Development of the Circum-Pacific Panthallassic Ocean during the Early Paleozoic (Paleoceanographic Mapping Project Report No. 10-0386}

Though the Pacific plate is less than 200 million years old, the Circum-Pacific ocean basin (Panthallassic ocean basin) has probably been in existence since Precambrian times. During the Early Paleozoic the Tasman trans-Antarctic, arid southern Andean margins of the Panthallassic ocean basin appear to have been the site of active subduction. This convergent system may have continued north into Southeast Asia, northern China, and southern Siberia. Continental reconstructions for the Late Cambrian, Late Ordovician, Late Silurian, and Late Devonian times are presented from a "Panthallassic" point-of -view. Paleomagnetic, biogeographic, and paleoclimatic evidence supporting three different Late Devonian reconstructions is reviewed.