Detecting transience in slow evolution landscapes using cosmogenic nuclides and high resolution morphometry

Abstract

Transient evolution and adjustment to changing tectonic and climatic boundary conditions is an essential attribute of landscapes. We present a new approach to detect and quantify transience in slow erosion landscapes over 100 ka timescales. We compare curvature and cosmogenic nuclides measurements (¹⁰Be and ²⁶Al) at hilltop sites with predictions of hillslope diffusion theory, in the slowly evolving quartzitic Serra do Cipó range in SE Brazil, and we observe a distinctive signature of an acceleration of denudation. The timing of this increase cannot be unequivocally associated with a single climatic event but is consistent with climatically-modulated important fluctuations in precipitation and erosion in this area during Middle and Late Pleistocene.