Kinematics of the Danakil microplate

Eagles, Graeme; Gloaguen, Richard; Ebinger, C. J.

doi:10.1016/s0012-821x(02)00916-0

Cited by 107 publications

(92 citation statements)

References 37 publications

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“…The 20-25 km thick crust beneath the MHR and TG is around twice that predicted by pure shear extension models (e.g., McKenzie, 1978) at the observed extension factor of~3 (e.g., Eagles et al, 2004;Redfield et al, 2003). Around 50-60% of extension is thus likely accommodated by magma intrusion (e.g.…”

Section: Links Between Extension Magmatism and Rift Morphologymentioning

confidence: 91%

“…The basin also contains non-marine evaporites from on-going evaporation of seasonal terminal saline lakes and the geothermal pools (Talbot, 2008). Plate reconstructions suggest that the Danakil basin has been the locus of strain in northern Afar since at least~11 Ma, with the increased distance from complex triple junction tectonics influencing central Afar resulting in a longer history of localised extension (Eagles et al, 2004).…”

Section: Danakil Depressionmentioning

confidence: 99%

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The development of extension and magmatism in the Red Sea rift of Afar

et al. 2013

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Despite the importance of continental breakup in plate tectonics, precisely how extensional processes such as brittle faulting, ductile plate stretching, and magma intrusion evolve in space and time during the development of new ocean basins remains poorly understood. The rifting of Arabia from Africa in the Afar depression is an ideal natural laboratory to address this problem since the region exposes subaerially the tectonically active transition from continental rifting to incipient seafloor spreading. We review recent constraints on along-axis variations in rift morphology, crustal and mantle structure, the distribution and style of ongoing faulting, subsurface magmatism and surface volcanism in the Red Sea rift of Afar to understand processes ultimately responsible for the formation of magmatic rifted continental margins. Our synthesis shows that there is a fundamental change in rift morphology from central Afar northward into the Danakil depression, spatially coincident with marked thinning of the crust, an increase in the volume of young basalt flows, and subsidence of the land towards and below sea-level. The variations can be attributed to a northward increase in proportion of extension by ductile plate stretching at the expense of magma intrusion. This is likely in response to a longer history of localised heating and weakening in a narrower rift. Thus, although magma intrusion accommodates strain for a protracted period during rift development, the final stages of breakup are dominated by a phase of plate stretching with a shift from intrusive to extrusive magmatism. This late-stage pulse of decompression melting due to plate thinning may be responsible for the formation of seaward dipping reflector sequences of basalts and sediments, which are ubiquitous at magmatic rifted margins worldwide.

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Section: Links Between Extension Magmatism and Rift Morphologymentioning

confidence: 91%

Section: Danakil Depressionmentioning

confidence: 99%

The development of extension and magmatism in the Red Sea rift of Afar

et al. 2013

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“…From plate reconstructions, the Danakil microplate is inferred to have been part of Nubia at ca. 11 Ma, and since then to have rotated counter-clockwise about a pole at 19°N and 42°E (Chu and Gordon, 1998;Eagles et al, 2002). This model implies oblique-slip to strike-slip motion along the Danakil microplate's boundary with the Nubia plate and all along the Tendaho-Gobaad discontinuity in the Afar Depression.…”

Section: Introductionmentioning

confidence: 87%

“…Barberi et al, 1972;Manighetti et al, 1998). At a smaller scale, deformation in Afar seems to have involved the rotation of at least two microplates (Danakil and Ali Sabieh blocks) sandwiched between the three major plates (Chu and Gordon, 1998;Eagles et al, 2002). From plate reconstructions, the Danakil microplate is inferred to have been part of Nubia at ca.…”

Section: Introductionmentioning

confidence: 99%

The August 2002 earthquake sequence in north Afar: Insights into the neotectonics of the Danakil microplate

