Late Mesozoic and Cenozoic tectono-thermal history and geodynamic implications of the Great Xing'an Range, NE China

The Mesozoic-Cenozoic tectonics of Northeastern China involves complex multistage interaction of different tectonic domains and has long been controversial. The tectono-thermal evolutionary history recorded by the widespread outcropped granitoids in the Great Xing'an Range (GXR) may provide significant constraints on the tectonics, illuminating the deep geodynamic process. Here, we present new low-temperature thermochronology data from the GXR, and thus, reconstruct the detailed thermal history. Zircon fission-track dating yielded a group of central ages ranging from 80 +/- 4 to 185 +/- 10 Ma, while apatite fission-track ages range from 55 +/- 3 to 75 +/- 5 Ma. The modeled time-temperature paths of all the samples reveal two relatively rapid cooling events at similar to 100-60 Ma and similar to 50-0 Ma, and one intervening reheating episode at similar to 60-50 Ma. The initial uplift, exhumation, and induced cooling events, which represent strong orogenic activity, are related mainly to closure of the Mongol-Okhotsk Ocean in the north and were subsequently influenced by the Paleo-Pacific plate subduction in the east. The evolution of the basin-mountain system consisting of the Songliao Basin and GXR, as well as the accretion, metamorphism, and magmatism at the Northeast Asian continental margin, are all dominated or indirectly influenced by the Paleo-Pacific subduction. This indicates that the Paleo-Pacific subduction had affected the evolution of the GXR to the west since the Jurassic. The significant reheating episode during the Late Paleocene to Eocene may be related to the heat flux derived from asthenosphere upwelling and igneous activity.