A re-examination of the paleo-position of Africa's eastern neighbours in Gondwana

Reeves, C.V.; Sahu, Bijaya Kumar; Wit, Maarten de

doi:10.1016/s0899-5362(02)00011-8

Cited by 74 publications

(44 citation statements)

References 16 publications

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“…Smith & Hallam 1970;Lawver & Scotese 1987;Reeves et al 2002). As a result, there is now widespread agreement on the Palaeozoic-Mesozoic configuration of Gondwana, although spatial and temporal correlations between the various terranes of West Antarctica remain problematic (Dalziel & Elliot 1982;.…”

Section: Keystone Of Gondwana Core Of Rodiniamentioning

confidence: 99%

Antarctica and supercontinent evolution: historical perspectives, recent advances and unresolved issues

Harley

Fitzsimons

Zhao

2013

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The Antarctic rock record spans some 3.5 billion years of history, and has made important contributions to our understanding of how Earth's continents assemble and disperse through time. Correlations between Antarctica and other southern continents were critical to the concept of Gondwana, the Palaeozoic supercontinent used to support early arguments for continental drift, while evidence for Proterozoic connections between Antarctica and North America led to the 'SWEAT' configuration (linking SW USA to East Antarctica) for an early Neoproterozoic supercontinent known as Rodinia. Antarctica also contains relicts of an older Palaeo-to Mesoproterozoic supercontinent known as Nuna, along with several Archaean fragments that belonged to one or more 'supercratons' in Neoarchaean times. It thus seems likely that Antarctica contains remnants of most, if not all, of Earth's supercontinents, and Antarctic research continues to provide insights into their palaeogeography and geological evolution. One area of research is the latest Neoproterozoic-Mesozoic active margin of Gondwana, preserved in Antarctica as the Ross Orogen and a number of outboard terranes that now form West Antarctica. Major episodes of magmatism, deformation and metamorphism along this palaeo-Pacific margin at 590 -500 and 300-230 Ma can be linked to reduced convergence along the internal collisional orogens that formed Gondwana and Pangaea, respectively; indicating that accretionary systems are sensitive to changes in the global plate tectonic budget. Other research has focused on Grenville-age (c. 1.0 Ga) and PanAfrican (c. 0.5 Ga) metamorphism in the East Antarctic Craton. These global-scale events record the amalgamation of Rodinia and Gondwana, respectively. Three coastal segments of Grenville-age metamorphism in the Indian Ocean sector of Antarctica are each linked to the c. 1.0 Ga collision between older cratons but are separated by two regions of pervasive Pan-African metamorphism ascribed to Neoproterozoic ocean closure. The tectonic setting of these events is poorly constrained given the sparse exposure, deep erosion level and likelihood that younger metamorphic events have reactivated older structures. The projection of these orogens under the ice is also controversial, but it is likely that at least one of the Pan-African orogens links up with the Shackleton Range on the palaeo-Pacific margin of the craton. Sedimentary detritus and glacial erratics at the edge of the ice sheet provide evidence for the c.

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Section: Keystone Of Gondwana Core Of Rodiniamentioning

confidence: 99%

Antarctica and supercontinent evolution: historical perspectives, recent advances and unresolved issues

Harley

Fitzsimons

Zhao

2013

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“…The history of this continental segmentation and subsequent movement is complex, but has been convincingly reconstructed using rigid plate models based on oceanic fracture zones and magnetic anomalies, and the rotation poles derived from them, and then refined further by alignment of piercing points at conjugate margins of the dispersed Gondwana fragments, using continental aeromagnetic and geological markers [Reeves and de Wit, 2000;Sahu, 2001;Reeves et al, 2002Reeves et al, , 2004Jokat et al, 2005]. First-order features of the evolution of the Indo-Atlantic Oceans appear now to be incontrovertible ( fig.…”

