Early structural development of the Okavango rift zone, NW Botswana

Kinabo, Baraka D.; Atekwana, Estella A.; Hogan, John P.; Modisi, M.P.; Wheaton, Daniel D.; Kampunzu, A.B.

doi:10.1016/j.jafrearsci.2007.02.005

Cited by 115 publications

(93 citation statements)

References 40 publications

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“…The unit I has sedimentological-stratigraphical characteristics and paleocurrent patterns suggesting that the Rift Initiation Tectonic System Tract is characterized by incipient extensional stress generating a wide synclinal depression, associated to the low rate, continuous and uniformly distributed tectonic activity (Morley 2002, Kinabo et al 2007, Kuchle et al 2011. The predominance of multi-storey amalgamated sandstone bodies without deposits from outside channel along this unit indicates low accommodation creation rate and is related to a uniform A/S ratio with positive-close to 0 values (Martinsen et al 1999, Scherer et al2014.…”

Section: Tectonic-stratigraphic Evolutionmentioning

confidence: 99%

“…Nevertheless, there is a lack of detailed studies on characterization of depositional systems and stacking patterns of the basin for each evolutionary stage, even more in the early stages in which the identification of depocenters, the depositional systems and their distributions in basins are poorly understood (Kinabo et al 2007, Morley 2002, Kuchle et al 2011, Scherer et al 2014.…”

Section: Introductionmentioning

confidence: 99%

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High resolution stratigraphy of initial stages of rifting, Sergipe-Alagoas Basin, Brazil

et al. 2017

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ABSTRACT:The present work aims to characterize the NeoJurassic to Neocomian succession of the Sergipe-Alagoas Basin, located in northeast region of Brazil, in order to discover the influence of tectonics on sedimentation in detailed scale and thus separating this sedimentary succession in tectono-stratigraphic units. Fieldwork observations and stratigraphic sections analysis allowed subdividing this rift succession into three depositional units that indicate different paleogeographic contexts. Unit I, equivalent to the top of Serraria Formation, is characterized by braided fluvial channel deposits, with paleocurrent direction to SE; unit II, corresponding to the base of Feliz Deserto Formation, is composed of anastomosed fluvial channel and floodplain facies associations; and unit III, equivalent to the major part of Feliz Deserto Formation, is characterized by delta deposits with polymodal paleocurrent pattern. The changes of depositional system, as well as paleocurrent direction, suggest that the previously described units were deposited in different evolutionary stages of rifting. Units I and II represent the record of a wide and shallow basin associated with the first stage of rifting. Unit I is characterized by incipient extensional stress generating a wide synclinal depression, associated to the low rate of accommodation and low tectonic activity. These two parameters progressively increase in unit II. The paleocurrent direction of unit I indicates that the depocenter of this wide basin was located at SE of the studied area. No conclusion could be done on paleocurrent from unit II because of the low amount of measurements. Unit III suggests a second stage marked by a deeper basin context, with a high rate of accommodation space associated with the lateral connection of faults and individualization of the half-graben. The scattering in the paleocurrent direction in this unit indicates sedimentary influx coming from several sectors of the half-graben. The boundary between these two stages is marked by a flooding surface that indicates an extremely fast transition and suggests a radical change in geometric characteristics of the basin due to the increase of tectonic activity.

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Section: Tectonic-stratigraphic Evolutionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High resolution stratigraphy of initial stages of rifting, Sergipe-Alagoas Basin, Brazil

et al. 2017

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“…It occurs in an intercratonic zone between the Congo craton to the northwest and the Kalahari craton (consisting of the Zimbabwe and Kaapvaal cratons) to the www.intechopen.com Geomorphic Landforms and Tectonic Controls Along the Eastern Margin of the Okavango Rift Zone, North Western Botswana as Deduced From Geophysical Data in the Area 171 east-southeast (e.g., Kinabo et al, 2007;2008). The development of the ORZ is thought to be taking place within a large structural depression known as the Makgadikgadi-OkavangoZambezi basin (MOZ) and is characterized by northeasterly trending folds and faults of the Ghanzi-Chobe belt (Cooke, 1984).…”

