Aborted propagation of the Ethiopian rift caused by linkage with the Kenyan rift

Corti, Giacomo; Cioni, Raffaello; Franceschini, Zara; Sani, Federico; Scaillet, Stéphane; Molin, Paola; Isola, Ilaria; Mazzarini, Francesco; Brune, Sascha; Keir, Derek; Erbello, Asfaw; Muluneh, Ameha; Illsley‐Kemp, Finnigan; Glerum, Anne

doi:10.1038/s41467-019-09335-2

Cited by 59 publications

(86 citation statements)

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“…The formation of the active volcanic centers of the Jemez lineament over this LAB step suggests that inherited structure from ancient features continues to play a role in controlling deformation in the region (Baldridge et al, ). Similar to the RGR, changes in rift deformation style occur in the East African rift system and are coincident with “steps” in crustal thickness attributed to deep‐seated Neoproterozoic sutures and other inherited weaknesses (e.g., Boone et al, ; Corti et al, ), suggesting that such controls are common in continental rift systems.…”

Section: Discussionmentioning

confidence: 99%

Perspectives on Continental Rifting Processes From Spatiotemporal Patterns of Faulting and Magmatism in the Rio Grande Rift, USA

Abbey

Niemi

2020

Tectonics

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Analysis of spatiotemporal patterns of faulting and magmatism in the Rio Grande rift (RGR) in New Mexico and Colorado, USA, yields insights into continental rift processes, extension accommodation mechanisms, and rift evolution models. We combine new apatite (U-Th-Sm)/He and zircon (U-Th)/He thermochronometric data with previously published thermochronometric data to assess the timing of fault initiation, magnitudes of fault exhumation, and growth and linkage patterns of rift faults. Thermal history modeling of these data reveals contemporaneous rift initiation at ca. 25 Ma in both the northern and southern RGR with continued fault initiation, growth, and linkage progressing from ca. 25 to ca. 15 Ma. The central RGR, however, shows no evidence of Cenozoic fault-related exhumation as observed with thermochronometry and instead reveals extension accommodated through Late Cenozoic magmatic injection. Furthermore, faulting in the northern and southern RGR occurs along an approximately north-south strike, whereas magmatism in the central RGR occurs along the northeast to southwest trending Jemez lineament. Differences in deformation orientation and rift accommodation along strike appear to be related to crustal and lithospheric properties, suggesting that rift structure and geometry are at least partly controlled by inherited lithospheric-scale architecture. We propose an evolutionary model for the RGR that involves initiation of fault-accommodated extension by oblique strain followed by block rotation of the Colorado Plateau, where extension in the RGR is accommodated by faulting (southern and northern RGR) and magmatism (central RGR). This study highlights different processes related to initiation, geometry, extension accommodation, and overall development of continental rifts. Plain Language SummaryWe identify patterns of faulting and volcanism in the Rio Grande rift (RGR) in the western United States to better understand how continental rifts evolve. Using methods for documenting rock cooling ages (thermochronology), we determined that rifting began around 25 million years ago (Ma) in both the northern and southern RGR. Rift faults continued to develop and grow for another 10 to 15 million years. The central RGR, however, shows that rift extension occurred through volcanic activity both as eruptions at the surface and as magma injection below the surface since~15 Ma. Interestingly, RGR faulting in the north and south parts of the rift occurs on a north-south line, while volcanism in the central RGR is along a northeast to southwest line. The differences in the location and orientation of faulting and volcanic activity may be related to the thickness of the lithosphere beneath different parts of the rift. Using these patterns of faulting and magmatism, we propose the RGR evolved through a combination of (1) oblique strain-extension diagonal to the rift and (2) block rotation-where the Colorado Plateau is the rotating block. This detailed study highlights different processes related to the accommodation of extension...

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Section: Discussionmentioning

confidence: 99%

Perspectives on Continental Rifting Processes From Spatiotemporal Patterns of Faulting and Magmatism in the Rio Grande Rift, USA

Abbey

Niemi

2020

Tectonics

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“…1,4). Today, fault systems west of Lake Turkana are largely abandoned, and Pliocene-Holocene fault activity has been focused around Lake Turkana and east of the lake (Morley et al, 1999a;Vétel et al, 2004;Vetel and Le Gall, 2006;Corti et al, 2019). The main Pliocene-Holocene volcanic activity is also focused along Lake Turkana (e.g., South, Central, and North Islands) and on the eastern side of the lake (Mount Kulal, Mount Marsabit) (Hackman et al, 1990;Curtis, 1991;Karson and Curtis, 1994).…”

Section: Lake Turkanamentioning

confidence: 99%

“…Although some short-lived extensional trends have affected the area east of Lake Turkana in the Plio-Pleistocene (Kino Sogo fault belt, Ririba Rift; Fig. 23), the area of consistent extension during this time has been Lake Turkana (Morley et al, 1999a Melnick et al, 2012;Corti et al, 2019;Knappe et al, 2020). It would appear that the attempts to propagate across the Anza Graben from the south (Suguta Valley-Kino Sogo fault belt) and from the north (Main Ethiopian Rift-Ririba Rift) failed, and extension was more easily focused west of the Anza Graben along Lake Turkana.…”

Section: Research Papermentioning

confidence: 99%

Early syn-rift igneous dike patterns, northern Kenya Rift (Turkana, Kenya): Implications for local and regional stresses, tectonics, and magma-structure interactions

