Intro to Earth Science Exam 1

Universe, Milky Way, Solar System

Objects from oldest to youngest

Red shift (Doppler shift,) galaxies observed moving away from one another, "echoes" of microwave radiation

evidence of the big bang

hydrogen

composition of the universe when it was young

dust aggregating towards the central plane, collisional coagulation

how is a planetesimal formed?

impact with a mars sized planetary body

how did the moon form?

Collapse of the Solar Nebula

What caused the solar system to form?

direct observation (rovers, landers, and humans) and indirect observation (meteorites)

how do we know about the planets in our solar system?

radiation, conduction, convection

What are the three types of heat transfer?

the tilt of Earth's axis

What causes Earth's seasons?

geosphere (mantle and plate tectonics,) atmosphere (wind,) and hydrosphere (water currents)

what parts of the earth experience convection?

seafloor spreading

The process that creates new sea floor as plates move away from each other at the mid-ocean ridges, evidenced by mid-ocean trenches and ridges

slab push

Magma pushes its way up through the crust, pushing the crust apart.

slab pull

the pulling of a tectonic plate as its edge subducts deep into the mantle

heat from inside the earth

what drives plate tectonics?

Fossils, Glaciers, complimentary coastlines, magnetic field reversals, & Rocks

evidence for plate tectonics

plate boundary

the region where two tectonic plates are in contact

volcanoes, earthquakes, and deep sea vents

what defines a plate boundary

divergent plate boundary

an area beneath the ocean where tectonic plates move away from each other

convergent plate boundary

A tectonic plate boundary where two plates collide, come together, or crash into each other.

transform boundary

A plate boundary where two plates move past each other in opposite directions

type of crust involved

what does type of plate boundary depend on?

granite, light

what is the composition and weight of continental crust

basalt, heavy

what is the composition and weight of oceanic crust

continental-continental convergence

happens where 2 continental plates collide and push up creating mountain ranges

oceanic-oceanic convergence

denser plate is subducted, deep trenches generated, volcanic island arcs generated

oceanic-continental convergence

more dense oceanic plate dives under continental plate. forms a trench. causes volcanoes, and earthquakes

Mafic

describes magma or igneous rock that is rich in magnesium and iron and that is generally dark in color, composition of magma generated at mid-ocean ridge

Felsic

Describes magma or igneous rock that is rich in feldspars and silica and that is generally light in color, composition of magma generated at oceanic-continental convergent boundary

hot spot

An area where magma from deep within the mantle melts through the crust above it. plume of hotter and lighter mantle material. stationary/does not move with other plates. theory established while studying hawaii

volcano

A weak spot in the crust where magma has come to the surface

by following volcanic trails

how can hotspots be used to track plate motion

Kimberlite

rare, ultramafic rock that can contain diamonds and other minerals formed only under very high pressures.

effusive volcanism

A type of volcanism in which the magma is very fluid and emerges gradually.

explosive volcanism

A type of volcanism in which pressure in the volcano builds up for a long time, so that an eruption much lava, rock and ash is ejected high into the air.

shield volcano

a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions. low viscosity, mafic magma.

Stratovolcano/Composite Volcano

A composite volcanic cone built of interlayered lava flows and pyroclastic materials. high viscosity, felsic magma

cinder cone

A steep, cone-shaped hill or small mountain made of volcanic ash, cinders, and bombs piled up around a volcano's opening

Caldera complex

depression formed at the summit of shield volcanoes

lava flow

the area covered by lava as it pours out of a volcano's vent

Tuff Ring

broad flat crater with low rims and shallow slope formed by a phreatomagmatic eruption

Tuff

A pyroclastic igneous rock composed of volcanic ash and fragmented pumice, formed when accumulations of the debris cement together.

Phreatomagmatic eruption

An eruption in which magma contacts cold water and contracts, either slowly, forming pillow basalts, or rapidly, forming ash.

flood basalt

Vast sheets of basalt that spread from a volcanic vent over an extensive surface of land; they may form where a rift develops above a continental hot spot, and where lava is particularly hot and has low viscosity.

gravity, atmospheric density, surface and atmospheric temperatures, cryovolcanism

factors affecting planetary volcanism

less gravity makes lava thicker

how does gravity affect volcanism?

determines how high it reaches

how does gravity and atmospheric density affect pyroclastic flow and eruptions

changes how the lava cools, hot atmosphere and surface means lava cools very slowly

how does surface temperature affect volcanism?

