Geol 110

This is a set of flashcards for Geol 110 NL

What is Geology?

The study of Earth and all its physical, chemical, and biological processes

Now includes study of other planets and extraterrestrial materials

Entire definition now how planets form and all the processes changing them

Why has the definition of of geology expanded

Enhanced technology has enabled us to have close ups of rock faces on other planets

Volcanology

Subfield studying eruption and history of volcanoes

Planetary geology

subfield studying the formation and evolution of other planets

Paleontology

subfield that started the study of geology

study of past life and evolution on earth through fossil examination

Structural Geology

subfield that studies how tectonic processes have shaped rocks and terrain

Mineralogy/Petrology

subfield that studies mineral and rock formation

Geomorphology

how landslides and glaciers impact the landscape

Hydrogeology

Study of water

Environmental Geology

Provides insight into processes that affect surfaces of the earth (both natural and human)

Provides potential solutions and best practices for a sustainable environment

Helps predict future changes related to human activity

When did humans start significantly impacting the environment

8,000 years ago rise in CO2 due to humans clearing forests in Europe and beginning of animal husbandry

Why did temperatures increase around 1850s

Industrial revolution led to the burning of coal which increased CO2 and began global warming

Environmental Factors impacting humans

Earthquakes, Climate, Floods, and Groundwater

How old is Earth

4.56 billion years old

What is the largest divider of geologic time?

Eons

What are the four Eons?

Hadean, Archaean, Protozoic, Phanerozoic

What is the current eon?

Phanerozoic

What are the three eras in the Phanerozoic?

Paleozoic, Mesozoic, Cenozoic

Paleozoic

541-251.9 mya life really started developing (invertebrates + plants)

First vertebrate was a fish

Towards the end life adapts to living on land

Ends with massive extinction

Mesozoic

251.9 - 66 mya

Dinosaurs came around due to permian extinction

reptiles dominate

Birds and mammals develop in this era

Asteroid causes mass extinction

Cenozoic

66 mya - now

mammal takeover due to dinosaur extinction

What percent of Earth’s History is Precambrian

88%

What is the age of the universe

13.8 billion years

When did the solar system form

4.567 billion years ago (know from calcium aluminum inclusion in meteorite)

When did the earth form

4.56 billion years ago

When did the first multicellular life appear

1.56 billion years ago

What percent of earth’s history lacked complex life

66%

When did dinosaurs appear

252 million years ago

When did dinosaurs die

65 million years ago

What percentage of Earth’s history was complete when dinosaurs came around

95.5%

What percentage of Earth’s history was complete when dinosaurs died

98.5%

When did the first homo sapien fossil appear

300,000 years ago

What percentage of Earth’s history had occurred when Homo Sapiens first appeared

99.994%

How long ago did Rome fall

1550 years ago

What percentage of Earth’s History had occurred by the fall of Rome

99.99997%

Relative Dating

Ranking things in order from youngest to oldest based on appearance

Does not involve absolute numbers

Largely based on where rock layers are in stack

On other planets, we use the presence of craters to relatively date rocks (more craters = plderolder)

Absolute dating

Gives the actual age (#)

Done primarily through isotopic dating

Isotopic dating

Measure the abundance of daughter isotopes and parent isotope to determine age of sample

Half life

time it takes for ½ of parent isotope to decay to daughter isotope

Carbon

half life 5,730 years, max useful 11,000 years

Uranium-Thorium

Half life 80,000 years

Uranium-Lead

half life 4,500,000,000 years

Three most recent yellowstone eruption dates

2.0 Ma, 1.3 Ma, .8 Ma

Average eruption time for yellowstone

600,000 years

Principle of Uniformitarianism

The present is key to the past

Processes that occur today have been ongoing and occurring throughout Earth’s history

Principle of Superposition

Unless layers of rocks have been overturned, the oldest rock layers are on the bottom with younger rock layers ontop

Original Horizontality

In most circumstances sedimentary rocks are deposited in large, flat sheets

Rock layers can be tilted during mountain building

Cross cutting relationships

Can be rocks cross cutting or faults

A rock that cuts across another must be younger than the one it is cutting across

Faults are cracks where things have been moved

Faults are younger than what they cut

Inclusions

a piece of rock included in another is older than the host rock

Xenolith

Foreign rock fragment

Lateral continuity

sedimentary rocks deposited in large flat continuous sheets

Faunal Succession

Organisms become more compelx with time

Unconformities

gaps in the rock record

Angular unconformity

Tilted rocks overlain by flat rocks

Means angled rocks had their tops eroded away causing missing rock record

Nonconformity

Igneous or metamorphic rock overlain by sedimentary rock

Means igneous/metamorphic rocks were uplifted than eroded away causing missing rock record