GEOLOGY

Detailed explanation-1: -To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.

Detailed explanation-2: -Cross dating is a method of using fossils to determine the relative age of a rock. Fossil remains have been found in rocks of all ages with the simplest of organisms being found in the oldest of rocks. The more basic the organism the older the rock is.

Detailed explanation-3: -Steno’s principles are essential for determining the relative ages of rocks and rock layers. In relative dating, scientists do not determine the exact age of a fossil or rock. They look at a sequence of rocks to try to decipher when an event occurred relative to the other events represented in that sequence.

Detailed explanation-4: -Superposition of rock units is a very simple and straightforward method of relative age determination. The principle states that in a sequence of undeformed sedimentary rocks the oldest beds are at the bottom and the youngest ones are at the top.