He has worked on numerous geological projects and mapped many areas of the state, with most of his work occurring in northern Queensland. Working in the Georgetown, BrokenRiver, Lolworth-Ravenswood, Charters Towers, and Mount Isa areas. He was a major contributor to the North Queensland Geology volume and map in the mid 90s.
He has also been involved in mapping areas of central Queensland such as the Anakie, Yarrol, and Connors areas. He has managed some of the mapping programs carried out, including the Anakie Project (completed in 1993), which is still regarded as the benchmark in the GSQ for how efficiently a project should be carried out.
During the late 80s Ian was one of the major innovators who began moving the Geological Survey of Queensland towards a digital environment by helping to introduce its first digital database for storing geological information, called REGMAP. Since then the GSQ has continued heading towards a totally digital environment.
Ian has represented the Geological Survey of Queensland at a large number of seminars, symposia and conference, and presented numerous papers. He currently organises Queensland’s portion of the Stratigraphic Names database.
In 2004 Ian Withnall was awarded the GSA’s W.R. Browne Medal for his contribution to the geology of Australia.
Ian Withnall has played a large role in the Geological Survey of Queensland, and is widely known for his detailed knowledge of the geology and mineralisation of north Queensland. He has published many reports on his work, most of which he was the senior or sole author.