Ice usually has tightly packed molecules at a low temperature. When it comes in contact with a higher temperature or room temperature, the ice molecules gain energy and the molecular tension increases which causes the state to change to liquid. Therefore, a <u>high temperature</u> causes an ice block to melt.
They can be dated using radioactive carbon. But for rocks older than 50 thousand years they look for layers of igneous rock or volcanic ash above and Bellow the layer of rock/fossil.
