Crustal reworking in the North China Craton at ~2.5 Ga: evidence from zircon U–Pb age, Hf isotope and whole rock geochemistry of the felsic volcano‐sedimentary rocks from the western Shandong Province

摘要: The western Shandong Province (WSP) is one of the typical Neoarchaean granite–greenstone belts in Eastern Block North China Craton (NCC) and an important region to investigate early Precambrian evolutionary history NCC. Taishan association, consisting a ~2.7 Ga komatiite–tholeiite sequence ~2.5 Ga felsic volcano-sedimentary sequence, major lithological assemblage WSP. In Qixingtai area, partly subjected anatexis, composed hornblende gneiss, voluminous fine-grained biotite gneiss plagioclase gneiss. SHRIMP zircon dating shows that protolith formed after ca. 2.53 Ga. tonalite intrusion into volcanic protoliths occurred at 2.52 Ga. Our age data constrain time formation area as 2.53–2.52 Ga. majority zircons from rocks have intermediate eHf(t) values (−1.2 +2.1). whole rock Nd isotopes yield eNd(t = 2522 Ma) +2.6 −1.8 TDM2 ages 3.03–2.68 Ga. These indicate pre-existing crust was reworked end (~2.5 Ga). The are rhyodacite–dacite andesite composition. display similar high SiO2 (65–72 wt.%) low MgO (1–2 wt.%) content. contrast, minor andesites lower (61–62 wt.%) higher (5.3–6.3 wt.%), suggesting more mantle contribution during their petrogenesis. However, Mg-rich identical rare earth element multi-element patterns with rhyodacite–dacites distinguish them sanukitoids. We suggest 2.53–2.52 Ga volcanics association products partial melting subducted oceanic crust. were produced by modification ascending tonalite–trondhjemite–granodiorite-type magma wedge. Our study indicates (1) tectonic regime WSP greenstone belt dominated arc-subduction system ~2.52 Ga (2) intrusive crustal reworking. other arc-like assemblages NCC provide clues understand nature tectonothermal events Neoarchaean. Copyright © 2013 John Wiley & Sons, Ltd.