A native Geordie, Dennis obtained a BSc in Geology from Durham University in 1959 before joining the British Antarctic Survey (BAS) and gaining an MSc from Birmingham University in 1964. His BAS experience included over-wintering in 1959-61 at Halley Bay Base and an exploratory sledging traverse in 1961 of some seven hundred miles to Tottanfjella with just one companion. He was subsequently awarded the Royal Geographical Society Ness Award in 1964 and the Polar Medal in 1968.
After his period with BAS he joined the Anglo-American Corporation of South Africa in their Marine Diamond Corporation subsidiary in South West Africa (now Namibia). Dennis was responsible for establishing a marine geophysics programme and control of off-shore mining operations much of the work being in the difficult surf zone where diamonds are found in crevasses in the bedrock.
In the late 1960s a skeleton organisation of three fledgling marine geology and geophysics units were set up in the Institute of Geological Sciences (now the British Geological Survey) and Dennis was the first experienced marine geologist to be recruited to the one based in Edinburgh. On account of his work in South West Africa he was immediately able to take the function of Deputy to the Unit Head before being promoted to lead the group from 1975 until his retirement in 1997.
In the 27 years Dennis spent with this unit, which had several changes of name and detailed functions over the period, he marked it indelibly with his personality. He built it into an elite group with an international reputation for innovation and quiet efficiency. Initially his particular strength was in organising marine surveys and in developing seabed instrumentation including a rock drill and an electro vibrocorer. Under his leadership BGS produced, in a remarkably short time during the 1980s, a complete set of geological maps for the UK continental shelf.
The completion of this Herculean task was celebrated by an exhibition in the Geological Museum in London in the early nineties and Dennis received the Society for Underwater Technology MoD Award for Oceanography in 1991. As funding patterns changed following the completion of the mapping programme, Dennis set up a number of joint industry programmes that enabled the group to thrive and extend its surveys into deep water and overseas work.
Dennis was much involved with the London-based Society for Underwater Technology, acting as Vice-President and Chairman of the Council & Executive Committee from 1984-87. He was also Chair of several other Committees, organised a number of technical conferences and had thirty-two publications to his credit.
He was very much a leader who led from the front and did so with quiet good humour and a twinkle in his eye. He had, however, a steely determination about him which quickly earned the respect of his colleagues. His activities in his retirement years were much restricted by ill health which he bore stoically and with great dignity, never losing his interest in events or his dry sense of humour.
Dennis Ardus was born on 16 March 1937 and died on 1 February 2008. He leaves behind his second wife Jane, and a combined family of four children (Fiona, Graeme, Zoë and Sarah, all now adults) together with four grandchildren.
Robert A Eden