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Changbaishan Mountains Gold Province, Liaodong, Jiapigou and Laoling Districts - Wulong, Sidaogou, Maoling, Baiyun, Linjiasandaogou, Xiaotongjiapuzi, Xiadapu, Xicha, Nancha, Huanggoushan, Caocuo |
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China |
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Au
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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The Changbaishan Mountains Gold Province in Liaoning and Jilin Provinces in NE China incorporates two main districts of significant lode gold deposits that have been mined for more than 100 years. These are located to the NE and SW respectively, separated by numerous, sporadically distributed, generally less significant deposits and clusters.
To the SW is the Liaodong District, which includes several clusters of deposits, the most significant of which are: Wulong,
Maoling,
Sidaogou,
Baiyun,
Linjiasandaogou and Xiaotongjiapuzi, all of which are hosted by Palaeoproterozoic metasedimentary rocks, intruded throughout the area by Jurassic granitoids.
Approximately 400 km to the NE are the deposits of the Jiapigou District in the Fushun-Antu region of Jilin province that are hosted by Archaean basement gneiss and amphibolite with widespread late Palaeozoic and Jurassic to Cretaceous granitoids. Most gold deposits of this latter district, which are described in a separate record, are distributed as a NW-SE trending belt within an Archaean greenstone-granite terrane, but are only ~5 km south of a Permo-Carboniferous granitoid province.
A third, less significant group of deposits defines the Laoling District, which is located ~150 km NE of Baiyun, between the Liaodong and the Jiapigou districts to the SW and NE respectively, and includes Xiadapu, Xicha, Nancha, Huanggoushan and Caocuo which are each briefly described below under the Laoling District heading. The geology in this cluster is dominated by an Archaean Nucleus, flanked to the SE by Palaeoroterozoic metamorphic rocks of the Jiao-Liao-Ji Belt, and to the NW, south and east by Mesoproterozoic to Palaeozoic sedimentary rocks. Gold mineralisation is hosted in all of these suites, which are intruded by Proterozoic and Early Jurassic to Late Cretaceous granitic rocks, and overlain by Mesozoic volcanic sheets.
Other deposits are scattered throughout, between and to the SW of these districts.
These districts represent the easternmost of a series of clusters of 'orogenic' style lode gold deposits distributed over the ~1500 km long northern margin of the North China Craton extending from the middle of Inner Mongolia, through northern Hebei and Liaoning, to Jilin Province. Together all of these clusters account for an endowment more than 900 tonnes of gold.
The northern margin of the North China Craton is characterised by east-west trending basement uplift blocks of metamorphosed Archaean and Palaeoproterozoic gneiss, schist, granulite, amphibolite and banded iron formation that have been episodically uplifted during Variscan (Permo-Carboniferous), Indosinian (Triassic) and Yanshanian (Jurassic to Cretaceous) tectono-magmatic events. Slightly metamorphosed Mesoproterozoic to Neoproterozoic shallow marine quartzite, slate and limestone, and Palaeozoic to Cretaceous shallow marine to continental sedimentary rocks, surround the uplifts. Most of the deposits are hosted by uplifted blocks of Precambrian metamorphic rocks, although Palaeozoic and Mesozoic felsic plutons are commonly found in close proximity and host around 30% of the mineralisation.
A selection of the more significant deposits of the three districts are described below:
Liaodong District
This district covers much of the Liaodong Peninsula and its hinterland to the east of the major, NNE-SSW continental scale Tan Lu Fault. It has also been referred to as the Qingchengzi Au-Ag Orefield (e.g., Li et al., 2020) and coincides with the Qingchengzi Pb-Zn-Ag Orefield. It is composed of supracrustal rocks that include metamorphosed Archaean tonalite-trondhjemite-granodiorite (TTG) gneiss, of the Northern Liaoning Complex in the north and the Jinzhou Complex in the south. Palaeoarchean basement dated between 3850 Ma and 3200 Ma has been identified near Anshan, north of the Liaodong Peninsula (Wu et al., 2008). Deformed Neoarchaean diorite, tonalite and granodiorite were emplaced at ~2.5 Ga (Lu et al., 2004). The Archaean basement is overlain by the Palaeoproterozoic mafic to felsic volcano-sedimentary Liaohe Group which contains detrital zircons with unimodal 207Pb/206Pb age peaks at ~2.2 to 2.1 Ga (Wang et al., 2020).
