Oceanography Ch 1,3,4

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an increase in the mass of body by accumulation or clumping of smaller particles

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accretion

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a multicelluar organism unable to synthesize its own food and often capable of movement

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animal

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the smallest particle of an element that exhibits the characteristics of that element

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atom

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the hypothetical event that started the expansion of the universe from a geometric point; the beginning of time

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big bang

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the initial formation of life on Earth

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bio synthesis

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the basic organizational unit of life on this planet

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cell

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a substance composed of two or more elements in a fixed proportion

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compound

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premise that stars and planets accumulate from contracting, accreting clouds of galatic gas, dust, and debris

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condensation theory

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the formation of layers in a material, with each deeper layer being denser (weighing more per unit of volume) than the layer above

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density stratification

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a substance composed of identical atoms that cannot be broken down into simpler substances by chemical means

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element

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tests that simplify observation in nature or in the laboratory by manipulating or controlling the conditions under which observations are made

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experiments

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a large rotating aggregation of stars, dust, gas and other drebris held together by gravity

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galaxy (there are approx 50 billion galaxies in universe and 50 billion stars in each)

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a speculation about the natural world that may be verified or disproved by observation and experiment

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hypothesis

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a large construct explaining events in nature that have been observed to occur with unvarying uniformity under the same conditions

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law

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the process (or result) of applying the scientific method to the ocean, its surroundings, and the life-forms within it

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marine science; oceanography

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a measure of the quantity of matter

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mass

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a complex structure of proteins and lipids that forms boundaries around and withing the cell. it is usually semipermeable, allowing some kinds of molecules to pass through but not others

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membrance

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the name of our galaxy; sometimes applied to the field of stars in our home spiral arm (Orion arm)

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Milky Way galaxy

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a close interminigling of different substances that still retain seperate identities. the porperties of a mixture are heterogenous

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mixture

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diffuse cloud of dust and gas

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nebula

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an element whose proportion in seawater varies with time and place, depending on biological demand of chemical reactivity. an element with a short residence time; for example iron, aluminum, silicon, trace nutrients, dissovled oxygen and carbon dioxide

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nonconservative constituent

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a compound or ion that is needed by autotrophs for primary productivity and that changes in concentration with biological activity

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nonconservative nutrient

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the great body of saline water that covers 70.78% of the surgace of the earth; one of its primary subdivisions, bounded by continents, the equater, and other imaginary lines

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ocean

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the science of the ocean

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oceanography

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the volcanic venting of volatile substances

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outgassing

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the time span, from about 2 billion to 400 million years ago, during which photosynthetic autotrophs changed the composition of earth's atmosphere to its current oxygen-rich mixture

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oxygen revolution

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the smallest unit of light engery

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photon

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a smaller, usually nonluminous body orbiting a star

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planet

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a tightly condensed knot of material that has not yet attained fusion temperature

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protostar

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a systematic way of asking questions about the natural world and testing the answers to those questions

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science

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the orderly process by which theories explaining the operation of the natural world are verified or rejected

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scientific method

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the diffuse cloud of dust and gas from which the solar system originated

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solar nebula

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the sun together with the planets and other bodies that revolve around it

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solar system

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a massive sphere of incandescent gases powered by the conversion of hydrogen to helium and other heavier elements

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star

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the explosive collapse of a massive star

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supernova

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simultaneous sampling at many locations

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synoptic sampling

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a general explanation of a characteristic of nature consistently supported by observation or experiment

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theory

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the great body of saline water that covers 70.79% of Earth's surface

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world ocean

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(essay) Trace the life of a typical star.

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-after fusion reaction begin, star becomes stable- neither shrinking or explanding, and burning its hydrogen fuel at a steady rate
-over a long and productive life, the star converts a large percentage of its hydrogen to atoms as heavy as carbon or oxygen
-this stable phase ends eventually
- the life history and death of a star depend on its initial mass
-when a medium-mass star (like our sun) begins to consume carbon and oxygen atoms, its engery output slowly rises and its body swellts to a stage named RED GIANT
-the dying giant slowly pulsates, incineratin its planets and throwing off concentric shells of light gas enriched with these heavy elements.
-however most of the harvest of carbon and oxygen is forever trapped in the cooling ember at the star's heart

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(essay) What is density stratification?

