Sedimentary Rocks
Weathering= rocks and sediments break down
Erosion= smaller pieces are moved to new locations
Three types:
1) Physical (mechanical)
2) Chemical
3) Biological
What is physical weathering? What is chemical weathering? What is biological weathering?
• NO changes in composition
• Size and shape change
• Factors:
Temperature
Frost wedging : water freezes and expands, cracking rocks
Pressure
Exfoliation : pressure of overlying rocks are removed, underlying rocks can expand
Chemical Weathering
• Mineral composition CHANGES
• Chemical reaction occurs
• New minerals form
• Agents:
Water- Hydrolysis
Oxygen- Oxidation
Carbon Dioxide- Cave
Acid - Living organism cause changes in rocks or sediment
Biological Weathering- When living things affect weathering (humans, animals, plants)
Factors that affect weathering: Climate!
Climate for chemical weathering: Warm temp, rainfall
Example: Painted desert
Climate for physical weathering: Cool, dry
Example: NC Mountians
Formation of Sedimentary Rocks
Even though igneous rocks are the most common in Earth’s crust, most of Earth’s surface is covered in sediment.
Sediments: pieces of solid rock material re-deposited on Earth's surface by forces ( wind, water, ice, gravity, rain, etc.)
Steps:
1) Weathered particles get moved downhill: (erosion)
2) Get laid down/sink: ( deposition)
3) Deposits become layered: (sorting)
4) Layers stack up on top of each other: (burial)
5) These processes add material to sedimentary basins
6) As burial occurs, layers are subjected to greater heat and pressure
7) These conditions cause lithification
• lithos = stone
• Two steps
• Compaction: excess water and air are squeezed out
• Cementation: new minerals form
What do sedimentary rocks look like?
The primary features of sedimentary rocks are horizontal layers called bedding.
• Graded bedding
• Bigger on the bottom
• Cross-bedding
• Slanted layers
Sedimentary Rock Classification
Organic sedimentary rocks: from once living things
Chemical sedimentary rocks: evaporites
Clastic sedimentary rocks: loose deposits on Earth's surface (most common)
Erosion= smaller pieces are moved to new locations
Three types:
1) Physical (mechanical)
2) Chemical
3) Biological
What is physical weathering? What is chemical weathering? What is biological weathering?
• NO changes in composition
• Size and shape change
• Factors:
Temperature
Frost wedging : water freezes and expands, cracking rocks
Pressure
Exfoliation : pressure of overlying rocks are removed, underlying rocks can expand
Chemical Weathering
• Mineral composition CHANGES
• Chemical reaction occurs
• New minerals form
• Agents:
Water- Hydrolysis
Oxygen- Oxidation
Carbon Dioxide- Cave
Acid - Living organism cause changes in rocks or sediment
Biological Weathering- When living things affect weathering (humans, animals, plants)
Factors that affect weathering: Climate!
Climate for chemical weathering: Warm temp, rainfall
Example: Painted desert
Climate for physical weathering: Cool, dry
Example: NC Mountians
Formation of Sedimentary Rocks
Even though igneous rocks are the most common in Earth’s crust, most of Earth’s surface is covered in sediment.
Sediments: pieces of solid rock material re-deposited on Earth's surface by forces ( wind, water, ice, gravity, rain, etc.)
Steps:
1) Weathered particles get moved downhill: (erosion)
2) Get laid down/sink: ( deposition)
3) Deposits become layered: (sorting)
4) Layers stack up on top of each other: (burial)
5) These processes add material to sedimentary basins
6) As burial occurs, layers are subjected to greater heat and pressure
7) These conditions cause lithification
• lithos = stone
• Two steps
• Compaction: excess water and air are squeezed out
• Cementation: new minerals form
What do sedimentary rocks look like?
The primary features of sedimentary rocks are horizontal layers called bedding.
• Graded bedding
• Bigger on the bottom
• Cross-bedding
• Slanted layers
Sedimentary Rock Classification
Organic sedimentary rocks: from once living things
Chemical sedimentary rocks: evaporites
Clastic sedimentary rocks: loose deposits on Earth's surface (most common)
Rocks and Minerals Webquest
Directions: Answer the following questions using the websites provided for each question (the titles are hotlinks)...Hotlinks didn't work when I copied it over
