Oceanography quiz questions review Professor MacDonald mentioned that there would be a picture mid ocean ridge with labels that we would have to match parts to on the exam trenches transform faults etc View slide from Ch 4 that classifies sediment table Lecture 1 What is the difference between a sea and an ocean A sea is smaller shallower partly enclosed and has a different salinity According to the Nebular Hypothesis the Sun Earth and other planets in our solar system formed from an enormous cloud of gas and dust What are the essential facts about the early Earth with respect to the following existence of oceans formation of Earth s core composition of the atmosphere effects of meteorites and existence of the moon The early Earth was composed of oxygen Why does Earth have a nickel iron core at its center surrounded by silicate mantle More massive core material sank to the center of the Earth and displaced materials that were already there Why is continental crust higher than ocean crust Continental crust is thicker and less dense so it floats higher on the mantle Continental and ocean crust have different levels because oceanic crust is denser and floats lower on the asthenosphere than continental crust because of isostasy Assuming no difference in structure what would happen if the two types of crust were made of the same material There would still be a slight difference because of the thickness of material in which they are made up of but the height would be nearly the same What invention made accurate open navigation possible by determining longitude Modern timepiece What is a scientific theory A theory is a well substantiated explanation of some aspect of the natural world that can incorporate facts laws logical inferences and tested hypotheses Charles Darwin considered a career as a minister What would have happened to the theory of evolution had he not become a scientist instead Russel Wallace would have published the same theory he was working half a word away but had discovered the same idea but Darwin published it first Radio Isotopes of Potassium K40 decay to Argon AR40 If a rock sample begins with 12 billion K40 atoms what will the quantities of K40 and AR40 be after 1 half life and 2 half lives After one half life 6 billion K40 atoms and 6 billion AR40 atoms After two half lives 3 billion K40 atoms and 9 billion AR40 atoms What is the concept of isostatic adjustment and what topic in the chapter does it apply to It is the vertical movement of crust as the result of the buoyancy of earth s lithosphere as it floats on the denser plastic like asthenosphere below Ex Oceanic crust floats lower in the mantle because it is denser than the continental crust What is the role of Oxygen on earth 1 Our bodies need oxygen to burn food and give energy to our cells 2 Oxygen in the upper atmosphere in the form of ozone protects the surface of the earth from most of the sun s harmful UV rays Lecture 2 Where do most of the largest earthquakes occur Convergent plate boundaries Why are oceanic ridges different from oceanic rises Rises spread quickly contain vast rock and ridges spread slowly and are more steep In relation to plate tectonics what is a major overall trend in earthquakes Earthquakes occur at plate boundaries What happens when plate tectonics causes two continents to collide at a convergent plate boundary Neither continent will subduct and mountains with form Transform plate boundaries are parallel to the relative motion between two plates What would happen if the direction of plate motion changed Either of the options given on multiple choice could happen depending on which direction the plate motion changed to Alfred Wegener s theory of continental drift seems so reasonable today Why was it rejected by a majority of scientists during the earth 20th century He didn t propose a believable mechanism to explain plate motion Why are earthquakes mainly found at the edge of plates Many occur and reflect the energy released when moving plates contact other plates along their edges Maps show that the distribution of worldwide earthquakes closely matches the plate boundaries How does an ocean basin form The Wilson Cycle heat source beneath the lithosphere begins a split in the continent The mature stage of the cycle is where the ocean basin is formed with a mid ocean ridge running down the middle of it When the plates come back together the ocean basin shrinks and is eventually destroyed Plate tectonic activity is primarily responsible What is the difference between an atoll and a guyot Guyots are volcanic features that include being flat on top and sometimes have shallow water deposits Atolls are reefs that continue to grow after volcanoes are submerged You are exploring an ocean basin and trying to determine whether it formed by seafloor spreading Which of the following evidence would you NOT expect to find in an actively spreading ocean The plate tectonic model states that the new sea floor is created at the mid ocean ridge where it moves outward by the process of sea floor spreading and is destroyed by subduction into ocean trenches Holt molten rock comes to the surface and spreads and convection of material in the mantle produces convection cells The alternating reversals of Earth s magnetic field throughout history have been recorded in sea floor rocks in a particular pattern How does this support plate tectonics The switching of earth s magnetic polarity through time is preserved in rocks The ocean floor has embedded in it a regular pattern of alternating magnetic stripes unlike anywhere on land Lecture 4 Global temperature rise increases the amount of cloud cover because of the higher moisture available in the atmosphere These clouds then reflect incoming solar energy disallowing some of that energy to heat Earth s surface In this way the overall effect of increased cloud cover is a decrease in air temperature What term may be used to describe this process Negative feedback loops because initial change is counteracted and the clouds decreased the overall air temperature Global temperature rise is causing polar ice to melt Because ice has higher albedo reflects solar energy than water loss of ice cover increases heat absorption in Polar Regions This accelerates ice melt What term may be used to describe this process Positive feedback loop The general scientific consensus is that if levels of human caused emissions continue to increase what will happen The Earth s climate
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