On the basis of petrographic observations, four distinct mineral assemblages are recognised in the granulites of the Liaohe Group (Liu, et al., 2019):
• Pre-peak amphibolite facies, which is preserved as fine-grained inclusions in the cores of garnet grains, represented by the assemblage of quartz, plagioclase, biotite and ilmenite at P = 0.66 to 0.71 GPa and T = 620 to 650 °C;
• Peak granulite facies, interpreted to have comprised garnet, sillimanite, plagioclase, quartz, biotite, ilmenite and melt at P = 0.96 to 1.10 GPa and T = 790 to 840 °C;
• Post-peak decompression, characterised by cordierite+sillimanite symplectites and cordierite + quartz coronas replacing garnet at P = 0.62 to 0.65 GPa and T = 725 to 785 °C; and
• Late cooling retrogression, which is indicated by the formation of staurolite, accompanied by the crystallisation of melt at P = 0.43 to 0.55 GPa and T = 595 to 625°C.
Three distinct ages have been determined for these rocks (U-Pb zircon and monazite; Liu, et al., 2019): i). 2200 to 2100 Ma for the protoliths, as detailed above; ii). 1945 Ma for the near-peak metamorphism, and iii). 1851 to 1839 Ma for the post-peak and late retrogressive metamorphism. The peak to post peak metamorphism at ~1.93 Ga marks the cratonisation of the Eastern Block of the North China Craton (Zhang et al., 2001; Luo et al., 2004).
The Liaohe Group was accompanied by voluminous Palaeoproterozoic granitoids, comprising pre-tectonic deformed 2.09 to 2.17 Ga A-type granites and undeformed post-tectonic 1.85 to 1.88 Ga (U-Pb zircon; Lu et al., 2004, 2006; Li and Zhao, 2007) alkaline syenites and rapakivi granites (Hao et al., 2004; Li and Zhao, 2007). Subsequently, the Liaodong Peninsula was covered by Neoproterozoic (Sinian) volcaniclastic rocks that have been metamorphosed to greenschist or amphibolite facies, followed by widely distributed Mesozoic volcanic rocks and plutons (Song et al., 1996), which are widely distributed in the region (Wang and Mo, 1996). The volcanic and plutonic rocks of these younger sequences have been divided into: i). Late Triassic (231 to 210 Ma) dolerite, diorite and monzogranite with microdiorite enclaves; ii). Jurassic (180 to 153 Ma) tonalite and diorite, and gneissic granite, which is medium-grained metaluminous to slightly peraluminous biotite granite dated at 164±7 Ma (Yang et al., 2003) and iii). Early Cretaceous (131 to 120 Ma) undeformed to slightly deformed diorite, granodiorite, monzogranite and syenogranite (Yang et al., 2004, 2007; Wu et al., 2005), including porphyritic hornblende-biotite granodiorite with an age of 124±2 Ma (Zhang, 2002). Numerous mafic to intermediate dykes accompanying the gold lodes have been dated as 135 to 115 Ma (Zhang, 2002).
Two styles of gold mineralisation have been differentiated in the district, one is quartz vein-type gold mineralisation, typically hosted in second or third order faults cutting Mesozoic granitoids, such as at Wulong, Xiayingzi, Xiadabao and Wangjiadagou, whilst the second is hosted by Archaean to Palaeoproterozoic rocks with broad alteration halos as at Sidaogou, Maoling, Baiyun, Xiaotongjiapuzi and Xianjinchang, hosted by Archaean metamorphic rocks. All are controlled by NE and NNE to ENE trending faults (Yang et al., 2003).
The Liaodong Peninsula hosts 6 large deposits, Wulong, Baiyun, Xiaotongjiabaozi, Maoling and Sidaogou, tens that are medium to small, and hundreds of occurrences (Cheng, 2017, Wang et al., 2018, Zhu et al., 2015). To 2018, the Liaodong District had produced ~380 t of gold (Feng et al., 2019). All are interpreted to be related to Mesozoic magmatism, despite the the intense Archaean and Palaeoproterozoic orogenic activity and magmatism within the host sequences.
Wulong - which has an endowment of >80 t of gold with an average grade of 5.35 g/t Au. It is located in Dandong City, SE Liaoning Province, NE China. Mesozoic intrusive rocks, mainly Jurassic 163±7 Ma (Wu et al., 2005) gneissose monzogranite batholiths, are widespread throughout the deposit area, as well as lesser Cretaceous 129±3 Ma (U-Pb zircon; Wei et al., 2003) granodiorite of the Sanguliu stock which is mainly found in the south. Other ages for biotite-granite, granite porphyry and fine-grained diorites at the Wulong deposit yielded ages of 155.4 ± 0.9 Ma, 154.2±1.2 Ma and 123.1± 0.9 Ma, respectively (LA-ICP-MS zircon U-Pb; Liu et al., 2019). Scarce, discontinuous relicts of the Liaohe Group occur within the Jurassic gneissose monzogranite in the south of the deposit area. The Jurassic pluton also contains abundant felsic to mafic dykes which include diorite, granite porphyry, lamprophyre and dolerite. The Cretaceous diorite was emplaced in two phases, the first of which was pre-mineral, as evidenced by cross-cutting gold-bearing quartz veins, whilst the second is interpreted to be syn-mineral. Gold-bearing quartz veins are cut by lamprophyre dykes, whilst granite porphyry is cut by dolerite (Zhang et al., 2020). The association of mineralisation with the diorites if consistent with age dating of sericite from gold ore that yields a 40Ar/39Ar plateau age of 122.8± 0.8 Ma (MSWD = 0.09; Liu et al., 2019) similar to that of the diorite.
