Sedimentary

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Rocks Minerals

• Sedimentary
• Igneous
• Metamorphic

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What are minerals?

• Minerals are naturally occurring, nonliving
  substances found in Earth.
• They have a chemical formula, and a definite
  internal structure.

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Characteristics of Minerals

• There are 3500 known minerals in Earths crust.
• No more than 20 of these are commonly found in
  rocks.
• Rocks are therefore made up of combinations of
  minerals cemented together under extreme heat and
  pressure.

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Rock forming minerals

• Feldspar
• Pyroxene
• Mica
• Olivine
• Dolomite
• Quartz
• Amphibole
• Clay
• Calcite

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Rock characteristics

• Porous, granular, or smooth
• Soft or hard
• Densities
• The appearance reflects its mineral composition
  and how it was formed!

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Identifying Minerals by physical characteristics

1. Color
2. Luster
3. Transparency
4. Cleavage
5. Fracture
6. Streak
7. Hardness

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Igneous Rocks

• Igneous from fire
• Magma molten material inside the earth.
• Lava molten material which flows on or above
  the earths surface.

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Igneous Rocks

• Igneous rock forms when molten rock cools and
  solidifies.
• Intrusive cools within the earth.
• Extrusive cools on or above the earths surface.
• Made of various mineral crystals.
• The more quickly the rock cools, the less the
  crystals grow.

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Examples of Igneous Rocks
Granite
Basalt
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Course Grained
Cooling is slow thousands to millions of
years Cools below the ground -
intrusive Minerals can be seen with the naked eye
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Fine Grained
This rock has cooled quickly days to
weeks Minerals do not have time to grow Grains
are very small above ground -
extrusive Example rhyolite
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Obsidian
If cooling is extremely quick (hours to days)-
then no minerals form. Example obsidian
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Sedimentary Rocks

• Rocks formed from compressed and cemented
  deposits of sediment.
• Sedimentary rocks are like recycled rocks.
• Contain older rocks and sometimes, fossils.

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Formation of Sedimentary Rocks

• Weathering causes rocks to break down waves,
  wind, rain
• Pieces of rock accumulate forming sedimentary
  rock

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Formation 2 ways

• Sediment accumulates- weight from layers above
  compress the sediment forming rock
• Minerals dissolved in water seep between bits of
  rock and glue them together

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Sedimentary Classified as 3 types

• Detrital from the Latin word detritus meaning
  to wear away.
• Rocks made from broken rock material.
• 2. Chemical when minerals are precipitated
  from a solution or left behind from evaporation.
• 3. Organic formed from the remains of
  once-living things.

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For thousands, even millions of years, little
pieces of our earth have been eroded--broken down
and worn awayby wind and water. These little
bits of our earth are washed downstream where
they settle to the bottom of the rivers, lakes,
and oceans. Layer after layer of eroded earth is
deposited on top of each. These layers are
pressed down more and more through time, until
the bottom layers slowly turn into rock.
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Examples of Sedimentary Rock
Sandstone- made up of small grains of quartz and
feldspar that form in layers
Limestone- made from the mineral calcite which
came from the beds of evaporated seas and lakes
and from sea animal shells
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Examples of Sedimentary Rock
Shale- made of compacted clay
Conglomerate- made of large sediments and small
particles such as sand and pebbles, medium to
large rock fragments. Held together by dissolved
minerals
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Examples of Sedimentary Rock
Gypsum
Made of sulfate mineral and formed as the result
of evaporating sea water in massive prehistoric
basins.
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Parent Rocks- Sedimentary
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Metamorphic

• Metamorphic rock is formed from other rocks as a
  result of heat, pressure, or chemical processes.
• Parent rock (original rock) undergoes intense
  heat and pressure within the Earth as a result,
  it changes mineral composition and texture.
• Metamorphose or metamorphism to undergo a
  change.

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Metamorphism
Parent rock/ minerals
Metamorphic rock and minerals
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Parent Rock Metamorphic

• Limestone
• Mudstone/ Shale

• Marble
• Slate

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2 Types of Metamorphic Rock

• Foliated Metamorphic Rocks mineral grains line
  up in parallel bands.
• Non Foliated mineral grains grow, change and
  are rearranged but not in layers.

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Rock Cycle
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• Magma cools and crystallizes to form igneous
  rock.
• 2. Igneous rock undergoes weathering (or
  breakdown) to form sediment. The sediment is
  transported and deposited somewhere (such as at
  the beach or in a delta, or in the deep sea).
• 3. The deposited sediment undergoes
  lithification (the processes that turn it into a
  rock). These include cementation and compaction.
• 4. As the sedimentary rock is buried under more
  and more sediment, the heat and pressure of
  burial cause metamorphism to occur. This
  transforms the sedimentary rock into a
  metamorphic rock.
• 5. As the metamorphic rock is buried more deeply
  (or as it is squeezed by plate tectonic
  pressures), temperatures and pressures continue
  to rise. If the temperature becomes hot enough,
  the metamorphic rock undergoes melting. The
  molten rock is called magma. This completes the
  cycle.

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