Ayele

Stuart

Bastow

et al. 2007

Journal of African Earth Sciences

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In August 2002, there was high seismic activity in Afar concentrated at the plateau margin of the northern Ethiopian rift east of Mekele, near the western part of the Danakil microplate. The spatial and temporal distributions of this seismic activity over four weeks indicate the NNW propagation of the Gulf of Aden rift across the Afar Depression towards the western Ethiopian plateau. Fault plane solutions for six larger earthquakes from the August 2002 sequence are estimated from moment tensor inversion of local broadband waveform data. The results show only normal faulting on NNW trending and NE dipping faults, which agree with tectonics of the area and distribution of aftershocks. No strike-slip component is observed in any of our fault plane solutions or those of other workers including Harvard CMT solutions in the region. Such motion would be indicative of oblique-slip deformation between the Nubian plate and the Danakil microplate consistent with counter-clockwise rotation of the microplate. Hypocentral depths of well-constrained events are 5-7 km, which is the approximate elastic plate thickness in the Main Ethiopian rift, possibly indicating the depth to the brittle-ductile transition zone in this part of the Afar Depression. The shallowness of the depth estimates agree with the macroseismic reports available from a wide area in northern Ethiopia. Potential future shallow crustal deformation may cause significant loss of human life and damage to property in the densely populated highland region around Mekele unless measures are taken in improving building standards. The b-value for this sequence is estimated to be 0.66 using a least squares fit, while it is 0.67 ± 0.16 from a maximum-likelihood approach. This estimated b-value is low or the frequency of occurrence of relatively larger magnitude events is high indicating that it is a highly stressed region as evidenced by the recent increase of the seismicity in the area.

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“…From 11 Ma, this extension has been driven by the rigid counter-clockwise rotation of the Danakil continental block and the clockwise rotation of the Ali Sabieh block to the south (e.g. Sichler 1980;Souriot & Brun 1992;Eagles et al 2002;Audin et al 2004; Fig. 1 inset).…”

Section: The Triple-rift Junction In Afarmentioning

confidence: 99%

Current deformation in Central Afar and triple junction kinematics deduced from GPS and InSAR measurements

Doubre¹,

Déprez²,

Masson³

et al. 2016

Geophys. J. Int.

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S U M M A R YKinematics of divergent boundaries and Rift-Rift-Rift junctions are classically studied using long-term geodetic observations. Since significant magma-related displacements are expected, short-term deformation provides important constraints on the crustal mechanisms involved both in active rifting and in transfer of extensional deformation between spreading axes. Using InSAR and GPS data, we analyse the surface deformation in the whole Central Afar region in detail, focusing on both the extensional deformation across the Quaternary magmato-tectonic rift segments, and on the zones of deformation transfer between active segments and spreading axes. The largest deformation occurs across the two recently activated Asal-Ghoubbet (AG) and Manda Hararo-Dabbahu (MH-D) magmato-tectonic segments with very high strain rates, whereas the other Quaternary active segments do not concentrate any large strain, suggesting that these rifts are either sealed during interdyking periods or not mature enough to remain a plate boundary. Outside of these segments, the GPS horizontal velocity field shows a regular gradient following a clockwise rotation of the displacements from the Southeast to the East of Afar, with respect to Nubia. Very few shallow creeping structures can be identified as well in the InSAR data. However, using these data together with the strain rate tensor and the rotations rates deduced from GPS baselines, the present-day strain field over Central Afar is consistent with the main tectonic structures, and therefore with the long-term deformation. We investigate the current kinematics of the triple junction included in our GPS data set by building simple block models. The deformation in Central Afar can be described by adding a central microblock evolving separately from the three surrounding plates. In this model, the northern block boundary corresponds to a deep EW-trending trans-tensional dislocation, locked from the surface to 10-13 km and joining at depth the active spreading axes of the Red Sea and the Aden Ridge, from AG to MH-D rift segments. Over the long-term, this plate configuration could explain the presence of the en-échelon magmatic basins and subrifts. However, the transient behaviour of the spreading axes implies that the deformation in Central Afar evolves depending on the availability of magma supply within the well-established segments.

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Kinematics of the Danakil microplate

Cited by 107 publications

References 37 publications

The development of extension and magmatism in the Red Sea rift of Afar

The development of extension and magmatism in the Red Sea rift of Afar

The August 2002 earthquake sequence in north Afar: Insights into the neotectonics of the Danakil microplate

Current deformation in Central Afar and triple junction kinematics deduced from GPS and InSAR measurements

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