Geology 103 - Skinner

Cosmology

The study of the origin, evolution, and nature of the universe

Stratification

The layering in sedimentary rocks; Layers less than 1 cm are laminations, bedding is thicker.

Orogeny

An episode of mountain building involving deformation;usually accompanied by igneous activity, metamorphism, and crustal thickening.

Angular Unconformity

An unconformity below which strata dip at a steeper angle than those above.

Disconformity

A type of unconformity above and below which the strata are parallel.

Nonconformity

An unconformity is which stratified sedimentary rocks overlie and erosion surface cut into ingenious or metamorphic rocks.

Big Bang Theory

The evolution of the universe came from a dense, hot state followed by expansion, cooling and a less dense state.

Magnetic Field

The area in which magnetic substances are affected by lines of magnetic force emanating from the Earth. (Magnetism is caused by the spin of electrons)

Age of Universe

14.7 Billion years

Age of Earth

4.5 Billion years

Terrestrial Planets

Mercury, Venus, Earth, Mars

Red Shift

Light emitted from distant galaxies that shows that the universe is expanding. Velocity increases with increasing distance (Raisin Bread example)

Earths Atmosphere Components

Nitrogen and Oxygen

Geological Time Scale-Today

Phanerzoic-Cenozoic-Quaternary-Holocene

Geological Time Scale- Relative dating

Discovered first!

Geological Time Scale- Numerical dating

(same as absolute) Obtained the numbers because of radiometric dating-date are obtained from the natural rates of decay of various radiometric elements.

Geological Time Scale Era's

Precambrian-Paleozoic- Mesozoic- Cenozoic

Sea Floor Spreading

the origin of new oceanic crust at spreading ridges that then moves away from ridges and is eventually consumed t subduction zones

Sea-floor spreading is driven by volcanic activity where?

along mid-ocean ridges. NOT folded mountain belts.

Plate Tectonics

Lithospheric plates move with respect to one another at divergent, convergent, and transform plate boundaries.

Plate Tectonics & Sea Floor Spreadin= Continental drift

Answered the big question of how continents moved!

Convergent

Where plate destruction occurs. When two plates collide and one of them is subducted back into the earth

Divergent

Where plates are separating and new oceanic lithosphere is forming. Most commonly form along the crests of oceanic ridges.

Transform

Where the plates slide laterally past one another

Slab Pull

Causes subduction. The subducting cold slab of lithosphere is denser than the surrounding warmer asthenosphere and pulls the rest of the plate as it descends into the asthenosphere.

Hot Spots

the location on Earth's surface where a stationary column or magma has slowly risen to the surface and formed a volcano. The hot spot remains stationary and leaves a trail of extinct volcanoes. CAUSED BY: Rising mantle plume or lava

Sea Trenches

A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab.

Composition of the Ocean Floor

Basalt rocks

KNOW THIS!

Both continental and oceanic crusts can form a plate

What are the 7 mineral groups?

Carbonate, Halide,Phosphate, Oxide, Silicate, Sulfate, Sulfide.

Which mineral group is most common?

Silicates

KNOW THIS

No cleavage=fractures

What are the chemical/mineral physical characteristics of the Earth?

1-Core 2-Mantle 3-Core

What is the rigidity of ht earth based on physical characteristics?

1-Inner Core 2-Outer Core 3-Mesosphere 4-Asthenosphere 5-Lithosphere

Who came up with continental drift?

Alfred Wegner

Continental Drift

The hypothesis that all continents were once joined together in a single land mass that broke apart, and moved. Named land= Pangea

James Hutton

Founder of modern geology- uniformitarianism=the present is key to the past (lightning example)

Superposition

Basis for relitive dating of strata and their contained fossils. Oldest on bottom

Original Horizontality

______
______
/////
/////
Material was once horizontal, must have been tilted. Not igneous rock, only sedimentary

Original continuity

--_____--
---___---
--------- Once continuity but something eroded it like a river. Sediment extends laterally in all directions until it thins and pinches out against a depositional basin.

Igneous Rocks

formed when magma or lava cools and crystalizes and when pyroclastic materials become consolidated.

Magma

Molten rock material BELOW the surface

Lava

Magma the reaches the surface; ABOVE

Igneous vs. Metamorphic and Melting

Igneous=melt and crystalize
Metamorphic= any rock altered in the solid state from preexisting rocks by any combination of heat and/or pressure.

Contact Metamorphism

Metamorphism taking place adjacent to a body of magma or beneath a lava flow from heat and chemically active fluids (INTRUSION)

What does limestone metamorphose into?

MARBLE (on test)

How do you metamorphose something?

Heat and pressure-burry it deeper and deeper/layer.

Shield rocks & their age?

...Ask TA

Prof Skinners favorite plate?

Jaun de Fuca

Erosion

Transport removes sediment. From source carries it elsewhere. Running water, glaciers, wind, waves.

Weatering

Breaks down bigger to smaller A-a. Same content.

Which type of rock is most common on the surface? Interior?

Sedimentary;Igneous

Classifying sedimentary rocks

Contain evidence of their formation: Fossils, Bedding, grain size.
Clastic, Chemical/Biochemical

Regression

Top to bottom: Sand, Shale, Limestone

Transgression

Top to bottom: Limestone, Shale, Sand

Fossiliferous Limestone without ripples form where?

In the ocean-limestone was once alive!

Graded Bedding=Turbidity current(Water flow)

Just know.

How to calculate half lives?

...

How do we absolute date?

Radiometric dating

Why do we not use carbon-14 dating?

Too short of a half life-only 70,000 years

Number 64

B

Inorganic chemical sedimentary rock

Precipitates from water

Sea-floor spreading is driven by volcanic activity ________.

along mid-ocean ridges

Most of the pulling force driving plate motion is produced ________.

at subduction zones

In addition to the two primary sources, plate motion may also be facilitated by convection occurring within the ________.

Asthenosphere

Unlike the lithosphere, the asthenosphere ________.

is able to flow over long periods of time

Most of the pushing force driving plate motion is produced ________.

mid-oceanic ridges

Relative ages expressed on the geologic time scale primarily resulted from the study of _____.

fossil content and spatial relationships among sedimentary rocks

The theory of Neptunism

states that rocks precipitate from water

Numerical ages for boundaries between time units on the geologic time scale primarily resulted from the study of _____, in conjunction with relative age data.

radiometric dating of igneous rocks

The idea that the facies we see in a vertical sequence will also replace each other laterally is refered to as?

Walther's Law