Ontario’s Geology as it pertains to finding caves
Marble is a metamorphic rock. It formed when limestone or dolostone was heated. Marble crystallizes to greater or lesser degrees depending upon the conditions and what impurities are present. In several caves I have seen beautiful patterns in the rock and swirling bands of earthy hue.
In Ontario, marble can be found in the Canadian shield, a vast tongue of heated and folded rock that dips down from the north and reaches Lake Ontario near Kingston. For the Ontario caver marble is important in that it holds many of the provinces caves. Marble caves tend to be smaller than their limestone counterparts – most being situated deep into the bush and so still awaiting discovery. Cave development takes place relatively slowly in marble because it dissolves to a lesser extent than it does in limestone.
In the above picture – a band of marble – deeply fractured and rich in titanite cuts out into one of the Province’s rivers. Water is thought to penetrate the rock from a lake some distance off and the resulting solution has carved out some sizeable cave tunnels.