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earth 222 definition
eam 1
| Question | Answer |
|---|---|
| oceanography | the scientific study of the oceans, with the goal of understanding the processes and phenomena that take place in the marine realm |
| geological oceanography | study of rocks and sediments and processes responsible for their formation; properties of rocks such as magnetism, occurrence of earthquakes |
| physical oceanography | how and why ocean currents flow, air sea interactions such as the generation of waves by wind |
| how and why ocean currents flow, air sea interactions such as the generation of waves by wind | composition of seawater and the processes controlling and altering its composition, including marine pollution |
| biological oceanography | marine biology, organisms that live in the oceans and their relationship with the environment |
| longitude and latitude | systems of imaginary lines dividing the surface of the earth |
| equator | reference point for latitude, real, point of earth with the biggest circumference |
| prime meridian | reference point for longitude |
| latitude | tells you how far north or south of the equator you are. you can go from 0 to 90. lines are called parallels, use polaris for north and southern cross for south |
| marine sextant | used to capture the angle between polaris and the horizon to tell latitude |
| longitude | . runs up and down. its the angle that is at the center of our planet between the location being considered and the location along the same ling of latitude intersecting. the max angle is 180º, lines are east and west of the prime meridian |
| hipparchus | divided the surface of the earth into 360º |
| ptolemy | showed the world as a globe |
| captain james cook | explored on the HMS endeavor and the HMS resolution |
| ben frank | published the first chart of the gulf stream |
| matthew maury | created the first reliable wind and currents charts |
| charles darwin | voyaged on the HMS beagle, studied geology and biology of the south american coastline |
| wyvile thompson and jon murray | directed the first modern, deep ocean, global sampling expedition on the HMS challenger |
| frigtjof nansen | allowed the Fran to be trapped in the arctic ice pack. drifted for almost four years, proved that there is no arctic continent (all ice) |
| meteor expedition | first to map the ocean bottom by echo sounding, recorded its depth. discovered the mid ocean ridge |
| glomar challenger | first drill ship that started the JOIDES program, which later took over deep sea drilling |
| ROV/AUV | remotely operated vehicles and autonomous vehicles. the difference is that remote are tethered to shops so that they can only travel so far, and autonomous are programmed to come back to the surface at one point. both have arms for taking samples |
| TOPEX/Poseidon NASA project | started a new generation of oceanographic satellites |
| seasat | NASA launched the first oceanographic satellite |
| seismology | the study of elastic waves that travel through the earth |
| earthquake | a phenomenon that results from the sudden release of stored energy in the form of low frequency waves called seismic waves. there is a focus, an epicenter, a fault, and a wave front |
| P waves | (primary), travel by squeezing and expanding the medium they travel through. they can travel though both solids and liquids (like sound waves) |
| s waves | (secondary), travel by sharing the medium they pass through. can travel only through solids since particles need to be bonded to each other to propagate these waves, similar to a bullwhip |
| surface waves | above, on the surface of the planet |
| crust | thin, light outermost layer |
| mantle | made of oxygen and silicon with Fe and Mg |
| core | consists of mainly Fe and Ni |
| how many layers of the earth are there | 5 |
| lithosphere | rigid outer layer, curst and uppermost mantle |
| asthenosphere | deformable layer of upper mantle, plastic layer like playdoh |
| continential crust | mainly composed of granite, a light colored low density igneous rock rich in Al, Si, O. rises high above the supporting mantle rocks |
| oceanic crust | composed of basalt, a dark colored high density volcanic rock rich in Si, O, Mg. does not rise above as the mantle |
| isostasy | the balance of an object floating upon a fluid medium. the height of the object above and below the surface of the medium is controlled by the mass of the object and its density (similar to ice floating above water) |
| challenger expedition | first systematic bathymetric survey (lead lines used to measure depth ,discovered the ocean floor isn't flat) |
| echo sounding | based on the reflection of a sound impulse from the sea floor |
| WWII | the navy further developed sonar tech for sound navigation and ranging |
| marie tharp | identified the presence of mid atlantic ridge and rift valley opening the way to the theory of tectonic plates and seafloor spreading |
| multibeam echo sounders | multiple sound beams used can cover a larger area |
| satellites | only see the surface, sending outgoing radar pulses to the ocean and they are then returned by the surface |
| hypsographic curve | plots the amount of earths surface at each elevation or depth |
| continenal margin | to transition between what is geologically continent and what is geologically ocean (1-2 km below the surface) |
| pacific ocean | largest, deepest, ringed by geologically active features. lots of islands and seamounts |
| atlantic ocean | long, narrow, parallel sides, 68% of the worlds freshwater runs into it but its saltier than pacific because of circulation. second biggest |
| indian ocean | delivery of lots of sediments to nothern part, 3rd largest |
| arctic ocean | 4th larges, broad continential shelves |
| passive continential margins | have a continental shelf and rise |
