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ROCKS AND MINERALS

af Alexandra Baldassarra

Pathetique Analysis

af Aaryan Naresh

Overview of Volcanoes

af Celina Lall

Classifying Igneous Rocks

af Seto Seto

Igneous Rocks

felsic

granite and rhyolite

magnesium and iron add colour variations

light grey

lots of minerals like quartz and feldspar

acid

intermediate

sodium present

more white than mafic

plagioclase

mafic

basalt and gabbro

pyroxene and calcium plagioclase

dark grey

mostly in oceans

basic

extrusive

magic, intermediate or felsic

formed by volcanoes

intrusive rocks

Dunite and peridotite

less than 45 percent silica

are green and black

contain olivine and pyroxene

form in the mantle

when viscous

gas bubbles remaining are called vesicles

gas can be released easily

usually becomes basalt

levels of viscosity

the higher the silicon dioxide level the more viscous

higher the temp the less viscous

Extrusive

Magma cools and crystallizes on the earths surface

Volcanic

vocab

pyroclasts: airborne fragments from a volcano

tephra: term for all airborne particles from a volcano

pilian eruptions: produce dacitic or rhyolitc lava

silica content

Mafic also called basic has a low silica content and a high iron and magnesium content

felsic also called acidic has a high silica content and a low iron and magnesium content

eight minerals that form ingneous rocks

Feldspar has two different types- sodium plagioclase and calcium plagioclase

olivine, pyroxene, amphibole, biotite, orthoclase, muscovite, quartz, feldspar

how ingenious rocks are formed

when it cools it solidifies to form igneous rock such as granite or basalt

when magma reacts the surface it is called lava

inside earth is molten magma

places ingneous rocks are found

volcanic arcs- andesite and diorite

continets- granite

ocean plates- basalt and gabbro

explosive vs non-explosive

Strombolian are short and eruptive that burst viscous basaltic lava

non explosive are called Hawaiian eruptions

Volcanic eruptions are based on

height of plume head

height of eruptive column

degree of fragmentation of the airborne volcanic products

volume of material

Different Types of Cooling

Slow followed by fast

porphyritic texture

smooth grained crystal matrix and large crystal structure

larger and smaller crystals

Very fast

results in glass

elements are frozen in place

no minerals grow

Hours to days

Fast

aphanitic texture

fine grained mineral textture

microscopic in size

Happens at earths surface

Days to weeks

Slow

phaneritic texture

mineral can be seen with naked eye

below earths surface

thousands to millions of years

Intrusive

Magma cools and crystallizes within the earth

Plutonic