The basement of the Songliao Basin is mainly composed of slightly-metamorphosed or unmetamorphosed Paleozoic strata, granites and gneiss. Petrographical studies indicate that the gneiss was originally the granitic int...The basement of the Songliao Basin is mainly composed of slightly-metamorphosed or unmetamorphosed Paleozoic strata, granites and gneiss. Petrographical studies indicate that the gneiss was originally the granitic intrusions which were deformed in the later stage. One undeformed granitic rock sample gives a U-Pb age of (305+++++++++++2) Ma, and the mylonitic granite yields a U-Pb age of (165++++++++3) Ma. Both of the two samples contain no inherited zircon, which suggests that there is no large-scale Precambrian crystalline basement beneath the Songliao Basin.展开更多
文摘The basement of the Songliao Basin is mainly composed of slightly-metamorphosed or unmetamorphosed Paleozoic strata, granites and gneiss. Petrographical studies indicate that the gneiss was originally the granitic intrusions which were deformed in the later stage. One undeformed granitic rock sample gives a U-Pb age of (305+++++++++++2) Ma, and the mylonitic granite yields a U-Pb age of (165++++++++3) Ma. Both of the two samples contain no inherited zircon, which suggests that there is no large-scale Precambrian crystalline basement beneath the Songliao Basin.
