Global Pleistocene-Holocene variations in denudation rates constrained from a joint analysis of cosmogenic nuclides and morphological data

At the end of the last glaciation, landscapes have undergone profound changes, with increased temperature and modification of precipitation regimes changing the way sediments are produced and transported at the Earth's surface. Records of past denudation rates are essential for understanding how landscapes responded to this transition, and to assess their sensitivity to local environmental, climatic and geomorphic conditions.  Terrestrial Cosmogenic Nuclides (TCN) can be used in different ways to constrain paleo-denudation rates over 10s ka timescales, but few datasets exist that display strong signals regarding the dependency of this response to local setting characteristics, and the diversity of the approaches limits the possibilities for a global analysis.

We propose a new approach to constrain changes in erosion rates over the Pleistocene-Holocene transition, using the well-known concept that erosion rates derived from concentrations average over a timescale inversely proportional to the erosion rate. By combining TCN data with topographic information, we constrain the amplitude of erosion changes across neighboring basins that are eroding at different rates. We highlight a complex pattern, with an overall pronounced several-fold increase in denudation rate when entering the Holocene. Intertropical high-relief settings appear to be more likely to displaying an increase in denudation rates, which might reflect a stronger sensitivity of these landscapes to periglacial processes, monsoon regime or threshold hillslope dynamics.