METAMORPHIC PETROLOGY (FUNDAMENTALS)

Question 1

This refers to predominantly solid state mineral and/or textural changes to preexisting protoliths
“to change form” a process that leads to changes in mineralogy, texture, and sometimes chemical composition

Answer 1

Metamorphism

Question 2

Agents of metamorphism

Answer 2

1.Temperature,
2.Pressure,
3.chemically active fluid
4. Differential stress*

Question 3

Types of metamorphism which results from INCREASING T and P consitions overtime w/c involces recyrstallization and neocrystallizaton to transform minerals in accordance with equilibrium

Answer 3

Prograde Met

Question 4

Type of Metamorphism which results to DECREASE T and P so that lower T/P minerals OVERPRINTS unstable ones with the AID OF VOLATILES

Answer 4

Retrograde Met

Question 5

Type of Met which progresses incrementaly from slight changes

Answer 5

Low-grade Met

Question 6

Type of Met which progresses incrementaly showing substantial changes

Answer 6

High-grade Met

Question 7

Determine if its Retrograde or Prograde
1. Neocrystallization
2. Overprinting with aid of volatiles
3. Recrystallization

Answer 7

1. PM
2. RM
3. PM

Question 8

Differentiate Prograde and retrograde metamorphism

Answer 8

Prograde metamorphism results from increasing temperature and pressure conditions over time which involves recrystallization and neocrystallization to transform minerals in accordance with equlibrium meanwhile Retrograde metamorphism occues when temp and pressure conditions decreases so that lower temp/press minerals overprints unstable minerals with the aid of volatiles

Question 9

This involves the use of mineral assemblages and their deformation chatacteristics to infer peak PT conditions of metamophism

Answer 9

Geothermobarometry

Question 10

This mineral occurs in LT HP in subduction zones

Answer 10

Glaucophane

Question 11

lower limits of metamorphism

Answer 11

Diagenesis
150-200 deg cel
<3kbar
10km depth

Question 12

Temp limit of diagenesis

Answer 12

150-200 deg cel

Question 13

Pressure limit of diaganesis

Answer 13

<3Kbar

Question 14

Depth limit of Diagenesis

Answer 14

10 km

Question 15

Upper limits of metamorphism

Answer 15

Anatexis (Partial melting) (600-800deg)

Question 16

this occurs when bulk composition of rocks changes as a result of chemical reactions with hot chemically active fluid of variable origin

Answer 16

Hydrothermal Alteration

Question 17

What are the anions or cations which serves as catalyts in hydrothermal alteration

Answer 17

H2O, CO2, CH4, K, Na, B, S, Cl

Question 18

Fluids derived principally from magma at oceanic spreading ridges, magmatic arcs or hotspots

Answer 18

Juvenile or magmatic fluids

Question 19

This infiltrates fractures and pore spaces at ocean spreading ridges and subduction zones

Answer 19

Seawater

Question 20

These are fluids derived from subduction zones which releases H2O from mica, amphibole and Serpentine and CO2 from limestone and dolostones

Answer 20

Devolatilization-derived fluids

Question 21

Associated with precipitation, surface water, and groundwater

Answer 21

Meteoric Fluids

Question 22

fluids which are stored in spaces between cyrtslas

Answer 22

Connate fluids

Question 23

Another name for connate fluids

Answer 23

Formation Pore Fluids

Question 24

What are the indicators of metamorphism by chemically active fluid?

Answer 24

1)Presence of Volatile rich minerals
2) Secondary Mienerals in vein fillings and fluid inclusions

Question 25

Common metamorphic minerals in increasing temparature stability

Answer 25

Chlorite -
Muscovite -
Biotite -
Garnet -
Staurolite -
Kyanite -
Sillimanite

Question 26

Two processes which promotes Hydrothermal Alteration

Answer 26

1) Deuteric Reactions
2) Metasomatic Reactions

Question 27

These involves reactons in which igneous rocks are metamorphosed due to its own hot-vapor-rich fluids
“Ginigisa sa sariling Mantika”

Answer 27

Deuteric Reactions

Question 28

deuteric reaction of micas results to

Answer 28

Chlorite

Question 29

deuteric reaction of clay results to

Answer 29

Sericite

Question 30

deuteric reaction of plag results to

Answer 30

Epidote

Question 31

This involves changes in solid rock compostion resulting from hydrothermal fluids exchanging components with an external source

Answer 31

Metasomatism

Question 32

The process in which ca plag turns to na plag when basaltic magma reacts with Na rich saltwater

Answer 32

Spilitization

Question 33

A process whereby elements are removed from the rock by during hydrothermal alteration

Answer 33

leaching

Question 34

Sites of metallic mineral deposit due to metasomatic processes

Answer 34

Oceanic Crust and Ophiolites

Question 35

Ore metals formed by metasomatic process in the ocean floor

Answer 35

Co, Cu, Mn

Question 36

Differentiate uniform from non-uniform stress

Answer 36

Uniform stress aka isotropic stress, lithstatic pressure or hydrostatic pressure or confining pressure is associated with burial depth in which forces are equal or of the same magntude in all directions thus producing dilation but not distortion in shape. While non-uniform or anisotropic or deviatoric stress forces varies with direction

Question 37

What rocks are produced by uniform stress?

Answer 37

Non-foliated met rocks with equant grains

Question 38

What rocks are produced by non uniform stress?

Answer 38

Inequant grains and foliated met rocks

Question 39

A metamorphic layering developed due to preferred aligned arrangement of inequant grains

Answer 39

Foliation or Foliated texture