Earth Materials

Question 1

What igneous rock forms ar MOR

Answer 1

Bassalt

Question 2

What is the mantle made of?

Answer 2

Peeridotite

Question 3

What is peridotie?

Answer 3

A coarse grained ultramafic rock

Question 4

How does basaltic magma form from an ultramafic mantle?

Answer 4

heating and decompression melting

Question 5

What is fertile mantle, and what is it called?

Answer 5

the mantle before melting occurs- Lherzolite

Question 6

What does lherzorite contain

Answer 6

40-90% olivene

Ortho + clioropyroxene

Question 7

What does hazburgite contain?

Answer 7

Olivene and chlinopyroxene

Question 8

What is oceanic crust made of?

Answer 8

Bassalt, dolerite, gabbro

Question 9

Where do island arcs occur? give an example

Answer 9

Oceanic crust beneath oveanic crust

Monseerat- Atlantic ocean crust under carrebbian plate

Question 10

Where do continental arcs occur?

Answer 10

Oceanc under continental

Mt St helens, one of chain of volcanoes- carrebien under atlantic

Question 11

How are granitoids produced?

Answer 11

1) melting of continental crusts

2) fractionisation of basaltic crust

Question 12

What compesition is andersite?

Answer 12

INTERMEDIATE

• Plagioclase, pyroxene, amphibole (water bearing)
• -hornblende

Question 13

What is an amphibole?

Answer 13

Mafic water bearing minerals

Question 14

Describe an amphibole under the microscope

Answer 14

ppl-colourless, green-brown, prismatic, moderate relief

xpl-

Question 15

What kind of volcanoes does continental subduction create?

Answer 15

EXPLOSIVE

Question 16

Give examples of continental subduction volcanoes

Answer 16

• Andes (south america)
• Parictuin mexixo
• costa rica centeral america

Question 17

What kind of mineralisetion does continental subdicion give rise to?

Answer 17

Porphyry copper- from hydrothermal fluids

Question 18

What is a stratvolcano?

Answer 18

Pyroclastic fragmeented rocks produced by violent erruption

Question 19

Describe a subduction volcano?

Answer 19

Errution of ANDERSITIC lavas and PYROCLASTIC deposits

STEEP SIDED COMPERSITE STRATAVOLCANOES

Question 20

What chain ov volcanoes does mt st helens belong too?

Answer 20

Cascades

Question 21

What is diorite?

Answer 21

Plutonic amdersite

• coarse grained intermediate
• biotite pyroxene and plagioclaise

Question 22

What does a pyroclastic flow consist of?

Answer 22

• Fragments of lava
• Crystals
• Glass shatds
• pummice
• Ignimbrite flows cool and form ash flow tuffs

Question 23

What kind of magmasdo arc volcanoes commonly errrupt?

Answer 23

• More silica rich
• DACITES AND RHYOLITES
• cold and freexe quickly- obsidian

Question 24

What is pummice?

Answer 24

Pummive forms when extreemly viscous magmas become frothy due to gas exolving out
When pressure drops it solididies to form PUMMICE

Question 25

What are the most common inerals in RHYOLITE and DACITE

Answer 25

alkali felspas and quartz | -some micas and hornblende in dacite

Question 26

What minerals are common in granite?

Answer 26

alkali fspa, qts, mica and hornblende

Question 27

What dominares felsic rocks

Answer 27

QTZ and FSPA

Question 28

What plates produce the Italian volcanoes

Answer 28

African under european

Question 29

Describe ETNA

Answer 29

- Feeder dykes STRATAVOLCANO - Strombolian cones found at lower levels - volcanic gasses from creaters

Question 30

What is calssed as ''vulcanian'' activicty?

Answer 30

Explosive- bombs up to 1 m

Question 31

What are LITORAL CONES

Answer 31

when lavas run into the sea and explode to form piles of pyroclastic debris

Question 32

To what depth does explosive activicty occur underwater?

Answer 32

!km after this water pressure is greater than explosion

Question 33

Describe Volcanello?

Answer 33

-Smaller 1890 - emiting gasses 95% steam 4.8% Co2 SO2 Hot mud

Question 34

Describe stromboli

Answer 34

ERupting for 40,000 years modest ''strombolian'' explosions

Question 35

How do volcanic debris form?

Answer 35

Pyroclastic flows have many gas bubbles wich isolate lava fragments.

Question 36

What is honfels?

Answer 36

a tough metamorphic rock. formed from sediments near plutonic microgranites

Question 37

What is Hyaloclasite

Answer 37

Glass cooled quickly by water. Brocken pillow lavas sit in it

Question 38

What magmas do ganitoid magmas erupt to give?

Answer 38

Rhyolitic lavas

Question 39

What colour and composition are granites?

Answer 39

Lighjt Fspa and qtz