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Prof. Michiel Olivier De Kock, University of Johannesburg, SA

5. Date of Commencement:
01/04/2019
6. Expected date of Completion:
31/03/2023

7. Interim report(max 500 words) including complete list of publications and patents
based on the work from the project:

An important stage of Earth’s crustal history is marked by the Neoproterozoic era spanning
between 1000 Ma and 540 Ma. It witnessed the assemblage and breakup of the Supercontinent
Rodinia and assembly of the Gondwana. The advent of the era is not only considered to herald
the amalgamation of Rodinia and to usher in a major change in the pattern of global tectonics.
The Earth’s atmosphere and hydrosphere also underwent rapid changes in chemistry with the
onset of the Neoproterozoic. The changes occurred in tandem with the new tectonic setting
related to ocean opening and continental collision that ensued at the closing of the
Meoproterozoic (Des Marais, 1997; Veevers, 1990).

The assembly and configuration of the Rodinia and its breakup profoundly controlled the
climatic changes, ocean circulation pattern, geo-biochemical changes and depositional
systems throughout the Neoproterozoic and Neoproterozoic-Phanerozoic transition (Kaufman
and Knoll 1995). The configuration of the Rodinia or of the Gondwana is still in debate. It is
likely that supercontinents have come and gone throughout the Earth’s history, but their
precise configurations are still not fully known. Resolution of the problem requires intensive
studies of Neoproterozoic basin-filling successions, which are observed in different
continental blocks, and correlation of basin-filling events on intracratonic as well as inter-
cratonic scale to develop a global perspective (Kaufman et al., 1992). Most directly,
continental assemblages and dispersals manifest first-order patterns in mantle convection and
geodynamics.

An integrated study of the stratigraphy and deformation pattern of the Purana basins of the
Dharwar cratons, namely the Bhima, Badami and the Kurnool basins are in progress. The
Badami succession unconformably overlies the Kaladgi basin and the basement granite,
gneiss and greenstone terrane of the western Dharwar craton, while Bhima directly overlies
the granite greenstone belts of the eastern Dharwar craton. The Kunnool Group overlies the
Lower Cuddappah succession along with and the basement granite, gneiss of the eastern
Dharwar craton. Kurnool, Bhima and Badami basins are undeformed or with local
deformation near the vicinity of faults and generally unmetamorphosed. The basins recorded
multiple episodes of transgression and progradation forming successive coarsening-up (CU)
and fining-up (FU) sequences. The succession of all three basis, as observed in field represents
basal immature siliciclastic successions deposited in cratonic rifts. Eventually they gradually
pass on to carbonate-shale successions, which represents passive margin settings. Detailed
analysis of sedimentary attributes of the sequences indicates that a successive fining-upwards
motif of deposition at a scale of more than a kilometer, observed in all the basins, was the
direct sedimentary response to eustatic sea-level fluctuations leading to variable changes in
accommodation space that were controlled by lithospheric dynamics. Physical and chemical
aspects of carbonate depositional systems and their potential in predicting climatic changes
on regional scale are in progress.

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