Paleoproterozoic granitic magmatism in the Luliang area, North China Craton: constraint from isotopic geochronology.

The Lufiang Paleoproterozoic metamorphic block is situated in the western margin of the middle segment of the Central Tectonic Zone, North China Craton. A lot of Paleoproterozoic intrusions of granodioritic to granitic in composition are distributed in the Precambrian block. Based on granitic assemblage and geochronologic data, the Paleoproterozoic granitoid can be divided four stages. In early extension stage, the Gaijiazhuang granite with 2364 Ma age intruded to metamorphic rocks. In the stage granitism coincided with the Luliang volcanism in the continental marginal rift. During the trasition from extension to late compression, the Chijianling granodiorites with 2150 Ma ages intruded into metamorphic strata. The 2063 Ma Daorengou adamellite, 1906Ma Huijiazhuang biotite granite and 1848Ma Shizhuang granodiorite are the representatives of the granitic magmatism in compression stage. The 1805Ma Dacaoping porphyritic granite, 1800 Ma Luyashan porphyritic granite and Yunzhongshan granite were formed in later extension stage. Zircon SHRIMP ages suggest that the previously incorporated Guandishan complex consists of different granitic intrusive and the complex should be disintegrated into the Huijiazhuang granite, Shizhuang granodiorite of compression stage and the post-oroginic Dacaoping granite.