1. Rocks and Rock Formation
Rocks are pieces of Earth’s crust!
Bedrock is the actual rock that makes up Earth’s crust. See picture…
These bedrock layers have been exposed by erosion!
Each layer is a different type

2. Rocks and Rock Formation
Smaller rocks are pieces of bedrock that have broken off. These are called sediments.
These are boulders…
These are pebbles and cobbles

3. Rocks and Rock Formation
There are several types of sediments. See ESRT p.7
Larger than 0.2 cm
Sand is .006cm - .2cm
Silt is cm cm
Clay is < .0004cm

4. Rocks and Rock Formation
Rocks made from sediments are called…
Sedimentary Rocks
Made from round pebbles
Made from angular pebbles
Made from sand
Made from silt
Made from clay
Sedimentary rocks made
from pieces of other
rocks are called…
CLASTIC!

5. Rock Formation: Clastic Sedimentary Rocks
How do CLASTIC sedimentary rocks form?
Compaction and cementation of land derived sediments
Sediments are transported- moved by the stream!
Sediments are deposited- dropped at stream mouth
Sediments pile up in layers!
Clastic rock forms by compaction and cementation of sediments
STREAM flowing to OCEAN

6. Rock Formation: Sedimentary Rocks
Organic (living) sediments form BIOCLASTIC rocks...
Small shell fish and other organisms die and and are deposited at the sea floor
Organic sediments are deposited, compacted and cemented…
Form limestone and other organic rocks

7. Rocks and Rock Formation
Sedimentary rocks
forming from fragments
of organisms are called…
Bioclastic!
Shells or plant remains

8. Evaporation from water forms
Rock Formation: Sedimentary Rocks
Evaporation from water forms
CHEMICAL EVAPORITES…
There are always sediments
dissolved in water
Water evaporates and sediments get left behind!
Rock salt is formed this way!
Rock Salt left from evaporation

9. Precipitation from water forms CHEMICAL PRECIPITATES
Rock Formation: Sedimentary Rocks
Precipitation from water forms CHEMICAL PRECIPITATES
Sediments form from a chemical reaction and are deposited…
Rock gypsum, dolostone and limestone form this way!
Rock Gypsum left from precipitation

10. Rocks and Rock Formation
Sedimentary rocks forming from evaporation or precipitation are chemical sed. Rocks!
Precipitates & Evaporates

11. Rock Formation: Sedimentary Rocks
Evidence of how sedimentary rocks form…
Ripple marks from water movement preserved in rock
Sandstone
Shell fossils from dead animals preserved in rock!
Limestone
Fossils ONLY form in sedimentary rock!!

12. Summary Questions…
1. Type of rock formed by compaction and cementation of sediments at the bottom of the ocean…
2. Rock gypsum left behind after precipitation of minerals is what type of rock…
3. Dolostone can be left behind after ocean water has evaporated . What type of rock is it?
4. Plant remains are compacted to form coal, which is what type of rock?
5. Clastic sedimentary rock made from compaction and _________ of sand is called ___________

13. Rock Formation: Sedimentary Rocks
Land-derived sediments form CLASTIC rocks
Large pebbles settle first!
Tiny clay sediments settle last!
Shale forms from clay at the top!
SHALE
Sandstone and siltstone form
Sand , then silt settle
Conglomerate forms from pebbles at the bottom
Sediments Settling in OCEAN

14. Rock Formation: Metamorphic Rock
How do REGIONAL metamorphic rocks form?
Existing rock is buried under heat and pressure
Existing rock buried deep!
Heat and pressure change the rocks…
…Crystals grow, rocks get harder and more dense
…Foliation and banding can occur too!

15. Rock Formation: Metamorphic Rock
How do CONTACT metamorphic rocks form?
Existing rock is heated by contact with magma
..Existing rock changes when it is heated
Crystals grow, rocks get harder and more dense

16. Summary Questions…
____ metamorphic rocks form when exiting rocks are buried deep below the surface.
Foliation and banding usually happen with what type of metamorphism?
Non-foliated rocks tend to form with what type of metamorphism?
Sandstone is metamorphosed to form a non-foliated metamorphic rock called _____. What type of metamorphism is this?

17. Each rock can change into any other rock!
Rock Cycle Animation
Each rock can change into any other rock!
Igneous rock can be broken into sediments…
…compacted and cemented to become…
SEDIMENTARY ROCK

18. Each rock can change into any other rock!
Rock Cycle Animation
Each rock can change into any other rock!
Igneous rock can be put under heat and pressure…
…metamorphosed and turned into…
METAMORPHIC ROCK

19. Each rock can change into any other rock!
Rock Cycle Animation
Each rock can change into any other rock!
Igneous rock can be buried and melted…
…turned into magma…
…and solidified back into…
IGNEOUS ROCK

20. Summary Questions…
What has to happen to a sedimentary rock to turn into an igneous rock?
What has to happen to a sedimentary rock to turn into an metamorphic rock?
What has to happen to a metamorphic rock to turn into an igneous rock?
What has to happen to a metamorphic rock to turn into an sedimentary rock?