|
Jiashengpan |
|
|
Inner Mongolia, China |
| Main commodities:
Zn Pb
|
|
 |
|
|
 |
Super Porphyry Cu and Au
|
IOCG Deposits - 70 papers
|
All available as eBOOKS
Remaining HARD COPIES on
sale. No hard copy book more than AUD $44.00 (incl. GST) |
|
|
The Jiashengpan sediment hosted zinc-lead deposit is located within the Mesoproterozoic Langshan-Zhaertai region near the northern margin of the North China Craton in western Inner Mongolia, ~90 km south-west of Byan Obo and 200 km WNW of Hohhot (#Location: 41° 13' 50"N, 109° 13' 21"E).
Regional Setting
The Langshan-Zhaertai polymetallic ore belt, which extends for ~600 km from west to east, contains significant Zn-Pb(-Cu) mineralisation hosted by Mesoproterozoic rift basin sedimentary rocks, and includes the giant Dongshengmiao and the Huogeqi, Tanyaokou and Jiashengpan deposits. The sequence exposed within the belt includes:
Archaean crystalline basement of the North China Craton, which comprises high-grade amphibolite-granulite facies metamorphic rocks, locally known as the Wulashan Group in the west or Langshan area, and as the Wutai Group in the east or Zhaertai area;
Proterozoic rift sedimentary and intercalated volcanic rocks which unconformably overlie the Archaean basement and were deposited throughout the entire belt. These have been subjected to sub-greenschist to lower amphibolite facies metamorphism. They have been divided into the Palaeo to Mesoproterozoic Zhaertai Group (detrital zircon; U-Pb, 2.5 to 1.8 Ga; Gong et al., 2016; basaltic metavolcanic rock of 1743±7 Ma; Li et al., 2007) and Neoproterozoic Langshan Group (youngest detrital zircon; U-Pb, 1.1 Ga; Gong et al., 2016; volcanic zircon; U-Pb, 810 Ma; Peng et al., 2010; Li et al., 2007).
Devonian Metamorphism - following collision between the Cambrian to Silurian, 520 to 420 Ma Bainaimiao Arc to the north and North China Craton, regional compression and crustal thickening led to the development of a Barrovian metamorphic belt with metamorphic zircon grains ranging between 412 and 374 Ma, with a weighted average of 399±6 Ma (Chen et al., 2014).
Carbonaceous to Triassic plutonic intrusions emplaced during continuing tectonic activity as the north dipping subduction of the Palaeo-Asian Ocean below the Amurian Superterrane/Central Asian Orogenic Belt proceeded to the north, culminating in the Solonker Suture. These intrusions were widely developed through the Langshan-Zhaertai belt, with lithologies ranging from diorite to granite (Zhang et al., 2014). Late Palaeozoic marine sedimentary rocks in the belt are regarded to have formed in the shallow water environment of a small basin, possibly the result of back arc or post-collisional extension, which was subsequently inverted during the Late Permian to Early Triassic. Similarly, at least some of the intrusions have been interpreted as products of collisional extension (Hu et al., 2015; Zhang et al., 2014).
Post-collisional Tectonism - following the collision between the Amurian Superterrane and the amalgamated North China Craton, continued convergence during the Triassic and Jurassic caused post-collisional over-thrusting, imbrication and considerable crustal thickening on the NW margin of the craton (Xiao et al., 2003).
Deposit Geology
The Jiashengpan deposit is located in the eastern Zhaertai region of the Langshan-Zhaertai polymetallic belt, hosted within the Palaeo- to Mesoproterozoic sedimentary sequence of the Zhartai (Zha'ertai or Chartai) Group which includes carbonaceous and silty dolostone and black carbonaceous slate/phyllite. This succession occurs in a third-order fault-basin in what is known as the Langshan-Zha'ertaishan Aulacogen along the northern margin of the North China Platform. Other rocks within the deposit area include gneiss and migmatite of the Archaean Wutai Group, and rare Permian and Cretaceous sedimentary rocks (Yu et al., 2019).
