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Rock Notes
**All Earth’s processes involve rocks and minerals**
 _____________________ – solid mass of mineral-like matter that naturally occurs
 3 groups:
 ________________________
 ________________________
 ________________________
Igneous Rocks
Formation of Igneous Rocks
 _______________________ igneous rocks
 Forms as ___________________ hardens __________________ the surface
 Only see them b/c erosion strips away the overlying rock
Example: granite
 ________________________ igneous rocks
 Forms from hardened __________________ (__________________)
 Example: rhyolite
Classification of igneous rocks
1. _____________________:
 ___________________-grained – _____________ cooling, ________________ crystals
 ________________-grained – lots of _____________ interconnected grains
 __________________ – ______________________ cooling on surface; _________________________
 __________________ – combination of fine and course grained, crystals form at different rates
2. _____________________:
 Granitic – light colored silicates (quartz & feldspar)
1. Major rock of continental crust
 Basaltic – dark silicate minerals and plagioclase feldspar
 Andesitic – composition b/w granitic and basaltic
Sedimentary Rocks
 ______________________ – weathered rock debris that are __________________ to other places
Formation of sedimentary rocks
1. __________________ – process of breaking rocks into sediment
2. ________________ – removal of rock
3. _________________ – sediments are dropped by water, wind, or gravity
4. ________________ – squeezes rock
5. __________________ – dissolved mineral are deposited between sediments
Mountains to Ocean
Big rocks are on the bottom and smaller grains/rocks are deposited later.
Classification of Sedimentary Rock
1. ____________________ Sedimentary Rocks – made of weathered bits of rocks and minerals
 Clay and quartz are main minerals
 Can be grouped by size of sediment:
 Course:
 Rounded – gravel size ‘conglomerate’
 Angular – ‘breccia’
 Medium – sand size grains ‘sandstone’
 Fine – ‘siltstone’
 Very fine – ‘shale’
2. ________________________ and _____________________ Sedimentary Rocks
 _________________ – formed from __________________________
 Example – limestone, rock salt, chert, flint, and rock gypsum
 _________________________ – shells and skeletal __________________ of _____________________
 Example – coquina, chalk, coal
Special features of sedimentary rocks
 Contain ________________________
 Can tell us ____________________ the rock formed and the ____________________________
 ___________________________ – oldest at bottom, youngest at top
 ___________________________ – rock formed along a beach or stream bed
 ___________________________ – form as wet mud or clay dries up and shrinks
Metamorphic Rocks
Formation of Metamorphic Rocks
 Changed by _______________________________________ (few km below the surface)
 Formation:
 _______________ metamorphism – hot magma moves into rocks
 Minor changes
 example marble
 ________________ metamorphism – large scale deformation and high grade changes
 During mountain building
Causes of metamorphism
1. ____________________ – (most important) it provides energy that drives chemical reactions that cause existing
minerals to recrystallize
 2 sources:
1. _____________ – ‘bakes’ rocks, it comes into ____________
2. Change in temperature – _________________ with ______________
2. _____________________ (stress)- increases with depth, applied in all directions
 The pressure causes the spaces b/w the grains to close, more compact and more dense
 Can also cause minerals to recrystallize into new minerals
 Mountain building causes folds in rocks
3. ________________________ – solutions surround mineral grains
 Water makes ions easier to move
 Increased temperature of solutions increases reaction rate
 Hydrothermal solutions
 Causes overall changes in rock’s composition
Classification of metamorphic rocks
 _________________________ metamorphic rocks – _______________ or banded appearance
 Example: gneiss, schist
 _________________________ metamorphic rocks – ___________________ appearance (mostly only 1 mineral)
 Example: marble made of calcite
Rock Cycle
 Rock cycle is a _____________________ process that causes rocks to __________ over long periods of time
 Needs energy for process to occur:
 ________________ – responsible of igneous and metamorphic
 ________________ – responsible for sedimentary