Zircon UPb Dating and Geological Significance for Jurassic Igneous Rocks in North Yellow Sea Basin

Abstract:

Zircon UPb dating analysis was performed on four igneous rock samples taken from the Jurassic debris of the drilling wells in North Yellow Sea Basin. Two sorts of ages are obtained, one is about the formation and evolvement of Precambrian metamorphosed basement and the other is about the collisional orogeny in Indo Chinese epoch. The age about metamorphism basement is distributed in 1.0—2.6 Ga, its main tectonic magma period is 1.4—1.8 Ga which includes three groups of UPb Concordia ages: 1 792±140 Ma, 1 447±110 Ma and 1 524±68 Ma. The age connected to the collisional orogeny between North China block and Yangze block in Indo Chinese epoch is distributed in 200—240 Ma. These two ages have a good relationship with neighboring blocks as Jiaobei terrane and Sulu orogene. They can provide important evidence for the tectonic evolvement of source area in Jurassic strata in North Yellow Sea Basin.