Gondwana


Gondwana

What's new?  Animations of the East Africa margin in Jurassic and Early Cretaceous times:

East Africa animation: Click here.

Somali Ocean animation: Click here.

Mozambique Ocean animation: Click here.

An explanatory Research Update is avalable here.  See below for earlier Updates.

'Atlas' software from Cambridge Paleomap Services Limited used throughout.

2017 February 23

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This page is your gateway to a wealth of information, work and ideas on the tectonic history of Gondwana, accumulated over many years.  For the non-specialist there is an Introduction to the principles of global tectonics [click here], for the serious researcher there are References to published work as well as the ‘grey’ literature [click here], for those wanting to learn more, there is a description of a 12-lecture course on Gondwana geodynamics that may be followed [click here] and, lastly, a section on Recent ideas and research [click here].

The core of the work is the development of a rigorous geometrical model for the re-assembly and dispersal of the whole of Gondwana with a global perspective but focusing particularly of the western Indian Ocean and the east coast of Africa from Somalia via Madagascar to South Africa.  The model comprises a series of Euler interval poles for the plate circuit Madagascar -> Africa -> Antarctica -> India that are available on request in Atlas TWR format.  'Atlas' software from Cambridge Paleomap Services [link to CPSL] has been the workbench for all these efforts. Insights gained from hands-on experience with the geological reconnaissance through geophysical mapping of many whole countries in eastern and southern Africa (as well as India and Australia), 1970-2016, is brought to bear wherever possible. The work forms part of IGCP-628, the Geological Map of Gondwana.

The animation at the top of this page demonstrates the application of the latest model (CR16ABGE) to our database of interpreted oceanic and continental features that form the geological record of Gondwana dispersal and the evidence of the earlier continuity of Precambrian geology across the whole continent of Gondwana.  The animation shows the development of the Indian Ocean as the Precambrian fragments of central Gondwana (pink) dispersed, emphasizing the constraints of the ocean fracture zones on the development of the model.

Products of large igneous provinces are shown in blue, active mid-ocean ridges in red, major transfroms in grey and extinct ridges dashed in black. Plume loci in a fixed mantle reference frame are shown as red circles (1100 km diameter) in the forward animation. Rifting within Africa is indicated in a somewhat stylised way, Cretaceous rifting in green and the current East Africa rifting in yellow. Karoo deposits, pre-dating Gondwana dispersal, are shown in orange. The animation supercedes that of  model CR15GSCC which is described in Reeves et al., 2016.  The differences are explained in the Recent Ideas and research notes click here.

A series of one hundred JPG images to accompany the animation has been generated at higher resolution.  These images show the ocean crust in colour, based loosely (and with permission) on the CGMW Geological Map of the World (2010). [Ref: Geological Map of the World, 3rd edition, scale 1 :25 000 000. Ph. Bouysse et coll. © CCGM-CGMV / 2010. www.ccgm.org]. The September 2015 edition of the images may be accessed here. Model CR16ABCL was used in May 2016 to generate a series of maps in equatorial equidistant projection that may be accessed here.

The animation above is an animated GIF file about 10 Mb in size. By right-clicking on the image and saving it to your computer it may then be imported as a video into a Powerpoint presentation, for example.  The images and the animations are free for teaching or research purposes, with acknowledgment. Please seek permission for commercial use.

Brief explanatory notes: Much of the Gondwana continent can still be found preserved as rigid Precambrian crustal fragments, shown in pink in the above imagess, that have retained the same size and shape that they had within unified Gondwana at the end of Precambrian times. In the reassembly they are separated by continental crust that has been stretched in rifting processes, and lost from view below Phanerozoic sediment. Igneous rocks related to the activity of the labelled mantle plumes - mostly large volcanic plateaus in the oceans - are shown in blue.  

Enquiries and suggestions for collaborative studies are always welcome.

2016 July 22

 

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Sample animations of continental movements

Indian Ocean, model CR13AABN, 2013 March 15 [Example 1]

Antarctica-Africa, 2012 April [Example 2]

Atlantic Ocean, 2010 December, London Sept 2011 [Example 3]

Bouvet Mantle Plume, 2010 [Example 4]

Southeast Africa-Antarctica [Example 5]

India's passive margins [Example 6]

Gondwana, London September 2009 [Example 7]