Department of Geology;
Northwest University;
Xi'an 710069;
China;
State Key Laboratory of Continental Dynamics;
Northwest University;
Xi'an 710069;
China;
Remote Sensing Application Institute of ARSC;
Xi'an 710054;
China;
geochronology; stratigraphy; strontium isotopes; marine sediments; global correlation; Guadalupian-Lopingian; Upper Yangtze region;