松辽盆地北部存在前寒武纪基底的证据

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

目前对松辽盆地是否存在前寒武纪结晶基底的认识存在分歧。笔者对松辽盆地北部早白垩世火山岩中锆石SHRIMP定年研究过程中,在多个样品中发现了古老锆石,其年龄表明这些锆石主要形成于前寒武纪,并且认为它们可能来源于盆地北部深层的基底岩石,是火山喷发过程中捕获的。锆石年龄大致可分为3组:(1848±34)Ma、(1600±29)Ma和(1293±41)Ma,指示了盆地基底在古元古代和中元古代期间经历的多次构造-岩浆作用事件,由此认为松辽盆地北部存在前寒武纪基底。

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 It is suggested in the northern Songliao basin, and their ages indicate that they mainly formed in the Precambrian. 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.