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-density is mass per unit volume
-in the early formation of still-fluid Earth it was sorted by density (heavy elements and compounds were driven by gravity towards its center, lighter gases rose to the outside
-the resulting layers (strata) are arranged with the densest at and near the Earth's center, the least dense as the atmosphere
-the process of density stratification lasted perhaps 100 million years, and ended 4.6 billion years ago with the formation of Earth's first solid crust

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(essay) How old is the oldest evidence for life on Earth? On what are those estimates based?

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The oldest fossils, (from northwestern Australia), are between 3.4 billion and 3.5 billion years old
-they are remnants of fairly complex bacteria-life oranisms, indicating that life must have originated even earlier, probably only a few hundred million years after a stable ocean formed
-evidence of an even more ancient beginning has been found in the form of carbon-based residues in some of the oldest rocks on Earth, from Akilia Island near Greenland
-these 3.85 billion year old specks of carbon bear a chemical fingerprint that may researches feel could only have come from a living organism

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the hot, plastic layer of the upper mantle below the lithosphere, extending some 220 to 400 miles below the surface. convection currents within this layer power plate tectonics

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asthenosphere

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the relatively heavy crustal rock that forms the seabeds, composed mostly of oxygen, silicon, magnesium, and iron, its density is about 2.9 g/cm^3

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basalt

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the ability of an object to flat in a fluid by displacement of a volume of fluid equal to it in mass

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buoyancy

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a way of grouping objects accoring to some stated criteria

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classification

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the transfer of heat through matter by the collision of one atom with another

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conduction

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the solid masses of the continets, composed primarly of granite

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continental crust

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the theory that the continents move slowly across the surface of Earth

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continental drift

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movement within a fluid resulting from differential heating and cooling of the fluid.

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convection current

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a region where plates are pushing together and where a mountain range, island arc, and/or trench will eventually form; often a site of much seismic and volcanic activity

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convergent plate boundary

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the innermost layer of Earth, compoed porimarly of iron, with nickel and heavy elements. the inner core is thought the be a solid 6,000 C sphere, the oter core at 5,000 C liquid mass

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core

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the outermost solid layer of Earth, composed mostly of ranit and basalt; the top of the lithosphere

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crust

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the mass per unit volume of a substance, usually expressed in grams per cubic centimeter

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density

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accumulation, usually of sediments

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depostion

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a region where plates are moving apart and where new ocean or rift valley will eventually form. a spreading center forms the junction

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divergent plate boundary

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a streamlined hill formed by a glacier

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drumlin

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a sudden motion of Earth's crust resulting from waves in Earth cause by faulting of the rocks or by volcanic activity

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earthquake

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a fracture in a rock mass along wich movement has occured

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fault

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the relatively light crustal rock-- composed mainly of oxygen, silicion, and aluminum-- that forms the continents. its density is about 2.7 g/cm^3

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granite

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a sensitive device that measures variations in the pull of gravity at different polaces on Earth's surface

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gravimeter

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a surgace expression of a plume of magma rising from a stationary source of heat in the mantle

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hot spot

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balanced support of lighter material in a heavier, displaced supporting matrix; analgous to buoyancy in a liquid

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isostatic equilibrium

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the brittle, relatively cool outer layer of Earth, consisting of the oceanic and continetal crust and the outermost, rigid layer of mantle

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lithosphere

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the rigid portion of Earth's mantle below the asthenosphere

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lower mantle

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molten rock capable of fluid flow (called lava above ground)

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magma

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a device that measures the amount and direction of residual magnetism in a rock sample

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magnetometer

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the layer of Earth between the crust and the core, composed of silicates of iron and magnesium. it accounts for about 68% of the Earth's mass

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mantle

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ascending columns of superheated mantle originating at the core- mantel boundary

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mantle plume

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the rigid inner mantel, similar in chemical composition to the asthenosphere

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mesophere

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hills of ridges of sediment deposited by glaciers

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moraine

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the outermost solid surface of Earth beneath ocean floor sediments, composed primarily of basalt

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oceanic crust

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an assemblage of subducting oceanic lithosphere scraped off (obducted) onto the edge of a continent

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ophiolite

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primary wave; a compressional wave that is associated with an earthquake and that can move through both liquid and rock

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P wave

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the zone of seismic and volcanic activity that encricles the Pacific Ocean

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Pacific Ring of Fire

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the "fossil" or remanent, magnetic field of rock

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paleomagnetism

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name given by Alfred Wegener to the original "protocontinent." The breakup of Panaea gave rise to the Atlantic Ocean and to the continents we see today

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Pangaea

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name given by Alfred Wegener to the ocean surrounding Pangaea

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Panthalassa

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one of about a dozen rigid segments of Earth's lithosphere that move independently. the plate consists of continental or oceanic crust and the cool, rigic upper mantle directly below the crust.

