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. Consider why this should be so in the context of the Rock Cycle.

The rock cycle is the changes rocks will go through, from igneous to sedimentary to metamorphic, or in some similar order. If a rock starts as igneous, it was previously magma that cooled to from said igneous rock. As the igneous rock becomes weathered and eroded (from a various number of instances including wind and rain), it becomes loose sediment. That sediment becomes compacted and cemented together into a sedimentary rock, which is a rock composed of many different minerals, fossils, and other objects. As the rocks are subjected to an intense amount of heat and pressure over a very long amount of time, they eventually become metamorphic rocks, which either melt into magma or get eroded back into sediment. And thus continues the rock cycle.

Rocks from the Precambrian Era are extremely hard to find for a few reasons. For one, because they have been through the rock cycle many times (most likely several hundred if not thousand) over the course of several billion years, their makeup could have been changed by the combination of melting, eroding, and weathering. This could make them extremely hard to analyze. Additionally, the rocks could be very hard to find because they are most likely buried extremely deep as additional rock layers have been created in the time since the Precambrian Era ended.