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Focused mid-crustal magma intrusion during continental break-up in Ethiopia
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  • Kevin Wong,
  • David Ferguson,
  • Penny Wieser,
  • Daniel Morgan,
  • Marie Edmonds,
  • Amdemichael Zafu Tadesse,
  • Gezahegn Yirgu,
  • Jason Harvey,
  • Samantha J Hammond
Kevin Wong
University of Leeds

Corresponding Author:[email protected]

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David Ferguson
University of Leeds
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Penny Wieser
UC Berkeley
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Daniel Morgan
University of Leeds
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Marie Edmonds
University of Cambridge
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Amdemichael Zafu Tadesse
Free University of Brussels (ULB)
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Gezahegn Yirgu
Addis Ababa University
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Jason Harvey
Leeds University
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Samantha J Hammond
Open University
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Significant volumes of magma are intruded into the crust during continental break-up, which can influence rift evolution by altering thermo-mechanical structure of the crust and thereby its response to extensional stresses. Rift magmas additionally feed surface volcanic activity and can be globally significant sources of tectonic CO2 emissions. Understanding how magmatism may affect rift development requires knowledge on magma intrusion depths in the crust. Here, using data from olivine-hosted melt inclusions, we investigate magma dynamics for basaltic intrusions in the Main Ethiopian Rift (MER). We find evidence for a spatially focused zone of magma intrusion at the MER upper-lower crustal boundary (10-15 km depth), consistent with geophysical datasets. We propose that ascending melts in the MER are intruded over this depth range as discrete sills, likely creating a mechanically weak mid-crustal layer. Our results have important implications for how magma addition can influence crustal rheology in a maturing continental rift.
28 Feb 2023Submitted to ESS Open Archive
01 Mar 2023Published in ESS Open Archive