Geology 1403 Lab Exam 1

rocks that form from the accumulation of materials that originate and are transported as solid particles derived from both mechanical and chemical weathering.

Detrital Sedimentary Rocks

no visible quartz grains

Difference between diorite and granite?

repetitive layering or grain alignment

foliated metamorphic rock

metamorphic rock that does not exhibit a banded or layered appearance

Non-Foliated Metamorphic Rock

marble, quartzite, serpentinite, hornfels, anthracite coal

Metamorphic rocks that are non-foliated

slate, phyllite, schist, gneiss

Metamorphic rocks that are foliated

granite pegmatite, granite, rholite and pumice, obsidian and volcanic tuff can be

What are the felsic composition igneous rocks?

peridotite

What igneous rock is ultramafic?

Cleavage patterns in minerals

granite pegmatite, diorite pegmatite and gabbro pegmatite

What igneous rocks have pegmatitic texture?

granite, diorite, gabbro and peridotite

What igneous rocks have phaneritic texture?

granite, diorite, gabbro, rhyolite, andesite and basalt

What igneous rocks can have porphyritic texture?

rhyolite, andesite and basalt

What igneous rocks have aphanitic texture?

obsidian

What igneous rocks have glassy texture?

pumice and vesicular basalt

What igneous rocks have vesicular texture?

Gabbro pegmatit, gabbro, basalt, vesicular basalt and obsidian and volcanic tuff can be

What are the mafic composition igneous rocks?

diorite pegmatite, diorite, andesite, and pumice, obsidian and volcanic tuff can be

What are the intermediate igneous rocks?

Sedimentary Detrital, grain size: gravel (> 2mm) has rounded rock fragments and mineral grains

conglomerate

Sedimentary detrital, grain size: gravel (> 2mm), angular grains

Breccia

Sedimentary detrital, sand grain size, characterized by abundant feldspar (>15%), rock fragments and mineral grains

Arkose Sandstone

Sedimentary detrital(clastic), sand grain size, characterized by mostly q grains (>90%), grains often rounded

Quartz Sandstone

Sedimentary detrital (clastic), sand grain size, characterized by abundant rock fragments (>15%), sand sized quartz and minerals grains

Lithic Sandstone

Sedimentary detrital, clay grain size, characterized by mostly clay minerals

Shale

A sedimentary rock that forms from the chemical activities of organisms

Biochemical sedimentary rocks

Sedimentary rock that has undergone some form of chemical alteration (ex. precipitate from a solution or settle from a suspension)

chemical sedimentary rock

Sedimentary, biochemical chemical, composed of mainly calcite (CaCO3), fossilized shell in a fine grained matrix

Fossiliferous Limestone

Sedimentary, inorganic chemical, (composition: mainly calcite) (CaCO3), spherical grains with concentric laminations

Oolitic Limestone

felsic to mafic, pyroclastic texture and extrusive

Volcanic Tuff

Biochemical chemical, Composition: mainly calcite (CaCO3), dull appearance and dense, uniform, fine grained rock with conchoidal fracture

Micrite (micritic limestone)

Sedimentary

microcrystalline

waxy appearance

conchoidal fracture

harder than glass

inorganic

Chert

wavy subparallel veins of lighter coloration and are visible on all surfaces of sample

exsolution lamellae

very thin, parallel grooves that are usually visible on only one cleavage surface of a sample

Striations

inorganic chemical, (composition: mainly halite (NaCl)), crystalline, salty taste and softer than glass

Rock Salt

Biochemical, composed of carbonized plant fragments, brown to brownish black, brittle and sooty

Lignite

sedimentary, Biochemical, (composed of calcite mainly), characterized by microscopic shells and powdery look

Chalk

protolith is bituminous coal, texture is nonfoliated, composed of carbon, characterized by black metallic sheen and is homogeneous (no visible grains)

Anthracite Coal

sedimentary, biochemical chemical, composed of mostly calcite, well sorted hash of shell fragments, porous and little visible matrix or cement

Coquina

sedimentary, Biochemical chemical, composed of carbonized plant fragments, black to dark brown; brittle, fine bands of dull and shiny coal

bituminous coal

Biochemical chemical, composed of plant fragments, characterized by brown, visible plant fragments, easily fragmented