The orebodies are all hosted by the Agulugou Formation of the Zhaertai Group, which is mainly composed of carbonaceous shale, marlstone and dolostone, some units of which have high contents of organic matter. The Agulugou Formation can be further subdivided into three units from bottom to top. The first and third have elevated K2O, SiO2 and Al2O3 contents, whilst the second is rich in MgO, SiO2, MnO and FeO. These lithologies were subjected to sub-greenschist to lower greenschist facies metamorphism (Yu et al., 2019).
Thrust faulting is extensively developed within the Jiashengpan deposit area, with one of the most prominent being the 335° striking and 60°N dipping F1 thrust that separates the Wutai Group in the north from the Zhaertai Group to the south. This structure had an associated broad zone of shearing and and mylonite development. The F1 structure is cut by the main intrusions exposed in the Jiashengpan deposit area, a late Palaeozoic biotite K feldspar granite. Other intrusions exposed in the deposit area include diorite, granite and granite-porphyry stocks are (Fu et al., 2010).
The lead-zinc orebodies of the deposit strike at ~350° and dip consistently to the north at ~70°, similar to the F1 fault. Mineralisation comprises several banded sulphide bodies which were folded with the host rocks and concentrated in the hinges of folds where they are thickened and of higher grade. The ore minerals comprise pyrite, pyrrhotite, sphalerite and galena which occur in layers, masses, disseminations and laminae. Sphalerite predominate in the lower parts of the deposit, with galena increasing upwards. The principal gangue minerals are dolomite, diopside, calcite, tremolite, plagioclase, K feldspar and quartz.
A study by Zhong (2014) proposed a two-stage model for the formation of the Jiashengpan deposit. This involved the deposition of early-stage sulphides that are characterized by the widely developed massive pyrite with fine-grained textures or framboidal structure, interpreted to indicate a syn-sedimentary to syn-diagenetic origin. Zn-Pb-sulphides were also observed as disseminated fine grains in dolostone, but in general, were of no economic interest. All the economically important Zn-Pb ores are interpreted to have formed during the late-stage mineralisation, with pyrite and pyrrhotite and hydrothermal gangue minerals such as quartz, calcite and dolomite. The late-stage mineralisation shows characteristics of being shear zone-controlled, such as mineral precipitation following mylonitic foliations of the host rocks. Yu et al. (2019) undertook 39Ar/40Ar dating of interpreted syn-ore hydrothermal muscovite
which yielded average dates of ~380 Ma, suggesting the Zn–Pb mineralisation occurred in the Devonian. An upper limit to mineralisation is provided by zircon U-Pb ages of post-ore granite of 277±2 Ma.
Reserves and Resources
The deposit is quoted (Inner Mongolian Bureau of Geology & Mineral Resources geologists, pers. comm., 1999) as having a resource of:
62 Mt @ 3.8% Zn, 1.3% Pb, 0.1g/t Au.
Yu et al. (2019) quotes metal content reserves of 1.68 Mt of contained Zn @ 3.95% Zn;
and 0.19 Mt of contained Pb @ 1.35% Pb.
These would equate to ~42 Mt of zinc ore and ~14 Mt of lead ore.
In addition to Zn-Pb orebodies, massive pyrite is mined as a sulphur resource.
The most recent source geological information used to prepare this decription was dated: 2019.
Record last updated: 22/11/2020
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.
Jiashengpan
|
|
|
Selected References:
|
Peng, R. and Zhai, Y., 2010 - Hydrothermal Mineralization on the Mesoproterozoic Passive Continental Margins of China: A Case Study of the Langshan‐Zha ertaishan Belt, Inner Mongolia, China: in Acta Geologica Sinica v.78, pp. 534-545.
|
Yu, C., Zhong, R.-C., Xie, Y.-L. and Li, W.-B., 2019 - Geochronological Study of the Jiashengpan Zn-Pb Deposit in Northern China: Implications for Base Metal Mineralization in Collisional Orogens: in Minerals (MDPI) v.9, 15p.
|
|
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.
|
Top | Search Again | PGC Home | Terms & Conditions
|
|
