Alexander Logie du Toit (1878-1948) – The Father of South African Geology


Alexander Logie du Toit,SchweizerThis man is revered in South African geological circles as the father of South African geology.  He was born in Newlands in Cape Town in 1878 and was educated at the Diocesan College in Rondebosch and the University of the Cape of Good Hope before heading on to study mining engineering at the Royal Technical College in Glasgow.  He then went on to study geology at the Royal College of Science in London and returned to Glasgow to lecture in geology, mining and surveying.  Perhaps the Scottish climate reminded him of Cape Town winters, but one cannot be sure.

Returning home in 1903 he was appointed as a geologist with the Geological Commission of the Cape of Good Hope and became a workaholic, mapping vast areas of the Karoo and writing papers on his findings.  Back in those days there were very few topographical maps of the country, no aerial photographs, no Google Earth, no satellite imagery to assist with the detailed work required.  Not to mention poor roads, baking Karoo heat and no motor vehicles.  In spite of these difficulties, this amazing man mapped out the entire Karoo supergroup, from the basal Dwyka Tillite to the final output of incandescent lavas of the Drakensberg which mark the end of Karoo sedimentation.   To this day his original observations stand the test of time and scrutiny, with subsequent geologists just filling in the detail.

All this first hand evidence made him a proponent of Alfred Wegener’s notions of ‘continental drift’ more correctly known as plate tectonics.  In 1923 he travelled to South America on a grant from the Carnegie Institution to study the geology of Argentina, Paraguay and Brazil.  His aim was to examine the continuation of geological formations and characteristics between the two continents.  He was able to demonstrate that this was indeed the case which gave him evidence for his book ‘Our Wandering Continents’ in which the evidence for continental movements were spelled out in well considered detail.  He proposed two continents, a northern Laurasia and a southern Gondwanaland separated by the Tethys Ocean.

 In 1920 he joined the Union Irrigation Department as a water geologist, and in 1927 became chief consulting geologist to De Beers Consolidated Mines, where he stayed until his retirement in 1941.

In 1933 he was awarded the Murchison Medal by the Geological Society of London and in 1943 became a Fellow of the Royal Society.

In 1949, the year after his death, the Geological Society of South Africa inaugurated a biennial lecture series in his honour that continues to the present day.  There is a crater on Mars named Du Toit in recognition of his work.

Du Toit’s reconstruction of Gondwana