Science tri 3- hon. Science erosion and weathering

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Rock Cycle

igneous rock

rock that forms when magma cools and solidifies

Extrusive

fine-grained igneous rock that forms when magma cools quickly at or near Earth's surface

Instrusive

igneous rock that has large crystals and formed when melted inside the Earth's surface. Rock cools slowly and hardens

Microscopic grains

Grains not visible to the eye, extrusive

Fine grains

Sand sized 0.5mm, extrusive or intrusive

Coarse grains

Larger than sand >2mm, intrusive

Felsic, Microscopic Grain

Pumice

Felsic, Fine Grain

Rhyolite

Felsic, Coarse Grain

Granite

Andesitic, Microscopic Grain

Obsidian

Andesitic, Fine Grain

Andesite

Andesitic, Coarse Grain

Diorite

Mafic, Microscopic Grain

Scoria

Mafic, Fine Grain

Basalt

Mafic, Coarse grain

Gabbro

mafic magma

Dark color, low viscosity, Shield cone volcano

andesitic magma

Medium or mixed color, mix of low & high viscosity, Composite volcano

felsic magma

Light colored, high viscosity, Cinder cone volcano

phaneritic texture

igneous rock texture in which minerals are easily visible without magnification

aphanitic texture

A texture of igneous rocks in which the crystals are too small for individual minerals to be distinguished.

porphyritic texture

An igneous rock texture in which large crystals are scattered on a background of much smaller crystals.

glassy texture

A texture formed when a rock cools so fast it doesn't have time to crystallize

pyroclastic texture

produced from debris of explosive eruption, has many air bubble canals

pegmatitic texture

a texture of igneous rocks in which the interlocking crystals are all larger than one centimeter in diameter

Laccolith

Relatively small, mushroom-shaped pluton that forms when magma intrudes into parallel rock layers close to Earth's surface.

Batholith

A mass of rock formed when a large body of magma cools inside the crust

Magma structures

volcanic neck

solid igneous core of a volcano left behind after the softer cone has been eroded

xenolith

a piece of rock within an igneous rock that is not derived from the original magma but has been introduced from elsewhere, especially the surrounding country rock.

Dike

Vertical igneous structure

Sill

Horizontal-ish igneous structure

intrusion

Igneous rock formed from magma flowing into existing rock

Aa

Blocky slow moving lava

Pahoehoe

A hot, fast-moving type of lava that hardens to form smooth, ropelike coils

shield volcano

Flatter, mafic lava, composed of mainly Iron & Magnesium. Ex. Hawaii

cinder cone volcano

Short & steep, felsic lava, composed of mainly potassium, calcium, and sodium, pyroclastic flow with tephra

Tephra

bits of rock or solidified lava dropped from the air during an explosive volcanic eruption; ranges in size from volcanic ash to volcanic bombs and blocks

composite volcano (stratovolcano)

Tall & steep, andesitic lava, erupts alternately lava and tephra.

Richter scale

Ranks earthquakes based on ground movement, each increase in whole number is 10x the ground movement (logarithmic)

Richter scale effects

0-2 Not felt

2-3 Little felt

3-4 Ceiling lights swing

4-5 Walls Crack

5-6 Furniture moves

6-7* Some buildings collapse

7-8 Many buildings destroyed

8< Total destruction

movement magnitude scale

A scale that rates earthquakes by estimating the total energy released by an earthquake

Modified Mercalli Scale

a 12 point scale developed to evaluate earthquake intensity based on the amount of damage to various structures

Earthquake

Shaking of the earths crust from the release of energy

elastic rebound theory

The theory that continuing stress along a fault results in a buildup of elastic energy in the rocks, which is abruptly released when an earthquake occurs.

