rock cycle test study guide.pdf - Free Printable

Rock Cycle Test Study Guide Solution

#### 1. Complete the diagram of the rock cycle below:

The rock cycle involves the transformation of rocks from one type to another through various processes. Here is how the diagram should be completed:

- Igneous Rock:
- Forms from Magma/Lava (melting and cooling).
- Can transform into Sedimentary Rock through weathering, erosion, deposition, and lithification.
- Can transform into Metamorphic Rock through heat and pressure.

- Sedimentary Rock:
- Forms from Weathering/Erosion and Deposition.
- Can transform into Metamorphic Rock through heat and pressure.
- Can return to Igneous Rock through melting and cooling.

- Metamorphic Rock:
- Forms from Heat and Pressure.
- Can transform back into Igneous Rock through melting.
- Can transform into Sedimentary Rock through weathering, erosion, and deposition.

- Magma/Lava:
- Melts from existing rocks and cools to form Igneous Rock.

#### Completed Diagram:
```
Igneous Rock
/ \
/ \
/ \
Magma/Lava Sedimentary Rock
\ /
\ /
\ /
Metamorphic Rock
```

---

#### 2. 2 or more elements combine to make a _______. Rocks are made of 2 or more _______.

- Answer: Minerals; Elements

Explanation: Rocks are composed of minerals, and minerals are made up of two or more elements combined in specific proportions.

---

#### 3. What provides the energy for the rock cycle above the ground? _______ in the _______.

- Answer: Solar Energy; Atmosphere

Explanation: Above-ground processes like weathering, erosion, and deposition are driven by solar energy, which powers wind, water, and temperature changes.

---

#### 4. What provides the energy for the rock cycle under the ground? _______ in the _______.

- Answer: Heat Energy; Earth's Interior

Explanation: Below-ground processes like melting, metamorphism, and volcanic activity are powered by heat energy from the Earth's interior, including the mantle and core.

---

#### 5. Can a sedimentary rock become an igneous rock before it becomes a metamorphic rock?

- Answer: No

Explanation: Sedimentary rocks typically undergo metamorphism before they can melt and become igneous rocks. The process usually follows this sequence: sedimentary → metamorphic → igneous.

---

#### 6. Can an igneous rock become a metamorphic rock before it is weathered into sediment?

- Answer: Yes

Explanation: An igneous rock can be subjected to heat and pressure to become a metamorphic rock before it is weathered and eroded into sediment.

---

#### 7. What do you need to do to change an igneous rock into a sedimentary rock?

- Answer: Weathering, Erosion, Deposition, Lithification

Explanation: Igneous rocks must first be broken down by weathering and erosion, transported by water or wind, deposited in layers, and then compacted and cemented (lithification) to form sedimentary rocks.

---

#### 8. What do you need to do to change a sedimentary rock into a metamorphic rock?

- Answer: Subject it to Heat and Pressure

Explanation: Sedimentary rocks must be buried deep within the Earth where they are exposed to high temperatures and pressures, causing them to change their mineral composition and structure without melting.

---

#### 9. What do you need to do to change a metamorphic rock into an igneous rock?

- Answer: Melt the Rock

Explanation: Metamorphic rocks must be heated to the point of melting, forming magma or lava, which then cools and solidifies to form igneous rocks.

---

#### 10. How can you tell the difference between an intrusive rock and an extrusive rock?

- Answer: Texture and Cooling Rate

Explanation:
- Intrusive Rocks: Form underground from slowly cooling magma. They have coarse-grained textures because the slow cooling allows crystals to grow large.
- Extrusive Rocks: Form on the surface from quickly cooling lava. They have fine-grained or glassy textures because the rapid cooling does not allow crystals to form.

---

#### 11. Where does an intrusive rock form? How fast does it cool and crystallize?

- Answer: Intrusive rocks form underground (e.g., in magma chambers). They cool and crystallize slowly.

Explanation: Slow cooling allows crystals to grow larger, resulting in a coarse-grained texture.

---

#### 12. Where does an extrusive rock form? How fast does it cool and crystallize?

- Answer: Extrusive rocks form on the Earth's surface (e.g., during volcanic eruptions). They cool and crystallize rapidly.

Explanation: Rapid cooling prevents crystal growth, leading to fine-grained or glassy textures.

---

#### 13. How does a porphyritic rock form?

- Answer: A porphyritic rock forms when magma cools in two stages:
1. Early Stage: Some crystals grow while the magma is still underground (slow cooling).
2. Late Stage: The remaining magma rises to the surface and cools rapidly, forming finer crystals around the larger ones.

Explanation: This results in a rock with both large crystals (phenocrysts) and a finer matrix.

---

#### 14. Name one igneous rock that has a "glassy" texture. What does "glassy" texture mean when referring to igneous rocks?

- Answer: Obsidian; Glassy texture means the rock is non-crystalline and has a smooth, shiny surface similar to glass.

Explanation: Obsidian is a volcanic glass formed when lava cools so quickly that no crystals can form.

---

#### 15. Define pluton

- Answer: A pluton is a body of intrusive igneous rock (magma) that has cooled and solidified beneath the Earth's surface.

Explanation: Examples include batholiths, dikes, and sills.

---

#### 16. Why does lava rise upward through the crust towards the surface?

- Answer: Lava rises due to buoyancy caused by its lower density compared to the surrounding rock. Additionally, pressure from gases dissolved in the magma drives it upward.

Explanation: As magma rises, pressure decreases, causing gases to expand and further push the magma toward the surface.

---

#### 17. What are high-silica magmas like? Explosive or calm? Do they produce ash or runny lava?

- Answer: High-silica magmas are viscous (thick and sticky) and tend to be explosive. They produce ash rather than runny lava because the high silica content makes the magma resistant to flow, trapping gases and leading to explosive eruptions.

Explanation: Examples include rhyolite and dacite magmas.

---

Final Answer Summary:

1. Completed diagram as described.
2. Minerals; Elements
3. Solar Energy; Atmosphere
4. Heat Energy; Earth's Interior
5. No
6. Yes
7. Weathering, Erosion, Deposition, Lithification
8. Subject it to Heat and Pressure
9. Melt the Rock
10. Texture and Cooling Rate
11. Underground; Slowly
12. On the Earth's surface; Rapidly
13. Two-stage cooling (early slow cooling for phenocrysts, late rapid cooling for finer crystals)
14. Obsidian; Non-crystalline, smooth, shiny
15. Intrusive igneous rock body
16. Buoyancy and gas pressure
17. Explosive; Produce ash

Final Boxed Answer:
\boxed{\text{See detailed explanations above}}