Question #2

Question 2:
It is generally true that the more ancient rocks (i.e. Precambrian) are less widely found exposed at the Earth’s surface and that their geologic histories are more difficult to interpret because of changes that occur in the ROCK CYCLE! Igneous rocks are formed from cooled magma. As the igneous rock becomes weathered and eroded, it looses sediment. That sediment becomes compacted and cemented together into a sedimentary rock. As the rocks are exposed to heat and pressure over hundreds of thousands of years, they eventually become metamorphic rocks. Therefore, rocks from the Precambrian Era are difficult to find because they have been through the rock cycle hundreds of times. Because of this, ancient rocks appear to very different today than they did during the era they were originally formed in. Also, they are often buried very deep into the rock as additional layers have formed over the years.