Portal de Periódicos da CAPES

Focused Mid‐Crustal Magma Intrusion During Continental Break‐Up in Ethiopia

2023; American Geophysical Union; Volume: 50; Issue: 11 Linguagem: Inglês

10.1029/2023gl103257

1944-8007

K.C. Wong, David Ferguson, Penny Wieser, Daniel Morgan, Marie Edmonds, Amdemichael Zafu Tadesse, Gezahegn Yirgu, Jason Harvey, Samantha J. Hammond,

High-pressure geophysics and materials

Abstract Significant volumes of magma can be intruded into the crust during continental break‐up, influencing rift evolution by altering the thermo‐mechanical structure of the crust and its response to extensional stresses. Rift magmas additionally feed surface volcanic activity and can be globally significant sources of tectonic CO 2 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.