How fast is the denudation of the Taiwan mountain belt? Perspectives from in situ cosmogenic 10 Be Florence Derrieux a , Lionel L. Siame a,b,f,⇑ , Didier L. Bourlès a,f , Rou-Fei Chen c,f , Régis Braucher a,f , Laetitia Léanni a , Jian-Cheng Lee c,f , Hao-Tsu Chu d,f , Timothy B. Byrne e a Aix-Marseille Université, CNRS-IRD-Collège de France, UM 34 CEREGE, Technopôle de l’Arbois, BP80, 13545 Aix-en-Provence, France b Institute of Earth Sciences, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan c Department of Geology, Chinese Culture University, 55, Hwa-Kang Road, Yang-Ming-Shan, Taipei, Taiwan d Central Geological Survey, Ministry of Economic Affairs, P.O. Box 968, Taipei, Taiwan e Center for Integrative Geosciences, University of Connecticut, Storrs, CT 06269, United States f LIA (Associated International Laboratory), ADEPT (Active Deformation and Environment Programme for Taiwan), Centre National de la Recherche Scientifique/Institut National des Sciences de l’Univers (France), National Science Council, Taiwan article info Article history: Received 18 September 2013 Received in revised form 27 February 2014 Accepted 17 March 2014 Available online 29 March 2014 Keywords: Denudation Cosmogenic nuclides [ 10 Be] Mountain building Taiwan abstract Quantifying denudation rates in a wide range of climatic and tectonic settings at various time and space scales is a critical step in calibrating and validating landscape evolution models. Focusing on Taiwan, we quantified centennial rates of denudation at the scale of the whole orogen, using in situ 10 Be concentra- tions measured in stream sediments collected at the outlets of major rivers. To assess denudation rates that are statistically significant, we applied both the mean square weighted deviation approach and the bootstrap technique. For the central segment of the belt, where the collision is considered to be near mature, the orogen-scale pattern of denudation shows a two-fold pattern: (1) higher denudation values on the order of 4–5 mm/yr characterize the eastern side of the belt (i.e., retro-wedge), with a slight increase towards the south and (2) lower denudation values on the order of 1–3 mm/yr on the western side of the belt (pro-wedge) with a minimum value centered on the main recess of the deformation front. To the north and to the south of the central segment, the denudation rates converge towards lower values on the order of 2–3 mm/yr. At the scale of the mountain belt, drainage basin metrics such as relief, hyp- sometric index and slope values seem to explain the observed variance in the data population, conversely to the first-order average precipitation pattern, suggesting a strong tectonic control on the regional pat- tern of denudation rates. Applied to the whole orogen, such field-based approach thus provides impor- tant input data to validate and calibrate the parameters to be supplied to landscape evolution models. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Orogenic settings resulting from tectonic evolution along con- vergent margins record connection between deep and surface pro- cesses (Davis et al., 1983; Selzer et al., 2008). Within orogenic wedges, horizontal and vertical tectonic movements indeed create a topographic relief that is in turn progressively destroyed by denudational processes (Willett, 1999), leading to landmass redis- tributions (Konstantinovskaia and Malavieille, 2005). Nevertheless, the interaction of deep and shallow processes is still poorly understood and the role these processes play in the exhumation of rocks, in the structural evolution of orogenic wedges, and in defining the relations between tectonics and climate-dependent surface processes are still debated (Dahlen and Suppe, 1988; Whip- ple and Meade, 2004; Cruz et al., 2010; Konstantinovskaya and Malavieille, 2011). However, as pointed out by Molnar (2009), it may be more pertinent to quantify independently the processes in- volved in mountain belt evolution rather than trying to study the interactions among them. As part of this effort, quantification of denudation rates in a wide range of climatic and tectonic settings at various time and space scales is a critical step in providing fun- damental input parameters to feed analog and numerical models of orogenic systems. The present-day denudational context of Taiwan is controlled by high uplift rates (e.g., Ching et al., 2011), linked to the north- west-directed collision of the north-trending Luzon arc against http://dx.doi.org/10.1016/j.jseaes.2014.03.012 1367-9120/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Aix-Marseille Université, CNRS-IRD-Collège de France, UM 34 CEREGE, Technopôle de l’Arbois, BP80, 13545 Aix-en-Provence, France and Institute of Earth Sciences, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan. Tel.: +33 442 971 760. E-mail address: siame@cerege.fr (L.L. Siame). Journal of Asian Earth Sciences 88 (2014) 230–245 Contents lists available at ScienceDirect Journal of Asian Earth Sciences journal homepage: www.elsevier.com/locate/jseaes