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Wutaishan District - Baizhiyan |
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Shanxi, 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 Baizhiyan iron deposit is located in the Wutaishan District, 170 km north-east of Taiyuan City in north-eastern Shanxi Province, north-eastern China (#Location: 39° 05' 10"N, 113° 46' 05"E).
The deposit falls within the Wutai Metallogenic Belt, hosted by deformed and metamorphosed immature to mature island arc marine volcaniclastic and sedimentary rocks of the Neoarchaean Wutai Greenstone belt. The 200 x 20 km Wutai Greenstone belt lies within the Archaean Liaoning-Hebei-Shanxi terrane of the northern margin of the North China craton.
The North China Craton is composed of the two older, north-south elongated, Eastern and Western Archaean Blocks, separated by a Central Orogenic Belt. It has been interpreted that the Eastern and Western Blocks collided at 2.5 Ga during an arc/continent collision, forming a foreland basin over the Eastern Block (the Quinglong foreland basin), a granulite facies belt on the western block, and a wide orogen between the two blocks. This was followed by post-orogenic extension and rifting, simultaneous with the development of a major ocean lapping onto the northern margin of the craton during the early Paleoproterozoic (Kusky and Jianghai, 2003).
A magmatic arc terrane, which is indicated to have developed in this ocean and was elongated east-west parallel to the northern margin of the craton, collided with that northern craton margin by 2.3 Ga, to form a 1400 km long orogen known as the Inner Mongolia-Northern Hebei Orogen. A 1600 km long granulite-facies terrane formed on the southern margin of this orogen, representing a 200 km wide uplifted plateau as a result of crustal thickening. This granulite facies terrane comprises a southern belt of reworked Archaean basement and a northern metamorphosed accretionary belt. To the south of this granulite terrane, the Archaean sequences have mainly been subjected to amphibolite facies matamorphism. The orogen was converted to an Andean-style convergent margin from 2.20 to 1.85 Ga, reflected by belts of plutonic rocks, accreted metasedimentary rocks, and a possible back-arc basin. A pulse of convergent deformation is recorded at 1.9 to 1.85 Ga across the northern margin of the craton (Kusky and Jianghai, 2003).
The Liaoning-Hebei-Shanxi terrane, which lies within the northern half of the North China craton is composed of the following major units: i). greenstone belts comprising fine-grained biotite gneiss, plagioclase amphibolite, metamorphosed ultramafic rock; chlorite schist, chlorite-albite schist, plagioclase quartzite, quartzite, and phyllite (eg. the Wutai Group); and ii). tonalite, trondhjemite and granodiorite.
Banded iron formations (BIF) units occur within the Baizhiyuan and Jinganku formations of the Wutai Group with isotopic ages of >2500 Ma. The Baizhiyan iron deposit comprises several BIF units that are concordant with the enclosing amphibolite, mica schist and gneisses of the Wutai Group, representing greenschist facies metamorphosed mafic and felsic volcanics and sedimentary rocks. Individual BIF units are from 30 to 50 m thick with strike lengths that range up to 3 to 5 km. The ores are mainly composed of banded: i). oxide facies of magnetite and quartz, ii). silicate facies of magnetite, quartz and grunerite, and iii). carbonate facies of siderite, ferrodolomite and other minerals.
Reserves of 180 Mt @ 33.31% Fe, 0.26% S, 0.06% P have been quoted (Rodionov, et al., 2004, USGS Open File Rept. 2002).
Baizhiyan is one of a group of similar, moderate to large iron deposits that form a northeast-trending belt.
The most recent source geological information used to prepare this decription was dated: 2006.
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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