Exam 1

Question 1

Petrology

Answer 1

Study of rocks using optical microscopy

Question 2

Reasons why we study petrology

Answer 2

1. Crust and mantle are igneous
2. Most metallics ores are associated w/ igneous rocks and process
3. Natural hazards
4. All of terrestrial planets/moons have igneous crust

Question 3

Exposed

Answer 3

1. Volcanic: by volcanic eruptions
2. Intrusive: exposed by uplift, erosion, glaciation
   -intrusive igneous rocks are usually older than other formations

Question 4

Melting

Answer 4

1. Isothermal decomposition
2. Add h20
3. Add heat

Question 5

Three broad environments

Answer 5

1. Extrusive (volcanic)
2. Intrusive (plutonic)
3. Hypobyssal (shallow intrusive rocks )

Question 6

System

Answer 6

Any part of the universe under study

Question 7

Surroundings

Answer 7

Everything else

Question 8

Phase

Answer 8

Any part of a system that is mechanically spectacle and can be studied -solid,liquid,gas

Question 9

Components

Answer 9

Are least number of chemical species that fully describe system

Question 10

Congruent melting

Answer 10

Melt w/ some composition as the source( melting 100%) usually never happens

Question 11

Systems 1,2,3

Answer 11

1. Open- transfer heat and matter across the boundary between the system and the surroundings
2. Closed - transfer of heat m/y
3. Isolated- no transfer of heat or matter ( not possible)

Question 12

OIB

Answer 12

Ocean island basalt (alkali olivine basalt)

Question 13

MORB

Answer 13

Mid ocean ridge basalt (tholeiite)

Question 14

IAT

Answer 14

Island arc thoeliite

Question 15

WPB

Answer 15

Within plate basalts (continental rift -highly alkaline )

Question 16

Primary basalt vs. primitive basalt

Answer 16

Primary basalt: first formed (usually don’t erupt )
Primitive: most mafic that are erupted

Question 17

Xenolith types

Answer 17

1. Eucrites (gabbro): ca plag, augite, olivine
2. Dunite and wehrlite: contain different proportion of mg rich olivine and diopside pyroxenes
3. Lherzolites and harzburgites: mg olivine, diopside, mg rich orthopyrozene
4. Garnet peridotite and elcogite: ca rich and ca poor pyroxene, olivine and rich garnet

Question 18

Hasashi kono

Answer 18

-Believed tholeittic lavas- contain on,y 1 group xenoliths
-mildly alkaline basalts: groups 1 and 2 xenos
-Highly alkali basalts: group 1,2,3 xenos
-stronglyy si deficient basalt: group 1,2,3,4 xenos

Question 19

I-type

Answer 19

Igneous source
- trondhjenite

Question 20

S-type

Answer 20

Sedimentary source
- Granite

Question 21

A-type

Answer 21

An orgenic , Alkalin
(Continental rifting)

Question 22

M type

Answer 22

charnocite (metamorphic rocks)

Question 23

Granite tends to be paraluminous

Answer 23

(Has alot of Alumnous ) S-type

Question 24

Tronjhendite tends to be both peraluminous and metaluminous

Answer 24

Depends on pressure
I type

Question 25

Metaluminous

Answer 25

Biotite
hornblende
(pyroxene)

Question 26

Peraluminous

Answer 26

Biotite
muscovite
garnet
cordierite
andaluite
Spinel

Question 27

Peralkaline

Answer 27

annite-rich
biotite
Fe-rich amphibole
(arfredsonite, riebeckite, eg.)
fayalite

Question 28

Melting (anatexis)

Answer 28

1. Addition of h2o
2. Decompression
3. Heating