Controls of surface erosion on the evolution of the Alps: constraints from the stratigraphies of the adjacent foreland basins |
| |
Authors: | F Schlunegger |
| |
Institution: | Institut für Geowissenschaften Allgemeine und Historische Geologie, Friedrich-Schiller Universit?t Jena, Burgweg 11, D-07749 Jena, Germany e-mail: fritz@geo.uni-jena.de, DE
|
| |
Abstract: | The combined information about the stratigraphies from the foreland basins surrounding the Swiss Alps, exhumation mechanisms
and the structural evolution of the Alpine orogenic wedge allow an evaluation of the controls of erosion rates on large-scale
Alpine tectonic evolution. Volumetric data from the Molasse Basin and fining-upward trends in the Gonfolite Lombarda indicate
that at ∼20 Ma, average erosion rates in the Alps decreased by >50%. It appears that at that time, erosion rates decreased
more rapidly than crustal uplift rates. As a result, surface uplift occurred. Because of surface uplift, the drainage pattern
of the Alpine hinterland evolved from an across-strike to the present-day along-strike orientation. Furthermore, the decrease
of average erosion rates at ∼20 Ma coincides with initiation of a phase of thrusting in the Jura Mountains and the Southern
Alpine nappes at ∼50 km distance from the pre-20-Ma thrust front. Coupled erosion-mechanical models of orogens suggest that
although rates of crustal convergence decreased between the Oligocene and the present, the reduction of average erosion rates
at ∼20 Ma was high enough to have significantly influenced initiation of the state of growth of the Swiss Alps at that time.
Received: 8 June 1998 / Accepted: 30 October 1998 |
| |
Keywords: | Wedge mechanics Erosion and tectonics Orogenic system |
本文献已被 SpringerLink 等数据库收录! |
|