Antler orogeny it have been tried—east dipping subduction, west-dipping subduction, and strike-slip motion. None of them is without serious problems and the nature and driving force of the orogeny remain uncertain. This much is known concerning the Antler orogeny: Based on stratigraphic relations near Antler Peak, of the Battle Mountains, Roberts introduced the term Antler orogeny in an abstract as follows: "The earliest orogeny, here named the Antler orogeny ... took place during Mississippian (?) and early Pennsylvanian time." That abstract was followed in 1951 by his geologic map of the Antler Peak quadrangle in the text of which he described the
Andean orogeny and then to the opening of the Drake Passage 45 million years ago. The separation from Antarctica changed the tectonics of the Fuegian Andes into a transpressive regime with transform faults. About 15 million years ago in the Miocene the Chile Ridge begun to subduct beneath the southern tip of Patagonia (55° S). The point of subduction, the triple junction has gradually moved to the north and lies at present at 47° S. The subduction of the ridge has created a northward moving "window" or gap in the asthenosphere beneath South America. Andean orogeny The Andean orogeny () is an