Publication Date:
2022-06-09
Description:
The Main Ethiopian Rift, East Africa, is characterized by the presence of major, enigmatic structures which strike
approximately orthogonal to the trend of the rift valley. These structures are marked by important deformation
and magmatic activity in an o
ff
-axis position in the plateaus surrounding the rift. In this study, we present new
structural data based on a remote and
fi
eld analysis, complemented with analogue modelling experiments, and
new geochemical analysis of volcanic rocks sampled in di
ff
erent portions of one of these transversal structures:
the Goba-Bonga volcano-tectonic lineament (GBVL). This integrated analysis shows that the GBVL is associated
with roughly E
–
W-trending prominent volcano-tectonic activity a
ff
ecting the western plateau. Within the rift
fl
oor, the approximately E
–
W alignment of Awasa and Corbetti calderas likely represent expressions of the GBVL.
Conversely, no tectonic or volcanic features of similar (E
–
W) orientation have been recognized on the eastern
plateau. Analogue modelling suggests that the volcano-tectonic features of the GBVL have probably been con-
trolled by the presence of a roughly E
–
W striking pre-existing discontinuity beneath the western plateau, which
did not extend beneath the eastern plateau. Geochemical analysis supports this interpretation and indicates that,
although magmas have the same sub-lithospheric mantle source, limited di
ff
erences in magma evolution dis-
played by products found along the GBVL may be ascribed to the di
ff
erent tectonic framework to the west, to the
east, and in the axial zone of the rift. These results support the importance of the heterogeneous nature of the
lithosphere and the spatial variations of its structure in controlling the architecture of continental rifts and the
distribution of the related volcano-tectonic activity
Description:
Published
Description:
75-91
Description:
2V. Struttura e sistema di alimentazione dei vulcani
Description:
2TR. Ricostruzione e modellazione della struttura crostale
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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