and magnetite. In the breccias, albite- and quartz- clasts are cemented by sulphide cements or veins, both suggesting late sulphide precipitation. In stratabound and semi-concordant ores, pyrite and chalcopyrite are intergrown with albite and quartz, with the appearance of bedding, with <10 µm grains of magnetite enclosed by albite, and were probably precipitated during albitisation. Where sulphides are associated with anhydrite, mineralisation is characterised by sulphide or anhydrite + dolomite ± calcite, with variable biotite or actinolite. Sulphates include anhydrite, gypsum and barite. Anhydrite is stratabound to semi-concordant and is restricted to the eastern part of the belt where it is intercalated with conformable sulphides. Where pyrite and anhydrite are in contact, the two minerals are intergrown. Gypsum also occurs as veins within the sulphide ores, with accompanying hematite, suggestive of an oxidised regime during formation. Only minor barite is found, occurring in fractures within sodic tuffs, and has no zonal pattern to the occurrence of anhydrite or sulphides (Wang et al., 1998).
NOTE: The Liaohe Group on the northern margin of the Liaodong Rift Zone and Jiao-Liao-Ji Belt also carries sediment hosted Zn-Pb mineralisation as at the Qingchengzi Pb-Zn-Au-Ag Ore Field as well as some gold mineralisation within the Changbaishan Mountains Gold Province.
The most recent source geological information used to prepare this decription was dated: 1998.
Record last updated: 24/12/2020
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
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An-Jian Wang, Qi-Ming Peng, Palmer M R 1998 - Salt dome-controlled Sulfide precipitation of Paleoproterozoic Fe-Cu Sulfide deposits, Eastern Liaoning, Northeastern China: in Econ. Geol. v93 pp 1-14
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Deng, J. and Wang, Q., 2016 - Gold mineralization in China: Metallogenic provinces, deposit types and tectonic framework: in Gondwana Research v.36, pp. 219-274.
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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