Provenance record of a foreland basin: Detrital zircon U-Pb ages from Devonian strata in the North Qilian Orogenic Belt, China

摘要

Devonian strata in the North Qilian Belt of the Qilian Orogen accumulated in a foreland basin formed through collision between the North China Craton and the Central Qilian Belt. U-Pb age data for 393 detrital zircons from four sandstone samples from the Lower to Middle Devonian Laojunshan Formation and Upper Devonian Shaliushui Formation range in age from 3.6. Ga to 0.4. Ga and indicate input from a multi-component source. Detrital zircons older than the early Mesoproterozoic (1.4. Ga) were likely derived from the North China Craton, whereas late Mesoproterozoic to Neoproterozoic zircons were derived from the Central Qilian Belt. Early Paleozoic zircons were derived from the North Qilian continental arc and associated ophiolites. The occurrence of Neoproterozoic zircons indicates that their source, the Central Qilian Belt, was likely once part of the Yangtze Block of the South China Craton prior to its separation from the craton in the late Neoproterozoic.