Quantifying the Effects of Mantle Processes and Climate Variability on HinterlandDenudation in the Central and Eastern Alps since the Oligocene

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Present-day tomographic mapping of the Alpine Moho identified two remnant mantle lithospheric slabs beneath the Central to Eastern Alps at ca. 135-165 km depth approximately along-strike the Periadriatic Lineament. This observation led to new hypotheses on mantle processes and mantle lithospheric slab geometries of the European and Adriatic plates since initial continental collision during the Oligocene. For example, slab break-off events are being proposed for the Oligocene and Early/Middle Miocene followed by subduction polarity reversal. Their potential influence on surface processes, i.e. hinterland denudation, preserved in the Miocene stratigraphic record and present-day bedrock will be the main focus of this proposal. We will take advantage of 2D kinematic fields created along the NFP-20E, TRANSALP and EASI profiles to reconstruct the 3D kinematic history of the Central to Eastern Alps and use this as input to state-of-the-art numerical landscape evolution / surface processes models (LEMs). By testing a range of magnitudes and wavelengths of mantle-induced surface uplift, added to this ‘baseline’ 3D kinematic field, we will be able to quantify the effect of mantle processes to hinterland denudation through modelling of erosional flux, bedrock and detrital thermochronological data. In order to distinguish mantle and climatic effects caused, for example, by the Miocene Climatic Optimum our LEMs will be subject to spatially and temporally variable precipitation. Hinterland denudation modelled in LEMs that contain both, mantle and climate components, will be compared to existing present-day bedrock and Miocene stratigraphic detrital thermochronologic data to evaluate whether any of the proposed mantle processes resulted in an observable surface response. Our novel mantle-to-surface numerical modelling approach not only continues our work during the first phase of the MB-4D SPP but also directly addresses its second phase Theme 2.