Early Cretaceous A-type granitic plutons are widely distributed in Shandong Peninsula,which are of great significance to understanding the regional tectonic evolution.Here we report geo-chemical characteristics,geochronological results,and zircon Hf-O isotope compositions of Wulian granites to reveal its origin and geological significance.Wulian granites share most characteristics of the A2-type granite.Zircon U-Pb LA-ICPMS analysis for Wulian A-type granites yields average age of 116.6±2.1 Ma.Zircon O isotope values range from 4.20‰ to 5.57‰,and these values are marginally identical to or slightly lower than those of mantle zircon(5.3‰±0.3‰).Zircon εHf(t)values(-26.1--23.5)indicate an enriched source.Integrated zircon Hf-O isotope compositions indicate that the source region of Wulian granites involves the components of ancient oceanic crust.Apatites from Wulian granites have the lower chlorine(0.06 wt.％-0.15 wt.％)and higher fluorine contents(2.11 wt.％-2.48 wt.％)compared with Haiyang pluton,together with their high(La/Gd)N,(La/Yd)N and low(Gd/Yb)N ratios and high oxygen state magma reflected from zircon,signifying that slab derived component was added into the overlying mantle region through fluid/melt.The geochemical characteristics of Wulian granites could be explained by the ridge(between the Izanagi and Pacific plates)subduction model,which began to influence the tectonic evolution of the Xuhuai region and Shandong Peninsula since～130±5 Ma.The following slab window between two plates plausibly explains regional extension,re-sulting in hot magma upwelling and the formation of the A-type granite belt.Integrating the Lower Yangtze River belt and Shandong Peninsula A-type granite proves the northward movement of the ridge between the Pacific Plate and Izanagi Plate.

Shuai Yuan;He Li;Lipeng Zhang;Congying Li;Haiyang Liu;Ying-Yu Xue;Weidong Sun

Center of Deep Sea Research,Institute of Oceanology,Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China;Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China;School of Marine Sciences,University of Chinese Academy of Sciences,Beijing 100049,China

地球科学学刊（英文版）

[1]Shuai Yuan;He Li;Lipeng Zhang;Congying Li;Haiyang Liu;Ying-Yu Xue;Weidong Sun-.Geochemical and Zircon Hf-O Isotopic Constraints on the Origin of Wulian A-Type Granite in Shandong Peninsula,Eastern China)[J].地球科学学刊（英文版）,2022(03):609-622

Wulian,Apatites,Yd,Izanagi,Xuhuai

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