Peat

inorganic chemical, softer than fingernail and sugary appearance

Rock Gypsum

Metamorphism that involves heat, pressure, and shearing, creates foliation

dynamothermal metamorphism

type of metamorphism caused by magma coming into contact with existing rock, does not create foliation

contact metamorphism

type of metamorphism that occurs when very hot water reacts with rock, altering its mineralogy and chemistry

hydrothermal metamorphism

Protolith is shale, Texture is foliated

(Cleavage: slaty)

(main minerals: micas, quartz)

metamorphic grade: lowest foliated

dull luster, breaks into hard flat sheets, rings when tapped by nail

Slate

Protolith is shale, Texture is foliated (microscopic crystals)

(main minerals: micas, quartz)

metamorphic grade: second lowest foliated

satiny sheen, breaks along wrinkled or wavy foliation surfaces, small mica minerals barely visible

Phyllite

Protolith is shale and granite

Texture is foliated (macroscopic crystals

metamorphic grade: second highest foliated

visible crystals of platy minerals (especially micas), breaks along scaly foliated surfaces, many mineral varieties such as (mica, granite and chlorite)

(brilliant luster, breaks along undulating surfaces, often with porophyoblasts)

Schist

Protolith is is shale and granite (felsic/mafic igneous rocks)

Texture is foliated (macroscopic crystals

(main minerals: micas, quartz, pyroxenes, amphiboles, feldspars)

metamorphic grade: highest foliated

alternating light-dark coloured layers(; contrasting composition)

Gneiss

black, two directions of cleavage NOT at 90 degrees, bright reflections off cleavage surface, long slender crystals, splintery fracture, glassy luster, H=5-6

amphibole

Protolith is quartz sandstone, Texture is nonfoliated (sandy, granular)

(main minerals: quartz)

Quartz sand grains fused together

fine to coarse grained

grains will not rub off like sandstone

harder than glass

quartzite

Protolith is limestone, Texture is nonfoliated (microcrystalline to coarsely crystalline)

(main minerals: calcite, dolomite)

fused calcite crystals, reacts to acid, softer than glass, coarse grained, color variable

Marble

Protolith is basalt(mafic to ultramafic igneous rocks)

Texture is nonfoliated (finely crystalline to fibrous)

dark with dull to waxy luster, has greenish bladed crystals with glossy or waxy luster, is fine to coarse grained

Serpentinite

Protolith is many possible but shale is common (any fine-grained rock adjacent to igneous intrusion)

Texture is nonfoliated (randomly oriented, porphyroblastic-large mineral crystal in a metamorphic rock which has grown within the finer grained groundmass)

dark gray, green to black, microcrystalline to fine grained, but may contain larger crystals of specific minerals, mat luster, dense, very hard

Hornfels

vesicular, mafic, extrusive, pyroclastic texture

Vesicular Basalt

Brown to greenish black to black

Perfect cleavage in one direction (basal/sheet)

Glassy luster

Elastic

H= 2.5-3

Biotite Mica

Colorless to white, yellow, pink, blue, to gray or brown

3 direction of cleavage NOT at 90 degrees (rhombic)

Glassy luster

Fizzes with HCL acid

Double refraction

H= 3

Calcite

Copper streak

Copper color

tarnishes brown or green

forms odd shaped masses

no cleavage

H= 2.5-3

Copper

Usually rusty gray, dull luster, rarely blue (sapphire) or red (ruby) forms 6 sided crystal, H=9

corundum

Purple, green, clear and many other colors

Translucent or transparent

Cubic crystals

4 directions of cleavage (octahedral)

Glassy luster

H= 4

Fluorite

Dark gray streak

Silver to lead gray

Cleavage in 3 directions at 90 degrees (cubic)

Dense

H= 2.5

Galena

Colorless to white

Cleavage good in one direction, poor in two others

Satiny luster

H= 2

Gypsum

Usually colorless to white (may be many colors)

Cleavage in three directions at 90 degrees (cubic)