Rock Cycle
1. What are the three main types of rocks? Igneous, Metamorphic, and Sedimentary
2. How does a sedimentary rock turn into a metamorphic rock? With heat and pressure
3. How does an igneous rock turn into a metamorphic rock? With heat and pressure
4. How do metamorphic rocks change into sedimentary rocks? Weathering and erosion, then compaction and cementation
5. How do igneous rocks change into sedimentary rocks? Weathering and erosion, then compaction and cementation
6. What is the beginning of the rock cycle? The end? There is no beginning or end because it is one giant circle
View this Rock Cycle animation
7. Quick cooling forms many small what? Small crystals
8. When you look at the desert monuments, what eroded away? Sandstone
9. The microscopic view of sandstone contains what two components? Cement and sand grain
10. What two things are needed to turn igneous rock into metamorphic rock? Heat and pressure
Rocks
11. List and define the 6 key characteristics that can help you identify rocks within the three main classes.
a. Crystals- Small, flat surfaces that are shiny or sparkly, like mirrors
b. Fossils- imprints of previously living things in the rock
c. Gas Bubbles- holes in the rock
d. Glassy Surface- shiny and smooth surface
e. Ribbon-like Layers or stripes
f. Sand or Pebbles- visible pebbles or sand grains in the rock
Rock Identification Key
12. For igneous rock, when magma cools slowly the crystals... are big
13. For igneous rock, when magma cools quickly, the crystals... are small
14. Of the types of igneous rock formed underground, which one is most familiar? Granite
15. When looking at sedimentary particle size, which material type has the largest particles and which has the smallest particles? Sand has the largest and clay has the smallest.
16. Which metamorphic rock forms under the highest temperature and highest pressure? Gneiss
Mystery Rocks
17. How much of earth’s surface is made of sedimentary rock? Three quarters
18. Give 4 examples of sediment that might eventually become sedimentary rock. Gravel, sand, silt, clay
19. What caused the appearance in the sedimentary rock in picture B? Can't see picture
Mohs Scale
20. What is Mohs Scale used for? To test the hardness of minerals
21. What mineral is a 10 on Mohs Scale? Diamond
22. Give an example of a mineral with a hardness of 7 (according to Mohs Scale). Tell me about that mineral. Quartz, component in all rocks, one of the most abundant minerals
23. If a mineral can scratch a penny, what number is it on Mohs Scale? 3
Directions: Answer the following questions using the websites provided for each question (the titles are hotlinks)...Hotlinks didn't work when I copied it over
Rock Cycle
1. What are the three main types of rocks? Igneous, Metamorphic, and Sedimentary
2. How does a sedimentary rock turn into a metamorphic rock? With heat and pressure
3. How does an igneous rock turn into a metamorphic rock? With heat and pressure
4. How do metamorphic rocks change into sedimentary rocks? Weathering and erosion, then compaction and cementation
5. How do igneous rocks change into sedimentary rocks? Weathering and erosion, then compaction and cementation
6. What is the beginning of the rock cycle? The end? There is no beginning or end because it is one giant circle
View this Rock Cycle animation
7. Quick cooling forms many small what? Small crystals
8. When you look at the desert monuments, what eroded away? Sandstone
9. The microscopic view of sandstone contains what two components? Cement and sand grain
10. What two things are needed to turn igneous rock into metamorphic rock? Heat and pressure
Rocks
11. List and define the 6 key characteristics that can help you identify rocks within the three main classes.
a. Crystals- Small, flat surfaces that are shiny or sparkly, like mirrors
b. Fossils- imprints of previously living things in the rock
c. Gas Bubbles- holes in the rock
d. Glassy Surface- shiny and smooth surface
e. Ribbon-like Layers or stripes
f. Sand or Pebbles- visible pebbles or sand grains in the rock
Rock Identification Key
12. For igneous rock, when magma cools slowly the crystals... are big
13. For igneous rock, when magma cools quickly, the crystals... are small
14. Of the types of igneous rock formed underground, which one is most familiar? Granite
15. When looking at sedimentary particle size, which material type has the largest particles and which has the smallest particles? Sand has the largest and clay has the smallest.
16. Which metamorphic rock forms under the highest temperature and highest pressure? Gneiss
Mystery Rocks
17. How much of earth’s surface is made of sedimentary rock? Three quarters
18. Give 4 examples of sediment that might eventually become sedimentary rock. Gravel, sand, silt, clay
19. What caused the appearance in the sedimentary rock in picture B? Can't see picture
Mohs Scale
20. What is Mohs Scale used for? To test the hardness of minerals
21. What mineral is a 10 on Mohs Scale? Diamond
22. Give an example of a mineral with a hardness of 7 (according to Mohs Scale). Tell me about that mineral. Quartz, component in all rocks, one of the most abundant minerals
23. If a mineral can scratch a penny, what number is it on Mohs Scale? 3