geol 211 intro to oceanography exam 1 jmu haynes

science

systematic process of asking questions about the world by gathering and studying information

marine science

process of discovering unifying principles in data obtained from the ocean, its associated life forms, and its bordering lands

galaxy

huge rotating aggregation of stars, dust, gas, debris; held by gravity

stars

massive spheres of incandescent gases

solar system

sun and family of planets

nebulae

large, diffuse clouds of dust and gas within galaxies, where stars form

supernova

expansion of a dying star, core collapses, energy explodes out

solar nebula

thin cloud from which sun and planets formed, probably struck by shock wave. 1. causing condensing mass to spin. 2. nebula absorbed heavy atoms from passing supernova remnant

accretion

the clumping go small particles into large masses

density stratification

iron sinks, lighter materials rose, forming crust

outgassing

volcanic venting of volatile substances

biosynthesis

early steps in evolution of living organisms from simple organic building blocks

planetesimals

outer objects of nebula, accretion of these forms terrestrial planets

giant impact hypothesis

earth's gravity captures asteroid the size of mars

peridotite

olivine pyroxene rock, dominant rock of upper mantle; found as fragments in volcanoes carried up by magmas from the mantle

origin of h2o in seawater

there are two hypotheses: water from volcanic eruptions (vapor)(outgassing), comets

lunar mare

areas where asteroids punctured surface of moon and molten material came up

4.6 billion years old

accepted age of earth

radiometric dating

radioactive isotopes decay at constant geometric rate; after certain amount of time, half parent will survive and half will decay into daughter

igneous rocks

made by cooling of molten rock, best for radiometric dating

geologic time scale

allows scientists to speak the same language, calendar of earth's history based on fossil changes, never repeats

lake baikal

worlds deepest lake

tectonics

study of movement and deformation of earths crust

wegener

came up with continental drift hypothesis

evidence for continental drift

continents fit together, fossil matching, rock matching, glacial deposits of same age

oceanic crust

made of volcanic rock (basalt), denser

continental crust

made of granite, less dense

radiation, conduction, convention

three ways of transferring heat

mid ocean ridges

spreading centers in middle of ocean where new crust is formed

evidence for seafloor spreading

oceanic crust gets older farther away from ridges, pillow lava rocks, earthquake depth varies in subduction zones

divergent, convergent, transform

three types of plate boundary motions

thermal gradient

heat moves from the hotter parts to the cooler parts, not uniform

atoll

ring shaped island of coral with lagoon in middle

ophiolites

pillow lava on land

seismic waves

travel through earth during earthquake

surface waves

seismic waves along surface

body waves

less dramatic seismic waves

mantle

made of oxygen, iron, magnesium, silicon

core

solid inner, liquid outer, made of iron and nickel,

lithosphere

cool rigid outer layer; crust and coolest part of mantle

asthenosphere

hot flowing layer in upper mantle below lithosphere

lower mantle

extends to the core, hot, flows much slower

buoyancy

ability of an object to float in a fluid by displacing a volume of fluid equal to its own weight

isostatic equilibrium

taller continents float on more dense crust that sinks lower

fault

a plane of weakness in rock

echo sounders

measure depth by bouncing high frequency sound waves off bottom of ocean

convection currents

slow flowing circuits of material within mantle

mantle plumes

continent sized columns of superheated mantle

hot spots

one of the surface expressions of plumes of magma rising

terranes

plateaus, isolated segments of seafloor, ocean ridges, ancient island arc, and parts of continental crust; thickness and low density prevents subduction

baythymetry

discovery and study of ocean floor topography

continental margin

submerged outer edge of a continent

ocean basin

deep sea floor beyond the continental margin

passive margins

continental margins facing the edges of diverging plates

active margins

continental margins near the edges of converging plates, earthquakes and volcanoes

shelf, slope, rise

three divisions of continental margins

shelf break

marks the abrupt transition from continental shelf to continental slope

submarine canyons

cut into the continental shelf and slope, often terminating on the deep sea floor in a fan shaped wedge of sediment

turbidity currents

mass movements of sediment, occur when turbulence mixes sediments into water above a sloping bottom

transform faults

fractures along which lithospheric plates slide horizontally

fracture zomes

inactive areas that show evidence of part transform fault activity

hypothermal vents

rocky chimneys or cracks from which dark, mineral laden hot water comes through

abyssal plains

flat, featureless expanses of sediment covered ocean floor found on periphery of all oceans

abyssal hills

small, sediment covered extinct volcanoes or intrusions of once molten rock

seamounts

volcanic projections that do not rise above the surface of the sea

guyots

flat topped seamounts that once were tall enough to approach or penetrate sea surface

trench

arc shaped depression in the deep ocean floor where a converging oceanic plate is subducted

island arcs

curving chains of volcanic islands and seamounts, almost always parallel to concave edges of trenches