EGU22-13175, updated on 28 Mar 2022
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Xenolith-based thermal and compositional lithospheric mantle profile of the central Siberian craton

Dmitri Ionov1,2, Zhe Liu1, Paolo Nimis3, Yigang Xu2, and Alexander V. Golowin4
Dmitri Ionov et al.
  • 1Géosciences Montpellier, University of Montpellier, Montpellier, France
  • 2Guangzhou Institute of Geochemistry, CAS, Guangzhou, China
  • 3Dipartimento di Geoscienze, Università di Padova, Padua, Italy
  • 4V.S. Sobolev Institute of Geology and Mineralogy, RAS, Novosibirsk Russia

Many aspects of structure and thermal state of >200 km thick cratonic lithospheric mantle (CLM) remain unclear because of insufficient sampling and uncertainties of pressure (P) and temperature (T) estimates. An exceptionally detailed record of equilibration temperature and composition for the central Siberian craton in the 60–230 km depth range was obtained using new and published petrographic and in-situ chemical data for ~200 garnet peridotite xenoliths from the Udachnaya kimberlite. The thermal profile is complex with samples between 35 and 40 mW/m2 model conductive geotherms as well as hotter layers in the middle and at the base (190–230 km) of the CLM. A previously unknown mid-lithospheric zone includes rocks up to 150° hotter than ambient geotherm, with high modal garnet and cpx, low-Mg# and melt-equilibrated REE patterns. We posit that hot domains with enriched compositions may form at depths where ascending melts stall (e.g., due to loss of volatiles and/or redox change) and react with wall-rock harzburgites. By contrast, we find no rocks rich in volatile-rich metasomatic amphibole, mica or carbonate, nor layers composed of peridotites with distinct melt-extraction degrees. The CLM base contains both coarse and variably deformed rocks heated and re-worked (Mg#Ol down to 0.86) by localized interaction with asthenospheric melts.

How to cite: Ionov, D., Liu, Z., Nimis, P., Xu, Y., and Golowin, A. V.: Xenolith-based thermal and compositional lithospheric mantle profile of the central Siberian craton, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13175,, 2022.


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