Lecture 4 - Mineral and Rocks 2

Question 1

what are the two categories of igneous rock

Answer 1

intrusive and extrusive

Question 2

how do intrusive igneous rock form

Answer 2

when magma trapped below surface cools slowly, solidifying over thousands or millions of years

Question 3

how do extrusive igneous rock form and what’s its other name

Answer 3

volcanic igneous rock

forms when magma/lava exits a volcano or rises up to the surface through a fissure

Question 4

what is the most important component of igneous rock and why

Answer 4

SiO2 — Silica content
silica accounts for nearly half or more of the mass/weight of igneous rock form

Question 5

how does silica content in igneous rock go back to volcanoes

Answer 5

magma (and lava) from statrovolcanoes is:
- very viscous (sticky)
- rich in silica

magma (and lava) from shield volcanoes is:
- rich in iron and magnesium
- does not contain much silica
- less sticky

Question 6

how do you classify magma/lava

Answer 6

as either felsic or mafic
- depending on silica content

Question 7

what happened with Mount Tambora
- Place
- Type of volcanoes
- Year
- what do they call the year after + why
- what happened

Answer 7

• Indonesia
• Stratovolcano, on subduction zone
• 1815: largest eruption in recorded history
• 1816: referred to as “year without summer” due to volcanic airborne material in atmosphere blocking sunlight
• temperatures dropped and crops failed, leading to food shortages in the Northern Hemisphere

Question 8

Characteristics of felsic magma/lava

Answer 8

• higher viscosity (stickier)
• less iron (Fe)
• richer in silica (SiO2)
• found near subduction zones

Question 9

Characteristics of mafic magma/lava

Answer 9

• lower viscosity (less sticky)
• richer in ion (Fe)
• less silica (SiO2)
• found at hot spots and mid-ocean ridges

Question 10

What type of magma (felsic or magic) does a stratovolcano on subduction zone create + example

Answer 10

Felsic magma/ lava rich in silica
Great Sitkin Volcano (Aleutian Islands, Alaska)

Question 11

What type of magma does Mount Kilauea create

Answer 11

Hot spot volcano
Mafic lava containing less silica

Question 12

if igneous rock greater than 65% silica what does it become

Answer 12

felsic

Question 13

what do felsic igneous rocks include

Answer 13

rhyolite and granite

Question 14

if igneous rock 55-65% silica what does it become

Answer 14

intermediate

Question 15

what does intermediate igneous rocks include?

Answer 15

andesite and diorite

Question 16

if igneous rock 45-55% silica, what does it become

Answer 16

mafic

Question 17

what do mafic igneous rocks include

Answer 17

basalt and gabbro

Question 18

if igneous rock less than 45% silica, what does it become

Answer 18

ultramafic

Question 19

what do ultramafic igneous rocks include

Answer 19

peridotite

Question 20

rank the order, lightest + less dense to darker and denser out of the three fine-grained extrusive (volcanic)

Answer 20

rhyolite (felsic) — andesite (intermediate) — basalt (mafic)

Question 21

rank the order, lightest + less dense to darker and denser out of the three coarse-grained intrusive

Answer 21

granite (felsic) — diorite (intermediate) — Gabbro (mafic)

this order also represents a decrease in silica and an increase in iron

Question 22

what does it mean if an extrusive igneous rock has a intrusive equivalent and vise versa

Answer 22

the process by which they form, and appearance differs, their content/composition is very comparable

Question 23

basalt is the extrusive equivalent of..

Answer 23

intrusive gabbro

Question 24

andesite is the extrusive equivalent of..

Answer 24

intrusive diorite

Question 25

rhyolite is the extrusive equivalent of…

Answer 25

intrusive granite

Question 26

what is granite

Answer 26

intrusive felsic

Question 27

what is rhyolite

Answer 27

extrusive felsic

Question 28

diorite

Answer 28

intrusive intermediate

Question 29

gabbro

Answer 29

intrusive mafic

Question 30

basalt

Answer 30

extrusive mafic

Question 31

andesite

Answer 31

extrusive intermediate

Question 32

which is typically lighter out of the intrusive or extrusive equivalents

Answer 32

intrusive is typically lighter than extrusive equivalents

Question 33

what are the characteristics of sulfur (S)