| active continental margins | no continental rise, ocean trench, the slope is lighter than the passive because it doesn't end on the ocean floor, but below in a trench. active because they are plate boundaries |
| continental shelf | the shallow, submerged extension of a continent |
| shelf break | determined by an abrupt change in slope. end of the continent where the true body of the ocean starts |
| continental slope | underwater cliff, the transition between the gently descending continental shelf and the deep ocean seafloor |
| submarine canyons | cut into the continental shelf and slope, terminating in a fan-shaped wedge of sediment. delivers sediment from the shelf to the rise |
| continental rise | marks the beginning of the deep ocean basins. formed by the accumulation of sediments at the base of the continental slope. gentler gradient than the slope |
| trenches | narrow steep-sided troughs. sometimes in the middle of the ocean, come with volcanoes above or under water |
| island arc | curving chains of volcanic islands and seamounts |
| deep ocean basin | includes a variety of features: abyssal plains, abyssal hills, seamounts, mid ocean ridges, and deep sea trenches |
| abyssal plains | flat portion of the ocean floor covered by sediments (not really flat, by the thickness of sediments make them look flat) |
| abyssal hills | small extinct volcanoes or intrusions of once molten rock covered by sediments |
| seamounts | underwater volcanoes that rise abruptly and steeply form the ocean floor (some are active, others are inactive) |
| guyots | flat topped seamounts due to weathering taking off the top |
| mid ocean ridge system | runs all the way through the bottom of the ocean. continuous system of mountain chains that run through ever ocean basin |
| rift valley | in the atlantic and indian ocean, in the middle of the mid ocean ridge, there is a dip in the elevation of the ridge |
| transform faults | fractures that run perpendicular to mid ocean ridges |
| fracture zones | long, narrow regions of broken or disturbed seafloor |
| step island hypothesis | animals can cross small channels, but not large oceans |
| land bridge hypothesis | continents were connected in the past |
| mechanisms | heavy continents pulled towards the equator by centrifugal force and by effect of the sun and the moon (NOT TRUE, no force could move the continents) |
| paleomagnetism | magnetic anomalies and wandering of magnetic poles |
| magnetic anomalies | a repetitive pattern of positive and negative magnetic intensities arranged in zebra stripe fashion |
| negative anomalies | weaker signal. represent regions of the seafloor where the curst is magnetized with revered polarity |
| positive anomalies | stronger signal, regions of normal polarity |
| 3 important assumptions of the pangea theory | 1. lithosphere broken into plates that move a few cm/yr and interact with each other at plate boundaries 2. lithospheric plates move on ductile asthenosphere. 3. plates consist of oceanic lithosphere only or oceanic and continental lithosphere. |
| divergent | plates move apart (mid ocean ridge) it corresponds to the global system of mountainous submarine ridges called oceanic ridges. spreading centers where new crust is being generated |
| convergent | plates move towards each other (subduction zones) |
| transform | plates slide past each other (transform faults) |
| where does the formation of new oceanic crust occur | rift valleys (divergent boundary) because magma chambers underneath in asthenosphere form new rock (lithosphere gets thin and asthenosphere breaks through) |
| pillow gazalts | linear feature that has been fractured and has lava seeping out |
| spreading rate equation | spreading rate = distance (cm)/age (years) |
| transform plate boundaries | transform faults where plates shear laterally past each other. offsets oriented perpendicular to the ridge axis and parallel to each other to accomodate spreading of linear ridge system on a spherical earth |
| fracture zones | lines that go across the mid ocean ridge. in the middle of them are the transform faults |
| 3 types of convergent plate boundaries | oceanic continental, oceanic oceanic, continental continental |
| oceanic continental convergent | the heavier oceanic plate is subducted and the light continental plate overrides it. lithosphere is subducted into the mantle, which melts and new magma gets sent back into the asthenosphere, forming volcanoes and causing earthquakes |
| oceanic and oceanic convergent | one plate is subducted (older/denser/colder) and other rides over it. forms deep sea trenches due to subduction, more partial melting of the lithosphere forms magma and volcanoes, but they are in the midl of the ocean so they form volcanic islands |
| continental continental convergent | neither plate subducts. instead, they just keep crunching together, building up mountains and generating earthquakes. can form continental sutures. |
| continental suture | take 2 continents and connect them together. causes subduction to no longer be active (can still have earthquakes or residual magma though) |
| subduction zone | regions in which the crust is recycled into the mantle |
| deep sea trench | arc shaped depressions where subduction occurs |
| convection | the transfer of heat in a fluid by the circulation of currents from one region to another |
| convection currents | circular moving lops of rising warm material and falling cool material. there are these in the asthenosphere that cause convergent plate boundaries |
| hot spots | represent surface expressions of plumes of magma rising from stationary sources of heat in the mantle. ex= hawaii |
| marine sediments | particles of various sizes derived from a variety of sources that are deposited on the ocean floor |
| inputs of marine sediments | rivers, wind, volcanoes, deep ocean water, outer spaces |
