Metamorphic Rocks (Non-foliated textures)

Question 1

Rocks that formed as a result of metamorphism.

Answer 1

Metamorphic Rocks

Question 2

A sub-branch of Petrology that focuses on the composition, characteristics and origins of metamorphic rocks.

Answer 2

Metamorphic Petrology

Question 3

What are the different textures under non-foliated metamorphic textures?

Answer 3

A. Hornfelsic Texture
B. Granoblastic Texture
C. Cataclastic Texture

Question 4

A fine-grained (<1.0 mm diameter), non- foliated fabric that develops by contact metamorphism, with predominantly equant grains.

Answer 4

Hornfelsic Texture

Question 5

Non-foliated metamorphic rocks that are derived from fine-grained protolith rocks that develop in metamorphic aureoles, adjacent to igneous intrusions.
-Evidence of baking and chilling

Answer 5

Hornfels

Question 6

Characterized by large (>1.0 mm diameter) equant grains or large inequant grains that lack foliation, occur in high grade rocks that form at elevated temperature and pressure conditions, and develop during metamorphism of a wide range of protoliths under uniform stress conditions.

Answer 6

Granoblastic Texture

Question 7

or simply quartzite, is a non-foliated, metamorphic rock with a granoblastic texture that contains >90% quartz and derived from quartz-rich protoliths, such as sandstone or chert.

Answer 7

Metaquartzite

Question 8

Differentiate Quartzolite, Quartz Arenite, and Quartzite.

Answer 8

These rocks are primarily composed of quartz. Quartzite contains a small percentage of feldspar, while quartz arenite is prone to weathering and erosion due to its sedimentary nature. In contrast, quartzite is more compact because of its metamorphic origins.

Question 9

Granoblastic, metamorphic
rock rich in calcite and/or dolomite, derived from recrystallization of limestone or dolostone protoliths from dynamothermal, burial, or contact metamorphism.
-Effervescent

Answer 9

Marble

Question 10

Also called tactite, is a granoblastic calc-silicate rock formed by contact metamorphism metamorphic of rocks carbonate through metasomatism from the release of silica and volatiles from the magma which also generates calc-silicate mineral assemblages and/or metallic ore deposits

Answer 10

Skarn

Question 11

Metamorphic rocks that show fractured, angular particles that form in response to the brittle crushing of grains during deformation in the upper crustal fault zones.

Answer 11

Cataclastic Texture

Question 12

Metamorphic rock with cataclastic texture derived from metamorphism of sedimentary or igneous breccias that develop during dynamic or dynamothermal metamorphism.

Answer 12

Metabreccia

Question 13

Cohesive metamorphic -
rock with cataclastic texture produced by brittle deformation in zones under low temperature, high strain, dynamic metamorphic conditions.

Answer 13

Cataclasite

Question 14

Glassy-metamorphic rocks produced by high strains generating localized melting in fault zones, and commonly occur as vein material in cataclastic rocks such as fault breccias and cataclasites.

Answer 14

Pseudotachylites

Question 15

How do we differentiate pseudotachylites from obsidians?

Answer 15

While both have glassy textures, Pseudotachylites have oriented grains and Obsidians have conchoidal fractures.

Question 16

High strain rate cataclastic rocks created by the tremendous short-term stresses that are typically associated with extraterrestrial rock bodies impacting earth.
-They have a glassy texture, evidence of baking, and chaotic clasts.

Answer 16

Impactites

Question 17

Non-crystalline, high- grade coals that are vitreous, light weight and jet black in color that commonly display conchoidal fractures, forms from bituminous coal experiencing metamorphism through burial or dynamothermal metamorphism.
-Can be distinguished by its luster.

Answer 17

Anthracite