Transcript Chapter 10 ROCKS

Chapter 10
ROCKS
Ch. 10.1 Rocks and the Rock
Cycle
• Magma is the parent material for all rocks.
• There are three types of rocks, classified
by how they are formed.
Igneous Rocks
• Formed when magma or lava cools and
hardens.
• Igneous is from the Latin term from fire.
Sedimentary Rock
• Formed when small fragments of rock or
organic material harden after being
compressed and cemented together.
Metamorphic Rock
• Forms when heat and or pressure, or
chemical processes change the form of
existing rock.
The Rock Cycle
• Any type of rock can be changed into any
other kind of rock and back again.
• Processes are…
• Melting and cooling—igneous.
• Compaction and cementation—
sedimentary.
• Heat and pressure—metamorphic.
Characteristics of Igneous Rocks
• Large or small crystals depending on
cooling rate. The slower the cooling
rate, the larger the crystals.
• Color depends on lava or magma
type…felsic produces lighter rocks; mafic
produces darker rocks.
• May have trapped gas bubbles (pumice
and scoria).
• Generally composed of silicate minerals.
Characteristics of Sedimentary
Rocks
• Form from cemented together rock
fragments, organic material, or from
minerals that precipitate out of water.
• May have layered structure from
deposition of various kinds of sediment
deposited in silt beds.
• Moving wind or water may cause ripple
marks.
• May contain fossils…remains or traces of
ancient plants or animals.
Characteristics of Metamorphic
Rock
• Local volcanism may cause contact
metamorphism.
• Tectonic activity may cause widespread
regional metamorphism. Usually deep
within the earth.
• May have enlarged or alternating bands of
crystals (foliated).
• May change soft sedimentary rock into
hard, durable rock.