Metamorphic Textures

Question 1

The size, shape, orientation, and interangular relationships of metamorphic rocks’ constituents that were influenced by temperature and pressure conditions or relict textures.

Answer 1

Metamorphic Textures

Question 2

Inherited textures from a metamorphic rock’s protolith.

Answer 2

Relic Texture

Question 3

Metamorphic textures based on the sizes of the notable grains in metamorphic rocks.

Answer 3

According to Grain Size

Question 4

Metamorphic textures based on the orientation of the grains in a metamorphic rock.

Answer 4

According to Grain Orientation

Question 5

ACCORDING TO GRAIN SIZE:

Texture defined by large relict grains from the protolith that have experienced deformation but retained its composition.

Answer 5

Porphyroclastic

Question 6

ACCORDING TO GRAIN SIZE:

Oval-shaped feldspar porphyroclasts that are particularly common in gneiss.

Answer 6

Augen

Question 7

ACCORDING TO GRAIN SIZE:

Oval-shaped quartz porphyroclasts that are particularly common in gneiss.

Answer 7

Flaser

Question 8

ACCORDING TO GRAIN SIZE:

Texture defined by large grains that experienced neocrystallization and growth in response to favorable temperature and pressure conditions due to metamorphism.

Answer 8

Porphyroblastic

Question 9

ACCORDING TO GRAIN ORIENTATION:

A texture of metamorphic rocks that exhinit planar arrangement of mineral grains or structural features of a rock.

Answer 9

Foliated

Question 10

ACCORDING TO GRAIN ORIENTATION:

A texture of metamorphic rocks that exhibit linear arrangement of mineral grains or structural features of a rock.

Answer 10

Lineation

Question 11

ACCORDING TO GRAIN ORIENTATION:

A texture of metamorphic rocks that lack the planar arrangement of mineral grains or structural features of a rock.

Answer 11

Non-Foliated

Question 12

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

Answer 12

Hornfelsic Texture

Question 13

Characterized by large (>1.0 mm in 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 13

Granoblastic

Question 14

Texture of 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 14

Cataclastic Texture

Question 15

Closely spaced layers along which metamorphic rocks break or cleaves readily to produce flat surfaces with a dull luster.

Answer 15

Slaty Cleavage

Question 16

Rock cleavage characterized by larger crystals and more wavy surfaces compared to slaty cleavage.

Answer 16

Phyllitic Cleavage

Question 17

A very common foliation defined by the sub-parallel arrangement of macroscopic platy minerals in closely spaced metamorphic layers.

Answer 17

Schistosity

Question 18

A foliation characterized by the arrangement of minerals into distinct color bands, which are commonly alternating light-colored quartz, and dark-colored biotites and amphiboles.

Answer 18

Gneissosity