Fault

Surface that a rock breaks and moves along

focus

point inside the earth where the energy for an EQ is released

Epicenter

the point directly above the focus on the earth's surface

seismic waves

vibrations that travel through Earth carrying the energy released from the focus during an earthquake

P waves (Primary waves)

travel through liquids, gases, and solids, pushes and pulls, faster, fastest waves

S waves (secondary waves)

travel through solids only; cause rock to move in a side-to-side or up & down motion, slower waves

L waves (surface waves)

travels slowest, most wide reaching, very destructive cause it travels on the surface and can move up/down, rolling motion

Subduction

The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary.

ocean trench

Deep valley in the ocean floor that forms along a subduction zone

island arc

A string of volcanoes that form as the result of subduction of one oceanic plate beneath a second oceanic plate.

James Huttton

1790, first one to theorize a "dynamic" earth

Alfred Wegener

1920, proposed theory of continental drift. Theorized a supercontinent, Pangea, in the distant past

Henry Hess

discovered seafloor spreading through the abnormal young igneous rocks on the ocean floor and offered it as an explanation for mid-ocean ridges

Allan Cox and Brent Dalrymple

Discovered the flipping of Earth's magnetic poles through the cooling of rocks

Fredrick Vine and Drummond Matthews

Used the magnetic patterns on the sea floor as proof for seafloor spreading

divergent boundary

The boundary between two tectonic plates that are moving away from each other, O-O or C-C, forms mafic rocks, shallow EQs, makes normal faults

transform boundary

A plate boundary where two plates move past each other in opposite directions, O-O O-C C-C, Offset features, strike slip faults, shallow EQs

strike-slip fault

occurs at transform boundaries

normal fault

occurs at divergent boundaries

reverse fault

occurs at convergent boundaries

Hot Spots

places where molten material from the mantle reaches the lithosphere, middle of a plate

Convergent Oceanic-Continental

Forms a trench, can cause shallow medium deep earthquakes, volcanoes, and mountains.

convergent oceanic-oceanic

Features: Trenches, volcanoes, shallow medium deep earthquakes, volcanic island arcs

Convergent Continental-Continental

Forms folded mountains shallow medium deep earthquakes.

Weathering

The breaking down of rocks and other materials on the Earth's surface.

mechanical weathering

the breakdown of rock into smaller pieces by physical means

chemical weathering

The process that breaks down rock through chemical changes

Four most prominent forces of erosion

Wind, Water, Glaciers, & Gravity

mass wasting

the downslope movement of rock, regolith, and soil under the direct influence of gravity

Landslide

a slide of a large mass of dirt and rock down a mountain or cliff

Mudflow

the flow of a mass of mud or rock and soil mixed with a large amount of water

Slump

A type of mass movement that occurs when a mass of material moves down a curved slope

Creep

the slow downhill movement of weathered rock material

Delta

a low triangular area where a river divides before entering a larger body of water

Alluvial Fan

a fan-shaped mass of material deposited by a stream when the slope of the land decreases sharply

dissolved load

Dissolved material in water

suspended load

The load contains small rocks and soil in suspension, which can make the river look muddy.

bed load

sand, pebbles, and boulders that are moved along the bed of a stream and that are too heavy to be carried in suspension

Fossil

The preserved remains or traces of an organism that lived in the past

Mold fossil

a space in a rock that has the shape of the remains of a living thing that once occupied that space.

Cast fossil

a model in the shape of a living thing or its remains, it forms when minerals or rock particles fill the space

trace fossil

the preserved evidence of the activity of an organism

Preserved remains

remains of organisms in tar, amber, or ice

mineral replacement

Fossils that preserve the structure of the original organically produced matter without actually preserving any of the original matter

carbon film

a type of fossil consisting of an extremely thin coating of carbon on rock

Index fossil

a fossil known to have lived in a short particular geologic age that can be used to date the rock layer in which it is found

Stratigraphy

the branch of geology concerned with the order and relative position of strata and their relationship to the geological time scale.

Law of Superposition

The top rock layer and its fossils is the youngest and the bottom is the oldest.