Answer 33

- an element (16 protons) and a mineral - has a distinctive yellow colour and odour - melts at a low temperature (108C) - it has a low density (approximately 2 grams/cubic centimeter or 2 grams/millimeter) and therefore feels “light”

Question 34

how many naturally occurring minerals are there on earth

Answer 34

4000

Question 35

minerals form when…

Answer 35

- magma cool - water rich in molecules that make-up minerals evaporates, allowing the molecules to crystallize (this is what occurs in underground caves)

Question 36

mineral crystals can be… (in terms of size)

Answer 36

- small if form in confined spaces (ex: between other solids/other minerals) - larger if given necessary time and space (ex: within geodes)

Question 37

what is stalagmite

Answer 37

upwards growing mound of mineral deposits (often CaCO3) that originated in water that dripped onto cave floor

Question 38

what is stalactite

Answer 38

icicle-shaped formations/mineral deposits that hang form ceiling of a cave

Question 39

what can stalagmites and stalactites contain

Answer 39

may contain other materials such as lava and even amberat which crystallized pack rat urine

Question 40

what is amberat

Answer 40

crystallized pack rat urine!

Question 41

what are geodes

Answer 41

hollow rock formations with minerals that have developed inside

Question 42

what mineral often develops inside a geode

Answer 42

quartz crystal SiO2

Question 43

geodes can form when…

Answer 43

- material around a hollow in the ground (ex: animal burrow) turns to rock - gas bubbles/pockets are found inside igneous rock/when lava cools around gas bubbles/pockets

Question 44

what do pockets in geodes do

Answer 44

they allow for water to seep in

Question 45

what happens over time with geodes

Answer 45

over time, water evaporates, leaving behind molecules that make up minerals. molecules crystallized forming mineral crystals

Question 46

how long does it take for crystals within pockets to form + what does a bigger crystal often mean (geodes)

Answer 46

thousands/millions of years, with the largest crystals typically being the oldest

Question 47

why are the quartz crystals different colours

Answer 47

- because of elemental impurities - precedes of additional elements/impurities in mineral crystals can give them variety of colours

Question 48

iron (Fe) turns a mineral crystal which colour?

Answer 48

red or purple

Question 49

titanium (T) turns a mineral crystal which colour?

Answer 49

bue

Question 50

Nickel (Ni) turns a mineral crystal which colour?

Answer 50

green

Question 51

Manganese (Mn) turns a mineral crystal which colour?

Answer 51

pink

Question 52

how can minerals be classified

Answer 52

- chemical composition - properties - crystal systems

Question 53

how many mineral classes are there ( + how many were there originally)

Answer 53

78 originally: 9 (known as Dana Classification System)

Question 54

what is the name of the mineral classification system that has only 9 classes

Answer 54

Dana Classification System

Question 55

native elements (mineral class)

Answer 55

singular elements existing on their own such as sulfur (S) or copper (Cu)

Question 56

sulfides (mineral class)

Answer 56

minerals containing sulfur ions (S2-) and other elemtents

Question 57

sulfates (mineral class)

Answer 57

minerals containing sulfatge ions (SO42-) and other elements

Question 58

halides (mineral class)

Answer 58

minerals containing chlorine (Cl-) or fluorine (F-) ion and other elements

Question 59

oxides (mineral class)

Answer 59

minerals containing oxygen atoms (O) or ions (O2-) and other elements

Question 60

carbonates (mineral class)

Answer 60

minerals containing carbonate ions (CO32-) and other elements

Question 61

phosphates (mineral class)

Answer 61

minerals containing phosphate ions (PO43-) and other elements

Question 62

silicates (mineral class)

Answer 62

minerals containing silicon combined with oxygen in various ways

Question 63

what is the chemical formula of Copper and what is it considered

Answer 63

Cu — mineral

Question 64

what is the chemical formula of Galena and what is it considered

Answer 64

PbS — a sulfide

Question 65

what is the chemical formula of Aragonite and what is it considered

Answer 65

CaCO4 — a carbonate

Question 66

what is Turquoise considered

Answer 66

a phosphate

Question 67

silicates are divided into

Answer 67

subgroups (because its such a big group)

Question 68

organics (mineral class)

Answer 68

not true minerals - contains materials such as amber which comes from trees and amberat, which comes from pack rats -they are not true minerals since they are organic - organic minerals contain Carbon (C), more specifically carbon-hydrogen bonds and may come form previously living beings