Timing of Quaternary volcanic rocks in Hebei plain

It is important to date the Quaternary volcanic rocks for understanding the neotectonic activities in Hebei plain. The500.25 meter drill hole CK3 located near Haixing Country of Hebei Province revealed 4 layers of volcanic rocks. The⁴⁰Ar/³⁹ Ar age of the first stage of Quaternary volcanic rocks is 2.36±0.05 Ma. Combined with the magnetostratigraphy of CK3 core, the time of volcanic activities in Hebei Plain should be about 1.3 Ma, 35-70 ka and 10-15 ka, respectively.