Colin Dunn (1941-2024)

Biogeochemist Extraordinarre

Colin Dunn died at the age of 83 on March 20, 2024 in Sidney, BC, Canada. He will be immensely missed by many members of the mineral exploration community worldwide.  

Following completion of his PhD at London University in 1972, Colin spent much of his career first at the Saskatchewan Geological Survey in central Canada and then at the Geological Survey of Canada (GSC; 1985-1998). Upon leaving the GSC, he and Sara moved to British Columbia (BC) in western Canada where he set up his flourishing consulting business which continued until recently. Colin was an active member of the AAG and in 2014 was awarded its highest honour, the Gold Medal for excellence in mineral exploration using biogeochemistry. A glimpse into the variety of his projects and publications can be gleaned from his book ‘Biogeochemistry in Mineral Exploration’, published by Elsevier in 2007.  

I was fortunate to have the office adjacent to Colin’s at the GSC; this resulted not only in our friendship but in our collaboration to improve and expand analytical capabilities for biogeochemical media and to compare ‘biosurveys’ (Colin) with ‘hydrosurveys’ (me) over the same areas. We travelled together to conferences and workshops worldwide, meetings where Colin seemed to know and greet almost everyone, a testament to his vivacious and warm personality. Colin was a great lis-tener, with an inquiring mind. He gave the best talks, so well organized and clear, just like his papers. His talks were well augmented with pho-tos from his field work, perhaps the most audacious being those photos showing treetop sampling by helicopter in British Columbia. It is a tech-nique that Colin and Rob Scagel, a forester, designed to collect surficial media in difficult, hilly densely treed areas. Colin emphasized to the skilled pilot that he must be careful to hover over the tallest tree lest the sampler be engulfed in severed twigs and needles! 

I asked a few people who worked on various research-oriented sur-veys with Colin to contribute some anecdotes. There is a clear theme running through all of them and it is a reflection on Colin’s character: always positive, enthusiastic (even under tough field conditions), gener-ous, ever-curious, keen to experiment with new species or techniques, patient, great sense of humour (British!), self-dep-recating, mentor, friend and collaborator. These friendships were usually cemented over a bottle of red and a good meal, curry if possible!

Dave Heberlein (Western Canada), with whom he often worked in BC, was amazed at Colin’s almost encyclopedic knowledge of the different metal uptake characteristics of various species and their tissues. Dave found that Colin was a delight to work with, so generous with his time and knowledge in teaching and advancing this field of mineral exploration. 

Tony Christie (New Zealand) first met Colin at the IAGS in Beijing in 1993. So impressed was he with Colin’s talks and chats, that he arranged to test the technique with Colin on various gold prospects over the years in New Zealand. Even in arduous conditions, Colin was jovial and positive, and keen to get the work done. Steve Hill (Australia) commented on how much Colin relished getting to know fellow researchers and their projects during his regular visits to Australia, especially into South Australia and western NSW to Broken Hill, Tibooburra, Arkaroola, Olympic Dam, Tunkillia and Kangaroo Island. Colin and Helen Waldron published an outstanding frontier study for the Geological Survey of South Australia on plant biogeochemistry across the South Australian portion of the Nullarbor Plain in which Colin adored the irony of conducting this study across a geographical feature named because of its apparent lack of trees (i.e. “null – arbor” meaning “no trees”).

Peter Rogers (Eastern Canada), a good friend from the mid-1980s, secured funding to carry out a reconnaissance biogeochemical survey using balsam fir and spruce twigs and bark in Eastern Nova Scotia with Colin. It was a resounding success, easily delineating most known metallogenic features, especially for gold and led to numerous joint projects some of which are described in Colin’s book. 

Dave Cohen (Australia) first met Colin in 1984 on a foray to the famous Hemlo gold deposit in northern Ontario, where he was collecting samples for his biogeochemistry MSc at Queen’s University. After instruction from Colin in the more subtle aspects of plant sampling, Colin asked “What species do you intend to sample?” Dave indicated it would be balsam fir, mountain maple, white spruce and alder. From Colin: “Ah, which of the two sub-species of alder are you sampling – Alnus crispa or Alnus rugosa?” And from Dave: “There are two sub-species?”, to which Colin replied “Yes, and they take up metals differently”. This is one of the rules Colin was adamant about: never mix species or sub-species in one survey! 

Helen Waldron (Australia) had the pleasure of working with Colin on many of his Australian projects as well as in Canada, Sweden and New Zealand. She recounts that he made a significant contribution to the use of biogeochemistry in exploration in Australia through the CRE LEME, courses, lectures, research projects and direct involvement in exploration programs for various commodities in several states, sampling a wide range of plants including, amongst others: spinifex, saltbush, mulga and eucalypts. Some projects he did just for fun, like searching for Ni accumulator plants at Ravensthorpe, sampling slime from hot springs in the Flinders Ranges and studying chemical variations in eucalypts at Dean Nicolle’s Currency Creek Arboretum.  

Examples of Colin’s excellent PowerPoint presentations (e.g. from Exploration ’07) and papers can be found online. Colin’s legacy is huge: his comprehensive book, many research papers and published surveys, and numerous people who have benefitted from his shared skill and knowledge but it is his indomitable fun-loving spirit that will be greatly missed by so many of us. 

Gwendy Hall (in association with the above-mentioned contributors)