Early Triassic Conversion from Source to Sink on the Southern Margin of the North China Craton: Constraints by Detrital Zircon U-Pb Ages

Abstract

Provenance analysis of sediments provides important constraints on basin formation and orogenic processes. With the aim to define the sedimentary provenance and tectonic evolution of the southern margin of the North China Craton, this paper presents new detrital zircon U-Pb data from Early Triassic sediments in the Yiyang area. The results showed major peaks at 1848, 458, 425, and 268 Ma and subordinate peaks at ca. 2500, 872, and 957 Ma on age spectra from the Liujiagou Formation. The Heshanggou Formation exhibited a major age peak at 445 Ma and subordinate peaks at 755 and 947 Ma. Integrated with the analysis of sandstone detrital compositions, we suggest that the sources of the Liujiagou Formation were mainly a mixture of the southern margin of the North China Craton and the North Qinling Orogenic Belt, whereas the Heshanggou Formation was derived primarily from the North Qinling Orogenic Belt. Age comparisons of detrital zircon geochronology collected from different basins in the North China Craton indicated that the paleogeography of the North China Craton during the Early Triassic was strongly asymmetric, wherein the uplifted highland along the southern margin of the North China Craton was relatively lower than the northern margin. Meanwhile, the marked shift in source region from the Liujiagou to the Heshanggou formations provides a constraint regarding the conversion from denuded zone to deposited zone along the southern margin of the North China Craton in the Early Triassic, which controlled the evolution of the provenance and sedimentary system.