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Zimudang, Shuiyindong, Nibao |
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Guizhou, 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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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The carbonate hosted, Carlin style Zimudang, Nibao and Shuiyindong gold deposits are located ~220 km SW of Guiyang, in southwestern Guizhou Province in the Golden Triangle of southern China (#Location: Zimudang - 25° 34' 27"N, 105° 28' 00"E; #Location: Shuiyindong - 25° 32' 13"N, 105° 32' 26"E; Location: Nibao - 25° 22' 24"N, 104° 55' 53"E).
The Golden Triangle is located at the southwestern margin of the Archaean to Proterozoic Yangtze Craton within the Phanerozoic Youjiang (or Nanpanjiang) basin. The Nanpanjiang basin was initiated by Cambrian extension of the Yangtze Precambrian basement, and contains sedimentary rocks that range from Cambrian to Triassic in age, although the bulk of outcrop is of Permian and Triassic age.
For detail of the regional setting see the Golden Triangle record.
The observed deformation within the Youjiang/Nanpanjiang basin is predominantly due to the Late Cretaceous Yanshanian orogen which resulted in smallscale folding and domal structures, with which gold deposits are commonly associated. Apart from minor dykes, there is no associated magmatic activity.
For background on the geological setting see the Golden Triangle record.
Zimudang
The gold mineralisation at is hosted by Late Permian to Early Triassic clastics and limestones in an intracratonic marine rift environment.
The deposit is hosted in the western axial section of the Huijiabao anticline, which also hosts the Shuiyindong gold deposit ~12 km to the SE. The axis of the Huijiabao anticline is NW‐trending with limbs dipping at 10 to 20° (Su et al., 2008). Several thrust faults are known in the district, including the WNW-ESE to east-west F1, and the NE to NNE aligned Anzichong, Taiping and Xiaozichong faults. Of these the F1 Fault is the most significant as it hosts the main ore body of the Zimudang gold deposit. This fault dips at <1 to 30°S, with a displacement that ranges from 40 to 60 m, and a fracture zone that can be as wide as 22 to 84 m, enclosing fault gouge intervals that are ~2 to 5 m thick (Tai and Li, 2006). The Xiaozichong and Taiping faults, which crosscut the anticline, constitute the western and eastern boundaries of the Zimudang gold deposit. Each of the latter pair of faults can be traced for >10 km. The Xiaozichong Fault in the west dips SE and the Taiping Fault to the east dips NWW. Both are post mineralisation structures (Li, 2013).
The Zimudang ore bodies occur in two main forms, namely fault controlled and strata‐bounded. The main No. I ore body is strictly controlled by the F1 Fault, concentrated in the centre of the fault zone, with disseminated mineralisation in the adjacent wall rocks. It has a planar lensoid form, striking east-west and dipping to the south at 15 to 25°. This ore body is >1700 m long and extends for >500 m down dip with a thickness ranging from 0.56 to 25.1 m (Li, 2013). The immediate hosts are mainly calcareous clay rocks, bioclastic limestone and breccias of these same lithologies, with some veins and veinlets of calcite, quartz, pyrite, realgar and clay minerals. These rocks contains ore minerals that include pyrite, arsenopyrite, marcasite and realgar, with a gangue assemblage that includes calcite, dolomite, quartz and hydromica.
Below the No. 1 orebody, six stratabound mineralised bodies have been delineated, hosted by the Longtan Formation and named No. II to VII inclusive. The average thickness of these mineralised zones ranges from 0.74 to 2.71 m (Tai and Li, 2006). The lithology of all six is very similar, and includes silicified limestone, fine sandstone, siltstone, silty clayrock and thin layered limestone (Li, 2013). The ore and gangue minerals are similar to those of the No. I ore body. Hydrothermal alteration assemblages include quartz, calcite, illite, kaolinite and white mica.
The Zimudang deposit has been reported to contain a resource of around 60 t of Au at grades of 5 g/t Au. In 2000 it was quoted as having reserves of 26.83 t of contained Au with an average grade of 6.2 g/t Au (Liu and Yu, 2001).
Shuiyindong
In 2018, the Shuiyindong Au deposit comprised four ore blocks, Shuiyindong, Xionghuangyan, Bojitian and Nayang, and was the largest sediment-hosted Au deposit discovered in the Youjiang Basin (Tan, 2015). The Shuiyindong deposit is controlled by the ~5 km wide and ~20 km long Huijiabao anticline, which has limbs dipping at low angles. The strata-bound orebodies are mainly on the flanks and crest of the anticline and are predominantly hosted by the Upper Permian Longtan bioclastic limestone. The units above and below the bioclastic hosted orebodies are typically composed of thick-bedded argillite, impermeable layers that promoted ore fluid passage and reaction with the bioclastic limestone, contributing to the formation of high-grade ore, locally containing >100 g/t Au. An unconformity between the Longtan and underlying Maokou Formation also hosts some low grade strata-bound ore. Tan et al. (2015) proposed that this unconformity was the structural conduit that fed ore fluids into the anticlinal core. No igneous rocks have not been identified in geologic mapping or drilling in the surrounding district, with the nearest being the 88 to 85 Ma Baiceng alkaline ultramafic dykes (Liu et al., 2010), ~20 km from this deposit. However, geophysical investigations (Bouguer gravity and magnetic surveys) indicate the presence of a pluton ~5 km below the surface at Shuiyindong (Liu, pers. commun., 2018 reported in Xie et al., 2018).
