Caves are an integral part of every limestone landscape. But because they are not easily accessible, most are seen only by cavers. However, sporting cavers discover and explore caves, producing maps that become a vital database within the science of geomorphology. It is then only a small step forwards to recognise the evolution of cave systems and their relationship to surface lowering, declining water tables and the whole gamut of landscape evolution.
In Britain and abroad, cave geomorphology has advanced with improved understanding of the geological influences on caves, the chemical processes behind them and the progressive development of very complex hydrological systems within karst terrains. The finer points have then proved economically invaluable in assessing limestones for the underground resources of both potable water and hydrocarbons that they contain.
There are clear benefits in comprehending cave inception during the earliest stages in the evolution of limestone porosity. Cavers, geologist and chemists have colluded in this valuable science, and have recently been joined by biologists now that the very significant role of microbes has been recognised. Cave biochemistry has become very trendy.
Back in the world of macro-geomorphology, evolving landscapes generally destroy their ancestral surface features, but a huge archive of evidence is preserved in the sediments in cave passages abandoned when their streams find new low-level routes. Scientific cavers from Bristol University have long been leaders in this field. The technique of uranium-thorium dating of cave stalagmites was developed in Canada by a McMaster University team consisting largely of ex-pat British cavers.
For cave science in Britain, the breakthrough was in 1975, when a stalagmite from a cave in the Yorkshire Dales was dated to 131,000 years ago. This was the first absolute age determined for any Quaternary feature in Britain pre-dating the 60 ka limit of radiocarbon analysis. Cave sediments from all parts of Britain now provide a chronological framework reaching back to the Anglian glaciation.
The next stage is aluminium-beryllium dating of clastic cave sediments to take the record back to a few million years. This has not yet been established within Britain, but British cavers have compiled a record going back more than two million years in the huge cave systems in the Gunung Mulu karst in Sarawak, Malaysia, which they have been exploring ever since the first foray on the Royal Geographical Society’s grand expedition of 1978.
In parallel with this chronology interpreted from radio-decay of the unstable isotopes in cave sediments, analysis of the stable isotopes within the stalagmitic calcite yields data on the palaeo-climates. Current techniques of micro-analysis are creating spectacular high-resolution records of past climates from cave stalagmites, and these are proving to be invaluable resources in interpreting the climate change that is so critical for our planet’s fragile environment.
Not bad for something that starts with enthusiastic cavers descending beneath the Yorkshire fells for their weekend adventures.
A Golden Age of British Cave Exploration runs from Friday 1 to Sunday 3 December. The event is aimed at the public, and a café bar will be open all day. Tickets will be available on the door or in advance on Eventbrite. Tickets for Friday's lectures cost £10, and £5 for Saturday and £5 Sunday.
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