Wits Isotope Geoscience Laboratory and Advanced Mass Spectrometry Facility
South Africa and Wits University has an incredibly rich legacy of isotopic research. In the early 1960s, Nicolaysen developed the Rb-Sr isochron technique for determining ages from the Rb-Sr isotopic composition of minerals and rocks. The isochron diagram was first called the “Nicolaysen diagram” or the “BPI diagram” after the Bernard Price Institute at Wits. In the 1970s and 1980s, scientists working at Wits performed the first isotopic measurements on a range of mantle rocks and diamond inclusions. The widely used two-stage terrestrial evolution curve for Pb was developed by Stacey and Kramers in 1975.
Hugh Allsopp Laboratory in the Bernard Price Institute (closed in 2003) - adapted from writing by Mike Jones
The isotope laboratory flourished under the leadership of Professor Hugh Allsopp, who dedicated his life to developments in the use of radioactive isotopes for the purposes of geochronology and research into the genesis of rocks. It is fitting that the laboratory was named the Hugh Allsopp Laboratory after his death in 1986. The group was significantly strengthened by Dr Hans Welke, a graduate of Oxford University, and together they were largely responsible for the international reputation BPI rapidly received in isotope research. The laboratory received a second enormous setback when Welke died shortly after Allsopp. 足球竞彩app排名 scientific contributions were made by several other staff members in the earlier years including Dr Jan Kramers in the 1970s, Dr Jay Barton between 1976 and 1986, and Dr Craig Smith (originally a doctoral student in the BPI) who took over leadership of the Hugh Allsopp Laboratory in 1987. Later appointments include Dr Erika Barton (also a previous doctoral student in the BPI) and Dr Johan Kruger, who succeeded Smith as head of the laboratory in 1996. During the thirty-year period (~1963–1993) the isotope team became the largest research group in the BPI, and the largest and longest-lived isotopic geochemistry facility in South Africa. Many South African graduate students from around the country, along with visiting scientists performed their isotopic analysis at the BPI in the 1970s and 1980s. It acquired new chemical laboratories and new modern mass spectrometers, and was on par with similar laboratories in the forefront of isotope research. Numerous postgraduate students were trained by the isotopes group. As a result of the efforts of leading team members and their students, and collaborative and often multi-disciplinary research, the laboratory achieved a very impressive publication record. Geochronological studies laid down the platform for a much better understanding of South African geological history and isotopic fingerprinting placed important constraints on the genesis of rocks and ore bodies and the evolution of the crust and upper mantle. Some studies have important economic implications and received generous support from the mining industry. Others involved more fundamental research and were funded through organizations such as the CSIR sponsored National Geodynamics Project.
In the late 1990s, the Hugh Allsopp Laboratory was separated from the rest of the BPI and was later merged with the Economic Geology Research Institute in 2001. The BPI was assimilated into the newly formed School of Geosciences in 2002.
The investigations and students involved are too numerous to detail here, but some important studies by BPI scientists are listed as important examples:
- Pb isotope studies of the genesis of Cu-Pb-Zn deposits in Namaqualand,
- U-Pb isotope studies of the genesis of U deposits in Beaufort Group sandstones and the Carbon Leader reef in the Witwatersrand,
- research into processes of concentration of Pt-group elements in the Bushveld Complex and the origin of the complex itself,
- analyses of sulphide inclusions in diamonds in order to determine their age relative to the host kimberlite and thus their origin,
- geochronology, tectonic history and evolution of the earth’s crust in South Africa particularly in the Archaean Barberton granite-greenstone belt, the early Proterozoic Limpopo belt and the mid-to-late Proterozoic Namaqua mobile belt,
- modelling the Pb evolution of the earth using ore body Pb isotope data,
- isotope studies and radiometric dating of kimberlite pipes and Karoo flood basalts in order to constrain the nature of their mantle source, and
- isotopic studies of kimberlite nodules and their implications for the evolution of the lithospheric mantle below southern Africa.
Earth Lab (2006 to 2023)
Allan Wilson established the Earth Lab in the School of Geosciences in 2006 which included XRF instruments, quad ICP-MS instruments as well as an ultra-clean preparation lab. The funding he raised for the Earth Lab came from the NRF, industry and the Wits Research Office. The Earth Lab in the Bernard Price Building was the mainstay of geochemical-based projects in the School for many years and provided the quality base and reputation to attract successful funding to purchase the laser system and sector field ICP-MS in 2016, and establish the Wits Isotope Geoscience Laboratory in 2017 and the Wits Advanced Mass Spectrometry Facility in 2022.
Wits Isotope Geoscience Laboratory (2017 onwards)
Wits Isotope Geoscience Laboratory (WIGL) is an ultra-trace clean laboratory, dedicated to isotope studies. The preparation of geological and environmental samples, including isotopic spiking, acid dissolution, and column chromatography, is conducted in the WIGL. Each isotopic system has a dedicated workplace, and the laboratory is also utilised to process environmental samples, including water and atmospheric particles. For more details on the ultra-clean lab, see details at this link.
Wits Advanced Mass Spectrometry Facility (2022 onwards)
Through two NRF-NEP grants to Robert Bolhar (grant holder and main applicant), Allan Wilson and Grant Bybee (co-applicants), and augmented by a recent renovation program (2021 onwards), one of the most advanced array of isotopic and trace elemental analytical equipment in Africa was established. For details of the instrumentation in the mass spectrometry lab in the recently established Earth Observatory, please see the details at this link.
The combined capabilities of our labs and instrumentation open up nearly the whole periodic table for isotope analyses: ideal for studying the astounding geological and paleontological heritage in southern Africa. Isotopic analyses are crucial to humanity’s understanding of the age of the Earth, Moon and other planets; the timing of mass extinction events (such as the meteorite that killed the dinosaurs); the age and origin of Earth’s oldest continents and formation of mineral deposits within this crust; and determining the age of diamonds and whether they are really forever.
