Geology 1010 exam 1

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Rhyolitc magma

in continental crust wet magma shallow 700-800 degrees 70% silica

ground mass/ background material

tiny rocks (in porphyritic rocks)

potassium (K)

2.6%

sodium(Na)

2.8%

Silicon (si)

27.7%

super volcanic eruption yellowstone huckleberry ridge eruption

2ma 2500km^3 ejecta

calcium(Ca)

3.6%

how fast do meteorites enter atmosphere?

40 km per sec

oxygen (O)

46.6%

iron (fe)

5%

Theia Impact

60 MA after earth formed it slammed into theia

Aluminum (AL)

8.1%

ash

<2mm most dangerous

andesitic magma

Andesite Line aka Ring of Fire • Won't find it any other place, even the rest of the Pacific ocean • All the boundaries are Subduction zones 60% SiO2 cooler than 1000 degrees

wet melting

Term for when a lot of water present in rocks means lower melting point

atomic #

# of protons in the nucleus of an element

Case Study: Krakatoa

- An Indonesia island volcano that erupted on Aug 26, 1883. - Equivalent of 200 million tons of TNT = 13,000x the yield of the Hiroshima A-bomb. -25 cubic km ejecta -heard from over 3,000 miles away - over 30,000 dead - several languages went extinct due to deaths - 2/3 island destroyed, new volcano built up since. (could erupt again)

How are minerals grouped?

- by a common anion

Geology in the News

- rocks in canada 4.02 GA - formed in response to meteor impacts about 500 MA after earth formed

Island Silicates

1 tetrahedron

Magnesium (Mg)

1.5%

how fast does 'fast' lava flow?

16 km per hour

James Hutton

1795 theory of the earth

super volcanic eruption Tambora

1815. 100km^3 ejecta. affected whole world. cold temps following eruption

How to id types of igneous rocks

1st: texture- how large are mineral crystals 2nd: compostion- what minerals are present?

anion

A negatively charged ion

Phenocrysts

Big crystals (in porphyritic rock)

Equilibrium Crystallization

Does not add or subtract anything when freezing. same chemical makeup

Principle of Uniformitarianism

Earth processes occurring today are similar to those that occurred in the past

volcanic (extrusive)

Erupts and then forms above ground

Solar Disk Model

Flatter, rotating disc of a bunch of H atoms that are being drawn closer and closer together

Types of Silicates

Island, Chain, Sheet, Framework

basaltic magma

Most Common Source: Mantle, mainly in mid ocean ridge, Dry Magma: Very little water mixed into it SiO2 content 50% >1100° Celsius hottest and deepest

Oxides

O, oxygen and metal

Chemistry of Earth's Crust

Oxygen, silicon, aluminum, iron, calcium, sodium, potassium, magnesium, all others

Non-Explosive Features

Pahoehoe and Aa

Lunar formation

Process in which a Moon is created

Sulfides

S, sulfer and metal

sulfates

SO4, plaster

Silicates

SiO4 ABUNDANT, silica tetrahedron

Nebular Hypothesis

Solar system evolved from an enormous rotating cloud called the solar nebula

Planetary Accretion

The gradual growth of a planet by collision and sticking

Actualism

The principle that the same processes and natural laws that operated in the past but they may occur more rapidly overtime.

Hot spots The Hawaiian problem

a lot of magma under the lithosphere allows volcanoes to form in hawaii. supporting ev. volcanoes over hot spot are the active ones as plate moves new volcanoes form over hotspot

Discontinuous Branch of Bowen's Reaction Series

after the temp it freezes it stops forming. olivine, pyroxene, amphibole, biotite, orthoclase, muscovite, quartz

decompression melting

as you decompress the rocks they will melt more easily

Fusion

atoms fuse together to make a single atom

pryoclastic sizes

bombs >64mm

framework silicates

building complex 3d structure using tetrahedron

Aphanatic

cant makeout individual crystals (extrusive)

Aa

close to solidifying (more brittle, jaggy rocks) has vesicles. trapped gas comes through vesicles

carbonates

co3, coral and shells

The continuous branch of Bowen's reaction series

continues to produce chemical formula changes based on the temp it is forming. calcium rich, plagioclase, sodium rich

Composition as sio2 drops intrusive and extrusive

felsic- light orange intermediate- greyish mafic- dark blacks and browns ultramafic- green and yellow

sheet silicates

flat structured 2d thin layer tetrahedrons, chick-fila sandwich

Sills

forms horizontally in layers of rock plutonic

Crystallization

freezing, magma cooling down

Viscosity controls

gas content high viscosity- more gas pressure and explosive low viscosity- less gass pressure and less explosive

Laccolith

gets stuck under surface and forms a pimple bellow surface and is exposed above ground

Lapilli

gravel size 64-2mm

active volcanos

hawaii- 7 alaska-41 other us-26

temperature

heat, several hundred degrees to melt rock

pyroclastic flow

hot gas cloud moved up and back down at extreme speeds. the cloud is extremely hot

Polymerization

joining monomers to form a polymer

explosive eruption hazards

lahars, pryoclasts, pyroclastic flow

Lahars

large mudslide (before eruption)

Vesicular

little pores in rock. gas trapped in cooling causes this (extrusive)

sheild volcano

low dome shape, most common, basaltic magma, low viscosity, large and wide

study tip for types of magma

low temp: high silica shallow: low temp shallower: more water content

rocks

made up of one or more minerals, 3 types, based on how they form

plutonic (intrusive)

magma cooled deep in earth

Volcanic Explosivity Index (VEI)

measures the explosiveness of volcanic eruptions on a scale of 1 to 8. VEI- 0 is very common VEI 8- extremely rare

lava

melted rock on Earth's surface

Magma

melted rock underground

partial freezing

minerals in rock freeze at diff temps

fractional crystallization

more common. a fraction of the material is lost when forming into rock. has dif compostion than started with

Stratovolcano, stratocones, composite volcanoes

more viscous magma, rhyolitic magma, typical volcanoe, explosive eruption

mineral

naturally occuring, crystalline, set chemical structure, solid, inorganic

Geology in the News

new age calculated for Antarctic plate -present finalized about 11 MA -15 million years younger than thought

Batholith

no certain shape but its HUGE plutonic

Glassy

no crystals, exception to color rule. they are felsic (extrusive)

dike

pipe-shaped structure filled with igneous rock, plutonic

Phosphates

po4, rarer (bones and fertilizer

Atoms

protons and neutrons in nucleaus

Viscosity

resistance to flow, how thick it is. high viscosity= peanut butter, low viscosity= water

Tephra (cinder) cone

short and steep, lots of pyroclasts, not powerful eruption. pops up and piles up until it rolls off

2 chain silicate

silicates chained together

Phaneritc

small crystals intrusive. less than a cm but still visible

Pyroclasts

solid debris/ejecta blasted out and propelled up.

Porphorytic

some crystals big some tiny, chocochip cookie (extrusive)

Pahoehoe

stringy, loopy. surface is crusted over, lava is still moving

Viscosity is controlled by

temperature(hotter it is the easier it flows) silicon content( lower the silica content, the easier it flows)

how to melt rock

temperature, partial melting, wet melting, decompression melting

Protostar

the earliest stage of a star's life 6GA

partial melting

the process by which different minerals in rock melt at different temperatures

Pegmatic

very large crystals 1cm< intrusive


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