Morphotectonic evolution of the central Kenya rift flanks: Implications for late Cenozoic environmental change in East Africa

Spiegel, Cornelia; Kohn, Barry P.; Belton, David; Gleadow, A. J. W.

doi:10.1130/g23108a.1

Cited by 69 publications

(78 citation statements)

References 22 publications

(29 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Similar results were reported by Foster and Gleadow [1996] and Spiegel et al [2007], with very slow cooling along both the western (Cherangani Hills) and eastern (Ndoto Mountains) rift shoulders from the Eocene through the middle Miocene.…”

Section: Eocene Through Middle Miocene Monotonic Slow Cooling or Rehesupporting

confidence: 75%

“…Foster and Gleadow, 1996;Spiegel et al, 2007], the samples remained at a relatively constant position below the surface (~3 km). This thermal history is quite analogous to the Grand Canyon [Fox and Schuster, 2014], suggesting that AHe results from there are applicable to our study.…”

Section: Apatite (U-th-sm)/he Resultsmentioning

confidence: 99%

“…However, apatite (U-Th)/He and fission-track data from the western rift flank (Cherangani Hills of northern Kenya) and from the presentday eastern rift flank southeast of Lake Turkana (Figs. 1 and 2) only reveal clear episodes of cooling during the late Cretaceous to Paleocene and during the late Neogene [Foster and Gleadow, 1996;Spiegel et al, 2007].…”

Section: Geological Setting and Tectonic Historymentioning

confidence: 99%

“…In the greater Turkana region and the western riftshoulder areas of northern Kenya (Fig. 1), these investigations have provided helpful constraints on the regional onset of Mesozoic and early Cenozoic rifting [Foster and Gleadow, 1996;Spiegel et al, 2007]. However, the spatial extent of the related tectonothermal events, the formation of older rift basins underlying the late Cenozoic rifts, and the role of their structures in influencing Miocene to Recent rifting is unclear.…”

Section: Introductionmentioning

confidence: 99%

“…Thermochronology studies have been carried out throughout the EARS aimed at unraveling the history of basin formation, rift-shoulder exhumation, and different tectono-thermal episodes associated with mantle-plume activity. These studies have addressed the tectonic evolution of the western branch of the EARS in the Rwenzori Mountains [Bauer et al, 2010;2012] and the Malawi and Rukwa rifts [van der Beek et al, 1998;Roberts et al, 2012], and the evolution of the eastern branch in Ethiopia [Pik, 2008], northern Tanzania [Noble et al, 1997;Mbede, 2001], and Kenya [Wagner, 1992;Foster and Gleadow, 1992;1996;Spiegel et al 2007]. In the greater Turkana region and the western riftshoulder areas of northern Kenya (Fig.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Cenozoic extension in the Kenya Rift from low‐temperature thermochronology: Links to diachronous spatiotemporal evolution of rifting in East Africa

et al. 2015

View full text Add to dashboard Cite

Key points: Data and modeling show Paleogene and middle Miocene cooling episodes  Cooling episodes separated by stable conditions, slow exhumation or subsidence  Extension pattern is compatible with random rift initiation above a plume This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/2015TC003949 ©2015 American Geophysical Union. All rights reserved. AbstractThe cooling history of rift shoulders and the subsidence history of rift basins are cornerstones for reconstructing the morphotectonic evolution of extensional geodynamic provinces, assessing their role in paleoenvironmental changes, and evaluating the resource potential of their basin fills. Our apatite fission-track and zircon (U-Th)/He data from the Samburu Hills and the Elgeyo Escarpment in the northern and central sectors of the Kenya Rift indicate a broadly consistent thermal evolution of both regions. Results of thermal modeling support a three-phased thermal history since the early Paleocene. The first phase (~65-50 Ma) was characterized by rapid cooling of the rift shoulders and may be coeval with faulting and sedimentation in the Anza Rift basin, now located in the subsurface of the Turkana depression and areas to the east in northern Kenya. In the second phase, very slow cooling or slight reheating occurred between ~45 and 15 Ma as a result of either stable surface conditions, very slow exhumation, or subsidence. The third phase comprised renewed rapid cooling starting at ~15 Ma. This final cooling represents the most recent stage of rifting, which followed widespread flood-phonolite emplacement and has shaped the present-day landscape through rift shoulder uplift, faulting, basin filling, protracted volcanism, and erosion. When compared with thermochronologic and geologic data from other sectors of the East African Rift System, extension appears to be diachronous, spatially disparate, and partly overlapping, likely driven by interactions between mantle-driven processes and crustal heterogeneities, rather than the previously suggested north-south migrating influence of a mantle plume.

