Zircon results indicate that since ca. 22 Ma, long-term exhumation rates have been highest across the western and central thrust domains (0.22-0.37 mm yr(-1)), and significantly lower along the eastern thrust front (0.10-0.17 mm yr(-1)). Since similar to 7 Ma, apatite results from these same regions suggest comparable and slightly higher denudation rates (0.14-0.46 mm yr(-1)), particularly within the eastern thrust domain, consistent with efficient erosional processes acting in the retroarc region. These results from the Patagonian retroarc region, particularly the predominance of < 7-4 Ma AHe ages, provide a new understanding for regional orogenic erosion models that are largely based on existing data from the windward regions. We suggest that retroarc denudation was enhanced by widespread Miocene structural uplift and unroofing of the fine-grained siliciclastic rocks of the marine Cretaceous Magallanes/Austral foreland basin. Furthermore, its location at the southern tip of the orogen, may have allowed additional moisture to reach the leeward side, leading to sustained late Cenozoic erosional denudation. (C) 2012 Elsevier B.V. All rights reserved.