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Liaoxi Belt - Baoguosi |
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Liaoning, 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 Baoguosi iron deposit is located 75 km west of Fuxin City in north-western Liaoning Province, north-eastern China (#Location: 42° 06' 15"N, 120° 50' 40"E).
The deposits falls within the Liaoxi Metallogenic Belt, hosted by metamorphosed marine volcaniclastic and sedimentary rocks of the 100 x 50 km Archaean Liaoxi greenstone belt. The banded iron formations (BIFs) that hosts the Baoguosi and other deposits are interpreted to have formed in a rift basin along the northern Neoarchaean continental margin on the Eastern Block 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 (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 Liaoxi greenstone belt includes the Xiaotaziguo, Dayinzi and Waziyiu formations of the Archaean Jianping Group, enveloped by tonalite, trondhjemite-granodiorite ganitoids. The main BIF unit that hosts the Baoguosi deposit occurs in the middle member of the Xiaotazhigou Formation.
The Xiaotazhigou Formation comprises: i). lower migmatitic biotite-plagioclase gneiss intercalated with plagioclase amphibolite and magnetite quartzite; ii). middle migmatitic biotite-plagioclase gneiss intercalated with granulite, magnetite quartzite and amphibolite; and iii). upper interbedded gneissic migmatite and migmatitic plagioclase amphibolite.
The BIF units at Baoguosi are concordant with the enclosing metamorphics. They are typically gneissic, banded or massive, with medium-to coarse-grained, crystalloblastic and xenomorphic granular crystalloblastic textures and comprise:. i). magnetite-quartzite and ii). hematite pseudomorphs-quartzite type. The dominant minerals in the orebody are magnetite and quartz with lesser hematite, pyrite, tremolite, actinolite, chlorite and biotite. The alteration assemblage with in the BIFs includes chlorite, biotite, sericite, and carbonate.
Reserves are 110 Mt @ 33.78% Fe, 0.015% S, 0.01% P for magnetite quartzite; and 35.81% Fe, 0.015% S, and 0.01% P for hematite quartzite (Rodionov, et al., 2004, USGS Open File Rept. 2002).
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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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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