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Handan Xingtai district - Fushan, Xishimen, Qicun, Guzhen Donghaozhuang |
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Hebei, China |
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Fe
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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 Handan-Xingtai district in Hebei Province, northern China encompasses the small Fushan, Xishimen, Qicun, Guzhen and Donghaozhuang 'skarn' iron deposits (#Location; Fushan - 36° 41'N, 113° 46'E; Xishimen - 36° 50'N, 114° 10'E; Qicun - 36° 56'N, 114° 17'E; Guzhen - 36° 38'N, 113° 59'E; Donghaozhuang - 36° 53' N, 114° 22'E).
Regional Setting
The Handan-Xingtai district iron mineralisation predominantly occurs along contact zones between Early Cretaceous intermediate-silicic intrusions and Middle Ordovician marine carbonates intercalated with numerous evaporite beds, which are developed over the central North China Craton.
The Western and Eastern Archaean blocks of the North China Craton were amalgamated across the intervening Palaeoproterozoic Trans-North China Orogen at ~1.85 Ga by (Zhao et al., 2005). The Handan-Xingtai district occurs within the southern part of the Trans-North China orogen, within unmetamorphosed Palaeozoic marine sedimentary rocks that unconformably overlay the crystalline basement, which is dominated by the Neoarchean to early Palaeoproterozoic Zanhuang Group. This basement group is composed of trondhjemite-tonalite-granodiorite (TTG) gneisses, schist, amphibolite and marble, the protoliths of which have been dated at 2.5 to 2.8 Ga by whole-rock Sm-Nd and zircon U-Pb geochronology of mafic volcanic sequences, TTG gneisses and associated mafic dykes (e.g., Wang et al., 2003; Zhao et al., 2005; Trap et al., 2009; Li et al., 2010; Yang et al., 2013). These rocks underwent amphibolite facies metamorphism during stabilisation of the North China craton at ca. 1.8 Ga (Wang et al., 2003; Zhai et al., 2005; Zhao et al., 2005).
The overlying Lower Palaeozoic sequence, mainly exposed in the western part of the Handan-Xingtai district, commences with ~600 m Cambrian sequence of red sandstones, shales, limestones and dolomitic limestones. The succeeding Early Ordovician strata are dominantly dolostones which conformably overlie Cambrian dolomitic limestones, whereas the Middle Ordovician rocks are limestones and dolomitic limestones with a total thickness of 600 to 800 m. Numerous evaporite beds, each of a few tens of metres in thickness, are intercalated with the Middle Ordovician carbonate rocks. Carboniferous and Permian shales, mudstones, siltstones, sandstones and coal beds, totalling ~1300 to 1600 m in thickness, unconformably overlie the Ordovician succession, and are mainly exposed in the eastern part of the district.
The Paleozoic succession is intruded by several major plutons, and numerous smaller stocks and dykes, all of which are dominanantly diorite and monzonite in composition, as well as syenite in the eastern part of the district. The dioritic and monzonitic intrusions were emplaced between 136±2 and 128.9±0.9 Ma (zircon U-Pb geochronology; Chen et al., 2008; Li et al., 2013; Shen et al., 2013; Deng et al., 2014; Sun et al., 2014), whilst the syenite pluton was emplaced at ~135 to 132 Ma (Chen et al., 2008). Geochemical and isotopic studies suggest the dioritic and monzonitic rocks were formed by mixing of crustal- and enriched mantle-derived magmas (Chen et al., 2008; Qian and Hermann, 2010). There appears to be a spatial relationship between both economic and uneconomic skarns in the district and the dioritic and monzonitic intrusions emplaced into Ordovician carbonate rocks. In contrast, no mineralization has been found to be associated with the syenitic pluton that intruded the Permian clastic rocks (IGSNC and HGI, 1976).
The Handan-Xingtai district has cumulative 'proved' reserves of 900 to 1000 Mt @ an average of 40 to 55 wt.% Fe in a number of deposits, including those listed above (Deng et al., 2015). The key deposits are as follows.
