The 2.2～2.1Ga magmatic event and its tectonic implication in the Lüliang Mountains,North China Craton
Paleoproterozoic magmas are widely distributed in Luliang Mountains,and the petrogenesis and tectonic setting of these magmas are significant for reshaping the geological evolution of the North China Craton.In this paper,we report Dujiagou feldspar porphyrite,intermediate basic volcanic rocks from the Jinzhouyu Formation of the Luliang Group and Ehutan gneiss in Luliang Mountains.SHRIMP U-Pb zircon dating of two Dujiagou feldspar porphyrite samples yield the ages of 2189±6Ma and 2186±3Ma,respectively,and one Ehutan dioritic gneiss sample gets a SHRIMP U-Pb zircon age of 2182±5Ma.Dujiagou feldspar porphyrites show the characteristics of A-type granite formed in a post orogenic setting.While,intermdiate basic volcanic rocks in the Jinzhouyu Formation and Ehutan gneisses have the characteristics of volcanic rocks formed in island arc setting.Considering the tectonic setting of 2.2~2.0Ga magmatic events in the North China Craton,the formation of the 2.2~2.1Ga magmatic rocks is probably related to its tectonic position during the Paleoproterozoic,with Luliang Mountains being located at the margin of the North China Craton.The 2.2~2.1Ga magmatic rocks in the study area were formed in both island arc and rift regimes at about same time.