TY  - JOUR
A1  - Erbello Doelesso, Asfaw
A1  - Melnick, Daniel
A1  - Zeilinger, Gerold
A1  - Bookhagen, Bodo
A1  - Pingel, Heiko
A1  - Strecker, Manfred
T1  - Geomorphic expression of a tectonically active rift-transfer zone in southern Ethiopia
JF  - Geomorphology : an international journal on pure and applied geomorphology
N2  - The Gofa Province and the Chew Bahir Basin of southern Ethiopia constitute tectonically active regions, where the Southern Main Ethiopian Rift converges with the Northern Kenya Rift through a wide zone of extensional deformation with several north to northeast-trending, left-stepping en-e & PRIME;chelon basins. This sector of the Southern Main Ethiopian Rift is characterized by a semi-arid climate and a largely uniform lithology, and thus provides ideal conditions for studying the different parameters that define the tectonic and geomorphic features of this complex kinematic transfer zone. In this study, the degree of tectonic activity, spatiotemporal variations in extension, and the nature of kinematic linkage between different fault systems of the transfer zone are constrained by detailed quantitative geomorphic analysis of river catchments and focused field work. We analyzed fluvial and landscape morphometric characteristics in combination with structural, seismicity, and climatic data to better evaluate the tectono-geomorphic history of this transfer zone. Our data reveal significant north-south variations in the degree of extension from the Sawula Basin in the north (mature) to the Chew Bahir Basin in the south (juvenile). First, normalized channel-steepness indices and the spatial arrangement of knickpoints in footwall-draining streams suggest a gradual, southward shift in extensional deformation and recent tectonic activity. Second, based on 1-k(m) radius local relief and mean-hillslope maximum values that are consistent with ksn anomalies, we confirm strain localization within zones of fault interaction. Third, morphometric indices such as hypsometry, basin asymmetry factor, and valley floor width to valley height ratio also indicate a north to south gradient in tectonic activity, highlighting the importance of such a wide transfer zone with diffuse extension linking different rift segments during the break-up of continental crust.
KW  - rift transfer zone
KW  - Ethiopia rift
KW  - renya Rift
KW  - morphometric indices
KW  - knickpoints
Y1  - 2022
U6  - https://doi.org/10.1016/j.geomorph.2022.108162
SN  - 0169-555X
SN  - 1872-695X
VL  - 403
PB  - Elsevier Science
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Corti, Giacomo
A1  - Cioni, Raffaello
A1  - Franceschini, Zara
A1  - Sani, Federico
A1  - Scaillet, Stephane
A1  - Molin, Paola
A1  - Isola, Ilaria
A1  - Mazzarini, Francesco
A1  - Brune, Sascha
A1  - Keir, Derek
A1  - Erbello Doelesso, Asfaw
A1  - Muluneh, Ameha
A1  - Illsley-Kemp, Finnigan
A1  - Glerum, Anne
T1  - Aborted propagation of the Ethiopian rift caused by linkage with the Kenyan rift
JF  - Nature Communications
N2  - Continental rift systems form by propagation of isolated rift segments that interact, and eventually evolve into continuous zones of deformation. This process impacts many aspects of rifting including rift morphology at breakup, and eventual ocean-ridge segmentation. Yet, rift segment growth and interaction remain enigmatic. Here we present geological data from the poorly documented Ririba rift (South Ethiopia) that reveals how two major sectors of the East African rift, the Kenyan and Ethiopian rifts, interact. We show that the Ririba rift formed from the southward propagation of the Ethiopian rift during the Pliocene but this propagation was short-lived and aborted close to the Pliocene-Pleistocene boundary. Seismicity data support the abandonment of laterally offset, overlapping tips of the Ethiopian and Kenyan rifts. Integration with new numerical models indicates that rift abandonment resulted from progressive focusing of the tectonic and magmatic activity into an oblique, throughgoing rift zone of near pure extension directly connecting the rift sectors.
Y1  - 2019
U6  - https://doi.org/10.1038/s41467-019-09335-2
SN  - 2041-1723
VL  - 10
PB  - Nature Publ. Group
CY  - London
ER  -