Fushan
The Fushan deposit contains 46 Mt @ 43 wt.% Fe, and is ~2 km north of the town of Xishu. It is related to the Fushan dioritic pluton, which contains numerous xenoliths of the Middle Ordovician carbonates ranging in size from a few metres to >1 km, and is composed of diorite and hornblende diorite, with subordinate monzodiorite. The hornblende diorite is mainly composed of 10 to 15 vol.% clinopyroxene, 35 to 45 vol.% hornblende and 40 vol.% plagioclase (An35–70; Chen et al., 2008), and is intruded by both diorite and monzodiorite (Yao, 1993). The diorite, which is characterised by well-developed skarn alterations along its southern margin, is medium grained, equigranular to porphyritic. The monzodiorite, which intrudes the diorite, lacks hydrothermal alteration, indicating it was emplacement after iron skarn mineralisation. A SHRIMP zircon U-Pb age dating of the hornblende diorite gave a date of 134.5±1.8 Ma (Chen et al., 2008), whilst two diorite samples returned a SHRIMP zircon U-Pb age of 126.7±1.1 Ma (Peng et al., 2004) and an LA-ICPMS zircon U-Pb age of 128.0±2.5 Ma (Wang, 2012), respectively. Weakly altered diorite, distal from the intrusive contact is composed of 40 to 55 vol.% plagioclase, 25 to 30 vol.% hornblende, ~10 vol.% biotite and ~5 vol.% alkali-feldspar, with accessory zircon, magnetite, titanite, and apatite.
The iron mineralization of the deposit is found along the contact zones between the diorite and several large carbonate xenoliths, locally extending into the carbonate wall rocks. Most of the ore occurs as lenses that are 660 to 1000 m long, 50 to 250 m wide and 10 to 200 m thick (Yao, 1993). Both endoskarn and exoskarn (Einaudi et al., 1981; Meinert, 1992) are well developed, although no obvious zonation is observed for the skarn assemblages. The endoskarn is dominated by widespread albite with minor diopside, whereas the exoskarn is composed of garnet, diopside, tremolite, actinolite and epidote. A mineralised sample of exoskarn reported by Deng et al. (2015) consists of 60 vol.% epidote, 20 vol.% magnetite, 10 vol.% calcite and 5 vol.% chlorite, with minor titanite, apatite and zircon.
Xishimen
The Xishimen deposit had a proved reserve of 106 Mt @ 43 wt.% Fe. The intrusive rocks in the mine area are dominated by monzonite and monzodiorite, with lesser diorite and porphyritic diorite dykes. The monzonite is commonly altered to albite and diopside and cut by diorite dykes (IGSNC and HGI, 1976). Diorite porphyrite has an age of 134.0±1.4 Ma (single LA-ICPMS zircon U-Pb determination; Li et al., 2013), and monzonite of 132.5±2.2 Ma (a SHRIMP zircon U-Pb ages; Chen et al., 2008) and 131.1±3.9 Ma (an LA-ICPMS zircon U-Pb age; Li et al., 2013). A weakly altered fine- to medium-grained, equigranular monzonite was found to contain 15 to 20 vol.% amphibole, 40 to 45 vol.% plagioclase, 20 to 35 vol.% K feldspar and 5 vol.% quartz, with accessory magnetite, titanite, apatite and zircon.
The deposit comprises 28 orebodies, all concentrated along contacts between the monzonite and Middle Ordovician limestone (Yao et al., 1993). Most are concealed at depths of 200 to 400 m below the present surface, with a few small and partly oxidised exposres. The main No. 1 orebody is tabular and lenticular, and is 5020 m long, 125 to 1076 m wide and 2 to 103 m thick, accounting for 95.4% of the total reserves (Yao et al., 1993). Well developed diopside-dominated skarn commonly occurs in the footwall of the iron orebodies, although hydrothermal alteration is also widely found in the marginal sections of the monzonite near the carbonate rocks contact, dominated by albite, with minor epidote and scapolite (1.71 to 2.03 wt.% Cl; Xu, 1987). Examples of the exoskarn within the No. 1 orebody consists of 70 vol.% diopside, 15 vol.% magnetite, 10 vol.% calcite and 5 vol.% tremolite, with minor titanite, apatite and zircon. Apatite typically has high F (3.33 to 3.64 wt.%) and moderate Cl contents (0.51 to 0.61 wt.%) (Deng et al., 2015).
Qicun
The Qicun iron deposit has proved reserves of 13 Mt @ 53 wt % Fe, and is is related to the composite Qicun intrusive stock, primarily composed of diorite and monzodiorite, with lesser monzonite dykes. The monzonite is commonly intruded by both diorite (128.9±0.9 Ma; LA-ICPMS zircon U-Pb; Sun et al., 2014) and monzodiorite (132.0±0.8 Ma; SHRIMP zircon U-Pb; Chen et al., 2008).
