1. Steno’s Laws

2. Uniformitarianism
The idea that all processes currently shaping the Earth are the same processes that shaped the Earth in the geologic past

3. Nicolas Steno Lived in the 1600s
Considered the “Father of Stratigraphy”
Didn’t accept what was in book, instead researched himself

4. Relative Dating
Determining which rock layers are older or younger without providing an exact age.
Just provides order of formation

5. Law of Superposition
In an undisturbed sequence of rock strata the oldest rocks are found below the newer rock.

6. Law of Original Horizontality
Layers of sediment are laid out by gravity into flat horizontal layers

7. Law of Lateral Continuity
Rock layers will extend horizontally until their environment changes

8. Law of Cross Cutting
If a rock layer is cut by either a fault of igneous intrusion the cut rock layer must be older than they layer that cuts it.

9. Erosional Surface A rock surface that has experienced erosion.
This mean part of the rock record has been erased through erosion

10. Unconformity A buried erosional surface that separates rock strata
Indicates deposition was not continuous
Used to describe any break in the geologic record

11. Disconformity
An unconformity between parallel sedimentary rock layers

12. Nonconformity
An unconformity between sedimentary rocks and metamorphic or igneous rocks
Sedimentary rocks deposited on top of eroded metamorphic or igneous rocks

13. Angular Unconformity
Horizontal sedimentary layers deposited on top of tilted eroded pre-existing layers

14. Intrusion
When liquid rock beneath the Earth’s surface squeezes into cracks and cools to form igneous rocks

15. Extrusion
When molten rock flows onto Earth’s surface and cools forming igneous rocks