Study Guide OCE1001 Chapters 1 2 5 Notes Questions and more diagrams Chapter 1 Physical processes at work in the ocean and interaction between the ocean and atmosphere determine and regulate the earth s climate Past climate changes can be monitored by our ocean Formation of Earth and the Solar System Nebular Hypothesis All bodies in the solar system formed from nebula Nebula cloud of gases and space dust hydrogen helium Gravity concentrates material at the center of cloud Sun Protoplanets form from smaller concentrations of matter eddies Protoearth Larger than Earth today Homogeneous composition Bombarded by meteorites Moon formed from collision with large asteroid Formation of stratified Earth 1 Heat and gravitational pressure melts the young homogeneous Earth 2 Gravity draws heavier elements towards the center nuclear fusion causes more heating 3 Lighter materials migrate to the surface and form the crust Origin of Earth s Atmosphere Outgassing occurred during density stratification Water vapor Carbon Dioxide Hydrogen Other gases Development of Earth s Oceans Outgasses water vapor fell as rain First oceans formed 4 billion years ago Salinity developed from dissolved rock elements Early acidic rain dissolved more minerals than today Lithosphere The continental and oceanic crusts are the outer shell of the Lithosphere Boundary between Lithosphere and Asthenosphere marks where the mantle material can flow Plumes of fluid mantle material lava rise through the lithosphere and creates crust Early Exploration of the Oceans Explorers used boats to seek fishing grounds Eratosthenes and Ptolemy used their knowledge of geometry to model and map a spherical world Greek early Phoenician navigators ventured open ocean proven by nautical archaeology Ocean helped trade and interaction between cultures Vikings came from Scandinavian countries Ship building and navigation was advanced First people to cross the Atlantic Era 1450 1650 marked a great expansion of European power Henry the Navigator established an institute for exploration and cartography By 1650 cartography had become a true science capable of prediction Definition of Latitude Longitude Longitude is the east or west separation from a arbitrary origin Latitude is the north or south separation along the meridian compared to the equator Significant People Darwin took a 5 year long voyage and he developed the theory of Evolution in 1859 If he did not publish it another scientist would have Franklin s chart of the Gulf Stream was first true map of a current Matther Maury first full time oceanographer Artic and Antarctic were last place of exploration Higher and Deeper Satellites provide an overview of processes that occur in entire ocean basins Submarines give access to seafloor processes and communities These tools have redefined marine science UNOLS University National Oceanographic Laboratory System One theory holds that life evolved at deep sea hydrothermal vents Age of Earth Radiometric age dating Spontaneous change decay Half life Earth is about 4 6 billion years old Theories Ptolemic theory Earth is the center of a system and heavenly bodies move around us Heliocentric theory Earth planets are part of a heavenly system orbiting the sun and the Earth rotates on its axis as it orbits Creationist theory all species were created at one time by a higher power Darwinism All of the present day species have evolved from ancestors that lived in earlier times Natural selection allows the forms best adapted to conditions to survive and reproduce Deluvian theory Catastrophism Earlier catastrophe like a great flood caused the present arrangement Plate tectonics Earth has gone through repeated cycles of the continents being joined together and then slowly breaking apart Chapter 2 Age of Earth Catastrophism thought that Earth is very young and events described in the Bible are responsible for the appearance of Earth s features Principle of uniformitarianism states that the forces which shaped Earth are identical to forces working today Alfred Wegener noted the similar shape of continents and proposed the unified land mass Pangaea Plate tectonics Alfred Wegener first proposed Continental Drift in 1912 He has many observations that went with his theory but the difficulty was that he did not propose a mechanism to explain plate motion He did not have a way a testing his hypothesis so his hypothesis failed Evidence of Earth s Layers The behavior of seismic waves generated by earthquakes give scientists some of the best evidence about the structure of Earth S waves cannot penetrate Earth s liquid core P waves are bent as they pass through the liquid outer core Richard Oldham liquid core Inge Lehmann solid inner core Continental Crust Granite Oceanic crust Basalt Mantle Silicon oxygen iron and magnesium Core Iron Note that Earth is density stratified which means that each deeper layer is denser than the layer above Lithosphere The cool rigid outer layer Asthenoshpere Hot partially melted layer which flows slowly Mantle Denser and more slowly flowing than the asthenosphere Outer Core Denser and more slowly flowing than the asthenosphere Inner Core Solid very dense and extremely hot As you can see the less dense layers float on the more dense hotter layers Radioactive decay produces heat at the core A critical boundary is the brittle ductile transition between crust and upper mantle Confirmation of the Theory of Plate Tectonics Age and distribution of ocean sediments The sediment in the ocean is thinner and younger than the age of the ocean indicates it should be The Oceanic ridges Oceanic ridges are clear indicators of past events Terranes Oceanic plateaus that form by uplifting and mountain building as they strike a continent PDRs transmit acoustic pulses and detect their echo from seafloor TWTT two way travel time Iceland is a hotspot on a spreading center Earth s magnetic polarity reverses periodically Recorded in ancient rocks Confirmation of the Theory of Plate Tectonics Apparent Polar wandering plate movement causes the apparent position of the magnetic poles to have shifted Paleomagnetism strips of alternating magnetic polarity at spreading regions The molten rocks at the spreading center take on the polarity of the planet while they are cooling When Earth s polarity reverses the polarity of newly formed rock changes Paleomagnetism and the Ocean Floor 1955 deep water rock mapping Magnetic anomalies regular pattern of North South magnetism
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