Pauline channelPosted on 2019 December
Next time you find a cliff or road cutting with lots of rock strata, try working out the age order using some simple principles: Sedimentary rocks are normally laid down in order, one on top of another. These processes result in geological unconformities , or breaks in the original stratigraphic sequence. Elephants, horses, pigs, rodents, and some monkey species have been used as index fossils because they underwent relatively rapid evolutionary changes that are identifiable in their teeth and other skeletal parts.
Then younger layers of sediment were deposited on them. Answers relative. Relative dating.