| classifications of marine sediments by source | Terrigenous Biogenous Hydrogenous Cosmogenous |
| terrigenous sediments | consists of fragments produced by weathering (physical and chemical), erosion, and transport/deposition by physical processes. Most common sediment by mass. sources= rivers, wind, glaciers, turbidity currents, volcanic eruptions |
| input from glaciers: ice rafting | when icebergs float out to sea, gradually melt, and dump sediments trapped in the ice |
| input from volcanoes | Volcanic ash and debris comes from volcanoes and is transported by wind or water. Most common at convergent boundaries |
| classification of terrigenous sediments | by grain size, shows how they were transported and where they accumulated |
| hjulstrom curve | shows relationship between grain size and horizontal current velocity that results in erosion, transportation, or sediment deposition. Velocity determines the size that can be moved |
| biogenous sediments | particles that are produced directly by marine organisms. Highest of continental shelves. Dominant type of mid depth ocean (in form of oozes). Calcium carbonate and silica |
| calcareous organisms | foraminifera (zooplankton) and coccolithophores (phytoplankton) |
| siliceous organisms | radiolaria (zooplankton), diatoms (phytoplankton) |
| zooplankton | animals |
| phytoplankton | algae |
| hydrogenous sediments | precipitate directly from sea water. form in specific environments with different compositions. manganese and phosphorites nodules, evaporites, sulfides, carbonates |
| manganese modules | rounded, hard lumps of Mn and Fe found on top of the ocean floor sediments. formed by precipitation around a central nucleation object |
| phosphorite nodules | occur at depths below 1,000m, mainly on continental shelves, indicate abundant biological activity in surface waters |
| evaporites | form when there is restricted open ocean circulation and evaporation is high. evaporation and water salinity increases, carbonates formed, then gypsum, then sodium chloride |
| sulfides | associated with hydrothermal vents along mid ocean ridge. contains Fe, Ni, Cu, Zn, Ag, and other metals in carrying proportions |
| hydrothermal vents/black smokers | hot springs discovered on ocean ridges. water descends on the ridge floor until it comes into contact with very hot rocks. hot chemically active water dissolves minerals and gasses and escaped upward through convection |
| hydrogenous carbonate deposits | precipitate directly from seater in tropical climates to form crystals |
| oolites | form in shallow, agitated tropical waters with high concentration of CaCO3. small, calcite spheres with a layered strcuture |
| cosmogenous sediments | from interplanetary dust and impacts by large asteroids and comets. consist of micrometeoroids that come from asteroids and comets or from collisions between asteroids |
| microtektites | translucent oblongs particles of glass formed by the impact of large meteors or small asteroids on the crust of the earth |
| neritic sediments | continental shelf. primarily terrigenous sediments. coarser like gravel, sand and silt |
| pelagic sediments | deep ocean floor. primarily biogenous. finer like silt and clay |
| prediction of shelf sediments | goes from sand (shallow), muddy sand, sandy mud, mud (deeper) |
| relict sediment | after sea level changes, sand/gravel will tell you where the beach used to be |
| what does the distribution of sediments in the deep ocean depend on | -Latitude -Distance from landmasses -Calcium carbonate compensation depth (CCD) |
| most common sediments in deep ocean | pelagic (red clay and biogenic ooze) that accumulate slowly |
| abyssal/red clay | fine grained, reddish brown terrigenous sediments that accumulate very slowly and cover the deepest abyssal basins. Produced by chemical weathering |
| chlorite | abundant at high latitudes where chemical weathering is less effective |
| kaolinite | abundant at low latitudes where chemical weathering is more effective |
| illite | found in greater abundance in southern hemisphere |
| 3 processes that control the distribution of biogenous sediments | 1. Production in surface waters: nutrients (N and P) are the ultimate factor controlling biological productivity 2. Dilution on the seafloor: biogenous oozes do not occur where influx of terrigenous sediment is high 3. Dissolution in deep waters |
| dissolution of biogenic particles in deep water | -dissolve as settle through water column. -very fast in calcareous oozes (absent below CCD) -Slow for siliceous: they sink + aren't limited in distribution by depth. Nutrient supply more important in controlling distribution of siliceous seds |
| CCD | - carbonate compensation depth. depth at which the rate of supply of calcium carbonate equals the rate of calcium carbonate dissolutoin - below it, water holds more carbonic aid to dissolve CaCO3 faster |
| distribution of calcareous oozes | along mid ocean ridge system in basins |
| fecal pellets | biogenous sediment particles that sink to the bottom of the ocean in 20-50 years |
| distribution of marine sediments | - siliceous oozes= along equator and high altitudes (high nutrients) - terrigenous sediments= coastlines - red/abyssal clay= track abyssal plains - glacial marine sediments= high latitudinal locations |
| stages of formation of new ocean basin | 1. embryonic 2. juvenile 3. mature 4. declining 5. terminal 6. suturing |
| embryonic | rift valley forms as continent begins to split |
| juvenile | seafloor basalts begin forming as continental sections diverge |
| mature | broad ocean basin wides, trenches develop and subduction begins |
| declining | subduction eliminates much of sea floor and oceanic ridge |
| terminal | narrow ocean basin, possibly shallowing because of sediment input |
| suturing | last of the seafloor is eliminated and continents collide |
Created by:
pcollick