Well developed faulting is divided into primary NNE striking structures, which include the Jixinggou Fault, as well as secondary and tertiary faults trending north-south, east-west, NW and NE. These structures controlled the magmatism and metallogenesis at Wulong. The spatial distribution of orebodies was controlled by sinistral displacement along the Jixingou Fault, aided by secondary faults that strike NNE and NW (Zhang et al., 2020). North-south and east-west trending postmineral faults are occupied by lamprophyre and dolerite, whilst north-south and NNE trending pre-mineral structures are dominantly extensional and filled by fine-grained diorite and granitic porphyry dykes (Liu et al., 2018; Yu et al., 2018).
Gold mineralisation is distributed around the Early Cretaceous Sanguliu granitic pluton (Feng et al., 2019), largely occurring as veins and veinlets hosted by Jurassic gneissose monzogranite and Cretaceous fine-grained diorite veins, mainly as quartz-veins and in alteration halos. Some 380 of the 447 orebodies identified in the deposit to 2019, occur as auriferous quartz veins, whilst 67 are silicified alteration zones. Most extend to depths of 200 to 300 m with an average thickness of 0.2 to 4.0 m. The largest orebody, V163, strikes NW, dips at 65 to 70°SW, has a strike length of 1230 m, vertical extent of ~290 m and thickness of 0.5 to 11.6 m. The next largest, V80, strikes NNE, dips at 80°E, has a strike length of 430 m, vertical extent of ~237 m and thickness of 0.3 to 2.5 m (Zhang et al., 2020).
Metallic minerals are dominantly pyrite, sphalerite, pyrrhotite, scheelite, chalcopyrite, arsenopyrite, bismuthinite and native gold, with a gangue assemblage that includes quartz, calcite, feldspar and sericite. The ore displays characteristic subhedral and anhedral granular textures, and metasomatic textures, and has disseminated, veinlet-disseminated and massive textures. Wall-rock alteration is pervasive, dominated by silica, pyrite, sericite and carbonate (Peng et al., 1994; Wang et al., 2010). Silica and pyrite are closely associated with gold mineralisation (Zhang et al., 2020).
Four stages of mineralisation have been distinguished:
Stage I - a barren, typically milky white vein stage without sulphides, but with native gold within the veins;
Stage II - pyrite and pale-grey quartz veining that crosscuts the milky quartz veins of the previous stage;
Stage III - quartz-polymetallic sulphide vein stage, characterised by sulphide enrichment, including pyrite, sphalerite, pyrrhotite and chalcopyrite, with dark-grey to black quartz, all of which crosscut Stage II veining. The pyrite, chalcopyrite and pyrrhotite are generally disseminated within the vein, with the latter being partially replaced by pyrite and chalcopyrite;
Stage IV - characterised by quartz and calcite, where carbonate veins cut quartz veins of the earlier stages (e.g., Stages I and II), typically occurring as coarse euhedral translucent quartz and calcite with a little accompanying pyrite.
Most of the gold at Wulong was emplaced during Stage III, occurring in its native form in pyrite and quartz. The gold grain-size ranges from 7 to 100 µm in diameter (Yu et al., 2018).
Maoling is located in Gaixian County of Liaoning Province, ~120 km west of the Wulong deposit. It is classified as an 'alteration-type gold deposit'. The deposit area is occupied by two metasedimentary rock units, the mid-Palaeoproterozoic Gaixan Formation of the Liaohe Group and the uppermost Palaeoproterozoic Yashulazi Formation of the Yongning Group, intruded by the Lower Jurassic Maoling Stock quartz monzonite.
The Gaixan Formation is the principal unit hosting the known gold mineralisation. It comprises lower to middle greenschist facies phyllites and schists, derived from thinly-bedded to massive pelites and siltstone, now dominantly an undifferentiated unit composed of sericite schist to phyllite, biotite schist and chlorite-sericite schist to phyllite. The unconformably overlying Yashulazi Formation occurs to the NE, east and south of the deposit area. It is principally composed of a fine-grained, pure quartzite in which any primary sedimentary fabric has been obscured by intense deformation and recrystallisation. The Maoling Stock intrudes rocks of the Gaixan Formation to the south of the deposit. It is a porphyritic quartz monzonite with K feldspar megacrysts up to 10 cm in length, exposed over an area of ~0.5 km2. The intrusion contains common thin aplite dykes that are texturally and compositionally similar to the voluminous Mesozoic intrusions surrounding the deposit area. A contact metamorphic aureole >1 km wide is described as surrounding the stock, characterised by an assemblage including sillimanite adjacent to the contact, grading outward through andalusite to distal biotite.
