New chronological constrains on the tectonic affinity of the Alxa Block, NW China

The origin and tectonic affinity of the Alxa Block in NW China is currently debatable. This study reports new stratigraphically-constrained LA-ICP-MS zircon U-Pb data from Precambrian rocks exposed in the westernmost part of the Alxa Block, to constrain their ages and provenance. Ages obtained for a granitic gneiss from the Longshoushan Group are mainly discordant yielding an upper intercept near 1200 Ma and a lower intercept between ∼350 and...