Week 1

Question 1

Geological Time

Answer 1

Describes a process that takes as long as 1,000 years or more to complete.

Examples: mountains (growing at a rate of 1 mm/year)
Geological change is hard to notice

Question 2

Age of the Earth

Answer 2

4.56 Billion years old

Question 3

Earth’s Time Eons

Answer 3

Earth’s time is broken into 4 Eons, Eras, Periods, and Epochs.

Question 4

Current earth Eon, Era, Period, and Epoch

Answer 4

Eon =  Phanerozoic
Era = Cenozoic
Period = Quaternary
Epoch = Holocene

Question 5

Fraction of life on earth only being composed of Microbial Life

Answer 5

Microbes made up 3 1/2 billion years out of 4 billion years of life. As microbes evolved and diversified through the planet, their metabolism had profound effects on the composition of the oceans, atmosphere, and surface sediment/soils.

Question 6

Nicolaus Steno

Answer 6

Nicola’s Seno’s investigations with sedimentary rock led to 3 principles of stratigraphy

Question 7

Stratigraphy

Answer 7

The layering of rocks

Question 8

Three principles of Stratigraphy

Answer 8

1. Principle of superposition
2. Original Horizontality
3. Original Lateral Continuity

Question 9

First Principle fo Stratigraphy

Answer 9

Principle of Superposition: in any stratigraphic succession, the oldest layer is at the bottom and any successive higher layers are younger.

Question 10

Second Principle of Stratigraphy

Answer 10

Principle of Original Horizontality: sediment must originally have been deposited in layers that were nearly horizontal and parallel to the surface on which they were accumulating.

Therefore, tilted rocks indicate an episode of crustal disturbance after the time of deposition.

Question 11

Third Principle of Stratography

Answer 11

Principle of Original Lateral Continuity: all strata extend in all directions until they terminate by thinning at the margins of the basin, and end abruptly against some barrier to deposition, or grade laterally into different kinds of sediment.

Example: a river cutting into a rock

Question 12

James Hutton

Answer 12

Considered as the father of geology, Hutton came up with uniformitarians and actualism (the present is key to the past). This means that, in order to explain a past event, we need to understand the present. However, this does not always hold true in events such as long-term changes (evolution of the atmosphere) or short-term changes (meteorite effects).

Hutton also came up with the term uncomformities.

Question 13

Unconformities

Answer 13

The Earth’s surface underwent cyclical events and that sequence of socks often showed hiatus’ in the rock “record” or strata. Unconformities happen because layers didn’t form or were weathered away.

Question 14

Three types of unconformities:

Answer 14

Angular unconformity, disconformity, and nonconformity.

Question 15

Angular unconformity

Answer 15

Horizontal layers on top of angular layers

Question 16

Disconformity

Answer 16

Younger horizontal rocks meet older horizontal rocks

Question 17

Nonconformity

Answer 17

Younger sedimentary rock meets older igneous/metamorphic rock.

Question 18

Charles Lyell

Answer 18

Created the Principle of Cross-Cutting Relationships and the concept of Inclusions

Question 19

Inclusions

Answer 19

Fragments within larger rock masses that are older than the rock masses in which they are enclosed

Question 20

Cross-Cutting Relationship

Answer 20

Magma will run through older rock. Magma causes sediment/rocks to crack and will intrude the rocks in a “dyke” formation.

Question 21

Biostratigraphy

Answer 21

Fossils are the remains of ancient organisms. They can include shells, teeth, bones, impressions, and animal tracks. The most common fossils in rocks over the past 500 million years are the shells of invertebrate animals, such as clams, oysters, and ammonites. The study of ancient life is called “paleontology”.

Question 22

Bioturbation

Answer 22

The process whereby sediments are disturbed by organisms living on, or in, the sediment. Below is a photo of animal tracks - known as trace fossils - thought to have been made by trilobites living in the seafloor mud around 500 million years ago.

Question 23

Formations

Answer 23

Certain rock units could be identified by the assemblies of fossils they contained. (Rocks having the same groups of fossils inside them).

Question 24

Principle of Succession

Answer 24

Life is unique to each period of earth’s history. Relating these to other life at the same period around the earth is called biostratigraphy.