LA-ICP-MS U-Pb dating of detrital zircon from Liuyehe basin in North Qinling Mountains

Aimed at exploration of basin-mountain coupling relationship between North Qinling Mountains and Liuyehe basin, the authors employed the detrital zircons age dating of the Carboniferous-Permian sedimentary rocks from Liuyehe basin located in North Qinling Mountains. The U-Pb dating results of 82 zircons gave rise to six age groups in an age range of 264±5~2834±40Ma, 260~542Ma, 800~1100Ma, 1320~1560Ma, 1640~2250Ma, 2300~2660Ma and 2720~2870Ma. Among the groups, the 260~542Ma age group represents the largest proportion of the measured points, followed in succession by 1640~2250Ma group, 2300~2660Ma group and 800~1100Ma group. A comparative study of the age structure and the Carboniferous cross-bedding shows that the provenance of the Liuyehe basin during the Carboniferous-Permian was probably located in the North Qinling Mountains during the Late Paleozoic. In addition, the detrital zircon age structure comparison shows that the sedimentary rocks of the southern Ordos basin and the Liuyehe basin have the same age spectrum characteristics, which in turn means that they had the same provenance during the Permian. Under the influence of late Caledonian orogeny, North Qinling area experienced rapid uplift and eventually completed the evolution of basin-mountain conversion. Later, along with the Shangdan strike-slip fault, the Liuyehe basin began to form due to the opening-up of the Mianlue Ocean, while the North Qinling Mountains became its main provenance.