Impacts on geological properties, rock formations, minerals and fossils
Climbing and caving are the two activities that make most use of rock formations. But apart from minor abrasion of rock faces and the wearing away of surface travertine deposits, their effects appear to be negligible (Speight, 1973).
The collecting of minerals, rocks formations and fossils gives more cause for concern. One of the most dramatic examples of the effect of rock collecting is that of the Petrified Forest National Monument in Arizona. Souvenir hunters have totally stripped various sites of their fossil tree covering. Similarly, frost-net features in the Rocky Mountains National Parkland have been destroyed by visitors who have removed the stones that once outlined the frost polygons (Scott-Williams, 1967). In New Mexico, "rockhounding" has become so popular that the 100 hectare Rockland State Park in New Mexico has been set aside specifically for mineral collecting in order to relieve pressure in other areas (Mitchell, 1967).
In less developed countries, lack of surveillance contributes to fossil depletion. This is the case in the fossil area of San Juan Raya, Puebla, Mexico. Also, at many sites, the eagerness with which cave formations such as stalactites are sought has made the use of elaborate protection devices necessary.