Flashcards
GEL 050 Lab Midterm 1
Cards in this deck (46)
- 1—Granite
Felsic (0-15%)
Intrusive (Coarse-grained, phaneritic)
May contain:
K-Feldspar, P-feldspar, quartz, biotite, amphibole, muscovite - 2—Diorite
Intermediate (15-45%)
Intrusive (Coarse-grained, phaneritic)
May contain:
P-feldspar, amphibole, biotite, small amount of k-feldspar, quartz
- 3—Gabbro
Mafic (45-85%)
Intrusive (Coarse-grained, phaneritic)
May contain:
Pyroxene, p-feldspar, amphibole, small olivine crystals
- 4—Peridotite
Ultramafic (85-100%)
Intrusive (Coarse-grained, phaneritic), forms in the mantle, rare to find on the crust
May contain:
Olivine, Pyroxene
- 5—Rhyolite
Felsic (0-15%)
Extrusive (Fine-grained, aphanitic)
May contain:
K-feldspar, p-feldspar, quartz, muscovite
- 6—Andesite
Intermediate (15-45%)
Extrusive (fine-grained, aphanitic)
May contain:
P-feldspar, amphibole, biotite, quartz, small amounts of k-feldspar
- 7—Basalt
Mafic (45-85%)
Extrusive (fine-grained, aphanitic)
May contain:
Pyroxene, amphibole, p-feldspar, small crystals of olivine
- 8—Obsidian
Extrusive (glassy texture)
No mineral composition: lava cooled extremely fast and solidified before minerals could crystallize
- 9—Pumice
Extrusive (vesicular)
Pumice is formed by quickly cooling rhyolitic lava that has gases trapped inside, forming many vesicles
- 10—Scoria
Extrusive (vesicular)
Scoria is formed by quickly cooling basaltic lava that has gases trapped inside, forming vesicles
- 11—Volcanic Tuff
Extrusive (Pyroclastic)
Tuff is compressed ash from a volcanic eruption with rocks trapped inside
- 12—Augite (Pyroxene)
Hard (5.5-6.0)
2 cleavages (close to 90 degrees)
- 13—Olivine
Hard (7)
Tiny crystals
Vitreous luster
- 14—Amphibole (Hornblende)
Hard (5.5-6)
2 cleavages (124 & 56 degrees)
blade like (acicular) crystal habit
- 15—Biotite
Soft (2.5-3)
1 cleavage - 0 degrees
Tabular - sheets
- 16—Chlorite
Soft (3.5-4)
No cleavage
Light green streak
- 17—Garnet
Hard (7)
Equant dodecahedron crystals
- 18—Gypsum (alabaster)
Soft (2)
White streak
No cleavage
- 19—Gypsum (selenite)
Soft (2)
Tabular form
3 cleavages (90 degrees)
- 20—Halite
Soft (2.5)
3 cleavages (90 degrees)
breaks into cubes
- 21—Calcite
Soft (3)
3 cleavages (75 degrees)
Waxy luster
Rhombohedral cleavage
- 22—Potassium (K) Feldspar
Hard (6)
2 cleavages (90 degrees)
exsolution laminae
- 23—Magnetite
Hard (6-6.5)
Magnetic
Dark grey streak
- 24—Muscovite
Soft (2-2.5)
Tabular form
1 cleavage (0 degrees)
Excellent cleavage
- 25—Opal
Soft (5-5.5)
No cleavage
Conchoidal Fracture
- 26—Hematite
Hard (>5.5)
Brown-grey streak
- 27—Plagioclase Feldspar
Hard (6)
2 cleavages (about 90 degrees)
Striations
- 28—Quartz
Hard (7)
No cleavage
Hexagonal prism, hexagonal pyramid on each end
- 29—Breccia
Siliciclastic
Gravel size grains (grains larger than 2mm)
Mostly angular and/or subangular grains
Poorly sorted
Quartz, rock fragments
High energy environments: streams, glaciers, landslides
Deposited close to source
*Can be modified with prefix quartz, arkose, lithic or wacke
- 30—Conglomerate
Siliciclastic
Gravel size grains (larger than 2mm)
Mostly subround and/or well rounded grains
Moderately sorted
Rock fragments, feldspar and quartz
High energy environments, streams, glaciers
Deposited somewhat close to source
*Can be modified with prefix quartz, arkose, lithic or wacke
- 31—Quartz Sandstone
Siliciclastic
Sand size grains (1/16-2mm)
Subround/round grains
Well sorted
Quartz grains
Low to medium energy environments: streams, beaches, sand dunes
*look for cross-bedding
- 32—Siltstone
Siliciclastic
Silt size grains (less than 1/16mm)
Round grains
Well Sorted
Quartz, clay minerals, micas, feldspars
Low energy environments: lake bottoms, river deltas
- 33—Claystone
Siliciclastic
Clay size grains (even smaller than silt)
Rounded grains
Well Sorted
Quartz, clay minerals, feldspars
lake bottoms, river deltas
- 34—Shale
Siliciclastic
Clay size grains
Rounded grains
Well Sorted
Quartz, feldspar, clay minerals
marshes, shallow ocean, flood plains
- 35—Coquina
Bioclastic
Shells, Coral Fragments
Gravel size grains
Poorly sorted
Angular grains
Coastal, shallow ocean, reefs (high energy)
- 36—Micrite
Chemical
Calcium carbonate
Microcrystalline
Conchoidal Fracture
Formed in lagoons
Reacts with HCl
- 37—Dolostone
Chemical
Dolomite
Microcrystalline
Formed in deep ocean, evaporating playa lake
Will react with HCl only when powdered
- 38—Chert
Chemical
Quartz, Siliceous shells from plankton
Microcrystalline
Conchoidal fracture
Deep ocean
- 39—Slate
Lowest grade metamorphism
Regional
Foliated
Flat, slaty cleavage
Parent rock: Mudstone or shale
- 40—Phyllite
Low Grade Metamorphism
Regional
Foliated
Has a luster
- 41—Schist
Higher grade metamorphism
Foliation (scaly)
Regional
Precede name with minerals that are predominate (muscovite schist, biotite schist)
- 42—Gneiss
High Grade Metamorphism
Foliation
Regional
Banded texture, minerals segregate into alternating layers (light and dark). Crystalline.
- 43—Hornfels
Nonfoliated
Microcrystalline texture
Very hard
Contact metamorphism
dull dark color (usually)
- 44—Serpentine
Nonfoliated
Contact metamorphism
Microcrystalline texture (no visible grains)
Usually shades of green
- 45—Quartzite
Nonfoliated
Contact
Sandy texture
Grains will not rub off like sandstone
Usually light color
- 46—Marble
Nonfoliated
Regional (or contact)
Microcrystalline (resembling sugar cube) or medium to coarse crystalline
Reacts with HCl
Information
- Description
- Geology Flashcards on GEL 050 Lab Midterm 1, created by Sean Begg on 28/01/2020.
- Created by
- Sean Begg · Jan 2020
- Updated
- Jan 29, 2020
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