13.11.2025

13:15, Lecture hall C.011

Dr. Dominic Wölki  (Universität Freiburg)

Radiogenic Isotopes in Peridotites: Tracing Mantle Circulation Through Time

Abstract: Peridotites act as geochemical archives that record mantle processes through time. Radiogenic isotope systematics, especially Hf–Nd, reveal how ancient melt depletion, later enrichment, and melt–rock interactions shape mantle domains. These isotopic signatures provide key insights into the circulation of material from mid-ocean ridges to subduction zones, linking mantle convection with crustal recycling. By integrating peridotite records across tectonic settings, we can trace the temporal and spatial evolution of mantle dynamics and Earth’s deep geochemical cycles.

Research Interest: Plate tectonics is the result of the Earth’s most efficient way to lose heat and causes upwelling and melting of mantle, forming new oceanic crust. This crust is recycled back into the mantle at subduction zones. These processes cause differentiation and element cycling, affecting the composition of the mantle, crust, and the atmosphere over geological timescales. To understand the Earth as a complex system today and in the future, it is important to understand the evolution and interaction of those reservoirs. My current research focuses on igneous petrology and isotope and trace element geochemistry aimed at answering the fundamental questions of high-temperature element cycling at convergent and divergent plate boundaries. Specifically, I am working on the geodynamic evolution and element cycling at subduction zones and the long-term compositional evolution of the Earth’s mantle. The Earth’s mantle has been neglected in understanding element cycling, especially in subduction zones. Volatiles (e.g., CO2), either recycled back into the mantle or degassed during magmatism affects the atmosphere and thus life on Earth. My main research is focused on three topics: (1) Small and large scale spatial and temporal heterogeneity in oceanic mantle domains. (2) The influence of mantle source composition on the formation of oceanic spreading centres and oceanic rises. (3) The recycling of elements in subduction zones and their influence on the composition of the melting residue, crust, and atmosphere. I am facilitating different different techniques like microscopy, electron microprobe, LA-ICP-MS and MC-ICP-MS to understand the long-term evolution of the Earths different reservoirs.

Link to homepage:  https://www.minpetro.uni-freiburg.de/team/woelki/woelki

Invited by: Elis Hoffmann