Disseminated gold mineralisation has been tested in two separate zones known as zones 1 and 4 (Lewis, 2003). The former had been much more intensely tested and documented, and hence is the basis of the description below. In both zones, gold mineralisation occurs within a sequence of phyllitic metapelites to meta-siltstones that have been metamorphosed to greenschist grade, and exhibit a complex history of ductile and brittle deformation events.
Zone 1 is a north-south elongated, moderately west-dipping, tabular body of mineralisation in the north of the deposit area. It is exposed over a strike length of ~700 and thickness of 200 m and persists for ~700 m down-dip, with as moderate plunge to the south. Its long dimensions are subparallel to the S2 foliation, and its boundaries crosscut stratification, with mineralisation in both well-bedded and non-stratified rocks. The northern section of the zone corresponds to a SE-dipping D2 fold limb, but to the south the zone boundaries cut eastward across the D2 folds. Grade continuity is good, with drill hole intervals of up to 150 m divided into 5 m composites having few to no such intervals assaying <1 g/t Au. The dimensions above are defined by the 0.5 g/t Au contour.
Mineralised phyllite to phyllitic siltstone comprises from a few up to 30% deformed quartz-sulphide veins, accompanied by a well defined alteration zonation from the surrounding unaltered country rock into the strongly mineralised core of the deposit. The unaltered periphery of the deposit grades inward to a broad outer halo of chlorite, sericite, weak silicification and fine-grained pyrrhotite that may extend up to a several hundred metres beyond the mineralised bodies. Quartz-sulphide veins are not common within this outer halo, but where present often have narrow selvages of fine-grained hydrothermal biotite and chlorite. Gold values are consistently anomalous, but normally do not exceed a few hundred ppb. This outer halo grades into a higher grade (i.e., >1 g/t Au) zone over a width that may vary from a few metres to as much as several tens of metres, and corresponds to an increase in the intensity of silicification, and abundance of sulphide and quartz+sulphide veins, which in intervals of >1 g/t Au is usually >5 vol.% of the rock. Individual quartz-sulphide veins have selvages of abundant hydrothermal biotite and chlorite. As the vein density increases, the selvages can coalesce into pervasive biotite-chlorite alteration.
Fine- to medium-grained pyrrhotite and fine- to coarse-grained arsenopyrite are the dominant sulphides. Where the sulphide content is poorest, pyrrhotite occurs as small disseminated blebs, usually oblate and parallel to the S2 cleavage plane. It also occurs as planar or folded sulphide veinlets that may either cross-cut and/or be deformed by S2, as well as occurring as a secondary mineral in quartz-dominant veins. It also commonly forms in pressure shadows adjacent to arsenopyrite grains, infilling fractures in coarse arsenopyrite rhombs, and infilling boudin necks in quartz veins. Arsenopyrite varies from fine-grained wallrock disseminations selectively concentrated in particular beds, to >1 cm rhombs in veins or in wallrock. Secondary sulphides occur locally, and include pyrite, sphalerite, galena and chalcopyrite.
Gold occurs in its native form or as electrum along fractures in arsenopyrite, pyrrhotite and quartz, within sulphide grains, as fine grains with pyrrhotite, and rarely as visible grains. Native gold occurs as grains that range from 0.5 to 200 µm.
Within the higher grade zones of the deposit, silicification varies from moderate to strong, and roughly correlates with quartz-sulphide vein density. Only rarely is it sufficiently intense completely obliterate pre-existing rock fabrics, and then only over an interval of a few metres, where the rock ranges from creamy white to light brown. K feldspar occurs as a late-stage alteration product, occurring as patches and microfracture infill, where it is very fine-grained, and difficult to identify in unstained hand-specimen.
At least four different veins styles have been differentiated:
• Quartz-sulphide veins containing variable quartz and pyrrhotite, with lesser arsenopyrite as dominant mineral assemblage. Both chlorite and biotite occur as accessory vein infill. These are by far the most abundant vein type within the mineralised zone, typically being only 1 to 2 cm in thickness, and occurring as semi-sheeted arrays or less commonly, as stockworks of irregular veins. Quartz is fine grained, clear grey and recrystallised with 120° triple junctions as seen in thin section. Sulphides range from fine-grained to coarse rhombs. These veins range from undeformed and planar, to folded and strongly boudinaged.
• Sulphide veins that are almost entirely composed of pyrrhotite and coarse arsenopyrite, which coexist with the quartz-sulphide veins, but in much lesser abundance. They are typically moderately folded, and may both cut and be cut by quartz-sulphide veins, suggesting the two sets formed roughly synchronously.
