Uplift rates versus exhumation rates in the northern argentine broken foreland

NOBILE, JC., DÁVILA, F.M.

Congreso; 23rd Latin American Colloquium; 2014

The northernmost Argentine broken foreland shows a distinct topographic and structural feature that can be visualized as the result of erosional exhumation and topographic growth due to rock uplift or to surface uplift. If we can quantify the erosion and growth we could understand what factors influence the relief (e.g., slab geometry, climate, tectonics, dynamic contribution to surface topography). The use of longitudinal river profiles to determine uplift rates has demonstrated to be a good quantitative technique (e.g., Roberts and White, 2010). We calculated the uplift velocities of Sierra de Ambato and Sierra de Aconquija using the inverse algorithm derived from the equation ∂z/∂x=U(t)-ν(0)xm (-∂z/∂x)n + κ(x)(∂2y/∂x2) (Roberts and White, 2010), where ν0 is the advective coefficient of erosion, m and n are positive constants that control the concavity of a river profile, κ is erosional diffusivity. Independent geological studies (low-temperature thermochronology, stratigraphy and structure, Dávila et al., 2012) proposed that the main uplift episode would have occurred at