| Depositional environment and tectonic implications of the Paleoproterozoic BIF in Changyi area, eastern North China Craton: Evidence from geochronology and geochemistry of the metamorphic wallrocks | |
Ting-Guang Lan ; Hong-Rui Fan; Fang-Fang Hu; Kui-Feng Yang; Ya-Chun Cai; Yong-Sheng Liu
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| 2014 | |
| 发表期刊 | Ore Geology Reviews
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| 卷号 | 61期号:1页码:52-72 |
| 摘要 | The Changyi banded iron formation (BIF) in the eastern North China Craton (NCC) occurs within the Paleoproterozoic Fenzishan Group. Three types of metamorphic wallrocks interbedded with the BIF bands are identified, including plagioclase gneisses and leptynites, garnet-bearing gneisses and amphibolites. Protolith reconstruction suggests that the protoliths of the plagioclase gneisses and leptynites are mainly graywackes with minor contribution of pelitic materials, the garnet-bearing gneisses are Fe-rich pelites contaminated by clastics, and the amphibolites are tholeiitic rocks. Trace elements of La, Th, Sc and Zr of the plagioclase gneisses and leptynites and the garnet-bearing gneisses support that these meta-sedimentary rocks were probably derived from recycling of Archean rocks with felsic and mafic materials differentiated into different rock types. Pb-207/(206) Pb ages of detrital zircons from the meta-sedimentary rocks concentrate at 2.7-3.0 Ga, confirming their derivation from the Archean rocks. The presence of several Paleoproterozoic detrital zircons (2240 to 2246 Ma), however, also suggests minor involvement of Paleoproterozoic materials. The Archean detrital zircons have epsilon(Hf)(t) values varying from -0.7 to 7.6, which mainly fall between the 3.0 Ga and 3.3 Ga average crustal evolution lines on the age vs. 410) diagram, further illustrating that the rocks providing materials for the meta-sedimentary rocks mainly originated from partial melting of a Mesoarchean crust. This is strongly supported by their crust-like trace element distribution patterns (such as Nb, Ta, P and Ti depletion) and ancient Nd depleted mantle model ages (T-DM = 2.9-3.4 Ga). In addition, the remarkably high epsilon(Hf)(t) values (7.5 to 93) of the Paleoproterozoic detrital zircons constrain the Paleoproterozoic materials to originate from a depleted mantle. The amphibolites show low SiO2 (465 to 52.8 wt%) and high MgO (5.68 to 10.9 wt.%) contents, crustlike trace element features and low epsilon Nd(t) values ( -4.5 to -0.3), suggesting that these ortho-metamorphic rocks were mainly derived from subcontinental lithospheric mantle with some contamination by Archean crustal materials. Since an intra-continental environment was required for the formation of the above metamorphic rocks, these rocks not only confine the depositional environment of the Changyi BIF to be an intra-continental rift, but also support the rifting processes of the eastern NCC during Paleoproterozoic. |
| 关键词 | Banded Iron Formation Metamorphic Wallrock Protolith Paleoproterozoic Continental Rift North China Craton |
| 学科领域 | 矿床地球化学 |
| 收录类别 | SCI |
| 语种 | 英语 |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.gyig.ac.cn/handle/352002/5212 |
| 专题 | 矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文 矿床地球化学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | Ting-Guang Lan,Hong-Rui Fan,Fang-Fang Hu,et al. Depositional environment and tectonic implications of the Paleoproterozoic BIF in Changyi area, eastern North China Craton: Evidence from geochronology and geochemistry of the metamorphic wallrocks[J]. Ore Geology Reviews,2014,61(1):52-72. |
| APA | Ting-Guang Lan,Hong-Rui Fan,Fang-Fang Hu,Kui-Feng Yang,Ya-Chun Cai,&Yong-Sheng Liu.(2014).Depositional environment and tectonic implications of the Paleoproterozoic BIF in Changyi area, eastern North China Craton: Evidence from geochronology and geochemistry of the metamorphic wallrocks.Ore Geology Reviews,61(1),52-72. |
| MLA | Ting-Guang Lan,et al."Depositional environment and tectonic implications of the Paleoproterozoic BIF in Changyi area, eastern North China Craton: Evidence from geochronology and geochemistry of the metamorphic wallrocks".Ore Geology Reviews 61.1(2014):52-72. |
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