• Quartz only veins, which are dominantly planar and undeformed, and cut both quartz-sulphide and sulphide veins. They may be >1 m in thickness, but with limited continuity, and are found locally within fault zones, where they may occur as tension gash arrays and can be strongly brecciated. The quartz is typically white and fine grained.
• Carbonate veins, that are thin, white crackle veinlets concentrated in patches both within and outside of the mineralised zones, crosscutting quartz-sulphide veinlets. They are only weakly deformed, and are interpreted to have formed later than all of the other vein sets.
Within the mineralised zone, sulphide and quartz-sulphide veins exhibit variable orientations and degrees of post-emplacement deformation, as follows:
i). Weakly-deformed veins that are either completely planar or only slightly buckled, which usually occur as isolated single veins, and frequently lack alteration selvages. Such veins tend to be oriented at high angles to the S2 foliation, mostly striking NNE with steep east dips, and cut more highly deformed veins.
ii). Moderately-deformed veins that occur as open to tight folds and occur as either isolated single veins or in sheeted vein sets. They are characterised by strong biotite-chlorite alteration envelopes and are folded about axial surfaces parallel to S2, and occasionally S1 foliations. The envelope that enclose the zone of veining strikes NE-SW and dips steeply NW to vertical. These veins are cut by the weakly deformed veins, but cut the more highly-deformed veins.
iii). Highly-deformed veins, which may be tightly folded, although more commonly are sub-planar, moderately- to highly-boudinaged and either transposed into parallelism with, or cut shallowly across S2 foliation. In the latter case, where they cut S2, they usually have slightly steeper dips. They generally have moderate to steep westerly, or less commonly, easterly dips. They mainly occur as sheeted sets, with strong alteration selvages.
Published NI 43-101 compliant Mineral Resources (Mundoro Capital website viewed December, 2020) are:
Measured + Indicated resources - 161 Mt @ 0.92 g/t Au for 148 t of contained gold;
Inferred resource - 63 Mt @ 0.8 g/t Au for 50 t of contained gold.
These resources are based a bulk mining open pit heap leach operation. Alternatively, an underground high grade operation resource of >60 t gold with an average grade of 8 g/t Au is quoted by Zhou et al. (2002).
The information in this summary is largely derived from "Lewis, P.D., 2003 - Maoling Gold Project, Liaoning Province, China, Technical Report; an NI 43-101 Technical Report prepared by Lewis Geoscience Services Inc., Canada, for Mundoro Mining Inc., 122p."
Sidaogou is 15 km SE of the Wulong deposit in Liaoning Province. The deposit has produced >18 t of gold (Song, 2010) at an average grade of 7.0 g/t Au (Zhang, 2002). It is classified as an 'alteration-type gold deposit', hosted by metamorphic rocks of the Gaixian Formation, part of the Palaeoproterozoic Liaohe Group, mainly meta-sandstone, schist and marble occurring in 'interbedded brecciation zones' (Wang et al., 2011; Feng et al., 2019). Mineralisation occurs within broad, NE-trending alteration zones that are spatially jointly controlled by NE-trending faults that are third-order structures related to the Yalu River Fault (Zhang, 2002) and by the Shujing anticline developed in the hanging wall of that fault. Mineralisation is also interpreted to be genetically related to Lower Cretaceous Yanshanian intermediate to felsic magmatic activity (Wang et al., 2011; Feng et al., 2019). Alteration with is principally characterised by quartz, feldspar, sericite and calcite with associated pyrite, pyrrhotite, chalcopyrite and arsenopyrite (Zeng et al., 2020).
The observed ore paragenesis indicates mineralisation occurred in four stages (after Feng et al., 2019): Stage I, early quartz and albite; Stage II, the main ore stage involving quartz, sericite, pyrite and gold; Stage III the secondary ore stage, with quartz, polymetallic sulphides ±scheelite ±biotite ±gold; and Stage IV, late ore stage with the formation of calcite, ankerite ±quartz ±sulphide). The associated hydrothermal wall rock alteration is dominated by albitization in Stage I, silicification during all strages, sericitization in Stage II, sulphidation during stages II and III, and carbonates during Stage IV, with minor biotite developed locally during Stage III. Gold mineralisation primarily occurred in Stage II accompanied by intensive silica and sericite alteration and and sulphidation of the metamorphic wall rocks, and to a lesser extent in Stage III, with weak alteration resulting from relatively weak activity and small fluxes of ore fluids (Feng et al., 2019). As Jurassic volcanic rocks are mineralised in the district and mineralisation related alteration has been dated at 134 Ma (K-Ar; Wu et al., 1990 and reference therein), the deposit is interpreted to be of that age (Feng et al., 2019).
