Top 10 Technological Advancements of CAGS 2013

Top10. New understanding on the Premesozoic structures of the Alxa Massif

Updated :03,05,2014

    Researcher Yang Z.Y. and his team from the Institute of Geomechanics, under the support of the SinoProbe fund, carried out clastic zircon U-Pb isotopic dating, Hf isotopic analysis and paleogeomagnetic research on the Mid-Late Devonian-Early Mid-Triassic sedimentary strata in the Hexi Corridor Zone - Alxa Massif, and discovered notable difference between the Mid to Late-Devonian clastic zircon found in Niushoushan area from their contemporaneous counterparts found in the North China Massif in terms of the U-Pb age spectra and the Hf isotopic characteristics. The Mid-Late Devonian, Late Carboniferous, Late Permian, Early Mid-Triassic paleogeomagnetic polarity in the Alxa Massif is also remarkably different from that in the North China Massif, indicating that the Alxa Massif was probably not part of the North China Massif in Late Proterozoic. Paleogeomagnetic results also demonstrate that the Indosinian Movement after Mid-Triassic caused the Alxa Massif to rotate approximately 30 degrees relative to the North China Massif, resulting in the eventual collage of the Alxa Massif with the North China Massif. This finding is a challenge to conventional understanding of the tectonic framework of the North China Massif.

Reconstruction of the Late Triassic paleogeography