Geology

Relative Dating

A technique used to determine which of two fossils is older

Number of extinction events in Paleozoic

2

Intra-Plate

Tectonic activity that occurs away from plate boundaries

Iron Meteorites

Solid chunks of iron and nickel

Homosapeins enter continent

Decrease in mammal population

Phanerozoic Eon

- Paleozoic Era
- Mesozoic Era
- Cenozoic Era

Paleozoic Era

- Cambrian
- Ordovician
- Silurian
- Devonian
- Carboniferous
- Permian

Cenozoic Era

- Tertiary
- Quaternary

Graben Fault

Depressed block of the Earth’s crust boardered by parallel faults

Horst Fault

Uplifted or up-faulted piece of rock

Central Atlantic Magmatic Province (CAMP)

The largest continental province which formed right before Pangea began to separate in the late Triassic, and early Jurassic periods

What was the Mesozoic era also called

Age of reptiles

How many extinction events were in the Mesozoic era

2

Mesozoic era

- Triassic
- Jurassic
- Cretaceous

The Central Atlantic Magnetic Province was formed when

End of triassic

Mesozoic animals in the ocean

Mollusks - ammonites, bivalves, Gastropoda, fishes, sharks, marine reptiles

Superposition

The oldest rocks are on the bottom, youngest rocks are on the top

Original horizontality

Layers of sediment are originally deposited horizontally under the action of gravity

Lateral continuity

Layers of sediment initially extend laterally in all directions

Fossil succession

- fossil organisms succeed one another in a definite and determinable order
- any time period can be recognized by its fossil content

Cross-cutting relationships

A fault or intrusion is younger than the rock it cuts across

Inclusions

Grains in rock are older than the rock itself

Angular unconformity

Tilted rocks are overlain by flat-laying rocks

Disconformity

A type of unconformity in which the beds above and below are parallel

Nonconformity

Metamorphic or igneous rocks in contact with sedimentary strata (non-conformity = non sedimentary)

Absolute Age

The number of years since the rock formed

Eon

The largest division of geologic time

Era

A chunk of time within an Eon

Period

A chunk of time within an Era

Number of extinction events in Mesozoic

2

Number of extinction events in history

5

Examples of sedimentary rocks

Sandstone, shale, limestone

Examples of metamorphic rocks

Slate, marble, gneiss

Craton

Ancient rock that makes up the base of continents

Shield (craton)

- made up of compressed/deformed crystalline rocks
- the exposed part of the craton

Platform (craton)

The hidden part of the craton

Sedimentary structures

Features that developed during or shortly after the deposition of the sediments

Types of sedimentary structures

- bedding
- cross-bedding
- graded bedding
- ripple marks
- mud cracks
- bioturbation
- tracks and trails

Cross Bedding

Formed as inclined layers of sediment are deposited across a horizontal surface

Transgression

Sea level rises

Regression

Sea level falls

Fossil preservation types

- impression
- compression
- petrifaction
- amber

Earth layers

- crust
- mantle
- outer core
- inner core

Outer core

Liquid layer of the core

Inner core

Solid layer of the core

Oceanic crust

Thinner and more dense
- younger

Continental crust

Thicker and less dense
- older

Lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust

Mesosphere

The strong, lower part of the mantle between the asthenosphere and the outer core

Plate boundaries

- divergent
- convergent
- transform

Transform boundaries

Places where tectonic plates slide along beside one another as they move
- faults
- San Andreas fault

Divergent boundaries

Plates pull apart from each other, moving in opposite directions
- ridges
- mid-Atlantic ridge

Convergent boundaries

Plates collide with each other
- volcanic activity
- volcanic arc

Subduction

One plate slides beneath another

Accretion of planets

Solids agglomerate to form larger and larger object, and eventually planets are produced

Differentiation

Chemical elements of a planetary body accumulate in different areas of that body, due to their physical or chemical behavior

Main evens of the Hadean Eon

- Solar system formation
- impact that created moon
- differentiation of earth
- heavy bombardment

Stromatolites

First organisms to send oxygen to the atmosphere

Banded iron formations (BIFS)

Distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert (red and black)

Great Oxidation Event

2.5 billion years ago; most atmospheric oxygen is of biological origin

Proterozoic Eon

- First Eukaryotes
- Multicellular Life
- Ozone Stabalization

Stony Meteorites

Silicate masses that resemble earth rocks

Stony-iron meteorites

Rare meteorites have a mixture of silicates and iron-nickel alloys

Impact diagnostic features

PDFs

Possible causes of Cambrian explosion

—-

Benefits of hard parts

- support of structure
- movement
- protection
- UV protection

Age of Fishes

Devonian Period

First Land Animals

Fins (lobes) evolved into legs

Carboniferous Common Deposits

Coal Deposits

Coal Formation

Accumulation of organic matter - buried and pushed down

The Great Dying

- Worst extinction event ever
Possible Causes:
- Volcanic activity releasing poisonous gasses
- Asteroid impact

Triassic Rifting

Large holes formed, magma rose and created igneous rocks

Most common deposit during Cretaceous

Chalk Deposits

Cretaceous Extinction

- 65 million years ago
- 11% of marine families
- last of the dinosaurs
- asteroid impact

Mesozoic plant evolution

- evolved to retain water and protect their reproductive stages from drying out
- perfection of seeds
- germination can be delayed until successful transport

Angiosperms

Cretaceous

Dominant form of animals in cenozoic

Mammals

Homosapiens

Modern humans “wise men”

Early homosapiens

Neanderthals

How old is the Earth?

4.6 billion years old

What drives plate tectonics?

Heat from the core

Study of layers rocks

Stratigraphy

Longest part of earth’s history

Precambrian time

Determining the relative age of a rock

- superposition
- cross cutting

Fining upward

- grain-size of sedimentary rocks become finer from bottom to top
- indicates sea-level rise

Cast

A fossil that is a solid copy of an organism’s shape, formed when minerals seep into a mold

Replacement

The original material of an organism is replaced with mineral crystals that can leave detailed replicas of hard or soft parts

Favorable environment for fossil preservation

Marine and transitional

When was Pangea formed

300 million years ago - end of paleozoic

Volcanic arc

Curved line of volcanoes that forms parallel to a plate boundary

Intraplate volcanism

Hot spots

What is an example of a Jovian Planet?

Neptune

Jovian Planet

Outer Planets - Gaseous

Impacts

Most fundamental process in the Solar System

Meteorite

A meteoroid that has hit earth’s surface

Nuna

Earth’s first supercontinent

Pennsylvanian

Coal deposits

Sea level rise causes

Melting of glacial ice and inflation of mid-ocean ridges

Background extinction rate

The average rate at which species go extinct over the long term

Percent of species dying to make an extinction considered “mass extinction”

75%