lost 1350 ft from top, devastated 160 sq mi of forest, mudflows, ash and debris launched 11 miles into the stratosphere

why was mount saint helens dangerous

temperature (hotter magmas are less viscous), composition, and dissolved gases in the magma

what determines magma behavior?

rhyolitic/andesitic lavas

higher silica content, more viscous

basaltic lava

low silica, flows easily

how easily gases escape from lava

how is violence of an eruption determined

Quiescent eruptions

Calm oozing of magma out of the ground produces lava flows. Usually associated with basaltic lavas of low viscosit

explosive eruption

an eruption that is thick and sticky, has a high gas content, and is high in silica

aa flow

a type of lava flow that has a jagged, blocky surface

pahoehoe flow

a lava flow with a smooth-to-ropy surface

lava tube

The empty space left when a lava tunnel drains; this happens when the surface of a lava flow solidifies while the inner part of the flow continues to stream downslope.

block lava

Lava that has a surface of angular blocks associated with material having andesitic and rhyolitic compositions

pillow lava

Basaltic ava that cools underwater, taking on a distinctive pillow-like shape as it hardens

pyroclastic material (tephra)

magma, ash and pieces of rock that are ejected into the atmosphere during an explosive volcanic eruption

pyroclastic flow

The expulsion of ash, cinders, bombs, and gases during an explosive volcanic eruption

Scoria

a glassy, mafic, igneous rock containing abundant air-filled holes

Pumice

A type of igneous rock that contains air bubbles. rhyolitic

fissure eruption

an eruption in which lava is extruded from narrow fractures or cracks in the crust

basalt plateau

a plateau built up by horizontal or nearly horizontal overlapping lava flows that erupted from fissures

lava dome

A mountain or hill made from highly viscous lava, which plugs the central conduit of volcanoes

Volcanism at convergent plate boundaries

Occurs at subduction zones, where two plates converge and the oceanic lithosphere descends into the mantle.

continental volcanic arc

mountains formed in part by volcanic activity caused by the subduction of oceanic lithosphere beneath a continent

volcanic island arc

a chain of volcanic islands generally located a few hundred kilometers from a trench where there is active subduction of one oceanic plate beneath another

intraplate volcanism

igneous activity that occurs within a tectonic plate away from plate boundaries

Large Igneous Provinces

a region in which huge volumes of lava and/or ash erupted over a relatively short interval of geologic time. basaltic

surge

a small amount of ash that separates from the main body of pyroclastic flow

Lahar

An avalanche of volcanic water and mud down the slopes of a volcano

Tsunami

A giant wave usually caused by an earthquake beneath the ocean floor.

Krakatoa

Volcano in Indonesia in 1883 that had a giant explosion and created a series of tsunamis killing 36,000

Minerals

occur naturally in rocks and soil, inorganic solids composed of 1 or more elements

Rocks

A naturally formed aggregate, or mixture, of minerals; have varied chemical compositions

elements held together by chemical bonds

how are minerals formed?

covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

ionic bond

Formed when one or more electrons are transferred from one atom to another

metallic bond

a bond formed by the attraction between positively charged metal ions and the electrons around them

van der walls bond

weak attractive force between electrical neutral atoms

Ordered internal structure

The atoms in the minerals are organized in a regular, repetitive geometric patterns or crystal structure.

Solid Solution Series

A series of minerals of identical structures that contain a mixture of 2 or more elements over a range of proportions. Ex calcic, albite

Polymorphs

Minerals with the same composition but different crystalline structures. ex. graphite, diamond

Mineral Identification

color, streak, luster, hardness, specific gravity, crystal habit, fracture/cleavage

Cleavage

A mineral's ability to split easily along flat surfaces. described by quality of break, number of planes, and angles between adjacent planes

fracture

The way a mineral looks when it breaks apart in an irregular way

Silicates

minerals that contain silicon and oxygen and usually one or more other elements. largest group of minerals

Nonsilicates

Mineral groups that lack silicas in their structures and account for less than 10 percent of Earth's crust.

No, it is organic

is coal a mineral?

Plutonic

An igneous rock that solidified at a considerable depth underground. (large crystal size)

Extrusive

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

size of crystals and rock texture

what does rate of cooling affect

Phaneritic

coarse-grained, crystals are large enough to be seen w/out a microscope, formed by slow cooling (intrusive)

Aphanitic

fine grained

glassy

crystal unable to form; Rapid rate of cooling prevents crystals from forming

Porphyritic

rock texture characterized by large, well-formed crystals surrounded by finer-grained crystals of the same mineral

Pegmatite

late stage crystallization of silicates

basalt and gabbro

examples of mafic igneous rocks