Gondwana


Gondwana

The above animation is powered by the plate rotation model to be published shortly in the journal Petroleum Geoscience.  In forward time, the growth of the oceans is demonstrated with the movement of the mid-ocean ridges in relation to the mantle plumes, the creation of the large igneous provinces (blue) and the pattern of fracture zones now evident in the topogprahy of the ocean floor.  In reverse time, the colours attributed to the ages of the ocean floor by the CGMW disappear progessively as the whole process of Gondwana dispersal is put into reverse.  The aimation is made from frames at intervals of 5 myr from 0 to 150 Ma and at 10 myr intervals 150 to 300 Ma. The Atlas software of CPSL was used throughout.   2017 December 1


Contents of this Section

1. An Introduction to the Principles of Global Tectonics  [click here] for the non-specialist.

2. References [click here] to published work as well as the ‘grey’ literature for the specilaist.

3. A Twelve-Lecture Course on Gondwana Geodynamics [click here] for those who want to learn.

4. Research Updates [click here] with recent ideas for discussion.

 

Background

The core of the work over many years has been the quest for a rigorous geometrical model for the re-assembly and dispersal of the whole of Gondwana, with a global perspective but focusing particularly on 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.  

'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), 1970-2017, is brought to bear wherever possible. The work forms part of IGCP-628, the Geological Map of Gondwana [link to IGCP-628].

The animation at the top of this page demonstrates the application of the latest published model (CR17ABHH) 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. 

Much of the Gondwana continent can still be found preserved as these rigid Precambrian crustal fragments 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 since been stretched in rifting processes and lost from view below Phanerozoic cover in rift zones and continental margins. Igneous rocks related to the activity of the labelled mantle plumes - mostly large volcanic plateaus in the oceans - are shown in blue.  

Active mid-ocean ridges are shown in red with major transforms in grey and extinct ridges dashed in black. Plume loci in a fixed mantle reference frame are shown as red circles (initially 1000 km in diameter) in the forward animation. Rifting within Africa is indicated in a somewhat stylised way, Karoo (Permian-Triassic) in orange, Cretaceous rifting in green and the current East Africa rifting in yellow. Karoo deposits, pre-dating Gondwana dispersal, are shown in pale orange. The animation supercedes that of  model CR15GSCC which is described in Reeves et al., 2016.  The differences are explained in the Research Updates click here.

What you see above is an animated GIF file about 6 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.

Enquiries and suggestions for collaborative studies are always welcome.

2017 December 1

 

Sample animations of continental movements

Some other animations are accesible below.  Most are somewhat dated but could easily be regenerated with more up-to-date rotation models where there is suffcient interest.

East Africa animation: Click here.

Somali Ocean animation: Click here.

Mozambique Ocean animation: Click here.

[An explanatory Research Update (No.5) is available here.]

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]

A series of one hundred JPG images to accompany an earlier 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.