TERRANES AND THE TECTONIC ASSEMBLY OF SOUTH-AMERICA - THE FIFTH CIRCUM-PACIFIC TERRANE CONFERENCE

A central theme of the 5th Circum-Pacific Terrane Conference held at S antiago, Chile, 11-14 November 1991, was the new theory that Australia and Antarctica separated from western North America during the Late P roterozoic, then crashed into Africa and South America to form Gondwan a in the Late Cambrian. Particular interest centered on the Precordill era Terrane, which came from central North America and was accreted to Argentina during the Ordovician, and on the Avalon Terrane, derived f rom northern South America and accreted to Laurasia during the Taconic Orogeny. The mobility of plates and terranes has been so great that b efore the Mesozoic the Circum-Pacific and Circum-Atlantic regions were one and the same.