Work

Off-rift volcanism during continental rifting: Observations and models with a focus on the Main Ethiopian Rift, East Africa

Year: 2025

Type: article

Abstract: The occurrence of volcanic activity outside a deforming continental rift valley (off-rift volcanism) is a typical feature of rift systems and different hypothesis have been invoked to explain this setting. In this paper, we first summarize observations from off-rift volcanoes in the Main Ethiopian Rift (East Africa) and then we review models -from early conceptual models to modern numerical and analogue experiments-proposed to explain this process. Overall, all these models suggest that off-rift volcanism may be attributed to two main end-member processes: (1) magma migration and (2) off-rift magma production. Magma migration involves extension-parallel lateral transfer of magma from below the rift depression to the rift margins; this process can explain volcanoes formed in the footwall of major boundary faults, in the plateaus close to the rift depression (the so-called flank volcanoes). Off-rift magma generation suggests instead that magma is produced away from the rift depression and is transferred to the surface via steep tectonic structures above the area of production. In both processes, pre-existing structures, inherited from previous tectonic events, are fundamental for controlling (shallow) magma transfer and emplacement, and the final characteristics of off-rift volcanoes. • Off-rift volcanism is a typical, poorly understood feature of continental rifts. • We summarize observations from off-rift volcanoes in the Main Ethiopian Rift. • We review conceptual, analogue and numerical models applied to explain this volcanism. • Off-rift volcanism may be explained by magma migration or off-rift magma production. • Inherited tectonic structures control (shallow) magma transfer in off-rift volcanoes.

Source: Journal of African Earth Sciences

DOI: 10.1016/j.jafrearsci.2025.105590

Authors: Giacomo Corti, Daniele Maestrelli, Marco Bonini, Federico Sani

Institutions: Institute of Geosciences and Earth Resources, National Research Council, University of Florence

Language: English

Topic: Geological and Geophysical Studies

Subfield: Geology

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,370