PAST TOPOGRAPHY AS KEY TO UNDERSTANDING THE EVOLUTION OF LANDSCAPES AND LIFE (Invited Presentation)

The elevation histories of large orogens of our planet reflect the competing roles of geodynamic processes in crust and mantle as well as erosion at the Earth’s surface. At the same time, mountains host a substantial proportion of the world’s species. Further, the long-term surface elevation of orogens not only affects local (e.g. rainfall, seasonality, biodiversity) but also global climatic conditions e.g. through atmospheric teleconnections. Mountain building, therefore, directly links to patterns of biomes and biodiversity at the interface of atmospheric, Earth surface and geodynamic processes. Yet, our understanding of the interactions among tectonics, climate and biodiversity of a given region are often underexplored.

Stable isotope paleoaltimetry relies on the systematic decrease in the heavy isotope (¹⁸O or D) of precipitation due to cooling of air parcels and associated condensation of water vapor during uplift. The resulting oxygen (δ¹⁸O) or hydrogen (δD) isotope-elevation relationships are frequently robust and permit to relate δ¹⁸O or δD of past rainfall to changes in surface elevation and rainfall seasonality.

Here we present δ¹⁸O , δ¹³C and clumped isotope (Δ₄₇) temperature data from the central European Alps (Switzerland) as well as the Anatolian plateau (Turkey) to identify the interactions of regional surface uplift and (global) climate change on paleo-environmental conditions during the Miocene (tectonic) history of both regions.

Our data highlight the need for robust low-elevation δ¹⁸O reference data that permit to evaluate differences in δ¹⁸O between low and high elevation sites and assess the impact of changes in rainfall seasonality as a response to global climate change or regional attainment of elevation-driven threshold conditions to atmospheric circulation. Given the rapid technological advances in modeling and proxy approaches to determine paleoelevation as well as phylogenetic techniques in recovering the evolutionary history of mountain species, understanding biodiversity and mountain building will develop into an important opportunity for the geological and biological sciences.