Formation Ages and Environments of Early Precambrian Banded Iron Formation in the North China Craton

2016 ◽  
pp. 65-83 ◽  
Author(s):  
Yu-Yheng Wan ◽  
Dun-Yi Liu ◽  
Hang-Qiang Xie ◽  
Alfred Kröner ◽  
Peng Ren ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Early Precambrian ◽  
The North

Depositional and Environmental Constraints on the Late Neoarchean Dagushan Deposit (Anshan-Benxi Area, North China Craton): An Algoma-Type Banded Iron Formation

2021 ◽  
Author(s):  
Xiaoxue Tong ◽  
Changle Wang ◽  
Zidong Peng ◽  
Yuhao Li ◽  
Weiduo Hao ◽  
...  
Keyword(s):  
Water Column ◽  
North China Craton ◽  
Ferrous Iron ◽  
Iron Reduction ◽  
North China ◽  
Hydrothermal Fluids ◽  
Iron Formation ◽  
Carbonate Facies ◽  
Banded Iron Formation ◽  
The North

Abstract The late Neoarchean, ~2.53 to 2.51 Ga Dagushan banded iron formation (BIF), is a typical Algoma-type BIF located in the northeast part of the North China craton. Despite having undergone upper greenschist to lower amphibolite facies metamorphism, the Dagushan BIF retains evidence of varied depositional facies, making it an ideal archive to evaluate the paleomarine environment and the paragenesis of the ore minerals. A transition from oxide to silicate to carbonate facies BIF is evident in a northward direction. The mineralogical composition shifts from magnetite and quartz in the south through a magnetite-quartz-cummingtonite/stilpnomelane assemblage in the transition zone to magnetite-siderite in the north. Such a distinct distribution of mineralogical facies correlates well with the depositional environment of the BIF. The carbonate facies BIFs formed in a near-shore, proximal environment, whereas the oxide and silicate facies BIF assemblages formed in deeper waters, distal to the paleoshoreline. The BIF samples display characteristic seawater-like rare earth element + yttrium (REE + Y) profiles with positive La and Y anomalies and heavy REE enrichment relative to the light REEs when normalized to post-Archean Australian shale. Positive Eu anomalies suggest a high-temperature hydrothermal contribution to the BIF. The absence of a negative Ce anomaly in nearly all samples, coupled with positive δ56Fe in magnetite in all mineralogical facies, indicates a dominantly anoxic water column contemporaneous with deposition of the BIF. At ~2.53 Ga in the Anshan area, seawater was mostly anoxic and rich in ferrous iron. Dissolved ferrous iron in upwelling hydrothermal fluids was oxidized and precipitated as Fe(III) oxyhydroxides in the photic zone leading to BIF formation. Proximal to hydrothermal vents, magnetite formed via the reaction of Fe(III) oxyhydroxides and aqueous Fe(II) supplied from the hydrothermal fluids and microbial dissimilatory iron reduction (DIR) coupled to organic carbon oxidation. Proximal to a paleoshoreline, siderite formed through DIR, as evidenced by the depleted δ13C values and the presence of graphite. Silicates, such as stilpnomelane and cummingtonite, are considered to be the metamorphic products of early diagenetic silicates (e.g., nontronite) that formed in the water column from admixtures of Fe(III) oxyhydroxides and amorphous silica.

A review on the Huoqiu banded iron formation (BIF), southeast margin of the North China Craton: Genesis of iron deposits and implications for exploration

2014 ◽  
Vol 63 ◽  
pp. 418-443 ◽  
Author(s):  
Xiaoyong Yang ◽  
Lei Liu ◽  
Insung Lee ◽  
Bohua Wang ◽  
Zhenbao Du ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
The North ◽  
Iron Deposits

Using In Situ Monazite and Xenotime U-Pb Geochronology to Resolve the Fate of the “Missing” Banded Iron Formation-Hosted High-Grade Hematite Ores of the North China Craton

2020 ◽  
Vol 115 (1) ◽  
pp. 189-204
Author(s):  
Li-Xing Li ◽  
Jian-Wei Zi ◽  
Jie Meng ◽  
Hou-Min Li ◽  
Birger Rasmussen ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Greenschist Facies ◽  
Iron Formation ◽  
High Grade ◽  
Banded Iron Formations ◽  
Banded Iron Formation ◽  
The North ◽  
Proposed Model

Abstract High-grade hematite mineralization is widely developed in banded iron formations (BIFs) worldwide. However, in the North China craton where Neoarchean-Paleoproterozoic BIFs are abundant, economic high-grade hematite ores are scarce. High-grade hematite ores hosted in the Paleoproterozoic Yuanjiacun BIFs represent the largest occurrence of this type of ore in the North China craton. The orebodies are fault controlled and show sharp contacts with lower greenschist facies metamorphic BIFs. In situ U-Pb geochronology of monazite and xenotime intergrown with microplaty hematite and martite in high-grade ore established two episodes of metamorphic-hydrothermal monazite/xenotime growth after deposition of the BIFs. The earlier episode at ca. 1.94 Ga is interpreted as the timing of lower greenschist-facies metamorphism, and the later episode at 1.41 to 1.34 Ga represents the timing of high-grade hematite mineralization. Petrography and microthermometry of primary fluid inclusion assemblages indicate that the high-grade hematite ore formed from hot (313°–370°C), CO2-rich, and highly saline (~20 wt % NaCl equiv) hydrothermal fluids. These fluids channeled along faults, which concentrated iron through interaction with the BIFs—a process similar to typical hematite mineralization elsewhere. The deposition of hematite was probably related to tectonic extension in the North China craton related to the breakup of the Columbia/Nuna supercontinent. Our results challenge a previously proposed model ascribing the scarcity of high-grade hematite ores in the North China craton to the lack of prolonged weathering conditions. Rather, we argue that the high-grade ore formed in lower metamorphic-grade BIFs at shallower depths than magnetite mineralization and was largely eroded during later exhumation and uplift of the craton.

The composition and genesis of the Mesoarchean Dagushan banded iron formation (BIF) in the Anshan area of the North China Craton

2014 ◽  
Vol 63 ◽  
pp. 353-373 ◽  
Author(s):  
Yanpei Dai ◽  
Lianchang Zhang ◽  
Mingtian Zhu ◽  
Changle Wang ◽  
Li Liu ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
The North
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