Iron mineralisation is found at the contacts between the monzodiorite and intensely folded Middle Ordovician limestone, with minor ore hosted within the monzodiorite. The principal iron orebodies occur on the eastern limbs of several synclines as tabular, lenticular, or irregular bodies that dip steeply to the northeast. They vary from 710 to 1260 m in length, 158 to 229 m wide and 5 to 16 m thick. Weakly altered monzodiorite comprises a fine- to medium grained, equigranular to porphyritic, pinkish-grey rock, and composed of 50 to 55 vol.% plagioclase, 10 to 15 vol.% hornblende, 15 to 20 vol.% alkali-feldspar and 10 to 15 vol.% quartz, with accessory zircon, magnetite, titanite and apatite. Both endoskarn and exoskarn are well developed and mainly comprise albite, diopside, garnet and epidote, with minor F-rich hornblende (1.43 wt.% F; Xu, 1987) and F-wilkeite (3.34 wt.% F and 0.61 wt.% Cl; Cao and Zhu, 1993). Examples of the diopside-dominated exoskarn sample comprises 60 vol.% diopside, 25 vol.% magnetite, 10 vol.% tremolite and 5 vol.% calcite with accessory zircon and apatite.
Guzhen
The Guzhen deposit contains 6.5 Mt @ 47 wt % Fe, and is related to the Guzhen dioritic pluton, which includes abundant xenoliths of the Middle Ordovician carbonates. The diorite, some entrained carbonate xenoliths, and the iron orebodies, are locally intruded by monzodiorite dykes. A medium grained, equigranular diorite consists of 40–55 vol.% plagioclase, 25–30 vol.% hornblende, 10 vol.% biotite and 5 vol.% alkali-feldspar, with accessory zircon, magnetite, titanite and apatite.
Iron mineralization is mostly localised along contacts between the diorite and entrained carbonate xenoliths within the intrusion. The orebodies typically have a lenticular, tabular or irregular shape, and are 80 to 420 m long, 50 to 70 m wide, and 15 to 20 m thick. Endoskarn alteration is dominated by albite and diopside, and is widespread within the diorite, whereas exoskarn is locally found in close proximity of iron ores and is dominated by garnet, diopside and epidote.
Donghaozhuang
This small deposit only contains 2.3 Mt @ 45 wt % Fe, and is spatially related to a diorite stock that intrudes Middle Ordovician carbonate rocks. Iron mineralisation is found along the contacts between the diorite and carbonate, and locally extends into the intrusive rocks. It is largely contained within four lenticular orebodies that are 50 to 240 m long, 10 to 100 m wide, and 10 to 20 m thick and account for 80% of the total reserve. Magnetite is the predominant metallic mineral, coexisting with diopside, epidote, actinolite, and phlogopite. The diorite is generally medium grained, equigranular to porphyritic, and composed of 40–55 vol.% plagioclase, 25–30 vol.% hornblende, 10 vol.% biotite and 5 vol.% alkali-feldspar, whereas the exoskarn comprises 55 vol.% phlogopite, 15 vol.% calcite, 15 vol.%diopside, 5 vol.% magnetite and 10 vol.%epidote.
The most recent source geological information used to prepare this decription was dated: 2015.
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.
Fushan Xishimen Qicun Guzhen Donghaozhuang
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Deng, X.-D., Li, J.-W. and Wen G., 2015 - U-Pb Geochronology of Hydrothermal Zircons from the Early Cretaceous Iron Skarn Deposits in the Handan-Xingtai District, North China Craton : in Econ. Geol. v.110, pp. 2159-2180
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Saidung, S., Starostin, V. and Prokofiev, V., 2017 - Ore-forming fluids of Xishimen skarn iron deposit, China: in Geology of Ore Deposits (Pleiades Publishing) v.59, pp. 176-182.
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Wen, G., Bi, S.-J. and Li, J.-W., 2017 - Role of evaporitic sulfates in iron skarn mineralization: a fluid inclusion and sulfur isotope study from the Xishimen deposit, Handan-Xingtai district, North China Craton: in Mineralium Deposita v.52, pp. 495-514.
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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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