Monday 20 November (Indoor meeting): 'Cave Development, at home and abroad.' Speaker: Tony Waltham. Tony Waltham left Imperial College, London in 1968, with a first degree in geology and a PhD in mining geology. A keen caver, he took up a lectureship in the institution now known as Nottingham-Trent University, where he taught miners until Britain’s coal mining industry died. He then moved through civil engineering into engineering geology. The combination of teaching engineering geology, ground engineering and a growing understanding of limestone ground from beneath led to research in the specialised field of geo-hazards, in particular on sinkholes and rock collapse over caves. Tony is recognised as one of the world experts on karst. His long list of published works includes numerous academic papers, accounts in more popular style, and more than a dozen books. Tony has received many awards, and may also be known to members as a result of his editorship of The Mercian Geologist, or as a board member of Geology Today. Tony’s wealth of experience exploring cave systems across the World, coupled with his engaging and enthusiastic style, combine to make an unforgettable evening.

Introduction from Tony: “Most of the world's caves lie in karst terrains that have been eroded out of limestones. Cave passages are polygenetic, developed above, at and below the water table. Current concepts recognise all of these, but also accept significant influence by geology structure. Erosion by through-drainage of rainfall water forms most caves, but a notable type is formed by rising sulphuric acid. Once formed, caves are modified by collapse (which can be on a truly gigantic scale) and by infill of sediments (which can yield a wealth of palaeo-environmental data). The lecture takes an overview of caves and their geomorphology, with numerous examples from Britain and far-flung karst terrains”.