EGU2020-5032, updated on 12 Jun 2020
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

High magma flux beneath Corbetti caldera (Ethiopia) accommodated by a ductile and compressible reservoir

Joachim Gottsmann1, Juliet Biggs1, Ryan Lloyd1, Yelebe Biranhu1, and Elias Lewi2
Joachim Gottsmann et al.
  • 1Univ. of Bristol, Dep. of Earth Sciences, Bristol, United Kingdom of Great Britain and Northern Ireland (
  • 2IGSSA, University if Addis Ababa, Ethiopia

Large silicic magma reservoirs preferentially form in the upper crust of 

extensional continental environments. However, our quantitative understanding of the link between mantle magmatism, silicic reservoirs and surface deformation during rifting is very limited. Here, we focus on Corbetti, a peralkaline caldera in the densely-populated Main Ethiopian Rift, which lies above a focused zone of upper mantle partial melt and has been steadily uplifting at ≤6.6±1.2 cm yr−1 for more than ten years. We show that a concomitant residual gravity increase of ≤9±3 μGal yr−1 by the intrusion of mafic magma at ∼7 km depth into a compressible and inelastic crystal mush best explains the uplift. The derived magma mass flux of ∼10^11 kg yr−1 is anomalously high

and at least one order of magnitude greater than the mean long-term mass

eruption rate. We demonstrate that periodic and high-rate magmatic rejuvenation of upper-crustal mush is a significant and rapid contributor to mature continental rifting.

How to cite: Gottsmann, J., Biggs, J., Lloyd, R., Biranhu, Y., and Lewi, E.: High magma flux beneath Corbetti caldera (Ethiopia) accommodated by a ductile and compressible reservoir, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5032,, 2020

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Presentation version 1 – uploaded on 04 May 2020
  • CC1: Questions and answers from the live chat during EGU2020, Michael Heap, 11 May 2020

    Q: Nice study. Which rheology do you consider for the mush?

    A: Viscoelastic as a first order approx

    Q: Eruptive potential of your intrusion?

    A: Very good q. our money is on alkali basaltic intrusion.  what it does with  peralk rhyolite parked at shallower levels is anyone's guess. Eruptive freq 1/1000 yrs

    Q: You say that the crysal mush is 'inelastic'. How do you model it mechanically - as plastic, viscoelastic?

    A: VE