Glassy luster

Salty taste

H= 2.5

Halite

Reddish-brown streak

Silver to steel gray in color

Uneven fracture

Glitter-like flakes

H= 5-6

Hematite (specular)

Red to reddish brown, dull/earthy luster, reddish brown streak, H=1.5-3

Hematite (earthy)

white, dull luster, occurs in powdery masses, earthy smell, H=2-2.5

Kaolinite

Yellow to yellowish brown

Dull/earthy luster

Rusty smell

Yellowish brown streak

H= 1.5-5.5

limonite

Black streak

Black to dark gray in color

Crystalline masses

Uneven fracture

Dense

Magnetic

H= 5.5-6.5

Magnetite

colorless to light tan, perfect cleavage in one direction (basal/sheet) transparent in thin sheets, glassy luster, elastic, H=2.5-4

Muscovite Mica

light to dark green, small granular grains, single crystals rare, glassy luster, conchoidal and uneven fracture, H=6.5-7

olivine

white to dark gray, two directions of cleavage at 90 degrees, striations common, usually on one cleavage face, glassy luster, white streak, H=6-6.5

plagioclase feldspar

Pink, white or green

Two direction of cleavage at 90 degrees

Exsolution lamellae common

Glassy luster

H= 6-6.5

potassium feldspar

Greenish-black streak

Crystalline masses or cubic crystal form

No cleavage

"Fools gold"

H= 6-6.5

pyrite

greenish black to black, two directions of cleavage at 90 degrees, dull to glassy luster, H=5.5-6

pyroxene (variety augite)

many color variations, occurs as crystallized masses or 6 sided single crystal forms (hexagonal pyramids and prisms) glassy luster, conchoidal fracture, H=7

quartz

Sphalerite

Yellow streak

Dark, Crystalline masses

Metallic luster on crystal faces

Resinous luster on cleavage surfaces

Rotten egg odor when scratched

H= 3.5-4

sphalerite

bright yellow, powdery masses, dull/earthy luster, rotten egg smell, H=1.5-2.5

sulfur

3.5

What hardness is a mineral scratched by a copper penny?

2.5

What hardness is a mineral scratched by a fingernail?

curved surface w a sharp edge

What is a conchoidal fracture?

6.5

What hardness must a mineral be to mark a streak plate?

5.5

What hardness must a mineral be to scratch glass?

white pink or green, pearly luster, feels soapy or greasy, H=1

talc

-crystals too small to be seen (need magnification)

-feels like sandpaper

-can be vesicular

Aphanetic

-crystals are large enough too see and can be used to identify the rock

Phaneritic

-has phenocrysts and ground mass

-cools from slow to rapid

Porphyritic

-wide range of grain sizes

-grain is not interlocked

-comes from volcanic ash

Pyroclastic

-very large

-forms in late stage of cooling

-cools fast

-lots of water and silica make the atoms move quickly

Pegmatic

igneous rocks are made of _________ minerals

silicate

-has lots of iron and magnesium

-less silicate

-dark: black/green

ferromagnesium silicate

-has less iron and magnesium

-more silicate

-light: pink, white, clear

nonferromagnesium silicate

felsic, phaneritic and intrusive (quartz, feldspar, and mica)

granite

mafic, aphanitic and extrusive (plagioclase feldspar, pyroxene, olivine)

basalt

ultramafic, very high iron and magnesium, phaneritic, very low silicate and intrusive

peridotite

intermediate, aphanitic and extrusive

(middle iron and magnesium, middle silica,plagioclase, amphibole) (pic has hornblende in it as well)

andesite

felsic, aphanitic texture, extrusive

EXAMPLE: Yellowstone park

rhyolite

felsic, intermediate or mafic, extrusive, glassy texture (no minerals)

EXAMPLE: lava cools instantly

obsidian

felsic to intermediate, vesicular texture, extrusive

EXAMPLE: lava cools instantly

pumice

-granite

-rhyolite

-obsidian

-pumice

felsic composition (4 types)

intermediate comp, phaneritic texture, intrusive

(plagioclase, amphibole)

diorite

-mafic comp intrusive

-plagioclase feldspare, pyroxene, olivine

-phaneritic texture

PLATE TECTONICS: oceanic crust

gabbro