The Shuiyindong deposit is ~12 km to the SE of Zimudang and is reported to contain 263 tonnes of Au at an average grade of 5 g/t Au in 52.6 Mt of ore (Xie, et al., 2018), although Hu et al., 2017 quotes proved reserves of 265 t of gold at 11 g/t Au in 24 Mt of ore.
Nibao
The Nibao gold deposit is located towards the northern apex of the Golden Triangle deposit, ~60 km WSW of Shuiyindong. It is structurally located on the northwestern flank of the NE-SW trending Erlongqiangbao anticline, which is cut by a series of NE striking faults (F1, F2, F3, F4 and F7), north-south striking F6 fault, and the NW-SE striking F11 fault. The core of the anticline comprises the Middle Permian Maokou Formation massive bioclastic limestone; altered breccia developed along the regional unconformity that separates it from overlying volcanic tuff; and interbedded sandstone, calcareous siltstone, bioclastic limestone, mudstone and multilayer coal seams of the upper Permian Longtan Formation. The southeastern limb of the anticline comprises thick marls and limestone of the Lower Triassic Yongningzhen Formation (Liu, P. et al., 2006). Gold mineralisation is mainly of stratabound and fault-controlled vein-type ores. The strata-bound ores are similar in character to the Shuiyindong deposit and are predominantly hosted in fracture zones associated with the anticline. The largest of the vein-type ores is orebody No. III, which is localised in the F1 fault fracture zone, and is ~2700 m long by ~200 to 540 m wide, and continues for more than 230 m down-plunge from RLs 1300 to 1070 m elevations (Zheng et al., 2016).
The Nibao deposit has proved reserves of 70 t of gold with an average grade of 2.62 g/t Au, which equates to 26.7 Mt of ore (Zheng et al., 2016). Of this, orebody No. III contains proved reserves of 39 t of gold at 3.42 g/t Au in 11.5 Mt of ore (Zheng et al., 2016).
The smaller Taipingdong deposit lies along the Huijiabao anticline between Shuiyindong and Zimudang.
The most recent source geological information used to prepare this decription was dated: 2020.
Record last updated: 22/3/2019
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.
Zimudang Nibao Shuiyindong
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Hu, N., Hu, R., Chen, H., Fu, S., Yang, J., Xu, L. and Luo, C., 2024 - Lithium and oxygen isotopic constraints on the source and evolution of ore-forming fluids: a case study from the Shuiyindong Carlin-type gold deposit, SW China: in Mineralium Deposita v.59, pp. 313-328.
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Jin, X.-Y., Hofstra, A.H., Hunt, A.G., Liu, J.-Z., Yang, W. and Li, J.-W., 2020 - Noble gases fingerprint the source and evolution of ore-forming fluids of Carlin-type gold deposits in the Golden Triangle, South China: in Econ. Geol. v.115, pp. 455-469.
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Jin, X.-Y., Zhao, J.-X., Feng, Y.-X., Hofstra, A.H., Deng, X.-D., Zhao, X.-F. ad Li, J.-W., 2021 - Calcite U-Pb Dating Unravels the Age and Hydrothermal History of the Giant Shuiyindong Carlin-Type Gold Deposit in the Golden Triangle, South China: in Econ. Geol. v.116, pp. 1253-1266.
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Li, J.-X., Hu, R.-Z., Zhao, C.-H., Zhu, J.-J., Huang, Y., Gao, W., Li, J.-W. and Zhuo, Y.-Z., 2020 - Sulfur isotope and trace element compositions of pyrite determined by NanoSIMS and LA-ICP-MS: new constraints on the genesis of the Shuiyindong Carlin-like gold deposit in SW China: in Mineralium Deposita v.55, pp. 1279-1298.
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Liu, Y., Hu, K., Han, S. and Sun, Z., 2015 - The Nature of Ore-forming Fluids of the Carlin-type Gold Deposit in Southwest China: A Case from the Zimudang Gold Deposit: in Resource Geology v.65, pp. 136-159.
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Su Wenchao, Heinrich CA, Pettke T, Zhang Xingchun, Hu Ruizhong and Xia Bin, 2009 - Sediment-Hosted Gold Deposits in Guizhou, China: Products of Wall-Rock Sulfidation by Deep Crustal Fluids : in Econ. Geol. v104 pp 73-93
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Xie, Z., Xia, Y., Cline, J.S., Pribil, M.J., Koenig, A., Tan, Q., Wei, D., Wang, Z. and Yan, J., 2018 - Magmatic Origin for Sediment-Hosted Au Deposits, Guizhou Province, China: In Situ Chemistry and Sulfur Isotope Composition of Pyrites, Shuiyindong and Jinfeng Deposits: in Econ. Geol. v.113, pp. 1627-1652.
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Zhao, J., Liang, J., Long, X., Li, J., Xiang, Q., Zhang, J. and Hao, J., 2018 - Genesis and evolution of framboidal pyrite and its implications for the ore-forming process of Carlin-style gold deposits, southwestern China: in Ore Geology Reviews v.102, pp. 426-436.
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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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