List and briefly describe the three types of unconformities. What is a fossil and what are two conditions that improve an organisms chances of being preserved. List and briefly describe the three types of radioactive decay? What are the four basic divisions (columns) of the Geologic Time Scale?

Briefly describe the three types of unconformities.

Disconformities -  bedding planes of the upper and lower rock units are parallel to the erosional contacts

Nonconformities - is a contact that separates an metamorphic rock unit or igneous intrusive rock from a younger sedimentary rock unit.

Angular unconformities - is a contact that separates an older underlying rocks that are deformed or tilted layered rock from a younger, gently dipping rock unit.

What is a fossil?

Fossils are remnants or traces of remains or preserved remains of ancient plants and animals.

Two conditions that improve an organisms chances of being preserved.

In a marine environment, rapid burial can be done where abundance of calcium carbonate can act as a cement and other minerals. The best chance of becoming part of the fossil record is when organisms living in environments possessed hard parts where rapid burial will occur following death. Hard parts of an organism are most likely to survive long enough until it is fossilized.

List and briefly describe the three types of radioactive decay.

Alpha decay - nuclear disintegration process that emits alpha particles

Beta decay - a high energy electron that is emitted from the nucleus

Gamma decay - nuclear reactions of all types are accompanied by gamma ray production

What are the four basic divisions (columns) of the Geologic Time Scale?

The four basic divisions of the geologic time scale are Eons, Eras, Periods, and Epochs.