Igneous Rocks

Question 1

What is a rock defined as?

Answer 1

A rock is a naturally occurring, multi-granular aggregate of minerals, and consists of fragments or pieces of one or more kinds of mineral.

Question 2

What are the three types of rocks and how do we classify them?

Answer 2

Igneous
Sedimentary
Metamorphic

we classify them based on the way in which they form

Question 3

What are Igneous rocks?

Answer 3

Rocks that form by crystallization, freezing or solidification of magma (800o – 1500oC)

They consist of interlocking crystals of various minerals – usually the common rock-forming minerals

Question 4

Name a typical igneous rock

Answer 4

Granite

Question 5

What is Magma and Lava?

Answer 5

rock in the molten state.

The solution contains dissolved elements, volatiles (water), gasses and mineral grains (crystals)

Question 6

What are Extrusive igneous rocks?(lava)

Answer 6

When magma is discharged from opening in earths crust it is called lava and a volcano is formed.
Lava is basaltic in composition and is generally fine-grained with small crystals due to its rapid cooling

Question 7

What are Intrusive igneous rocks?(Magma)

Answer 7

These can again vary considerably in size from large structures such as 𝐩𝐥𝐮𝐭𝐨𝐧𝐬 to small 𝐯𝐞𝐢𝐧𝐬 𝐨𝐫 𝐬𝐡𝐞𝐞𝐭𝐬 within the rock.

The 𝐚𝐛𝐲𝐬𝐬𝐚𝐥 rocks are those that formed at great depth while the hypabyssal rocks formed closer to the surface

Question 8

how do we classify igneous rock?

Answer 8

on a purely 𝐜𝐡𝐞𝐦𝐢𝐜𝐚𝐥 basis

The primary division is into the categories of:
𝐚𝐜𝐢𝐝, 𝐢𝐧𝐭𝐞𝐫𝐦𝐞𝐝𝐢𝐚𝐭𝐞, 𝐛𝐚𝐬𝐢𝐜 and 𝐮𝐥𝐭𝐫𝐚𝐛𝐚𝐬𝐢𝐜