/
AI Flashcards
Save to my account
Sign up
AI Flashcards
Igneous Processes and Magma Basics
Study
1
Question
What are igneous rocks and how are they related to magma?
Answer
Formed from solidified magma or lava.
2
Question
What is decompression melting?
Answer
Melting caused by pressure decrease at constant temperature.
3
Question
What triggers decompression melting at mid-ocean ridges?
Answer
Rising mantle material lowers pressure, causing melting.
4
Question
What is flux melting?
Answer
Melting due to addition of volatiles that lower melting temperatures.
5
Question
Which elements are most abundant in magma by percentage (as given in the pie chart)?
Answer
Oxygen, Silicon, Aluminum (by order shown).
6
Question
What is the effect of adding water or CO2 to hot rocks?
Answer
Promotes flux melting by lowering mineral melting points.
7
Question
What is the term for the layer beneath the crust involved in magmatism?
Answer
Mantle (specifically asthenosphere portion involved in melt formation).
8
Question
What is the Moho?
Answer
The Mohorovičić discontinuity; boundary between crust and mantle.
9
Question
What does decompression melting produce at subduction zones?
Answer
Magma formed as mantle rocks melt due to pressure changes.
10
Question
What is the main cause of mantle rocks melting during convection?
Answer
Decrease in pressure as rocks rise to shallower depths.
11
Question
What is the general consequence of magmatic processes for volcanic activity?
Answer
Magma accumulation and ascent can lead to eruptions.
12
Question
What is magma?
Answer
Molten rock beneath Earth's surface, formed when rocks melt in the mantle or crust.
13
Question
Which rocks form from solidified magma or lava?
Answer
Igneous rocks arise from cooling and solidification of magma or lava.
14
Question
What best describes a basaltic magma image?
Answer
Dark lava flow with basaltic composition and dark rock.
15
Question
What best describes an andesitic magma image?
Answer
Intermediate lava flow colors indicating andesitic composition.
16
Question
What best describes a rhyolitic magma image?
Answer
Visually high silica lava eruption with light-colored rhyolitic material.
17
Question
What happens to rocks at high pressure in the mantle, initially?
Answer
They may remain solid at ambient mantle temperatures despite high pressures.
18
Question
Where is water released that aids flux melting in plate tectonics?
Answer
From subducting slab released into overlying mantle wedge.
19
Question
What is the main consequence of magmatic processes for volcanism?
Answer
Magma generation, accumulation, and ascent drive volcanic eruptions.