Download Main Rock Types and their Subgroups

Main Rock Types and their
Subgroups
SPANGENBERG
EARTH SCIENCE
2014
Igneous Rock
 Volcanic rock
 Formed by solidification of lava
 Subgroup 1: Mafic/Felsic
 Mafic: dark color; low silica (left picture)
 Felsic: light color; high silica (right picture)
Igneous Rock
 Subgroup 2: Extrusive/Intrusive
 Extrusive: Small fine grains; cooled quickly on earth’s surface
where there are cooling items like air and water (right picture)
 Intrusive: Large coarse grains; cooled slowly under the earth’s
surface where it is relatively warmer (left picture)
Sedimentary Rock
 Formed from broken off rock binding together – only
type of rock that can contain fossils


Clastic: Formed when sediment is compacted and cemented
together – a more physical binding (right picture)
Chemical: Formed when minerals or sediment are chemically
binded together because of some chemical reaction like
oxidation (rust); can also happen when minerals are left
behind by evaporating water (left picture)
Lithification
 The process of making sedimentary rock from
sediments

Includes both compacting and cementation
Metamorphic Rock
 Formed through the intense heat and
pressure under the earth’s crust when other types of
rock is pushed there
 Foliated/Non-foliated

Foliated comes from a certain magnitude and direction of
pressure on the rock
Rock Cycle – watch video
 http://www.schooltube.com/video/503ca205aae459
f47494/The-Rock-Cycle
 Watch the above video
Other terms
 Silica – makes rocks light in color
 Viscosity
 Different Magma types
Basaltic
 Andesitic
 Rhyolitic – most viscous! It has the most silica (sand) content

 Weathering = breaking
 Mechanical – when something (water, tree, etc) gets into small
cracks and breaks rock apart
 Chemical – chemical reactions like oxidation (rust) break rock
apart; fundamentally changes the rock
 Erosion = transport