NOTE: No clear description of the dimensions and mineralisation has been encountered in the English language literature, but is assumed to be similar to the Maoling 'alteration-type gold deposit' described above.
Baiyun is located in Liaoning Province, ~90 km WNW and 100 km NE of the Wulong and Maoling deposits respectively. It falls within the broader Qingchengzi Pb-Zn-Au-Ag polymetallic ore field. The Baiyun deposit has reserves of >20 t of contained gold, with grades ranging from 1.20 to 42.0 g/t Au (mean = 5.86 g/t), and is composed of >20 orebodies (Sun et al., 2019).
The principal units within the Baiyun deposit area and immediate surrounds are the Dashiqiao and Gaixian formations of the Palaeoproterozoic Liaohe Group. These units are intruded by 1 to 8 km diameter Proterozoic granite and monzonitic granite bodies. The Dashiqiao Formation is composed of amphibolite, marble and tremolite schist, whilst the Gaixian Formation comprises marble, granulite and schist. All of these are intruded by the Late Triassic 224.2±1.2Ma (LA-ICPMS zircon U-Pb; Duan et al., 2012) Shuangdinggou biotite monzogranite and Xinling granite, and by quartz porphyry, diorite porphyry and lamprophyre dykes. The quartz porphyry dykes generally follow east-west trending faults and are mostly found in the hanging wall of orebodies. They are composed of ~10 vol.% subhedral to euhedral, 0.1 to 1.0 mm quartz phenocrysts set in a fine-grained, 0.02 to 0.04 mm, groundmass of quartz and plagioclase, and where adjacent to ore veins, have been sericitised and carry pyrite. The microdiorite dykes, which strike NW-SE and east-west, crosscut orebodies and are unaltered, are assumed to be post-mineral. They are composed of plagioclase, quartz, amphibole and biotite (Sun et al., 2019).
The Baiyun orebodies are primarily hosted by altered sillimanite-biotite schist and granulite of the Gaixian Formation. Two mineralisation styles are distinguished within the deposit. The dominant of these is the 'alteration-type gold deposit' (e.g., the No. 1, 2 and 11-4 veins), which is composed of veins (largely quartz free) that are spatially associated with faults that dip at 30 to 40°S. The remainder of the mineralisation occurs as 'auriferous quartz veins' (e.g., the No. 60-2 vein), which include a variety of quartz types, and are controlled by faults dipping 30 to 40°SE (Zeng et al., 2020).
Adjacent to veining within the ore zone, the host rocks have been pervasively sericitised and silicified, with the latter introduced during the development of quartz veins, as well as muscovite, chlorite and minor carbonate, mainly calcite. The altered schist also contains 2 to 5 vol.% pyrite and traces of chalcopyrite, mainly occurring as blebs within pyrite grains. Pyrite is typically disseminated, but may also locally occur as polycrystalline masses or bands (Zeng et al., 2020).
Gold occurs as electrum and is concentrated within both quartz veins and altered wallrocks, with fine-grained 5 to 70 µm electrum having an Au/Ag ratio from 67:33 to 75:25. Silver is also present as hessite (Ag2Te).
Three mineralising stages have been differentiated at Baiyun (Zeng et al., 2020):
i). Pyrite-quartz - characterised by 0.2 to 2.0 m thick veins composed of ~94% coarse-grained (1 to 3 cm) crystals of milky quartz (Qz1) and ~6% 0.2 to 5.0 cm subhedral to euhedral pyrite (Py1) that is commonly fractured, and is typically disseminated within the vein. Some of electrum post-dates Py1, dominantly occurring as veinlets along fractures in Py1 and along Py1 boundaries. Gold-bearing veins of this stage cut altered schists within brittle fractures.
ii). Pyrite-quartz-chalcopyrite veinlets and stockworks composed of fine-grained quartz (Qz2), fine-grained pyrite (Py2) and chalcopyrite. These veins range from 0.2 to 8.0 cm in thickness containing finer grained (<0.2 mm) grey quartz grains (Qz2) that crosscut veins carrying stage 1 quartz (Qz1). Finer-grained (<1 mm) pyrite (Py2) accompanies and is intergrown with Qz2 in these veins and may represent a second hydrothermal event. Electrum occurs as inclusions in Py2 or is intergrown with Qz2. In alteration-related orebodies, hessite occurs as inclusions within Py2.
iii). Quartz–carbonate veinlets that cross-cut veins and alteration zones related to the previous two stages. Barite also occurs in these veinlets, but no gold.
