U-Pb Age of Detrital Zircons and Its Geological Significance from Maoniushan Formation in the Wulan County, Northern Margin of Qaidam Basin

Key words: 
• detrital zircons /
• U-Pb dating /
• tectonic events /
• Late Devonian /
• Maoniushan Formation /
• northern margin of Qaidam Basin

Abstract: This paper studied the age distribution of detrital zircons of sandstone in Maoniushan Formation of Upper Devoion of Wulan country from northern margin of Qaidam Basin using LA-ICP-MS U-Pb isotopic age of zircons. The results show that the detrital zircons of sandstone has a wide range of zircon age, which can be divided into 5 peak interval. This sequence of the strata possibly was deposited in the Late Devonian and not earlier than the end of Early Devonian according to the regional geological correlation and paleontological data. The age distribution of detrital zircons indicate that there may be events of five regional geological structure in this area, and the most prominent is the Early Paleozoic, followed by Neoproterozoic and Early Paleoproterozoic-Late New Archean, which imply that the three periods of metamorphism and magmatic activity is relatively active and provide the main source of zircon for this strata with a mixture of multi-source characteristics. The obtained age data indicate the multi-provenance of the sandstone. In addition, there are less Archean detrital zircon having a high degree of harmony, which has provided some basis for the possible existence of Archean old strata, but needs further research.