NS008-01
The Bushveld Complex Drilling Project: an ICDP project on the origins, emplacement and consequences of the world's largest known igneous intrusion

Tuesday, 15 December 2020: 16:00
Virtual
Susan Jane Webb, University of the Witwatersrand, School of Geosciences, Johannesburg, South Africa, Robert Bruce Trumbull, Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany, Lewis D Ashwal, University of the Witwatersrand, Johannesburg, South Africa, Frederick Roelofse, University of the Free State, Geology, Bloemfontein, South Africa, David Khoza, Council for Geoscience, Pretoria, South Africa and Ben Hayes, University of the Witwatersrand, School of Geociences, Johannesburg, South Africa
Abstract:
The objective of the International Continental Scientific Drilling Program(ICDP) Bushveld Complex Drilling Project (BCDP) is to develop nearly continuous reference sections through the ~8 km-thick Bushveld Complex. Most of the layered mafic sequence is buried beneath the surface, accessible only in mines or exposed in fortuitous outcrops which lack vertical continuity. The reference sections will be studied by multinational, multidisciplinary teams addressing fundamental questions about the nature of the magma sources, melting processes, magma chambers and magma emplacement that gave rise to enormous magma volumes and rich mineralization, about 2000 million years ago. The reference sections will provide a valuable benchmark for tracking lateral layer variations.

The National Core Facility in Donkerhoek, operated by the South African Council for Geoscience will provide long-term curation for the cores which will be documented using ICDP protocols. Existing core materials, such as the well-studied Bellevue core, will be expanded with new ICDP boreholes and substantial core donations from the South African mining industry (ca. 6000 m, value ca. 1.5 million US$).

The scientific objectives are grouped into 5 broad themes:

  • Magma chamber processes, melt sources and magma evolution
  • Interaction of mantle melts with the crust and the origin of felsic magmas
  • Origin of ore deposits
  • Geophysical properties and geodynamic processes
  • Hydrogeology and the deep biosphere

Preliminary work on the project has commenced with the acquisition of 6852 m of donated drill core that has been transferred to the National Core Library and the University of the Free State in Bloemfontein. These donated (and existing) cores have significantly reduced the amount of drilling required to compile a complete reference section in the Northern and Eastern limbs of the Bushveld Complex. In the Northern Limb, there is still a gap of ~650 m, and in the Eastern limb ~3000 m will need to be drilled. Preliminary work on curating these donated cores and analyzing available geophysical borehole logging data has begun.

The coordinators of the project would like to invite all parties interested in contributing to this project, either scientifically or financially, to contact us. The official website for the project is: http://bushveld.icdp-online.org

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