Zircon U–Pb Dating,the Petrological And Geochemical Constraints On The Proterozoic Igneous Rocks Along The Southern Margin Of North China Craton

The Paleo-Mesoproterozoi Xiong’er volcanic rocks belt is located in the Zhongtiao,the Xiaoshan,the Xiong’er and the Waifang mountains alone the southern margin of North China Craton. It is particularly important to study Xiong’er volcanic rocks and intrusive rocks for understanding the tectonic evolution and dynamics background of the North China Craton i. At the same time,it can provide the relevant evidence to research the assembly and breakup of the Paleo-Mesoproterozoic Columbia supercontinent. Major results and understanding as follows:(1)The quartz monzodiorite and dacites had the characteristics of low Na,Mg,Al,Ti,P values and high K,Fe values,belonging to Calcium alkaline-high K Calcium alkaline types rocks.(2) The Waifang diorite dykes intruding into the upper part of the Xiong’er Group yielded emplacement mean ages of 207Pb/206 Pb from 1744 ± 19 Ma to 1764 ± 11 Ma, and dacite with age of 1785±29Ma. These ages constrained the formation of Paleo-proterozoic igneous rocks.(3) Trace elements show that the magma source of igneous rocks were derived from an enriched lithospheric mantle along the southern margin of North China Craton, with some degrees of the crustal mixing characteristics.(4) This paper argues that the Xiong’er volcanic rocks and the same period time intrusive rocks at the southern margin of North China Craton were to related to rifting of the North China Craton, correponding to breakup of the North China Craton.