Zircon U-Pb age and Hf isotope of Quanyishang A-type granite in Yichang: signification for the Yangtze continental cratonization in Paleoproterozoic

摘要: Zircon U-Pb age and Hf isotope, major trace element compositions were reported for granite at Quanyishang, which intruded into the Kongling complex in Yichang, Hubei Province. The results show that Quanyishang is rich silicon alkalis but poor calcium magnesium, displays enrichment Ga, Y, Zr, Nb depletion Sr Ba, exhibiting post-orogenic A-type affinity. 90% zircons from are concordant, give a middle Paleoproterozoic magmatic crystallization (mean 1854 Ma). Initial isotope ratios (176Hf/177Hf)i of range 0.280863 to 0.281134 they have negative eHf(t) values with minimum −26.3. These depleted mantle model ages (TDM) 2.9–3.3 Ga 3.0 Ga), average crustal (Tcrust) 3.6–4.2 3.8 Ga). A Mesoarchean grain 207Pb/206Pb 2859 Ma has slightly high TDM (3.4 Ga) similar Tcrust (3.8 zircons. All these data suggest source materials unusually old, least ⩾2.9 (even Eoarchean). event remelting, resulted formation Paleoproterozoic, recorded cratonization Yangtze continent. process may relation extension collapse deep crust Archean ages, response transition stage assembly breakup Columbia supercontinent.