W7L2 igneaous

Question 1

two ways of classifying rocks

Answer 1

QAPF classification mineral classification

SiO2 or silica content classification chemical classification

Question 2

intrusive igneaous rocks definition

Answer 2

Intrusive rock, also called plutonic rock, igneous rock formed from magma forced into older rocks at depths within the Earth’s crust, which then slowly solidifies below the Earth’s surface, though it may later be exposed by erosion

Question 3

intrusive igneaous rocks form

Answer 3

are the result of the crystallisation of a magma within the Earth’s crust

Question 4

the longer igneaous rocks in magma

Answer 4

longer they are in magma the more rounded becasue magma can dissolve thme so angular → rounded

Question 5

contact points

Answer 5

contact
described as being sharp
some distance inside country rock, rocks have been subject to thermal alteration by heat

Question 6

xenoliths

Answer 6

black intrusions

Question 7

Large scale single intrusions

Answer 7

1-50 km
known as Plutons
either stocks or bell jar Pluton (depends on shape)
if smaller than 10 km they are small Plutons or stocks

Question 8

Small sclae intrusions: sills

Answer 8

sills - concordant (horizontal) sheet-like intrusions

Question 9

small scale intrusions laccoliths

Answer 9

laccoliths - lens shaped intrusions; ʻinflated sillsʼ

Question 10

small scale intusions dykes

Answer 10

discordant (vertical) , sheet like intrusions
cross section of a dyke: coarse grained middle, fine grained edge, chilled margin and then baked margin ( heat)
moves through these, not stationary like in Pluton

Question 11

Intueison Morphology: composite intrusions

Answer 11

centred complexes

nested complexes

Question 12

intusion morphology: batholiths

Answer 12

large scale, composite intrusions, multiple intrusions in same place

Question 13

intrusion morphology diatreme

Answer 13

gets wider when reaching surface of earth .

“ice cream cone” shape