Reprint of "Depositional environment and tectonic implications of the Paleoproterozoic BIF in Changyi area, eastern North China Craton: Evidence from geochronology and geochemistry of the metamorphic
Ting-Guang Lan; Hong-Rui Fan; Fang-Fang Hu; Kui-Feng Yang; Ya-Chun Cai; Yong-Sheng Liu
刊名Ore Geology Reviews
2014
卷号63页码:444-464
关键词Banded Iron Formation metamorphic Wallrock protolith paleoproterozoic continental Rift north China Craton
英文摘要

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. 207Pb/206Pb 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 εHf(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. εHf(t) 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 (TDM = 2.9–3.4 Ga). In addition, the remarkably high εHf(t) values (7.5 to 9.3) of the Paleoproterozoic detrital zircons constrain the Paleoproterozoic materials to originate from a depleted mantle. The amphibolites show low SiO2 (46.5 to 52.8 wt.%) and high MgO (5.68 to 10.9 wt.%) contents, crust-like trace element features and low εNd(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.

语种英语
内容类型期刊论文
源URL[http://ir.gyig.ac.cn/handle/42920512-1/11182]  
专题地球化学研究所_矿床地球化学国家重点实验室
作者单位1.State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China
2.State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
3.Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
推荐引用方式
GB/T 7714
Ting-Guang Lan,Hong-Rui Fan,Fang-Fang Hu,et al. Reprint of "Depositional environment and tectonic implications of the Paleoproterozoic BIF in Changyi area, eastern North China Craton: Evidence from geochronology and geochemistry of the metamorphic[J]. Ore Geology Reviews,2014,63:444-464.
APA Ting-Guang Lan,Hong-Rui Fan,Fang-Fang Hu,Kui-Feng Yang,Ya-Chun Cai,&Yong-Sheng Liu.(2014).Reprint of "Depositional environment and tectonic implications of the Paleoproterozoic BIF in Changyi area, eastern North China Craton: Evidence from geochronology and geochemistry of the metamorphic.Ore Geology Reviews,63,444-464.
MLA Ting-Guang Lan,et al."Reprint of "Depositional environment and tectonic implications of the Paleoproterozoic BIF in Changyi area, eastern North China Craton: Evidence from geochronology and geochemistry of the metamorphic".Ore Geology Reviews 63(2014):444-464.
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