REMAGNETIZATION IN SOUTHEAST CHINA AND THE COLLISION AND SUTURING OF THE HUNAN AND YANGTZE BLOCKS

Nearly all paleomagnetic studies in south China have encountered problems with remagnetization. The region underwent widespread tectonic deformation during the Mesozoic and the warm, humid climate causes rapid weathering of surficial sediments. Paleomagnetic results from three Carboniferous formations from three provinces in southeast China reveal two possible overprinting ages: one is probably a post-folding Cretaceous remagnetization and the other appears to be a Jurassic overprint which may be associated with the collision and suturing of the Yangtze and the Huanan or North China Blocks. The Jurassic overprint is found in sediments with both magnetite and hematite as primary magnetic remanence carriers. The remagnetization pre-dates deformation in at least one of the formations, further constraining the overprint to the Jurassic or late Triassic.