Metamorphic Rocks (Part 3 - Metamorphic Facies and Series)

Question 1

Distinctive mineral assemblages in metamorphic rocks that form in response to a particular range of temperature and/or conditions.

Answer 1

Metamorphic Facies

Question 2

Include non-foliated, fine-grained hornfels rocks and coarser-grained rocks. Formed by heat-induced metamorphism, and commonly localized around intrusions.

Answer 2

Hornfels Facies

Question 3

4 Hornfels Facies

Answer 3

Albite-Epidote Hornfels Facies
Hornblende Hornfels Facies
Pyroxene Hornfels Facies
Sanidinite Hornfels Facies

Question 4

Low grade metamorphism characterized by the zeolite mineral group, and commonly exist with quartz, analcime, laumontite, heulandite and wairikite.

Answer 4

Zeolite Facies

Question 5

Low-grade metamorphism commonly produced from basalt, greywackes and mudstones.

Answer 5

Prehnite-Pumpellyite Facies

Question 6

Medium grade metamorphism characterized by green minerals including epidote, chlorite and actinolite in foliated and non-foliated metamorphic rocks.

Answer 6

Greenschist Facies

Question 7

Medium to high grade metamorphism characterized by the start of the appearance of staurolite.

Answer 7

Amphibolite Facies

Question 8

Medium to high grade metamorphism commonly dominated by granoblastic texture in non-foliated rocks. Common rocks include gneisses, charnockites and migmatites.

Answer 8

Granulite Facies

Question 9

Medium to high grade metamorphism from low temperature conditions, characterized by blue minerals, such as glaucophane, aegirine and kyanite, giving its blue-colored appearance.

Answer 9

Blueschist Facies

Question 10

High-grade metamorphism resulting in fine- to coarse-grained dense, dark green rocks, commonly along with reddish-brown garnet porphyroblasts.

Answer 10

Eclogite Facies

Question 11

A sequence of facies that occurs across a metamorphic terrane due to differences in pressure and temperature (P/T) conditions.

Answer 11

Metamorphic Facies Series

Question 12

Geothermal Gradient, Metamorphism and Rock Textures of Contact Facies Series

Answer 12

> 80°C/km, Contact Metamorphism, Non-foliated

Question 13

Geothermal Gradient, Metamorphism and Rock Textures of Buchan (Abukama)

Answer 13

40-80°C/km, Dynamothermal & Contact Metamorphism, Foliated & Non-foliated

Question 14

Geothermal Gradient, Metamorphism and Rock Textures of Barrovian

Answer 14

20-40°C/km, Dynamothermal Metamorphism, Foliated

Question 15

Geothermal Gradient, Metamorphism and Rock Textures of Sanbagawa

Answer 15

10-20°C/km, Dynamothermal Metamorphism, Foliated

Question 16

Geothermal Gradient, Metamorphism and Rock Textures of Franciscan

Answer 16

<10°C/km, Dynamothermal Metamorphism at subduction zones, Foliated