Mock up of revision missed

Question 1

What system is used to classify sedimentary rocks?

Answer 1

Wentworth size classes

Question 2

What are the 3 main categories on the Wentworth size classification?

Answer 2

Gravel
Sand
Mud

Question 3

On the Wentworth classification what is the description for gravel size? (largest to smallest)

Answer 3

Boulder
Cobble
Pebble
Granule

Question 4

On the Wentworth classification what is the description for sand size? (largest to smallest)

Answer 4

Very coarse sand
Coarse sand
Medium sand
Fine sand
Very fine sand

Question 5

On the Wentworth classification what is the description for mud size? (largest to smallest)

Answer 5

Silt
Clay

Question 6

What is basal cleavage?

Answer 6

minerals with one cleavage

Question 7

What is prismatic cleavage?

Answer 7

when the planes of breakage occur along 2 non parallel planes and are perpendicular (90*)

Question 8

What is non-prismatic cleavage?

Answer 8

when the 2 cleavage directions are not perpendicular

Question 9

How do cleavages in potassium feldspar intersect?

Answer 9

90*

Question 10

How does the prismatic cleavage in hornblende intersect?

Answer 10

56* and 124*

Question 11

What is cubic cleavage?

Answer 11

when 3 cleavages intersect at 90*

Question 12

What terms can be used to describe singular crystals?

Answer 12

Acicular (needle like)
Columnar
Tuberose
Tabular
Equant (equal dimensions)
Bladed (long flattened blades)
platy
foliated (easy separated into sheets)

Question 13

What terms can be used to describe aggregates?

Answer 13

Fibrous
Radiating
Dendritic (tree/ moss like)
Granular
Botryoidal
Massive (no distinct form)

Question 14

what does botryoidal mean for aggregate description?

Answer 14

bubble like surface (AKA reniform)

Question 15

What are the properties of quartz in thin section for PPL?

Answer 15

low relief
colourless

Question 16

What are the properties of quartz in thin section for XPL?

Answer 16

Birefringence first order greys up to first order yellow
Extinction might be sweeping

Question 17

What are the properties of muscovite (mica) in thin section for PPL?

Answer 17

Colourless
Moderate relief
perfect cleavage

Question 18

What are the properties of muscovite (mica) in thin section for XPL?

Answer 18

High birefringence (3rd order)

Question 19

What are the properties of chlorite in thin section for PPL?

Answer 19

green and pleochroic
moderate relief

Question 20

What are the properties of chlorite in thin section for XPL?

Answer 20

1st order birefringence
anomalous interference colours

Question 21

What are the properties of plagioclase in thin section for PPL?

Answer 21

Colourless
non-pleochroic
low relief

Question 22

What are the properties of chlorite in thin section for XPL?

Answer 22

1st order greys
polysynthetic twinning (multiple parallel twins)

Question 23

What are the properties of microcline in thin section for PPL?

Answer 23

Colourless
Non pleochroic
low relief

Question 24

What are the properties of microcline in thin section for XPL?

Answer 24

1st order greys
cross hatched twinning

Question 25

What are the properties of calcite in thin section for PPL?

Answer 25

Colourless (May exhibit pale pastels) Low to moderate relief

Question 26

What are the properties of calcite in thin section for XPL?

Answer 26

Extremely high birefringence (may look pastel) Polysynthetic "calcite" twinning in coarse grain- fine grain may be colour swirl

Question 27

How much silica will be basalt and rhyolite?

Answer 27

Basalt <50% SiO2 (low silica) Rhyolitic 75% SiO2 (silica rich)

Question 28

How is olivine best recognised?

Answer 28

High relief Shape = sub-equant and sub rounded Cleavage - none but curved fracture Birefringence - high Alteration- common on fractures

Question 29

How does the pleochroism change for biotite?

Answer 29

brown pleochroism (pale yellow brown to dark brown)

Question 30

What is quartz made of?

Answer 30

SiO2 (silicon dioxide)

Question 31

What are 2 types of plagioclase feldspar?

Answer 31

Albite (NaAlSi3O8) Anorthite (CaAl2Si2O8)

Question 32

What are 2 examples of alkali feldspars?

Answer 32

Orthoclase - (KAlSi3O8 Albite - (NaAlSi3O8)

Question 33

What type of zoning can occur in plagioclase feldspar?

Answer 33

Oscillatory zoning due to growth ring variation of CA and Na compositions)

Question 34

How will plagioclase appear in hands specimen?

Answer 34

white blocky grains

Question 35

How will plagioclase composition change between mafic and granite?

Answer 35

Mafic = Ca rich Granite= Na rich

Question 36

How will plagioclase feldspar grains appear in volcanic rocks?

Answer 36

lath-shaped

Question 37

What is the real name for white and dark mica?

Answer 37

White = muscovite Dark= biotite

Question 38

What will acidic evolved magmas be like?

Answer 38

75wt% silica Relatively rich in Si, Na and K

Question 39

What are plutonic rocks?

Answer 39

ones formed from a large magma body which take a long time to lose heat

Question 40

What will plutonic rocks generally be like?

Answer 40

granular texture due to large interlocking crystals

Question 41

What type of volcanic rock will form from slow cooling from a magmatic body like a batholith?

Answer 41

Gabbro

Question 42

What type of volcanic rock will form from fast cooling from lava or effusive process

Answer 42

basalt

Question 43

What process starts metamorphism with temperature range?

Answer 43

diagenesis at around 100-150*

Question 44

What leads to an end of metamorphism in terms of temp and process?

Answer 44

anatexis at ~900*

Question 45

What is a typical product of diagenesis?

Answer 45

Zeolites

Question 46

What is associated with low pressure high temp metamorphism?

Answer 46

contact or regional metamorphism associate with volcanism and plutonism

Question 47

What is high pressure low temperature metamorphism linked to?

Answer 47

Regional metamorphism in rapidly subsiding areas of subduction zone