Chapter 3 (part 2) Flashcards
The geologic time scale is divided into a number of types of units of differing size. From the largest units to the smaller units, they are:
- Eons
- Eras
- Periods
- Epochs
List 5 Chronostratigraphic units:
- Eonothem
- Erathem
- System
- Series
- Stage
In order from oldest to youngest, the three Eons are:
- Archean
- Proterozoic
- Phanerozoic
In order from oldest to youngest, the three eras are:
- Paleozoic
- Mesozoic
- Cenozoic
List the Periods of the Mesozoic Era:
- Cretaceous
- Jurassic
- Triassic
List the Periods of the Cenozoic Era:
- Neogene
- Paleogene
List the Epochs of the Cenozoic Era:
Neogene Period
• Holocene
• Pleistocene
• Pliocene
• Miocene
<u>Paleogene Period</u>
• Oligocene
• Eocene
• Paleocene
List the Periods of the Paleozoic Era:
- Permian
- Carboniferous
- Devonian
- Silurian
- Ordovician
- Cambrian
The structure of the atom consists of:
- Nucleus
- Electrons
• Various subatomic particles
What happens when atoms decay?
- Radioactive decay occurs by releasing subatomic particles and energy.
- The radioactive parent element is unstable and undergoes radioactive decay to form astable daughter element.
<em>Example: Uranium, the parent element, undergoes radioactive decay, releases subatomicparticles and energy, and ultimately decays to form the stable daughter element, lead.</em>
The rate of decay is not affected by changes in the following:
- Pressure
- Temperature
• Other Chemicals
Potassium-40 is found in these minerals:
- Potassium feldspar
- Muscovite
- Amphibole
- Glauconite
Uranium may be found in:
- Zircon
- Uraninite
- Monazite
- Apatite
- Sphene
Why are Earth Rocks Younger than Meteorites and Moon Rocks?
- The Earth is geologically active. The older rocks may have been eroded away.
- Older rocks may have been deeply buried under sedimentary rocks, or beneath thrustsheets.
- Older rocks may have been heated, metamorphosed, or melted, and their dates “reset”to the time of heating, metamorphism, or melting.
