Planet Earth Geology

Kim Weborg-Benson - Geo 165-01

Catastrophism Definition

The theory that is opposite of uniformitarianism.

This theory tries to explain that the changes in the earth’s crust was caused by catastrophic events.

Uniformitarianism Definition

The theory that is opposite of catastrophism.

This theory explains that the earth’s crust was changed by normal events that still happen today.

Key quote of Uniformitarianism

“The present is the key to the past“

Age of the Earth

4.6 Billion

Nebular Hypothesis

Theory that the solar and stellar systems were developed from a primeval nebula.

At the same time.

Inner Core

Composed of IRON & NICKEL

Radius: 1,220 km

Temp: 5,700 °C

Solid

Outer Core

Composed of IRON & NICKEL & SULFUR

Thickness: 2,260 km

Temp: 3,700–7,700 °C

Liquid

Mantle

Composed of peridotite

Thickness: 2,900 km

More dense Liquid

Crust composed of?

Composed of Basalt, Granite

Thickness: 7-70 km

Solid

Dynamic Planet

Earth is a dynamic planet due to the inside being hot & radioactive while the outside is cold.

Qualitative

Observations - red, light, heavy

Quantitative

Measuring the color with wavelengths or weighing

Pseudoscience

Collection of ideas that may appear scientific but aren’t

Hypothesis

A proposed explanation for an observation that can be tested.

Deductive Reasoning Example

If all animals that fly are birds, then so are bats

Inductive Reasoning

Establishes evidence to infer truth

Shale

fine grained, thin layering rock (fissle)

Sediment

Pieces of rock that have been weathered & eroded

James Hulton

He came up with uniformitarianism “the present is the key to the past“

Theory of Plate Tectonics

Earth’s brittle Lithosphere is broken into plates that move relative to each other over the plastic asthenosphere

Asthenosphere

The upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.

Lithosphere

The rigid outer part of the earth, consisting of the crust and upper mantle

Who thought up continental drift

Alfred Wegener

How was Continental Drift supported?

Showed hypothesis with LOT of evidence

What was the hypothesis for continental drift?

The continents used to fit together as a single supercontinent we named Pangea & have since “drifted” to where they are now.

Why did the theory of continental drift not stand?

The reason why it failed was because there wasn’t enough evidence to support the hypothesis.

Continental Shelf

the true edge of the continent

Paleomagnetism

Magnetism stays with the rock when it cools, so you can see where magnetic north was when that certain rock cooled from magma.

Plate Boundaries

Divergent

Convergent

Transform

Divergent Plate Boundaries

Plates moving away from each other

Convergent Plate Boundaries

Plates moving towards each other

Transform Plate Boundaries

Plates moving next to each other in opposite ways

Rift zones & the Breakup of a continent

upwarping

continental drift

linear sea

mid ocean rift

Element

A group of atoms with a specific number of protons, having specific universal, & unique properties.

Mid Ocean Ridge

Divergent boundary within an ocean plate, where new lithosphere and crust in the created as the 2 plates spread apart

Natural Resources

Items that are found within earth that are valubale and limited

Example of natural resources

Coal, Water, Gold

Fossil Fuels

Energy resources (typically hydrocarbon) derived from ancient chemical energy preserved in the geological record.

Examples of Fossil Fuels

Coal, Oil

Coal

Former swamp-derived (plant) material that is part of the rock record

Petroleum

A fossil fuel from shallow marine rocks.

Made of oil & natural gas

Reservoir

rocks which allow petroleum resources to collect and move

Special characteristics of oceanic crust

high density, more brittle, thinner

special characteristics of continental crust

low density, more ductile, thicker

Where’s the youngest part of the sea floor

near the ridge

Where’s the oldest part of the sea floor

in the trenches

When was the sea floor explored

late 60’s

Geosphere

The solid, rocky parts of the Earth, including the crust, mantle, and core

Atmosphere

gases that are part of the Earth, mainly nitrogen & oxygen

Hydrosphere

The water part of the Earth, solid, liquid, or gasses (literally any water)

Cryosphere

The part of the hydrosphere (water) that is frozen, found mainly at poles

Biosphere

The living things that inhabit the Earth

Magma

Liquid rock within the Earth

Lava

Liquid rock on the surface of the Earth

Definition of crust

Outermost chemical layer of the Earth, defined by its low density & higher concentration of lighter elements

Sea Floor Topography

refers to the physical features & contours of the sea floor, which are influenced by various geological processes

Examples of sea floor topography

Continental shelves, deep ocean plains, mid-ocean ridges, deep ocean trenches

Volcanic arcs are a product of what happening?

The subduction of an oceanic plate under a continental plate

Why does it appear that Hawaii is “moving”?

The Hot spot underneath the pacific plate pushes up magma while the pacific plate moves

Why do Hot Spots occur?

Change in chemistry in the mantle

Mantle Plum

Column of magma from deep within the mantle

Hot spot definition

mantle plume magma breaks through the surface

Mineral def

Naturally occurring, inorganic, solid, narrowly defined chemical property, ordered internal atom structure

How minerals form

Cooling of magma/lava, in solution, organisms construct carbonate shell, metamorphisms

mineral physical properties

crystal form, color, luster, quality & intensity of light reflected from surface, streak

Streak of a mineral

color of powdered mineral

hardness of a mineral

resistance to abrasion

mineral shape properties

cleavage, fracture

Silica Tetrahedron

Magnetic reversals

refers to the phenomenon where Earth’s magnetic field changes direction, resulting in the magnetic north and south poles to switch directions

Lithification

process where loose sediments become solid rocks through compaction and cementation

common rock forming minerals

Quartz, K-Feldspar, Plagioclase, Micas, Calcite

What’s the most significant mineral?

Silicate

Thermal convection

cells driven by the heat from Earth’s interior

Convection current

magma in the mantle

Slab-pull

Subducting colder slab pulls rest of plate down into the asthenosphere.

The pull of the oceanic lithosphere helps the plate separate.

Ridge-pull

Gravity pushes plate from higher ocean rides to trenches.

What’s the building blocks of rocks?

MINERAL!

Steno’s Law

Minerals can be different colors, big or small, but the angle between equivalent faces are the same

think the box minerals (cleavage)

Luster of a mineral

Quality & intensity of light reflected from the surface of the mineral.

Which Paleoclimate evidence was used by Alfred Wegener to support continental drift?

Rocks formed by glaciers in South America & South Africa

This layer of the Earth is Liquid Iron & Nickel

Outer core