LA-ICP-MS U-Pb Dating of Detrital Zircons from the Marine Volcanic-Sedimentary Rock in the Northern Kamste, Eastern Junggar and Its Geological Significance

There has been a controversy in zircon U-Pb ages of marine volcanic-sedimentary detrital rock,which occurred in 10 km away from the northern Kamste in Eastern Junggar.Thus,the zircon U-Pb ages of detrital rock were measured by the LA-ICP-MS method.And 100 detrital zircons had been tested totally,of which 90 ages of these zircons are useful.The dating results have shown that:(1)the formation age of this rock stratum may be Early Carboniferous,because the deposition time was later than 333.2 Ma which has been limited by the youngest age of detrital zircon.(2)There are multiple provenances for this rock stratum,which are proved by the contrast results between detrital zircon dating results and regional magmatic events as follows: Early Cambrian(523.1 Ma,535.1 Ma)detrital zircons might source from Precambrian crystalline basement of Junggar,but need further research;Middle-Late Ordovician(440.0 Ma,460.9 Ma) detrital zircons came from pyroclastic rocks of Huangcaopo Group;Early Silurian(429.3 Ma)detrital zircon might originate from the Lower Silurian stratum,which was deposited in the surrounding of this study area;Middle Devonian((371.5±2.5) Ma)detrital zircons derived from the strata of Zhuomubasitao Formation and Wulusubasitao Formation;and Early Carboniferous((336.4±0.8)-(353.5±0.7) Ma)detrital zircons stemmed from the stratum of Nanmingshui Formation.(3) In addition,there is a zircon aged 2,676.2 Ma having the harmonic degree of 99%,which has provided some basis for the possible existence of Precambrian ancient crystallization basement,but needs further evidence.