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plate

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the theory that Earth's lithosphere is fractured into plated that move relative to each other and are driven by convection currents in the mantle. most volcanic and seismic activity occurs at plate margins

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plate tectonics

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force per unit area

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pressure

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the disintegration of unstable forms of elements, which releases subatomic particles and hear

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radioactive decay

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the process of determining the age of rocks by observing the ratio of unstable radioactive elements to stable decay products

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radiometric dating

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a logarithmic measure of earthquake magnitude. a great earthquake measures about 8

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Richter scale

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a linear lowland between mountain ranges usually caused by crustal extension

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rift valley

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secondary wave; a transverse wave that is associated with an earthquake and that cannot move through liquid

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S wave

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the height of the ocean surface

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sea level

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the theory that new ocean crust forms at spreading centers, most of which are on the ocean floor, and pushes the continents aside. power is thought to be provided by convection currents in Earth's upper mantle

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seafloor spreading

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referring to earthquakes and the shock of earthquakes

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seismic

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a low-frequency wave generated by the forces that cause earthquakes. some kinds of these waves can pass through Earth.

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seismic wave

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an instrument that detects and records earth movement associated with earthquakes and other disturbances

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seismograph

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the junction between diverging plates at which new ocean floor is being made

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spreading center (aka spreading zone)

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the downward movement into the asthenosphere of a lithospheric plate

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subduction

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an area at which lithospheric plate is decending into the astehnosphere. the zone is characterized by linear folds (trenches) in the ocean floor and strong deep-focus earthquakes

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subduction zone (aka Wadati-Benioff zone)

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a very large mantle plume

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superplume

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an isolated segment of seafloor, island arc, plateau, continental crust, or sediment transported by seafloor spreading to a position adjacent to a larger continenal mass; usually different in compoition from the larger mass

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terrane

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a plane along which rock masses slide hoizontally past one another

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transform fault

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places where crustal plates shear laterally past one another. crust is neither produced nor destroyed at this type of junction

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transform plate boundary

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speed in a specified direction

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velocity

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(1880-1930) German scientist who proposed the thoery of continental drift in 1912.

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Alfred Wegener

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(1908-1993) Canadian geophysicisit who proposed the theory of plate tectionics in 1965.

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John Tuzo Wilson

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(essay) How can seismic waves be used to "see" inside Earth?

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-seismic waves form in two types: surface & body waves
-surface waves can sometimes be seen as an undulating wave-like motion in the ground & can cause most of the porperty damage suffered in an earthquake
-body waves (P & S waves) are less dramatic, bu they are useful for analyzing Earth's interior structure.
-the time of tansit through Eath, the changes in the sound of the waves (analogous to our hearing bass/treble), the attenuation of the waves, and the later arrival of faint echos all can be used to analyse the interior

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(essay) How can Earth's magnetic field be "frozen" into rocks as they form?

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-a compass needle points toward the magnetic north pole because it aligns with Earth's magnetic field
-tiny particles of an iron-bearing magnetic mineral called magnetite occur naturally in basaltic magma
-when this magma erupts at mid-ocean ridges, it cools to form solid rock
-the magnetic minerals act like miniature compass needles
-as they cool to form new seafloor, the magnetic minerals' magnetic fields align with Earth's magnetic field.
-thus the orientation of Earth's magnetic field at that particular time becomes frozen in the rock as it solidifies
-any later change in the strength or direction of Earth's magnetic field will not significantly change the characteristics of the field trapped withing the now-solid rocks

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(essay) Earth is 4,600 million years old, and the ocean nearly as old. Why is the oldest ocean floor so young-- rarely more than 200 million years old?

