Drilling through the largest magma chamber on Earth: Bushveld Igneous Complex Drilling Project (BICDP)

Abstract

Abstract.A scientific drilling project in the Bushveld Igneous Complex in South Africa has been proposed to contribute to the following scientific topics of the International Continental Drilling Program (ICDP): large igneous provinces and mantle plumes, natural resources, volcanic systems and thermal regimes, and deep life. An interdisciplinary team of researchers from eight countries met in Johannesburg to exchange ideas about the scientific objectives and a drilling strategy to achieve them. The workshop identified drilling targets in each of the three main lobes of the Bushveld Complex, which will integrate existing drill cores with new boreholes to establish permanently curated and accessible reference profiles of the Bushveld Complex. Coordinated studies of this material will address fundamental questions related to the origin and evolution of parental Bushveld magma(s), the magma chamber processes that caused layering and ore formation, and the role of crust vs. mantle in the genesis of Bushveld granites and felsic volcanic units. Other objectives are to study geophysical and geodynamic aspects of the Bushveld intrusion, including crustal stresses and thermal gradient, and to determine the nature of deep groundwater systems and the biology of subsurface microbial communities.

Subsurface Microbial Colonization at Mineral-Filled Veins in 2-Billion-Year-Old Igneous Rock from the Bushveld Complex, South Africa

“…In addition to contamination control using fluorescent microspheres and microbial cells extracted from the bulk rocks with ultra-low cell abundances, new visualization approaches were successfully developed to enumerate microbial cell densities at fractures and veins that exceeded 10 10 cells/cm 3 [13,14]. This contribution extends the formation age of igneous rocks for microbiological investigations by targeting mafic and ultramafic rocks formed 2.05 billion years ago in the Bushveld Complex of northeastern South Africa, which is the largest mafic-ultramafic layered intrusion on Earth [15,16]. The Bushveld drilling project of the ICDP is undertaking a 2.5-km deep drill hole in the lower zone and base of the intrusion, where ultramafic rocks are expected to possess the chemical signature of the mantle endmember of mantle-crust mixing during magma emplacement [17,18].…”

Fe-Ti-V-(P) resources in the Upper Zone of the Bushveld Complex, South Africa

“…4), indicating a major change of magma composition between UUMZ and the underlying part of the MZ. It is thought that an injection of new magma changed the Trumbull et al 2015). Modified after Barnes & Maier (2002).…”

“…The Bushveld Igneous Complex Drilling Project (BICDP) (Trumbull et al 2015) is part of the work of the International Continental Drilling Program (ICDP), an international organisation supporting scientific continental drilling projects. Directed by two research groups from Germany (GFZ -German Research Centre for Geosciences) and South Africa (University of the Witwatersrand, Johannesburg) the BICDP started in 2014 and is currently in the planning stage.…”