Other significant gold deposits in the Qingchengzi Pb-Zn-Au-Ag polymetallic ore field include the Linjiasandaogou and Xiaotongjiapuzi gold deposits, 11 and 15 km SSE of Baiyun and the Gaojiapuzi silver deposit immediately to the NW of Xiaotongjiapuzi. The Qingchengzi Pb-Zn-Au-Ag polymetallic ore field also contains a cluster of numerous lead-zinc deposits that form a core to the district, the largest of which are Qingchengzi, Zhenzigou, Erdao and Xiquegou - see the separate Qingchengzi Pb-Zn-Au-Ag polymetallic ore field record. The main gold deposits of the ore field are located to the NE of the Pb-Zn mineralisation, although, these and other gold occurrence in the district appear to form a halo peripheral to the Pb-Zn deposits. Most of the gold mineralistion is within the Gaixian Formation. All of this mineralisation is interpreted to be associated with the Triassic magmatism represented by the Shuangdinggou and Xinling granitoids (e.g., Duan et al., 2012; Zeng et al., 2020).
Jiapigou District
The main deposits of this district are described in the separate Jiapigou District record.
Laoling District
The Laoling District is another cluster of deposits located ~150 km NW of Baiyun, between the Wulong-Sidaogou cluster to the south and the Jiapigou District to the NE, and includes the following deposits:
Xiadapu - a NNW trending quartz lode deposit controlled by NNW trending faulting, near the city of Qingyuan in Liaoning, hosted by granite, and related to a Lower Cretaceous granite porphyry, with resources of between 5 and 20 t of gold (Zeng et al., 2020).
Xicha - a NNW trending series of veins and lenses forming a quartz lode deposit controlled by NE to NNE trending faulting, near the city of Jian in Jilin, hosted by Proterozoic marble, and related to a Lower Cretaceous albite porphyry, with resources of between 5 and 20 t of gold (Zeng et al., 2020).
Nancha - near the city of Tonghua, in Jilin, hosted in a Proterozoic metamorphosed volcanic–sedimentary sequence, mainly represented by marble and schist, and related to a Lower Cretaceous 103.6 Ma diorite porphyry. The distribution of the orebodies is controlled by NNE-trending brittle-ductile shear zones and faults. The gold orebodies comprise auriferous, NNW-trending lenticular, bedding parallel, quartz lode veins and auriferous altered rocks. Mineralisation can be divided into three stages: i). quartz–pyrite; ii). quartz–gold–polymetallic sulphide; and iii). quartz-carbonate, with gold introduced mainly in the second stage (Chai et al., 2016). Published resources are between 5 and 20 t of gold (Zeng et al., 2020).
Huanggoushan - a NE-trending lenticular, bedding parallel, quartz lode deposit, controlled by NE trending faulting near the city of Lenjiang, in Jilin, hosted by Proterozoic marble and 178 Ma biotite granite, and related to a Lower Cretaceous 103.8 Ma diorite porphyry, with resources of between 5 and 20 t of gold (Zeng et al., 2020).
Caocuo - containing >20 t of contained Au at an average grade of 10 g/t Au (Zhou et al., 2002), this deposit is hosted in schist, phyllite and slate of the Proterozoic Liaohe Formation. Orebodies are localised by NE-trending shear zones, and intersections with secondary faults and folds. Ores contain a high proportion of arsenopyrite, pyrite, lesser pyrrhotite, galena chalcopyrite and sphalerite.
The most recent source geological information used to prepare this decription was dated: 2020.
Record last updated: 10/12/2020
This description is a summary from published sources, the chief of which are listed below.
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Chai, P., Sun, J.-G., Hou, Z.-Q., Xing, S.-W. and Wang, Z.-Y., 2016 - Geological, fluid inclusion, H-O-S-Pb isotope, and Ar-Ar geochronology constraints on the genesis of the Nancha gold deposit, southern Jilin Province, northeast China: in Ore Geology Reviews v.71, Part 1, pp. 1053-1071.
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Duan, X., Zeng, Q., Yang, J., Liu, J., Wang, Y. and Zhou, L., 2014 - Geochronology, geochemistry and Hf isotope of Late Triassic magmatic rocks of Qingchengzi district in Liaodong peninsula, Northeast China: in J. of Asian Earth Sciences v.91, pp. 104-124.
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Feng, H., Shen, P., Zhu, R., Tomkins, A.G., Brugger, J., Ma, G.,Li, C. and Wu, Y., 2023 - Bi/Te control on gold mineralizing processes in the North China Craton: Insights from the Wulong gold deposit: in Mineralium Deposita v.58, pp. 263-286.
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Han, J., Deng, J., Zhang, Y., Sun, J., Wang, Q., Zhang, Y., Zhang, X., Liu, Y., Zhao, F., Wang, L. and Lin, Z., 2022 - Au mineralization-related magmatism in the giant Jiapigou mining district of Northeast China: in Ore Geology Reviews v.141, 19p. doi.org/10.1016/j.oregeorev.2021.104638.
