Igneous Rock
How does intrusive and extrusive igneous rock differ in where they form?
Intrusive rock cools below the surface (INterior)
Extrusive rock cools above the surface (EXterior)
What is the root word in 'sedimentary'? Describe what that word means and explain how it relates to sedimentary rock.
'Sediment' is the root word. Sediments are the broken pieces of rock that are created from weathering. Sediments are related to sedimentary rocks because sedimentary rocks are made of 'glued' sediments.
Describe in your own words what a metamorphic rock is.
A rock that has transformed into another type of rock due to extreme pressure and/or heat.
In Hawaii, some beaches are made up of dark-colored rocks that line the coast. These rocks are usually smooth and porous.
Which type of rock is it based on these clues? Be specific about the type (don't just say metamorphic, igneous, or sedimentary; give the sub-type). Justify your conclusion (EXPLAIN WHY).
It is extrusive igneous rock. 'Porous' means that there are lots of small holes, which indicate that it cooled too quick for oxygen to escape. The Hawaiian Islands are volcanic islands, so it makes sense to find igneous rock in an area that has lots of volcanoes.
How does intrusive and extrusive rock differ in the amount of cooling time they have? How does this impact the amount of crystals they have?
Intrusive rock takes a long time to cool below the surface which allows more crystals to form.
Extrusive rock cools very quickly above the surface, so there's very little time for crystals to form.
What are the first 2 steps in the formation of sedimentary rock? Briefly explain what happens during each of them.
Step 2: Erosion - rocks are transported from one place to another by forces such as wind, water, gravity, and living things
Describe what foliation is. What type of metamorphism creates rock that is foliated?
Foliation occurs when rocks are exposed to extreme pressure. The pressure forces the crystals inside the rock to align and create stripes. Regional Metamorphism creates rocks that are foliated.
A geologist found a rock with distinct layers of dark and light brown. They found it in a sand dune that has lots of large rock formations that are made of the same material.
Which type of rock is it based on these clues? Justify your conclusion (EXPLAIN WHY).
It is a sedimentary rock. Sedimentary rocks have layers of sediment that have been cemented together. If there is a lot of sand in the area, the rock is likely to be sandstone.
Describe the texture of intrusive and extrusive igneous rock. Explain why they have the texture they do.
Intrusive: rough, coarse texture due to the large crystals inside the rock
Extrusive: Smooth, glossy texture due to a lack of crystals, or lots of air bubbles due to oxygen getting stuck inside the rock during quick cooling
What are the last 3 steps of the formation of sedimentary rock? Briefly explain what happens during each of them.
3. Deposition - sediments are dropped off in a body of water
4. Compaction - sediments are compacted due to pressure
5. Cementation - sediments are 'glued' together and form a new sedimentary rock
Describe what contact metamorphism is. Where does this type of metamorphism commonly occur?
Contact metamorphism occurs when a rock is changed into another type of rock due to extreme heat. This commonly occurs to rocks that surround a magma chamber.
Miners were sent to the Himalayan Mountains to excavate rocks found underground. They mined for rocks that are durable and have bands of white.
Which type of rock is it based on these clues? Be specific about the type (don't just say metamorphic, igneous, or sedimentary; give the sub-type). Justify your conclusion (EXPLAIN WHY).
This rock is regional metamorphic rock. The Himalayan Mountains were created from convergent plate boundaries. At this type of boundary, 2 plates are pushing towards each other, creating extreme pressure on the rocks in that area. The bands of white are from foliation which is very common in regional metamorphic rocks.
What types of rocks can turn into an igneous rock? What are the steps for those types of rocks to become an igneous rock?
Any rock can become an igneous rock. A rock would need to be exposed to enough heat to melt into magma or lava. Once the rock cools, it will be a new igneous rock.
What are the three types of sedimentary rock?
1. Clastic
2. Organic
3. Chemical
Describe what regional metamorphism is. Where does this type of metamorphism commonly occur?
Regional metamorphism occurs when a rock is transformed into another rock due to extreme pressure (and some heat). This commonly occurs at convergent boundaries or at the bottom of the ocean.
A magma chamber has cooled and become dormant. There are 2 types of rocks that formed from this magma chamber. Rock 1 is found in the perimeter of the magma chamber. Rock 2 is found in the inside of the magma chamber.
What type of rocks are Rock 1 and Rock 2? Be specific about the type (don't just say metamorphic, igneous, or sedimentary; give the sub-type). Justify your conclusion (EXPLAIN WHY).
Rock 1 is Contact Metamorphic rock. If it is surrounding a magma chamber, that means the rocks touching the magma were exposed to intense heat and were baked into a new type of rock.
Rock 2 is Intrusive Igneous rock. If it is inside the magma chamber, that means this rock used to be magma until it cooled into igneous rock below the surface.