Earth Science- Unit 5: Igneous, Sedimentary, and Metamorphic rocks

Rock

A naturally occuring solid aggregate of one or more minerals.

Rock cycle

A visual representation of the relationship between earth’s products and the processes responsible for their formation.

Who is credited with the creation of the rock cycle?

James Hutton

Clastic Sedimentary rocks

Granular rocks formed by the transportation, deposition, compaction, and cementation formed by a sediment. Ex. Sandstone, Limestone, shale.

Chemical sedimentary rock

Crystalline sedimentary rocks formed by the precipitation of mineral matter carried in earths waters. Ex. Oceans, lakes, rivers. Ex. Chemical Limestone.

Organic sedimentary rock

Sedimentary rocks formed from the remains of once living organisms. Ex. Organic limestone, chalk, coal.

Stratification

The layering in sedimentary rocks.

Strata

A layer of rock

Cross bedding

A secondary layering at an angle to the main rock layers.(formed as a result of moving ripples and doons.)

Ripple Marks

Small, wavelike ridges of sediment formed by wind or moving water.Fo

Fossils

Naturally preserved, remains, impressions, or traces of once living organisms.

Clast

A fragment of a preexisting rock.

Boulder

>256mm- bigger than a basketball

Cobble

256mm-64mm- between the size of a tennis ball and a basketball

Pebble

64mm-4mm- In between the size of a pebble and a tennis ball.

Granule

4mm-2mm- In between the size of a pebble and the size of rice.

Sand

2mm-1/16mm- large enough to see and feel but are small.

Silt

1/16mm-1/256mm- Too small to see but large enough to feel

Clay

<1/256mm- Too small to see and feel

A conglomerate has…

rounded clasts

A breccia has….

angular clasts

Sorting

The degree of similarity of particle size.(the more similar the particle size, the greater the sorting.)

Chemical Limestone

Can range from multiple colors. Made of the mineral calcite that reacts with acid.

Rock Gypsum

Rock gypsum can be clear, white. Both are crystalline and are softer than a fingernail.

Rock Salt

Made of crystalline precipitated salt and is as hard as a fingernail.

Organic Limestone

Remain of once living organisms layered and fizzes with acid.

Coquina

Coquina are a bunch of fragments of shells.

Chalk

It is going to feel powdery and earthy. Made of shells. Will fizz with acid.

Coal

A black, somewhat shiny brittle, low specific gravity sedimentary rock. Formed from the remains of plants.

Overburden

Anything located above the coal seam that needs to be removed

Reclamation

returning the land to a usable or as close to original state possible.

Underground Mining

the mining process that happens underground.

Room and Pillar mining

Mining technique that is effective and keeps that wall above not stable.

Longwall mining

The modern mining technique used to mine.

Acid mine drainage

Rain and ground water picking up sulfur contaminants from the mine causing the water to become acidic as they enter the waterways.

Acid Precipitation

The result of the coal burning releasing ash into the sky resulting in acid precipitation.

Global Warming

The long term, rapid increase in earth’s average surface temperature, caused by human activities.

Porosity

The amount of a rocks total volume that is opened spaced or pores.

Permeability

The ability of a substance to allow fluids or gasses to pass through.

Impermeable

A substance to not allow fluids or gasses to pass through.

Source rock

An organic rich rock that can produce significant amounts of oil and gas.

Reservoir rock

A porous and permeable subsurface material capable of providing significant quantities of oil and gas.

Cap rock

An impermeable rock layer located above a reservoir rock that traps the oil and gas beneath it.

Anticline

An a shaped, upfolding of rock layers

Syncline

A u shaped, down folding of rock layers

Fault

A break or crack in the rocks along which motion has occured.

Igneous Rocks

Rocks formed by the cooling and crystallization of molten rock(magma/lava).

Pluto

the roman god of the underworld

Plutonic(Intrusive)Igneous rocks

Rocks that form underground therefore cooling slower creating crystal sizes that are larger.

Vulcan

The roman god of forge and fire

Volcanic(extrusive)Igneous rocks

Rocks that form above earth’s surface and therefore cool quickly creating crystal sizes that are smaller.

Aphanitic

(fine grained) crystals in general too small to be seen with the inaided eye. Considered to have a volcanic texture because crystal sizes are small therefore cooling quickly.

Phaneritic

(Coarse grained) General crystal size is large enough to be seen with the unaided eye and formed plutonically where the grains are large as they cooled slowly underground.

Pegmatitic

Extremely large crystal size, often creating gem quality materials.

Porphyritic

Characterized by two distinct grain sizes; larger crystals called phenocrysts that formed plutonically surrounded by a fine grain matrix known as the ground mass that formed volcanically.

Vesicular

Trapped air bubbles and is a volcanic igneous rock trapping the air within because it cools quickly that forms when lava is ejected on earth’s surface.

Glassy

When lava cools instantly not allowing any mineral crystals to form giving it a glassy texture. Note the conchoidal fracture!

Extrusions(lava flows)

Igneous rock bodies that form on earth’s surface are called extrusions.

Aa

Rocky, rough, feels rough

Pahoehoe

Smooth, Ropey

Intrusions(plutons)

Igneous rock bodies that form underground are called intrusions.

Batholith

Extremely large(greater than 100 square kilometers) irregularly shaped plutons. Batholith’s commonly form the core of some mountains such as The Adironacks, The black hills of south dakota, the sierra nevada’s, the ozarks.

Stock

Large(less than 100 kilometers) irregularly shaped plutons that are often vertical extensions of a batholith. S

Sill

a sill is a tabular, or sheet like igneous intrusion that is concordant(parellel to) the surrounding rock layers.

Dike

a dike is a tabular, or sheet likes igneous intrusion that is discordant(not in line with) to the surrounding rock layers.

Laccolith

A mushroom shaped igneous intrusion that forms when magma squeezes between rock layers and uplifts the overlying rock layers.

Volcanic Neck

A solid column of igneous rock that forms when magma crystallizes in the central vent of a volcano, and is later exposed as the softer flanks(sides) erode away.

Metamorphic rock

A rock formed by the solid state alteration of preexisting rocks under the influence of heat, pressure, and chemically active fluids(magma/lava).

Metamorphism

The process by which a metamorphic rock is formed.

what changes are associated with metamorphism

1.May become more dense, 2.colour may lighten, 3.Crystal size may enlarge, 4.May develop foliation, 5. New minerals may form.

Regional(dynamic) metamorphism

Metamorphism that affects large geographic areas exposed to significant heat and pressure associated with plate collisions.

Foliation

The alignment of mineral grains creating the layering in metamorphic rocks.

Contact(thermal) metamorphism

Metamorphism that effects small geographic areas exposed to significant heat associated with molten rock.

Nonfoliated

Metamorphic rocks that will not show layering