Chapter 3 - Igneous Rocks Flashcards
What is magma?
Molten rock beneath the Earth’s surface.
What is the difference between intrusive and extrusive igneous rocks?
Intrusive rocks form below the surface (slow cooling, large crystals), while extrusive rocks form at the surface (fast cooling, small crystals).
What is Bowen’s Reaction Series?
It describes the sequence of mineral crystallization in cooling magma.
What is the difference between mafic and felsic magma?
Mafic magma is rich in iron and magnesium (darker, denser), while felsic magma is rich in silica (lighter, less dense).
What is the geothermal gradient?
The rate at which temperature increases with depth within the Earth.
Why is Bowen’s Reaction Series important in understanding the formation of different types of igneous rocks?
Bowen’s Reaction Series shows how different minerals crystallize at different temperatures, explaining the varying compositions of igneous rocks (from mafic to felsic).
Discuss how the cooling rate of magma affects the texture of igneous rocks.
Slow cooling forms large crystals (phaneritic texture), rapid cooling forms small crystals (aphanitic texture), and very rapid cooling can form glassy textures.
