Lecture 3: Deep time

Question 1

What is superposition?

Answer 1

Superposition of rocks refers to the age, lower rocks are older

Question 2

What is original horizontality?

Answer 2

The rock layers were originally horizontal, any angle may indicate uplift and erosion

Question 3

What is inclusion and intrusion?

Answer 3

Where rocks from deeper levels can be found in the sedimentary newer rocks, this can be due to erosion

Intrusion is where magma has seeped into and intruded a rock layer

Question 4

What are faults?

Answer 4

Faults are fractures where rocks on either side have moved relative to each other due to tectonic forces.

Question 5

What are unconformities?

Answer 5

Unconformities are gaps in the geological record caused by erosion or non-deposition of sediment, representing missing time in rock layers.

Question 6

What are angular unconformities?

Answer 6

Angular Unconformity occurs when tilted or folded rock layers are eroded and then overlain by younger, horizontally deposited layers, indicating a period of deformation and erosion.

Question 7

What are nonconformities?

Answer 7

Nonconformities occur when sedimentary rock layers are deposited on top of much older igneous or metamorphic rocks that have been exposed and eroded, representing a significant gap in the geological record.

Question 8

What is biostratigraphy?

Answer 8

Biostratigraphy is the branch of stratigraphy that uses fossil organisms to date and correlate rock layers, helping to establish the relative ages of geological formations.

Question 9

What is magnetostratigraphy?

Answer 9

Magnetostratigraphy is the study of the magnetic properties of rock layers to determine their age and correlate geological formations based on Earth’s past magnetic field reversals.

Question 10

What are the three eras of life?

Answer 10

Paleozoic (570ma to 250ma) - Old life

Mesozoic (250ma to 66ma) - middle life

Cenozoic (66ma to present) - Recent life

Question 11

Name the periods within the Paleozoic era (old to new)

Answer 11

Cambrian (541–485 Ma)
Ordovician (485–443 Ma)
Silurian (443–419 Ma)
Devonian (419–359 Ma)
Carboniferous (359–299 Ma)
Permian (299–252 Ma)

“Can Oscar See Down Colored Pants?”

Question 12

Name the periods within the Mesozoic era (old to new)

Answer 12

Triassic (252–201 Ma)
Jurassic (201–145 Ma)
Cretaceous (145–66 Ma)

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Question 13

Name the periods within the Cenozoic era (old to new)

Answer 13

Paleogene Period (66–23 Ma) – Mammals diversify
- Paleocene Epoch (66–56 Ma)
- Eocene Epoch (56–34 Ma)
- Oligocene Epoch (34–23 Ma)

2. Neogene Period (23–2.6 Ma) – First hominins appear
   - Miocene Epoch (23–5.3 Ma)
   - Pliocene Epoch (5.3–2.6 Ma)
3. Quaternary Period (2.6 Ma–Present)
   - Pleistocene Epoch (2.6 Ma–11,700 years ago)
   - Holocene Epoch (11,700 years ago–Present)

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