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Free keywords:
Passive unloading; Sediment redistribution; Isostatic rebound; Holocene deformation; Rock uplift; Lithosphere flexure
DDC:
550 - Earth sciences
Abstract:
We present a compilation of data of modern tectono-geomorphic processes in the Central European Alps 11 which suggest that observed rock uplift is a response to climate-driven denudation. This interpretation is 12 predominantly based on the recent quantification of basin-averaged Late Holocene denudation rates that are 13 so similar to the pattern and rates of rock uplift rates as determined by geodetic leveling. Furthermore, a GPS 14 data-based synthesis of Adriatic microplate kinematics suggests that the Central Alps are currently not in a 15 state of active convergence. Finally, we illustrate that the Central Alps have acted as a closed system for 16 Holocene redistribution of sediment in which the peri-Alpine lakes have operated as a sink for the erosional 17 products of the inner Central Alps. 18 While various hypotheses have been put forward to explain Central Alpine rock uplift (e.g. lithospheric 19 forcing by convergence, mantle processes, or ice melting) we show with an elastic model of lithospheric 20 deformation, that the correlation between erosion and rock uplift rates reflects a positive feedback between 21 denudation and the associated isostatic response to unloading. Thus, erosion does not passively respond to 22 advection of crustal material as might be the case in actively converging orogens. Rather, we suggest that the 23 geomorphic response of the Alpine topography to glacial and fluvial erosion and the resulting disequilibrium 24 for modern channelized and associated hillslope processes explains much of the pattern of modern 25 denudation and hence rock uplift. Therefore, in a non-convergent orogen such as the Central European Alps, 26 the observed vertical rock uplift is primarily a consequence of passive unloading due to erosion.
