Rock in' Inside Earth

Rock in' Inside Earth

by chalita rodgers

​Rocks cover the entire Earth!

​How are rocks classified?

​​​According to how they formed

►Igneous- solidification of molten rock

►Metamorphic -recrystalization with an increase of temperature and/or pressure

►Sedimentary- Compaction and cementation of buried sediments

​

Rocks are further classified according to :

(1)texture and

(2)mineral content

Multiple Choice

What are the 3 classes of rocks that exist on Earth?

• Igneous, Sedimentary, Metamorphic

• Lava, Sedimentary, Metamorphic

• Igneous, Clastic, Metamorphic

• Igneous, Sedimentary, Foliated

​Sedimentary Rocks

​Always involve water for formation. Because they involve water, they are only found in the upper portion of the earth’s crust (a thin “veneer” covering the earth)

​Sedimentary Rock Types​

​ 3 Types

​

Clastic (fragmental) Sedimentary Rocks

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​Crystalline Sedimentary Rocks

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​Bioclastic Sedimentary Rocks

​Clastic (fragmental)​

​Formed from burial, compaction, & cementation of sediments (from ANY other type of rock)

​

Sediments in order of decreasing grain size:

Pebbles, sand, silt, clay.

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►Cements: dissolved minerals precipitate out in the saturated water of pore spaces in sediment layers forming the “glue”

►Common cements in rock: calcite, quartz, hematite

​Crystalline Sedimentary Rocks

​

​§Formed from mineral crystals from evaporation or precipitation- can be microscopic to coarse (very large) in size.

​

Example 1:Evaporation of sea water leaves behind rock salt (halite crystals) 

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​​Example 2: Seawater becomes supersaturated with calcium carbonate (CaCO3) which comes from seashells of marine organisms, dropping mineral deposits of calcite on the ocean floor= limestone!

 

​Bioclastic Sedimentary Rocks:

​§Formed from the remains of living organisms being compacted and cemented together.

§

Example 1: coral and seashells from dying organisms deposit on the ocean floor. Over time they will compact and cement together to form limestone (coquina version)

​​

Example 2: dead plant remains

From marshy areas compact to form bituminous coal

​Sedimentary rocks are the only types of rocks which contain fossils!

Multiple Choice

In order for sedimentary rocks to form, what must be present?

• Heat

• Wind

• Water

• Animals

​Igneous Rocks

​Formed by cooling and solidification of molten rock

​

​Molten Rock Types

​ Lava - molten rock above Earth's Surface

​ Magma - molten rock below Earth's Surface

​

​Igneous rocks are classified according to environment of formation

Igneous Rock Types​

​ 2 Types

​

Extrusive Igneous Rock

Intrusive Igneous Rock

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​​Extrusive Igneous Rock

​Volcanic - formed outside a volcano by a lava flow or just beneath the surface

​

​Cool fast, thus will have fine  grains or small crystals, and in some cases no crystals at all (non crystalline= glassy)

​

​HOLES = Gases that were trapped in rock create bubbles & pop

​NO CRYSTALS = Mineral cooled so fast that crystals do not have time to form

​​​Intrusive Igneous Rock

​Plutonic - formed deep within a magma chamber or cooling pluton

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​Cool slowly, thus will have  Coarse grains or larger crystals

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​Example: Pegmatites

​ ►Igneous rocks with extremely coarse texture (large crystals) 

Multiple Choice

If an igneous rock has holes in it, what type of igneous rock is it?

• Intrusive

• Extrusive

​Metamorphic Rocks

​Formed by increases in temperature and pressure

​

​Any existing rock can be metamorphosed and changed into a metamorphic rock

​

​​The “parent rock” becomes recrystallized

↑ the size of crystals/grains and/or new minerals form

Metamorphic Rock Types​

​ 2 Types

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Foliated Metamorphic Rock

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Nonfoliated Metamorphic Rock

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​Foliated Metamorphic Rock

​Banding/Extreme Foliation

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​►Extremely high Pressure causes recrystallization to form alternating layers of felsic and mafic minerals

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Multiple Choice

A rock that began as molten magma. What type of rock is this?

• Sedimentary

• Igneous

• Metamorphic

Multiple Choice

What type of rock would you expect to find fossils?

• Metamorphic

• Old

• Igneous

• Sedimentary

Multiple Choice

A rock formed by smaller pieces of rock that settled at the bottom of a lake millions of years ago. What type of rock is this?

• Sedimentary

• Igneous

• Metamorphic

Multiple Choice

A rock formed by heat and pressure is what type of rock?

• Sedimentary

• Igneous

• Metamorphic

Multiple Select

A metamorphic rock can become ______(more than 1 answer)..

• Sedimentary

• Igneous

• Metamorphic

• None of these