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Prøveforelesning
Mandag 18 august, 10:15-11:00, Aud 3, ZEB-bygningen:
Grain size evolution and its importance for lithospheric/upper mantle dynamics
https://uio.zoom.us/j/66599759776
Kreeringssammendrag
Under jordskorpen ligger mantelen, en smeltet steinmasse som stadig er i bevegelse. Her er det mye olivin, et mineral som ikke lar seg dekompressere likt i alle retninger. I sin avhandling undersøker Yijun Wang systematisk effektene av såkalt anisotrop viskositet, ved enkel skjærdeformasjon og komplekse deformasjoner i subduksjonssoner. Wang bruker flere numeriske metoder anvendt både utenfor og innenfor det geodynamiske modelleringsprogramet. Studien forklarer både geodynamikken i jordens indre og ved jordskjelv.
Hovedfunn
Populærvitenskapelig artikkel om Wangs avhandling:
Texture evolution in subduction models, influenced by anisotropic viscosity: Simple tests, cluster analysis, and numerical implementation
The Earth’s mantle—the hot, slowly moving molted rock beneath our feet—flows in complex ways that shape the movement of continents and causes earthquakes and volcanic activity. The doctoral research work by Yijun Wang is about how one key mineral in the mantle, called olivine, behaves when squeezed and stretched deep underground.
Previously it has been found that olivine doesn’t respond to deformations equally in all directions—something known as anisotropic viscosity in terms of earth science. This uneven flow attribute of olivine can change the way the mantle moves and how we detect it using seismic waves. In her studies Wang used 3D numerical models to investigate the flow patterns.
Both simple shear box models and large geodynamic models (e.g., subduction) show that this directional behavior of olivine matters most in regions with strong deformation, such as near the edge of sinking plates, introducing a weakening or strengthening effect. Wang also developed a method to include these effects in large-scale simulations of Earth’s interior. The findings of the doctoral work helps to better understand the deep Earth and improves the accuracy of models used to study earthquakes and tectonic processes. It also helps explain patterns we observe in seismic data, bringing us closer to seeing the hidden dynamics beneath the surface.
Foto og annen informasjon:
Pressefoto: Yijun Wang, portrett; 1000px. Foto: Privat
