Wark, David (1939 - 2005)

After completing a Bachelor of Science (BSc) and Diploma of Education at the University of Melbourne, David Wark taught in a high school for four years. Afterwards he moved to Zambia, then England where he taught for another two years. Wark then returned to Australia and was hired as a research assistant in the Geology Department at the University of Melbourne. David Wark devoted himself to his work and was soon producing some significant results, in particular he used ‘Lexan’ fission track maps to co-discover, in lunar material, the new mineral Tranquillityte. He also used similar and other techniques to characterize other mineral phases such as Zirconolite and Monazite in lunar rocks.

One day his supervisor (Professor John Lovering) handed him some Allende meteorite samples with the instruction to, “See what you can find in those white inclusions …”. Wark spent many hours per day searching the samples of Allende’s Ca-Al-rich Inclusions (CAIs) with instruments including a scanning electron microscope and a microprobe. Among his many finds, David Wark demonstrated that thin layers of spinel-plus-perovskite, alteration products and pyroxene were ubiquitous on coarse CAIs, and that this sequence of layers was identical to that making up the individual bodies in Fine-grained aggregates. These layers were soon referred to as ‘Wark-Lovering’ rims by his colleagues. The ‘discovery’ of rims and of their similarity to fine-grained CAI bodies was David’s most important work, and has stimulated many other studies, although the origin of rim layers still remains uncertain almost 30 years later.

After presenting his ‘Rims’ work at the Lunar Science Conference in Houston, Wark was invited to attend the California Institute of Technology (Caltech) and was eventually offered a job there. His work at Caltech led to new ways of classifying CAIs and also a method for distinguishing ‘framboids’ from ‘palisades’, where he described the latter as captured CAIs-within-CAIs. Back at Melbourne University David Wark could not find funding for his research so worked as a dogsbody in the Geology Department while finishing his Ph.D. part-time. Soon afterwards he moved to the Neutron Activation lab in Tucson, where he remained for six years. Upon his return to Melbourne, Wark was once again unable to obtain funding for meteorite research and obtained a job in industrial research, first on coal combustion and then on beach sand minerals. During this time his desire to continue his research on meteorites and the Wark-Lovering rims did not faulter, so he spent the next seven years self-funding this private research.