Metamorphic Rocks

Question 1

Texture

Answer 1

sizes, shapes, and arrangements

Question 2

Foliated metamorphic rocks

Answer 2

layering and parallel alignment of platy (flat) mineral crystals
E.g. micas

Question 3

How does foliated rock occur

Answer 3

result of pressure (shearing and smearing of crystals) and recrystallization

Question 4

Slaty rock cleavage

Answer 4

very flat foliation

developed along flat, parallel, closely spaced shear planes in tightly folded clay or mica rich rocs

Question 5

Slate

Answer 5

rocks with excellent slaty cleaving

Question 6

Phyllite Texture

Answer 6

wavy and/or wrinkled foliation or fine grained platy minerals
intermediate grade metamorphism
metallic luster
developed oblique or perpendicular to weak slaty cleavage

Question 7

Phylite

Answer 7

fine grained metamorphic rock
satiny, silver, green, brassy, metallic cluster
wavy foliation
wrinkled appearance

Question 8

Schistosity

Answer 8

scaly glittery layering of visible (medium-course grained) platy materials and/or linear alignment of long prismatic crystals
intermediate - high metamorphism

Question 9

Schist

Answer 9

medium-course grained, scaly, foliated metamorphic rock

formed by intermediate-grade-metamorphism mud,shale, slate, other rocks rich in clay

Question 10

Gneissic Banding

Answer 10

alternating layers or lenses of light and dark medium - course grained minerals
high grade metamorphism

Question 11

Non foliated metamorphic rocks

Answer 11

no obvious layering (foliates)

stretched fossils, long prismatic crystals grown parallel to the pressure field

Question 12

Crystalline Texture

Answer 12

medium-coarse grained aggregate of inter grown, equal sized, visible crystals
non foliated

Question 13

Gneiss

Answer 13

medium-course grained rock

biotite/quartz

Question 14

Marble

Answer 14

fine-course grained
non foliated
intermediate- high grade metamorphism

Question 15

Microcrystalline Texture

Answer 15

fine grained aggregate of inter grown microscopic crystals

non foliated

Question 16

Hornfels

Answer 16

fine grained - non foliated

microcrystalline texture

Question 17

Sandy Texture

Answer 17

Medium - course grained aggregate of fused, sand sized grains

Question 18

Quartzite

Answer 18

medium - course grained
non-foliated metamorphic rock
fused quartz grains - sandy texture

Question 19

Glassy Texture

Answer 19

homogenous texture - no visible grains or other structures
breaks along glossy surfaces
resembles glass

Question 20

Anthracite Coal

Answer 20

non-foliated metamorphic rock
“Hard Coal”
smooth, homogeneous, glassy texture, curved conchoidal fractures
low-intermediate metamorphism

Question 21

Stretched or Sheared Grains

Answer 21

deformed pebbles, fossils, or mineral crystals that have been stretched out, shortened or sheared

Question 22

Porphyroblastic texture

Answer 22

arrangement of large crystals, porphyroblasts, set in a finer-grained groundmass

Question 23

Hydrothermal veins

Answer 23

factures “healed” (filled) by minerals that precipitated from hydrothermal fluids

Question 24

Folds

Answer 24

Bends in rock layers that were initially flat, like a folded stack of paper

Question 25

Lineations

Answer 25

lines on rocks at the edges of foliations, shear planes, slaty cleavage, folds, or aligned crystals

Question 26

Step 1 - classification Meta

Answer 26

Determine rocks textural features
foliated / non-foliated
texture of rock

Question 27

Step 2 - classification Meta

Answer 27

Determine and record the rock’s mineralogical composition and/or distinctive features

Question 28

Step 3 - classification Meta

Answer 28

Determine name of rock

Question 29

Step 4 - classification Meta

Answer 29

Name of parent rock

Question 30

Step 5 - classification Meta

Answer 30

Common use of rock