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age of formations
Is a Maastrichtian age for the Tsagayan (=Amur, Heilongjiang) really credible in light of biogeography and stage of evolution? Considering that the Tsagayan lay between NA and Mongolia, which were biogeographically linked in the Maastrichtian, and had more derived and different faunas by then (fewer lambeosaurs) the Tsagayan hadrosaurs seem too primitive and diverse for such a late age. Godefroit said NE Asia was completely isolated: "how, no one knows." Is that credible?
Nemegt age: Yes, Shuvalov included an IGEM figure of about 75 Ma for the upper Barun Goyot, which suggests the overlying Nemegt is Edmontonian in age. But the margin of error is 7 Ma- an entire stage! The top of the Barun Goyot might be as young as mid-Maastrichtian.
Regarding the Javelina: T. Lehman once wrote the K-T signature hasn't been found, and the Puercan may be missing there, suggesting an unconformity.