Section: The Okavango Rift Zonementioning

confidence: 99%

“…The development of the ORZ is thought to be taking place within a large structural depression known as the Makgadikgadi-OkavangoZambezi basin (MOZ) and is characterized by northeasterly trending folds and faults of the Ghanzi-Chobe belt (Cooke, 1984). The strike of the main bounding rift-related faults is 030 -050 o in the north and 060 -070 o in the south (Kinabo et al, 2007;2008). The orientation of the faults on the surface is influenced by pre-existing faults and folds of the basement rocks Kinabo et al, 2007;2008).…”

Section: The Okavango Rift Zonementioning

confidence: 99%

“…Recent studies suggest that faults associated with this rift are still in a juvenile stage (Kinabo et al, 2007), therefore the ORZ provides us with a unique opportunity to investigate the earliest developmental stages of continental rifts such as fault growth and propagation. In areas where the faults are mostly buried beneath large accumulations of sediment, have subdued surface relief, and or where access and travel is limited, as is the case in the ORZ (Kinabo et al, 2007;Modisi et al, 2000), it is difficult to accomplish structural mapping of such areas. For these areas, important structural information regarding rift processes can be obtained from magnetic data Grauch, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Geomorphic Landforms and Tectonism Along the Eastern Margin of the Okavango Rift Zone, North Western Botswana as Deduced from Geophysical Data in the Area

Shemang¹,

Molwalefhe²

2011

New Frontiers in Tectonic Research - General Problems, Sedimentary Basins and Island Arcs

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Thermal perturbations beneath the incipient Okavango Rift Zone, northwest Botswana

et al. 2015

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We used aeromagnetic and gravity data to investigate the thermal structure beneath the incipient Okavango Rift Zone (ORZ) in northwestern Botswana in order to understand its role in strain localization during rift initiation. We used three-dimensional (3-D) inversion of aeromagnetic data to estimate the Curie Point Depth (CPD) and heat flow under the rift and surrounding basement. We also used two-dimensional (2-D) power-density spectrum analysis of gravity data to estimate the Moho depth. Our results reveal shallow CPD values (8-15 km) and high heat flow (60-90 mW m À2 ) beneath a~60 km wide NE-trending zone coincident with major rift-related border faults and the boundary between Proterozoic orogenic belts. This is accompanied by thin crust (<30 km) in the northeastern and southwestern parts of the ORZ. Within the Precambrian basement areas, the CPD values are deeper (16-30 km) and the heat flow estimates are lower (30-50 mW m À2 ), corresponding to thicker crust (~40-50 km). We interpret the thermal structure under the ORZ as due to upward migration of hot mantle fluids through the lithospheric column that utilized the presence of Precambrian lithospheric shear zones as conduits. These fluids weaken the crust, enhancing rift nucleation. Our interpretation is supported by 2-D forward modeling of gravity data suggesting the presence of a wedge of altered lithospheric mantle centered beneath the ORZ. If our interpretation is correct, it may result in a potential paradigm shift in which strain localization at continental rift initiation could be achieved through fluid-assisted lithospheric weakening without asthenospheric involvement.

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Early structural development of the Okavango rift zone, NW Botswana

Cited by 115 publications

References 40 publications

High resolution stratigraphy of initial stages of rifting, Sergipe-Alagoas Basin, Brazil

High resolution stratigraphy of initial stages of rifting, Sergipe-Alagoas Basin, Brazil

Geomorphic Landforms and Tectonism Along the Eastern Margin of the Okavango Rift Zone, North Western Botswana as Deduced from Geophysical Data in the Area

Thermal perturbations beneath the incipient Okavango Rift Zone, northwest Botswana

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