Depositional timing and provenance of the Lugezhuang Formation in the Jingshan Group in the Jiaobei terrane: New evidence from detrital zircon U-Pb ages and rare earth elements of arkose-quartzite in Mayudian, Shandong Province

As the Lugezhuang Formation of Jingshan Group is one of the most important parts of the Paleoproterozoic meta-sedimentary rocks in the Jiaobei terrane, accurate determination of its depositional timing and provenance is of great geological significance for further exploring the genetic relationship between the Jingshan Group and the Fenzishan Group.A comprehensive study on mineral inclusions, cathodoluminescence(CL)images, LA-ICP-MS U-Pb dates, and in-situ rare earth element(REE)compositions of detrital zircons indicates that the age of detrital zircons of the arkose-quartzite of the Lugezhuang Formation in the Muyudian area ranges from 2502 Ma to 1970 Ma, of which the youngest group age of detrital zircons is circa 2079 Ma.Combined with its metamorphic age of circa 1934 Ma of the Lugezhuang Formation, it is preliminary determined that the depositional timing of the Lugezhuang Formation ranges from 2079 Ma to 1934 Ma.On the basis of above and published data, detrital zircons from the Lugezhuang Formation of Jingshan Group, Lieryu Formation of South Liaohe Group and Mayinghe Formation of the Ji'an Group all have a single peak of 2200~2100 Ma.The Xiaosong Formation and Zhujiakuang Formation of Fenzishan Group, Liangzishan Formatin of North Liaohe Group and Dataishan Formation of Laoling Group are all characterized by peak ages greater than 2500 Ma.Combining with geology of the Jiao-Liao-Ji belt, it is speculated that the Xiaosong Formation and Zhujiakuang Formation of the Fenzishan Group might be deposited close to the passive continental margin, while the Lugezhuang Formation of the Jingshan Group might be deposited closer to the magmatic island arc.Therefore, the rocks of Fenzishan Group and Jingshan Group might be simultaneously deposited in different sedimentary facies.