Igneous Rocks(with slides from “ms simmons”)

Magma forms igneous rocks

What is magma? Hot molten (melted) rocks

When magma cools inside the earth, it forms igneous rocks

When magma (lava)cools outside the earth, it forms igneous rocks

Magma and lava

Molten rocks Inside the earth = magma

Outside the earth = lava

How does magma escape to the outside? (Magma escapes to the outside through ______)

Volcano

Intrusive rocks Formed when magma cools INSIDE

the earth.

Extrusive rocks Formed when magma (as lava) cools

OUTSIDE the earth.

In-

Ex-

Cooling Intrusive vs. Extrusive rocks: which will cool

faster?

Formed at earth’s surface

Lava’s minerals cool and harden quickly

Forms tiny crystals

Obsidian

Rhyolite

BasaltAndesite

Formed below earth’s surface

Magma’s minerals cool and harden slowly

Forms coarse crystals

Gabbro Granite

Diorite

Quiz As the head geologist of an expedition, you

come across an unknown mineral.

1. How do you convince your colleagues that it’s indeed a mineral? (hint: how do you define a mineral?) Name 5 defining criteria of the mineral that make it a mineral. a. minerals are solid

2. Name 3 properties of the mineral that you’d test to identify the mineral.

Quiz1. What is magma? i.e. what is it made of?

2. What is lava? i.e. how is it different from magma?

3. Which type of rocks does lava form when it cools?

4. Which type of rocks does magma form when it cools?

5. Define a mineral. (name 5 criteria)a. minerals are solid