Topic 10

Question 1

Hematitization is commonly associated with which type of alteration in rocks?

A. Silica replacement
B. Iron oxidation leading to a reddish hue
C. Carbonate deposition forming white streaks
D. Sulfide mineralization creating metallic luster

Answer 1

B. Iron oxidation leading to a reddish hue

Question 2

What is the primary result of greisenization in granite?

A. Formation of a greenish hue due to the presence of chlorite
B. Alteration of feldspar to form quartz and mica (muscovite)
C. Conversion of granite into basalt
D. Introduction of sulfide minerals

Answer 2

B. Alteration of feldspar to form quartz and mica (muscovite)

Question 3

Which of the following geological processes can lead to silicification?

A. Hydrothermal activity
B. Volcanic eruptions
C. Groundwater action
D. All of the above

Answer 3

D. All of the above

Question 4

When a veinlet cuts across a vein in veinlet chronology, what does this indicate?

A. The veins formed before the veinlets
B. The veins formed after the veinlets
C. The veins and veinlets formed simultaneously
D. The veins are unrelated to veinlets

Answer 4

A. The veins formed before the veinlets

Question 5

Alteration of an igneous rock during the final crystallization stages (very high-T) of the molten rock, but some changes can be delayed after solidification.

A. Deuteric Alteration
B. Retrograde Alteration
C. Prograde Alteration
D. Hydrothermal Alteration

Answer 5

A. Deuteric Alteration

Question 6

Secondary Biotite forms at high temperature replacement (240-500°C) of plagioclase and Fe-mags due to hydrothermal and regional metamorphic process.

A. True
B. False

Answer 6

B. False

Question 7

Chemical formula of Magnetite (Secondary).

A. Fe3O4
B. Fe4O3
C. Fe3O5
D. Fe4O4

Answer 7

A. Fe3O4

Question 8

A sulphate mineral that is common in VMS and mixing zones of high-sulfidation epithermal deposits.

A. Gypsum
B. Anhydrite
C. Barite
D. Alunite

Answer 8

C. Barite

Question 9

Anhydrite occurs in neutral and acidic zones (pH 6-2). It is abundant in ____________, especially where acid and neutral mix. It is also indicative of boiling.

A. Alteration zones
B. Boiling zones
C. Cooling zones
D. Permeable zones

Answer 9

D. Permeable zones

Question 10

10. (Fe₂O₃) a mineral that is common in oxidized (hypogene) skarn deposit.

A. Specularite
B. Magnetite
C. Calcite
D. Magnesite

Answer 10

A. Specularite

Question 11

Is a ubiquitous iron sulfide alteration mineral occurring in most hydrothermal deposits.
A. Calcite
B. Epidote
C. Albite
D. Pyrite

Answer 11

D. Pyrite

Question 12

Characterized by the destruction of primary minerals, such as feldspar and mica, and the formation of clay minerals.

A. Advanced Argillic
B. Propylitic
C. Potassic
D. Skarn

Answer 12

A. Advanced Argillic

Question 13

Form as a result of alteration that occurs when hydrothermal fluids interact with a protolith of either igneous or sedimentary origin.

A. Argillic
B. Propylitic
C. Potassic
D. Skarn

Answer 13

D. Skarn

Question 14

Vuggy silica is characterized by small cavities developed in a rock resulting in a spongy appearance, caused by extreme ______________ of all minerals and major elements.

A. heating
B. acidic leaching
C. oxidation
D. NOTC

Answer 14

B. acidic leaching

Question 15

Alunite is an analog of __________ and, a very low-T supergene, where aluminum replaces Fe³⁺.

A. Gold
B. Cassiterite
C. Wolframite
D. Jarosite

Answer 15

D. Jarosite

Question 16

Hydrothermal alteration zone that occurs under low temperatures and higher pH, with minerals like chlorite, epidote, and carbonates

Answer 16

Propylitic

Question 17

Which hydrothermal alteration zone is characterized by high temperatures, potassium enrichment, and minerals such as orthoclase, sanidine, and microcline?

Answer 17

Potassic

Question 18

Characterized by the alteration of primary minerals to secondary minerals such as muscovite, kaolinite, and sericite

Answer 18

Phyllic

Question 19

Which sulfide mineral is a common indicator of gold deposition during the retrograde stage of hydrothermal processes?

Answer 19

Pyrite

Question 20

This is part of your oxy-salts group specifically as Tungstates that has the chemical formula of CaWO4

Answer 20

Scheelite

Question 21

Sodium can substitute for potassium in alunite, and when the Na content is high, it is called ____________

Answer 21

Natroalunite

Question 22

Greisenization happens when fluids rich in fluorine, boron, or other volatiles interact with the granite, altering its original minerals like feldspar and turning them into _____________.

Answer 22

Greisen

Question 23

____________ is a late-stage clay mineral, it overprints hypogene alteration or as supergene mineral in nearly all hydrothermal deposits.

Answer 23

Kaolinite

Question 24

It is the alteration type occurrence of opal.

Answer 24

Advanced argillic

Question 25

These are minerals at or near-surface.

Answer 25

Supergene Minerals

Question 26

Primary hydrothermal/unaltered minerals

Answer 26

Hypogene Minerals

Question 27

It is a process or alteration associated with oxidizing fluids, forming high Fe3+ / Fe2+ ratio

Answer 27

Hematitization

Question 28

Retrograde alteration of epidote: ___________ and ___________.

Answer 28

Chlorite and Calcite

Question 28

Conversion of a carbonate mineral or rock into a silicate mineral or rock; common in prograde stage of skarn and porphyry deposits.

Answer 28

Silication