show abstract

Section: Eocene Through Middle Miocene Monotonic Slow Cooling or Rehesupporting

confidence: 75%

Section: Apatite (U-th-sm)/he Resultsmentioning

confidence: 99%

Section: Geological Setting and Tectonic Historymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Cenozoic extension in the Kenya Rift from low‐temperature thermochronology: Links to diachronous spatiotemporal evolution of rifting in East Africa

et al. 2015

View full text Add to dashboard Cite

show abstract

Evolution, distribution, and characteristics of rifting in southern Ethiopia

et al. 2014

View full text Add to dashboard Cite

Southern Ethiopia is a key region to understand the evolution of the East African rift system, since it is the area of interaction between the main Ethiopian rift (MER) and the Kenyan rift. However, geological data constraining rift evolution in this remote area are still relatively sparse. In this study the timing, distribution, and style of rifting in southern Ethiopia are constrained by new structural, geochronological, and geomorphological data. The border faults in the area are roughly parallel to preexisting basement fabrics and are progressively more oblique with respect to the regional Nubia-Somalia motion proceeding southward. Kinematic indicators along these faults are mainly dip slip, pointing to a progressive rotation of the computed direction of extension toward the south. Radiocarbon data indicate post 30 ka faulting at both western and eastern margins of the MER with limited axial deformation. Similarly, geomorphological data suggest recent fault activity along the western margins of the basins composing the Gofa Province and in the Chew Bahir basin. This supports that interaction between the MER and the Kenyan rift in southern Ethiopia occurs in a 200 km wide zone of ongoing deformation. Fault-related exhumation at~10-12 Ma in the Gofa Province, as constrained by new apatite fission track data, occurred later than the~20 Ma basement exhumation of the Chew Bahir basin, thus pointing to a northward propagation of the Kenyan rift-related extension in the area.

show abstract

From source to sink in central Gondwana: Exhumation of the Precambrian basement rocks of Tanzania and sediment accumulation in the adjacent Congo basin

et al. 2016

View full text Add to dashboard Cite

Apatite fission track (AFT) and (U‐Th)/He (AHe) thermochronometry data are reported and used to unravel the exhumation history of crystalline basement rocks from the elevated (>1000 m above sea level) but low‐relief Tanzanian Craton. Coeval episodes of sedimentation documented within adjacent Paleozoic to Mesozoic basins of southern Tanzania and the Congo basin of the Democratic Republic of Congo indicate that most of the cooling in the basement rocks in Tanzania was linked to erosion. Basement samples were from an exploration borehole located within the craton and up to 2200 m below surface. Surface samples were also analyzed. AFT dates range between 317 ± 33 Ma and 188 ± 44 Ma. Alpha (Ft)‐corrected AHe dates are between 433 ± 24 Ma and 154 ± 20 Ma. Modeling of the data reveals two important periods of cooling within the craton: one during the Carboniferous‐Triassic (340–220 Ma) and a later, less well constrained episode, during the late Cretaceous. The later exhumation is well detected proximal to the East African Rift (70 Ma). Thermal histories combined with the estimated geothermal gradient of 9°C/km constrained by the AFT and AHe data from the craton and a mean surface temperature of 20°C indicate removal of up to 9 ± 2 km of overburden since the end of Paleozoic. The correlation of erosion of the craton and sedimentation and subsidence within the Congo basin in the Paleozoic may indicate regional flexural geodynamics of the lithosphere due to lithosphere buckling induced by far‐field compressional tectonic processes and thereafter through deep mantle upwelling and epeirogeny tectonic processes.

show abstract

Morphotectonic evolution of the central Kenya rift flanks: Implications for late Cenozoic environmental change in East Africa

Cited by 69 publications

References 22 publications

Cenozoic extension in the Kenya Rift from low‐temperature thermochronology: Links to diachronous spatiotemporal evolution of rifting in East Africa

Cenozoic extension in the Kenya Rift from low‐temperature thermochronology: Links to diachronous spatiotemporal evolution of rifting in East Africa

Evolution, distribution, and characteristics of rifting in southern Ethiopia

From source to sink in central Gondwana: Exhumation of the Precambrian basement rocks of Tanzania and sediment accumulation in the adjacent Congo basin

Contact Info

Product

Resources

About