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Hart, C.J., Goldfarb, R.J., Qiu, Y., Snee, L., Miller, L.G. and Miller, M.L., 2002 - Gold deposits of the northern margin of the North China Craton: multiple late Paleozoic-Mesozoic mineralizing events: in Mineralium Deposita v.37, pp. 326-351.
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Li, J, Wang, K.-Y., Cai, W.-Y., Sun, F.-Y., Liu, H.-L., Fu, L.-J., Qian, Y. and Lai, C.-T., 2020 - Triassic gold-silver metallogenesis in Qingchengzi orefield, North China Craton: Perspective from fluid inclusions, REE and H-O-S-Pb isotope systematics: in Ore Geology Reviews v.121, 23p. doi.org/10.1016/j.oregeorev.2020.103567.
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Liu, J., Liu, F.-X., Li, S.-H. and Lai, C.-K., 2019 - Formation of the Baiyun gold deposit, Liaodong gold province, NE China: Constraints from zircon U-Pb age, fluid inclusion, and C-H-O-Pb-He isotopes: in Ore Geology Reviews v.104, pp. 686-706. doi.org/10.1016/j.oregeorev.2018.12.006
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Liu, J., Zhang, L.-J., Wang, S.-L., Li, T.-G., Yang, Y., Liu, F.-X., Li, S.-H. and Duan, C., 2019 - Formation of the Wulong gold deposit, Liaodong gold Province, NE China: Constraints from zircon U-Pb age, sericite Ar-Ar age, and H-O-S-He isotopes: in Ore Geology Reviews v.109, pp. 130-143.
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Liu, Y., Wei, J., Tan, J., Ulrich, T., Zhang, D., Lahaye, Y., Zhang, X. and Chen, J., 2022 - Sulfide micro-textures and in-situ compositions from the Wulong gold deposit, northeastern North China Craton: Implication for ore-forming processes: in Ore Geology Reviews v.148, 18p. doi.org/10.1016/j.oregeorev.2022.105028.
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Sun, G., Zeng, Q., Li, T., Li, A., Wang, E., Xiang, C., Wang, Y., Chen, P. and Yu, B., 2019 - Ore genesis of the Baiyun gold deposit in Liaoning province, NE China: constraints from fluid inclusions and zircon U-Pb ages: in Arabian Journal of Geosciences, doi.org/10.1007/s12517-019-4459-0, 18p.
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Yang, J.-H., Wu, F.-Y. and Wilde, S.A., 2003 - A review of the geodynamic setting of large-scale Late Mesozoic gold mineralization in the North China Craton: an association with lithospheric thinning: in Ore Geology Reviews v.23, pp. 125-152.
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Yu, B., Zeng, Q., Frimmel, H.E., Qiu, H., Li, Q., Yang, J., Wang, Y., Zhou, L., Chen, P. and Li, J., 2020 - The 127 Ma gold mineralization in the Wulong deposit, Liaodong Peninsula, China: Constraints from molybdenite Re-Os, monazite U-Th-Pb, and zircon U-Pb geochronology: in Ore Geology Reviews v.121, doi.org/10.1016/j.oregeorev.2020.103542
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Yu, B., Zeng, Q., Frimmel, H.E.,Wang, Y., Guo, W., Sun, G., Zhou, T. and Li, J., 2018 - Genesis of the Wulong gold deposit, northeastern North China Craton: Constraints from fluid inclusions, H-O-S-Pb isotopes, and pyrite trace element concentrations: in Ore Geology Reviews v.102, pp. 313-337.
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Zeng, Q., Wang, Y., Yang, J., Guo, Y., Yu, B., Zhou, L. and Qiu, H., 2020 - Spatial-temporal distribution and tectonic setting of gold deposits in the Northern margin gold belt of the North China Craton: in International Geology Review doi.org/10.1080/00206814.2020.1737839 32p.
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Zhang, P., Kou, L., Zhao, Y., Bi, Z., Sha, D., Han, R. and Li, Z., 2020 - Genesis of the Wulong gold deposit, Liaoning Province, NE China: Constrains from noble gases, radiogenic and stable isotope studies: in Geoscience Frontiers v.11, pp. 547-563
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Zhang, P., Kou, L.-L., Zhao, Y., Bi, Z.-W., Sha, D.-M., Li, Z.-M. and Han, R.-P., 2019 - Fluid inclusions, H-O, S, Pb, and noble gas isotope studies of the Baiyun gold deposit in the Qingchengzi orefield, NE China: in J. of Geochemical Exploration v.200, pp. 37-53.
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Zheng, J., Chen, B., Liu, S. and Bao, C., 2022 - A Triassic orogenic gold mineralization event in the paleoproterozoic metamorphic rocks: evidence from two types of rutile in the Baiyun gold deposit, Liaodong Peninsula, North China Craton: in Econ. Geol. v.117, pp. 1657-1673.
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