CARBON-ISOTOPE AND MAGNETIC POLARITY EVIDENCE FOR NON-DEPOSITIONAL EVENTS WITHIN THE CAMBRIAN-ORDOVICIAN BOUNDARY SECTION NEAR DAYANGCHA, JILIN PROVINCE, CHINA

Carbon isotope and magnetic polarity stratigraphic results from the Ca mbrian-Ordovician Boundary section at Xiaoyangqiao, near Dayangcha, Ji lin Province, China, in comparison to a contemporaneous section at Bla ck Mountain, Australia, indicate strata equivalent to major portions o f the Australian sequence are either absent or are restricted to highl y condensed intervals. These intervals are correlative with regressive sea level events identified in Australia and western North America, s uggesting regional or eustatic sea level changes strongly influenced d eposition of the Xiaoyangqiao sequence. These results also suggest the Xiaoyangqiao section is unfavourable as the site of the Cambrian-Ordo vician Boundary Global Stratotype Section and Point.