“APPA-LAY-CHA” VS. “APPA-LATCH-A”: POTENTIAL ORIGINS OF FUNDAMENTAL DIFFERENCES BETWEEN THE NORTHERN AND SOUTHERN SECTORS OF THE APPALACHIAN OROGEN

It has long been recognized that the character of the northern and southern Appalachians differs significantly. Ophiolites along the Appalachian Orogen may provide insight into how fundamental differences in the subduction setting may be responsible for some of these contrasts. We present metamorphic, spatial, and geochronological data on two ophiolites from the southern Appalachians (Dadeville, USA; Baltimore, USA) and three ophiolites from the northern Appalachians and Caledonides (Thetford Mines, Canada; Unst, UK; Leka, Norway). We highlight similarities and differences between the ophiolite complexes and discuss how the geometry of earliest subduction may have controlled system architecture, what is preserved and the mechanisms responsible.