Section: The Origins Of Africa Madagascar India and The Indo-atlantmentioning

confidence: 99%

Reconciling the Origins of Africa, India and Madagascar with Vertebrate Dispersal Scenarios

Masters¹,

Wit²,

Asher³

2006

IJFP

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Africa, India and Madagascar were once part of the supercontinent of Gondwana. This land mass began to fragment approx. 170 million years ago, and by 83 million years, all of the major components we recognize today were separated by tracts of water. Madagascar’s fossil record and estimates of the timing of the extant vertebrate radiations in Madagascar are not easily reconciled with this history of fragmentation. Fossil faunas that lived prior to approx. 65 million years had a cosmopolitan flavour, but this was lost after the Cretaceous-Tertiary boundary. Phylogenetic reconstructions of most extant Malagasy vertebrate radiations indicate divergence times that postdate the End-Cretaceous (lemurs, tenrecs, cichlid fish) and even the Early Miocene (chameleons, carnivores, rodents). Most biogeographic explanations of these groups rely, therefore, on Simpson’s model of sweepstakes dispersal (see also cover figure), but there are significant problems in applying the model to migrations from Africa to Madagascar, although its application is not so intractable between India and Madagascar. Alternative migration routes for consideration lie: (1) along the suite of fracture zones between Antarctica and Africa/Madagascar (known as the Antarctic-Africa Corridor), which may have been exposed episodically above sea level; (2) along a series of submerged basaltic ridges/plateaus with known or suspected continental crust between Antarctica and Africa/Madagascar/India flanking the Antarctic-Africa Corridor (e.g. the Madagascar Ridge, Mozambique Ridge, Conrad Plateau, Gunnerus Ridge); (3) between Africa and Madagascar along the Davie Ridge (parts of which are known to have been exposed episodically above sea level); (4) along the Deccan hotspot corridor between India and greater Africa.

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“…This is substantially later than the fragmentation event of the Gondwanan supercontinent that has kept these landmasses separated by ca 400-1200 km of open ocean for the last 120 Myr (million years) [16][17][18]. Although it is therefore evident that oceanic dispersal has played a pivotal role in the current distribution pattern of chameleons, the geographical origin of the family and the direction of dispersal are still uncertain.…”

Section: Introductionmentioning

confidence: 99%

Large-scale phylogeny of chameleons suggests African origins and Eocene diversification

2013

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Oceanic dispersal has emerged as an important factor contributing to biogeographic patterns in numerous taxa. Chameleons are a clear example of this, as they are primarily found in Africa and Madagascar, but the age of the family is post-Gondwanan break-up. A Malagasy origin for the family has been suggested, yet this hypothesis has not been tested using modern biogeographic methods with a dated phylogeny. To examine competing hypotheses of African and Malagasy origins, we generated a dated phylogeny using between six and 13 genetic markers, for up to 174 taxa representing greater than 90 per cent of all named species. Using three different ancestralstate reconstruction methods (Bayesian and likelihood approaches), we show that the family most probably originated in Africa, with two separate oceanic dispersals to Madagascar during the Palaeocene and the Oligocene, when prevailing oceanic currents would have favoured eastward dispersal. Diversification of genus-level clades took place in the Eocene, and species-level diversification occurred primarily in the Oligocene. Plio-Pleistocene speciation is rare, resulting in a phylogeny dominated by palaeo-endemic species. We suggest that contraction and fragmentation of the Pan-African forest coupled to an increase in open habitats (savannah, grassland, heathland), since the Oligocene played a key role in diversification of this group through vicariance.

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A re-examination of the paleo-position of Africa's eastern neighbours in Gondwana

Cited by 74 publications

References 16 publications

Antarctica and supercontinent evolution: historical perspectives, recent advances and unresolved issues

Antarctica and supercontinent evolution: historical perspectives, recent advances and unresolved issues

Reconciling the Origins of Africa, India and Madagascar with Vertebrate Dispersal Scenarios

Large-scale phylogeny of chameleons suggests African origins and Eocene diversification

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