SHRIMP U-Pb zircon age of Late Mesozoic tuff(lava) in Luanping basin, northern Hebei, and its implications
SHRIMP U-Pb zircon age of Late Mesozoic tuff(lava) in Luanping basin, northern Hebei, and its implications
复制标题
作者：
Li Peixian
对冀北方滦平盆地大北沟组中新近发现的层状凝灰岩和凝灰质砂岩进行了SHRIMP锆石U-Pb定年，年龄分别为133.9± 2.5Ma和130.1± 2.5Ma。井上村东张家沟组顶部凝灰熔岩的SHRIMP锆石U-Pb年龄为135.4± 1.6Ma。综合研究表明，冀北方滦平盆地沉积了完整的热河生物群序列，135 Ma是热河生物群出现的最低年代层位。作者认为大北沟组与大店子组的界线年龄为130 Ma，这一资料有助于侏罗系与白垩系界线的研究。
The recently discovered bedded tuff and tuffaceous sandstone within the Dabeigou Formation in Luanping basin of northern Hebei were dated by SHRIMP zircon U-Pb technique at 133.9±2.5 Ma and 130.1± 2.5 Ma respectively. The SHRIMP zircon U-Pb age of 135.4±1.6 Ma for the top tufflava of the Zhangjiagou Formation at eastern Jingshang Village was also obtained. A comprehensive study indicates that a complete Jehol biota-bearing succession is deposited in Luanping basin of northern Hebei, and that 135 Ma is the lowest chronohorizon from which Jehol biota appeared. The authors hold that the boundary between Dabeigou Formation and Dadianzi Formation is 130 Ma in age, the data is helpful to the study of the boundary between Jurassic and Cretaceous.