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-the light, ancient granitic continents ride high in the lithospheric plates, rafting on the moving asthenosphere below
-in subductio, heavy basaltic ocean floor (and its overlying layer of sediment) plunges into the mantle at subduction zone to partially remelted, but the light granitic continents ride above, too light to subduct
-the subducting plate may be very slight more dense than the upper asthenosphere on which it rides, and so is pulled downard into the mantle by gravity
-because the ocean floor itself acts as a vast "conveyor belt" transporting accumulated sediment to subduction zones where the seafloor sinks into the asthenosphere, no marine sediments (or underlying crust) are of great age.
-the ocean floor is recycled; the continents just jostle above the fray

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small sediment-convered inactive colcano or intrusion of molten rock lass then 200 meters (650 feet) high, thought to be associated with seafloor spreading. abyssal hills punctuate the otherwise flat abyssal plain

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abyssal hill

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flat, cold, sediment-covered ocean floor between the continental rise and the oceanic ridge at a depth of 3,700 to 5,500 meters. ___ are more extensive in the Atlantic and Indian Oceans than in the Pacific

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abyssal plain

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the continental margin near an area of lithospheric plate convergance

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active margin (aka Pacific-type margin)

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the discoery and study of submerged contours

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bathymetry

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the submerged outer edge of a continent, made of grantic crust: inclueds the ocntinental shelf and continental slope.

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continental margin

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the wedge of sediment forming the gentle transition from the outer (lower) edge of the continental slope to the abyssal plain; usually associated with passive margins

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continental rise

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the gradually sloping submererged extention of a continent, composed of grantic rock overlain by sediments; has feathers similar to the edge of a nearby continent

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continental slope

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a relatively dense aggregation of fishes, squid, and other mesopelagic orangisms capable of reflecting a sonar pulse that resembles a false bottom in the ocean. its postion varies with the time of day

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deep scattering layer (DSL)

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accumulation, usually of sediments

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deposition

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area of irregular, seismically inactive topography marking the position of a once-active transform fault

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fracture zone

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a flat-topped, submerged inactive volcano

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guyot

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a spring of hot, mineral-and gas-rich seawater found on some oceanic ridges in zones of active seafloor spreading

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hydrothermal vent

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one of the several periods (lasting several thousand years each) of low temperature during the last million years. glaciers and polar ice were derived from ocean water, lowering sea level at least 100 meters (328 feet)

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ice age

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permant cover of ice; formally limited to ice atop land, but informally applied also to floating ice in the Arctic Ocean

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ice cap

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a large mass of ice floating in the ocean that was formed on or adjacent to land

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iceberg

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curving chain of volcanic island and seamounts almost always found paralleling the concave edge of a trench

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island arc

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deep-ocean floor made of basaltic crust

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ocean basin

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young seabed at the active spreading center of an ocean, often unmasked by sediment, bulging above the abyssal plain. the boundary between diverging plates

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oceanic ridge (aka mid-ocean ridge even though less than 60% of the length exist as mid-ocean)

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the 23degree 27' "tilt" of Earth's rotational axis relative to the plane of its orbit around the sun

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orbital inclination

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the continental margin near an area of lithospheric plate divergance

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passive margin

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a circular or elliptical projection from the seafloor, more than 1 kilometer in height, with a relatively steep slope of 20-25 degrees

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seamount

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shelf break

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the abrupt increase in slope at the junction between continental shelf and continental slope

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a deep, v-shaped valley running roughly perpendicular to the shoreline and cutting across the edge of the continental shelf and slope

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submarine canyon

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the extension of a person's sense by remote sensores and manipulators

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telepresence

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an arc-shaped depression in the deep-ocean floor with very steeo sides and a flat sediment-filled bottom coinciding with a subduction zone. most occur in the Pacific

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trench

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an underwater "avalanche" of abrasive sediments thought responsible for the deep sculpturing of submarine canyons and means of transport for sediments accumulating on abyssal plains

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turbidity current

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chaotic fluid flow

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turbulence

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(essay) Satellites orbit in space. How can a satellite conduct oceanographic research? Why does the surface of the ocean "bunch up" over submerged mountains and ridges?

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-satellites cannot measure ocean depths directly, but they can measure small variations in the elevation of surface water using radar beams
-this is useful because the pull of gravity varies across Earth's surface depending on the nearness (or distance away) of massive parts of Earth
-an undersea mountain or ridge "pulls" water toward it from the sides, forming a mount of water over itself, and that mount is detected by the orbiting satellite

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(essay) What are submarine canyons? Where are they found, and how are they thought to have been formed?

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-Submarine canyons cuts into the continental shelf and slope, often terminating on the deep-sea floor in a fan-shaped wedge of sediment
-most geologist believe that the canyons have been formed by abrasive tubidity currents plunging down the canyons