1. Nacional Center for Research and Conservation of Caves, CECAV – Instituto Chico Mendes de Conservação da Biodiversidade, ICMBio , Brasília , 70635-800 , Brazil
2. Earth Sciences Department, Sapienza University of Rome and CERI, Research Centre for Geological Risk, P.le Aldo Moro n. 5 , I-00185 Rome , Italy
3. Department of Geography, University of Brasilia , Brasilia , 70910-900 , Brazil
4. Institute of Geosciences, University of Brasilia , Brasilia , 70910-900 , Brazil