Download 6.1 Rocks and the Rock Cycle

6.1
Rocks and the Rock Cycle
Three Major Types of Rock
• rock~ collection of one or
more minerals or organic
material
• Igneous~ forms when magma
or lava hardens and cools
• Magma~ molten rock
beneath Earth’s surface
• Lava~ molten rock above
Earth’s surface
• Sedimentary~ formed when sediment
deposits ( rock, mineral crystals, and organic
matter broken in fragments) harden
• Metamorphic rock~ rock that forms when
existing rock is altered (pressure and heat)
The Rock Cycle
• ~ series of processes in which rock forms,
changes from one type to another, is
destroyed, and forms again by geological
processes
Properties of Rocks
• All rock has physical and chemical properties
that are determined by how and where rock
formed
• Bowen’s reaction series~ pattern that
illustrates the order in which minerals
crystallize from cooling magma according to
their chemical composition and melting point
Chemical Stability of Minerals
• ~ measure of the tendency of a chemical
compound to maintain its original chemical
composition rather than break down to form a
different chemical
• Depends on strength of bonds
• Most resistant to weathering have the highest
number of bonds between Si and O
Physical Stability of Rocks
• Rocks have natural zones of weakness that are
determined by how and where the rocks form
• Sedimentary~ weakness between layers
• Metamorphic~ break in layers that form as the minerals
align
• Igneous~ have evenly spaced zones of weakness called
joints that form as the rock cools and contracts