Unit 4: Geological History Flashcards
Age of Earth
4.5 Billion Years Old
Images to study in the lesson
Go to the lesson and study the symbols of the rock type and environment it represents.
an intrusion or a break is always younger than the rock it cuts across
Principle of crosscutting relationships
What was most common in the past but no so common now?
volcanic eruptions
meteorite impacts
What leaves behind evidence of the conditions that were present when formed?
Rocks & Fossils
Additional Image To Study
To to the lesson and study how to read the geological cross section.
Identify the four levels of geological time from longest to shortest
eon
era
period
epoch
Unconformities are:
represent a gap in time
form when there is erosion
when no deposition of sedimentary rock took place.
Relative dating is identified
by identifying the lowest layer as the oldest layer and the top layer as the youngest layer
Possible reason for the dinosaurs going extinct.
meteor
Uniformitarianism
- Says that the present holds the key to the past.
- thought of by James Hutton.
- Helps explain Earth’s past.
Which is closer to a T-Rex? Humans or Stegosaurus?
Humans
Using isotopes to determine age is called
absolute dating and radiometric dating
An increase in the number and diversity of life in the fossil record occurred when?
Between the Precambrian Eon and Phanerozoic Eon
When did the “Age of Mammals” occur?
Cenozoic era
