Untitled Flashcards Set

Volcanos:

A mountain form by the eruption of magma/ lava 800 active

Volcanoes are manly at convergent plate boundaries.

Ocean continent: west coast of South America. Northwest of pacific coast of the United States.

Continent-convergent examples: Japan and Indonesia and South Caribbean. Hotspot are in Hawaii Yellowstone, Flagstaff.

Eruption style depends on viscosity of the magma.

Factors that affect viscosity

Chemical composition: magic low viscosity.

Temperature high temps equal low viscosity.

Amount of volatiles: dissolved glasses in the magma.

Violent explosion eruptions : high viscosity magma, fesic

Gentle Hawaiian style eruptions: low viscosity basaltic.

Two different type of lava flows:

Pahoehoe: smooth, textured surface

Aa-sharp: lava rocks, fragmented.

Glasses: CO2 H2O SO2

CO2 and H2O must common gasses erupted.

High viscosity: (Felisic eruptions) glasses, thick lava, tons of palvarieed rock tons of volcanic ash and dust.

Pyroclastic material: is what is erupted from high viscosity Eruptions.

Types of volcanos:

Shied: erupts basaltic lava example: Hawaii.

Cinder cone: smallest (1000)

Single vent eruption.

Composite volcanos: high viscosity magma

Chemical composition of each eruption can vary between felsic.

Explosive eruption: mount Hellen’s, mount rainier and Mount Fuji.

Types of volcanos: shield, cinder cone, composite, and caldera

Caldera examples: crater Lake is Yellowstone, Giant eruptions when a composite volcano can collapse.

Fissure volcanos: lava is erupted from a linear fissure, can result in basalt plateaus

Low viscosity and lava flowing.

Pyrodastic examples: destroyed Pompeii and the Caribbean island Martinique 19-28k dead.

LAHar: volcanic mudflow and rapid melting.

Volcanic pipe: Diamond’s

Sills: lava squeeze horizontal layers

Dikes: vertical across the sounding rocks.

Batholith: largest type of volcanic landform examples are Sierra Nevada Mountain’s.

Flood Basalt Plateau:

Formed from eruption of basaltic examples: Columbia river plateau

Maintaining building: orogenesis are mostly at convergent plate boundaries.

Types of Deformation:

Simplest Elastic deformation: applied stress deforms the material but upon release of the stress the material returns to normal.

When the elastic limit is exceeded rock can fail either by brittle deformation or by ductile deformation. The rock body can either fracture or fold.

Fractures that determine:

Temperature: high temperatures result in ductile deformation

Low= bertile deformation

Pressure: also increase with depth resulting in

Rock types: igneous and non-folated met rocks sediment and foliated rocks and ductile deformation.

Time: stress applied over a long time which is ductile deformation.

Ductile deformation: results in folds

Anti-cline: oldest rock are exposed at the center.

Syncline: youngest rock at the center.

Examples: Appalachian valley and diagram providence

Brittle Deformation is a fault

Faults:

Strike slip faults: motion along the fault is horizontal (one side slides past the other)

Dip slip faults: motion along the fault is vertical

Reserved: hanging wall up due to compression

Normal: hanging wall down due to extension

Examples: Nevada basin and range province

Other ways to make mountain ranges:

Accretionary wedge sediments: a wedge of sediment that collects in the deep sea trench as a continent.

Mountain range:

costal mountain ranges is a California coast ranges

A mountain range formed from sediment that accumulated in the trench. Those settlements are “scraped off” the subjecting plate onto the edge of the continent.

ForeArc Valley:

Exotic Terranes (land)

Ancient island volcanic arc that were originally for off the coast of the continent but were later attached to the edge. Due to their travel along the oceanic plate.

Examples: the coastal geology of the Pacific Northwest.

Isostasy: the attempt of a continent to stay in gravitational equilibrium as it is either loaded on unloaded.

Example: 1000/10000: years Greenland

Active continental margin that is a plate boundary

Passive continental margin: a continental margin that is not a plate boundary

Development of the geologic time scale

First: development of the relative GT

Then: after discovery of radioactive.

16,000’s Irish Auglilican Bishop - Jame ussher

Used to date: biblical interpretation to date the earth.

Late 1600’s Danish Physician: Niels stensen

3 principle to help events in earths history in their proper temporal sequence:

Principle one:

Any layer in an under deformed sequence of strata is OLDER than the layers alone and volume than the layers below it.

Principle two:

The original horizontality that layers of sediment are typically deposited in a horizontal position.

Principle three:

Low of cross cutting relationship