EGU2020-19001
https://doi.org/10.5194/egusphere-egu2020-19001
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

‘Water’ content as a tool to estimate rheological differences in the lithosphere of young extensional basins

Nóra Liptai1,2, Thomas P. Lange1,3, Levente Patkó1,3,4, Márta Berkesi1,3, Csaba Szabó2,3, and István J. Kovács1,2
Nóra Liptai et al.
  • 1MTA CSFK Lendület Pannon LitH2Oscope Reseach Group, Geodesic and Geophysical Institute, Research Centre for Astronomy and Earth Sciences, Sopron, Hungary
  • 2Geodesic and Geophysical Institute, Research Centre for Astronomy and Earth Sciences, Sopron, Hungary
  • 3Lithosphere Fluid Research Laboratory, Institute of Geography and Earth Sciences, Eötvös Loránd University, Budapest, Hungary
  • 4Isotope Climatology and Environmental Research Centre, Institute for Nuclear Research, Debrecen, Hungary

Nominally anhydrous minerals in the lithospheric mantle, such as olivine and pyroxenes can host a small amount (tens to hundreds of ppm) of structurally bound hydroxyl (‘water’). Numerous studies pointed out that water has a strong effect on the rheological properties of the lithospheric mantle, such as melting temperature, electrical conductivity, viscosity and seismic wave propagation speed. Water content of mantle xenoliths can thus be used to estimate such rheological properties which can then be compared with geophysical observations.

In this study we present effective viscosities and electrical resistivities calculated with the use of ‘water’ contents of upper mantle xenoliths from the Carpathian-Pannonian region (CPR). The CPR is a young extensional basin in Central Europe, where intraplate alkali basalts sampled the lithosphere in five areas, including locations from both the central and marginal regions. ‘Water’ contents are generally higher in xenoliths from the marginal areas compared with those from the central areas of the CPR, due to significant hydrogen loss during the extension in the Miocene (Patkó et al., 2019). It is demonstrated that due to the different ‘water’ contents, the lithospheric mantle in the central areas can be characterized with higher effective viscosity and electrical resistivity, and thus can be considered as more rigid than the marginal areas. This relative rigidity induced by lithospheric thinning may be a general feature of extensional basin systems worldwide, and can be regarded as a ‘self-healing’ mechanism of the extending lithosphere.

 

References:

Patkó, L., Liptai, N., Kovács, I. J., Aradi, L. E., Xia, Q.-K., Ingrin, J., Mihály, J., O’Reilly, S. Y., Griffin, W. L., Wesztergom, V., Szabó, C., 2019. Extremely low structural hydroxyl contents in upper mantle xenoliths from the Nógrád-Gömör Volcanic Field (northern Pannonian Basin): Geodynamic implications and the role of post-eruptive re-equilibration. Chemical Geology, 507, 23-41.

How to cite: Liptai, N., Lange, T. P., Patkó, L., Berkesi, M., Szabó, C., and Kovács, I. J.: ‘Water’ content as a tool to estimate rheological differences in the lithosphere of young extensional basins, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19001, https://doi.org/10.5194/egusphere-egu2020-19001, 2020

Displays

Display file