Morley

2020

Geosphere

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Four areas (Loriu, Lojamei, Muranachok-Muruangapoi, Kamutile Hills) of well-developed Miocene-age dikes in the northern Kenya Rift (Turkana, Kenya) have been identified from fieldwork and satellite images; in total, >3500 dikes were mapped. Three areas display NNW-SSE– to N-S–oriented dike swarms, with straight, radial, and concentric patterns in zones <15 km long, and indicate NNW-SSE to N-S regional maximum horizontal principal stress (SHmax) directions in the early to middle Miocene. Individual dikes are typically <2 m wide and tens to hundreds of meters long and have accommodated <2% extension. In places (Loriu, Lojamei, Lokhone high), dikes trend at a high angle to the rift trend, suggesting some local influence (e.g., overpressured magma chamber, cracked lid–style dike intrusions over a sill or laccolith, preexisting fabric in basement) on orientation, in addition to the influence from regional stresses. Only a minor influence by basement fabrics is seen on dike orientation. The early- to middle-Miocene dikes and extrusive activity ended a long phase (up to 25 m.y.) of amagmatic half-graben development in central Kenya and southern Turkana, which lay on the southern edge of the early (Eocene–Oligocene) plume activity. The Miocene dike sets and extension on major border faults in Turkana contrast with larger, more extensive arrays of dikes in evolved systems in the Main Ethiopian Rift that are critical for accommodating crustal extension. By the Pliocene–Holocene, magmatism and intrusion along dikes had become more important for accommodating extension, and the tectonic characteristics began to resemble those of rift basins elsewhere in the eastern branch of the East African Rift.

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“…The Ethiopia-Yemen and the East African plateaus bound the TD in the northeast and southwest, respectively (Figures 1a and 2a). Within the TD, the~300-km-wide Turkana rifted zone include, from west to east, the North Lockichar rift basin, the Turkwell rift basin, the Kerio rift basin, the Lake Turkana rift basin, and the Kino Sogo fault belt (Figures 4a, 4b, 5a, and 5b;Dunkelman et al, 1989;Rosendahl et al, 1992;Ebinger et al, 2000;Bonini et al, 2005;Vetel et al, 2005;Vetel & Le Gall, 2006;Brune et al, 2017;Corti et al, 2019). Ebinger et al (2000), Bonini et al (2005), and Vetel and Le Gall (2006) Vetel & Le Gall, 2006).…”

Section: The Neogene-quaternary Earsmentioning

confidence: 99%

“…These rifts will be referred to here as the Kenya-Sudan Rifts (KSR). The N-S to NE-SW trending Neogene-Quaternary rifts are represented by segments of the Eastern Branch of the EARS including the Turkana rifted zone (Figure 1a; e.g., Bonini et al, 2005;Brune et al, 2017;Corti et al, 2019;Dunkelman et al, 1989;Ebinger et al, 2000;Emishaw et al, 2017;Morley, Wescott, et al, 1999;Rosendahl et al, 1992;Vetel et al, 2005;Vetel & Le Gall, 2006).…”

Section: Introductionmentioning

confidence: 99%

Development of Late Jurassic‐Early Paleogene and Neogene‐Quaternary Rifts Within the Turkana Depression, East Africa From Satellite Gravity Data

Emishaw

Abdelsalam

2019

Tectonics

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The Turkana Depression (TD) is a NW trending topographic corridor within the East African Rift System between the Ethiopia‐Yemen plateau in the northeast and the East African plateau to the southwest. The Anza rift within the TD is a NW‐SE trending failed arm of a late Jurassic rift‐rift‐rift triple junction. This rift is correlated with the Sudan and South Sudan rifts. The Anza rift is intersected by the East African Rift System represented by the N‐S trending Turkana rifted zone. We image the lithospheric structure beneath the TD using satellite gravity data. We also use these data to model crustal density distribution beneath the Kino Sogo fault belt, part of the Turkana rifted zone. Our results show thinner crust (23–28 km) and lithosphere (140–150 km) beneath the TD. We interpret this as due to extension that resulted in the formation of the Kenya‐Sudan and South Sudan rifts. Our results also show that crustal depth between 0 and 4.8 km is dominated by N‐S density contrast anomalies and between 4.8 and 14.5 km by E‐W anomalies. We interpret the N‐S anomalies as due to the presence of Precambrian structure that might have facilitated strain localization during the initiation of the Kino Sogo fault belt. Differently, we interpret the E‐W anomalies as due to the presence E‐W trending faults that were formed in association with the development of the Anza rift and/or Turkana rifted zone and were later filled with Mesozoic and Cenozoic mafic dikes.

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Aborted propagation of the Ethiopian rift caused by linkage with the Kenyan rift

Cited by 59 publications

References 58 publications

Perspectives on Continental Rifting Processes From Spatiotemporal Patterns of Faulting and Magmatism in the Rio Grande Rift, USA

Perspectives on Continental Rifting Processes From Spatiotemporal Patterns of Faulting and Magmatism in the Rio Grande Rift, USA

Early syn-rift igneous dike patterns, northern Kenya Rift (Turkana, Kenya): Implications for local and regional stresses, tectonics, and magma-structure interactions

Development of Late Jurassic‐Early Paleogene and Neogene‐Quaternary Rifts Within the Turkana Depression, East Africa From Satellite Gravity Data

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