Differential Uplifting Rates Across the Magellan Fault: Interactions Between South American and Scotia Plates

Abstract

The Isla Grande of the Fueguian Archipielago is located on two plates, the South American Plate to the north, and the Scotia Plate to the south. Both plates are separated by the Magellan Fault, assumed a transform fault. Dealing with the sea-level evidences, significant differences between north and south have been estimated. The trailing-edge coast has been uplifting during the Pleistocene at a rate of 0.02 mm/yr between 3 and 1.4 Myers and at a higher rate of 0.05 mm/year for the last 1,4 Myers. As the Mid-Holocene sea-level fluctuation was recorded at both sides of the fault, it was possible to discern an uplifting trend of 0.3 mm/yr to the north (San Sebastián and Rio Chico coastal plains), and to a higher uplifting trend of 1.3 mm/yr to the south of the fault, at the Beagle Channel area. Along the northern side of the plate boundary, the uplifting rates also vary from west to east: 3.3 mm/yr at the western side and 0.2 mm/yr for the eastern side. These increasing uplifting trends were achieved managing different methods, and are explaining an increase in the modern tectonic activity.