Evidence for the existence of Precambrian Basement under the northern Songliao basin

Divergent views exist as to whether the Precambrian basement under the Songliao basin exists or not. Older zircons were discovered in a number of samples during the SHRIMP zircon dating of Early Cretaceous volcanic rocks in the northern Songliao basin, and their ages indicate that they mainly formed in the Precambrian. It is suggested that they were probably captured from the basement rocks during Early Cretaceous volcanic eruption. Three age groups have been broadly distinguished for the captured zircons:(1848±34) Ma, (1600±29) Ma and(1293±41) Ma, which implies that the basement of the northern Songliao basin experienced multiple tectono-magmatic events during the Paleo- and Mesoproterozoic. Therefore, it is believed that the Precambrian basement exists under the northern Songliao basin.