Lecture 3

Beschreibung

Marine Environment Flussdiagramm am Lecture 3 , erstellt von chloe allen am 28/05/2017.
chloe allen
Flussdiagramm von chloe allen, aktualisiert more than 1 year ago
chloe allen
Erstellt von chloe allen vor mehr als 7 Jahre
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Zusammenfassung der Ressource

Flussdiagrammknoten

  • Emergence of ocean basins 
  • we used to be one big continent = continetal dift first established in 1858, antonio snider-pellegrini, noted similiar foosils also 1831-1914 edward suess seen fern fossils present acorss all southern continents
  • supercontinent - gondwana and tethys ocean land briges between continents. 
  • edward - tries to explain oceans via cooling and sinking of materials with diff densities
  • Alfred wgeener 1880-1930matches continents at 200m isobath - proposes continental drift theory largely reject - lack mechanism evidence - plant fossils-animal fossils-geological formations such as coal bed - Paleoclimatological evidence from glacial deposits - s gondwana 
  • emergence of plate tectonics - continental drift evidence -formation of mountain range via compression & folding -Collision between plate throws up mountian ranges - Rift valleys and transform fualts consistent with tension from sea floor spreading 
  • crustal motionFour key observationsGeographical location of earth quakes - epicentres show plate boundariesGeographical variability of crustal heat flow - decreases away from spreading centreGeographical variability of thickness of deep-sea sediment - thickness increases away from spreading centreMagnetic anomalies-  orientation reverses - shows regular patterns away from spreading centre 
  • Seismic Earthquakes are concentrated •Oceanic ridges •Transform faults •Trenches •Island Arcs Earthquake magnitude •Highest at trenches- compression •Lowest at ridges- spreading
  • Geomagnetism the earths magnetic field reverses approx. every 0.1 to 1 Ma this is seen in basaltic rocks - solidified magma from volcanic eruptions - they are ricj in iron = ferromagnetic material - retains orientation od magnetic field upon cooliing - terrestrial rcords also document the reverse 
  • Vine-matthews-morley Hypothesis Independently developed in the 60- hypothesis -new ocean crust formed at ocean ridgea-magnetic orientation preserved - magnetometer records should reveal magnetic anomalies - magnetic orientation should show striped pattern parallel to ridges 
  • volcanic chains oceanic crust moves over hot spot = hawian chain - youngest is the most active - oldest is subside. - subsudence and erosion eventually turn islands into guyots - emperor seamount chain 
  • pacific ring of fire Earths most active volcanoes driven by friction associated with convergence/subduction these are common ocean-ocean convergence
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