ALP-CLIM-TE

Neogene Paleoelevation and Paleoclimate of the Central Alps - Linking Earth Surface Processes to Lithospheric Dynamics

01/09/2017 to 31/12/2020

This project integrates stable isotope altimetry records (d18O/dD) of the Central Alps with a high-resolution, global, isotope tracking paleoclimate model. We envisage testing between different Miocene to present surface uplift scenarios driven by lithospheric scale geodynamic processes inferred from AlpArray seismic imaging. For instance, if true that accretion of crustal material to the overriding plate results in short-wavelength orogen uplift and foreland basin subsidence, we would expect to see a steady increase in the change of oxygen isotopes in precipitation as a function of elevation, Delta(d18O), or Delta(z) between high Alpine regions and the foreland over time. In contrast, if the opening of slab gaps, slab breakoff, and subduction polarity reversals produce long-wavelength uplift signals affecting both the orogen and its foreland, the resulting changes in surface elevation might be more variable in time and result in a Delta(d18O) = 0 (if foreland and high-alpine elevations increased in a similar manner). However, in the latter case absolute changes in d18O can be expected. Testing these hypotheses requires a multidisciplinary approach involving tools that go beyond the methods commonly employed in stable isotope paleoaltimetry. We address this challenge through an integration of isotope-enabled paleoclimate models (ECHAM5-wiso) with new paleoclimate proxies (stable isotope and clumped isotope studies) collected from the foreland basin and high-elevation regions of the Alps. These experiments will bridge spatial and temporal scales of environmental change over the Alps, thereby forming a baseline for evaluating past climate influences on paleoaltimetry, erosion and exhumation studies across the AlpArray study area. Furthermore, establishing a surface elevation record will inform the debate about the timing of slab inversion and/or tearing in the Western Alps, and serve as a point of reference for thermochronology and geo-dynamic modelling studies that investigate the coupling between tectonics and erosion, and the crust-mantle processes responsible for shaping the European Alps. This study directly contributes to Research Themes 1, 2, 3 and Activity Fields E, F of the 4D-MB priority research program.