OCE: Exam 1 - Study Guide

1) History of Oceanography (Chap. 1)

- Who were the first people set off on marine expeditions and why did they do so?

  - Polynesians, for exploration and migration.

- What advances in ship building technology (as discussed in lecture) have aided advances in ocean exploration?

  - Durable ships, navigational instruments like the sextant and compass.

- What was the Lapita culture and how did they sail?

  - Known for using star paths and ocean swells for navigation.

- How did mariners navigate before modern 20th-century technology?

  - Using stars, landmarks, and ocean currents.

- What/when are the major periods of ocean exploration discussed in class?

  - Ancient, medieval, and modern periods.

- What were the first major scientific oceanographic expeditions?

  - The Challenger Expedition.

- What are some of the tools used by past and modern oceanographers?

  - Sounding lines, sonar, GPS, satellites.

- How did people first know the Earth was spherical?

  - By observing ships disappearing hull-first over the horizon.

- How was the Earth’s circumference first calculated (not detailed)?

  - Using shadow angles (Eratosthenes method).

- Understand latitude and longitude of the earth and relationship to nautical units.

  - Latitude is based on the Earth’s spherical shape; 1 nautical mile = 1 minute of latitude.

- Be able to calculate your lat. and long. using pre-20th century methods as done in discussion class.

  - Calculated through celestial navigation using sextants.

- Be able to convert units from one to another.

  - Converting nautical miles to kilometers or meters.

2) Origins (Chap. 1)

- What is the scientific method?

  - A process of observation, hypothesis, testing, and conclusion.

- What is a ‘scientific theory’?

  - A well-substantiated explanation of some aspect of the natural world.

- Know what and when (roughly) were the major events of the Universe and the Earth and life discussed in class.

  - Big Bang (~13.8 billion years ago), formation of Earth (~4.5 billion years ago), origin of life (~3.5 billion years ago).

- What is the Nebular Hypothesis of sun and solar system formation?

  - The solar system formed from a cloud of gas and dust.

- What is solar/planetary accretion?

  - The process by which planets form from dust particles colliding and sticking together.

- What is density stratification?

  - Earth's layers formed based on density differences.

- Know the layers of the Earth (Continental Crust, Oceanic Crust, Mantle, Outer core, Inner Core).

  - Layers are based on density, with the crust being the least dense, and the core being the most dense.

- Where did the ocean water and ocean salt come from?

  - Volcanic outgassing and comet impacts.

- Understand the 3 atmospheres the earth has had in the past.

  - Primordial (hydrogen and helium), secondary (volcanic gases), current (oxygen-rich).

- Know the various theories of how and when life first evolved on Earth discussed in class.

  - Theories include the primordial soup and hydrothermal vent hypotheses.

- What type of organism was the first life?

  - Likely simple prokaryotes.

- What are the ‘major’ events of life discussed in class?

  - Evolution of multicellular organisms, Cambrian explosion, vertebrates, mammals, humans.

- How do we determine the age of a rock or fossil?

  - Radiometric dating and relative dating.

3) Plate Tectonics (Chap. 2)

- What lines of evidence did Wegner use to support his Continental Drift hypothesis?

  - Fossil distribution, rock formations, and the fit of the continents.

- What lines of evidence support Harry Hess’ Seafloor Spreading hypothesis?

  - Mid-ocean ridges, symmetrical magnetic stripes on the ocean floor.

- Describe, in basic terms, Plate Tectonic Theory, and how Plate Tectonics explains the motions of the continents.

  - Earth’s crust is divided into plates that move due to mantle convection.

- Know and be able to explain the basic character of Earth’s magnetic field and how these can be used to reconstruct the past positions of continents.

  - Earth's magnetic poles reverse over time, recorded in rocks.

- Know and be able to explain the magnetic anomaly and age patterns on the seafloor.

  - Symmetrical patterns of magnetic stripes on either side of mid-ocean ridges correspond to seafloor age.

- What types of plate boundaries are there? What are their features and surface expressions?

  - Divergent (mid-ocean ridges), convergent (trenches), transform (faults).

- Where on Earth are some famous examples for each type of boundary (as discussed in class)?

  - San Andreas Fault (transform), Himalayas (convergent), Mid-Atlantic Ridge (divergent).

- What is a hot spot?

  - A volcanic region fed by underlying mantle plumes, like Hawaii.

- You should be able to calculate a spreading rate from ocean crust or volcanic island age data using:

  - Rate = Distance / Time.

- You should be able to identify locations on Earth that are likely to have earthquakes, volcanoes, mountain ranges, etc., based on the type of plate boundary present.

  - Earthquakes and volcanoes are common at convergent and divergent boundaries.

- In very general terms, how have the continents been arranged and moved over the past 600 million years?

  - Pangaea formed and broke apart, leading to the current continental configuration.

4) Marine Physiography (Chap. 3)

- What tools are used to measure ocean depth?

  - Echo sounders, sonar, satellite altimetry.

- Understand the hypsographic curve.

  - A graph showing the distribution of Earth's surface elevation and ocean depth.

- What/where are passive and active continental margins? What are their similarities and differences?

  - Passive margins: broad, shallow, tectonically inactive; active margins: narrow, tectonically active.

- How do you calculate the slope of the continental shelf, slope, etc.?

  - Slope = Rise/Run or Depth/Distance.

- Understand the general characteristics (and how they are formed) of continental shelves, continental slopes, cont. rises, submarine canyons, abyssal plains, abyssal hills, trenches, deep-sea fans, turbidity currents, turbidites, seamounts, guyots, atolls, mid-ocean ridges (and the differences between fast and slow ridges).

  - Formed by erosion, sedimentation, and tectonic activity.

- What types of organisms might you see as you walk along the seafloor of the continental shelf or deep ocean basin?

  - Corals, deep-sea fish, tube worms.

- Be able to label the major features of an ocean basin cross-section (or map view).

  - Features include continental shelf, slope, rise, abyssal plain, mid-ocean ridge.

- What are some features that can be found on a mid-ocean ridge axis?

  - Hydrothermal vents, rift valleys.

- How does a mid-ocean ridge differ from a mid-ocean rise?

  - Ridges are steep and slow-spreading, rises are flatter and fast-spreading.

- What are the main features of deep-water coral ecosystems found on continental slopes or seamounts?

  - Slow-growing corals adapted to cold, dark environments.

5) Marine Sediments (Chap. 4)

- Know sediment collection methods covered and what types of samples they collect.

  - Dredges collect surface samples, cores collect deep samples.

- Know the system of naming sediment types by their source, by location, by delivery agent, and by grain size (don’t need to memorize exact size...but order). Where, generally, do you find each type? What is a delta?

  - Lithogenous (land), biogenous (organisms), hydrogenous (precipitated from water), cosmogenous (space), volcanogenic (volcanic); delta: sediment deposited where rivers meet the sea.

- For each of the five major types of sediment (lithogenous, biogenous, cosmogenic, hydrogenous, volcanogenic), what are their sources, delivery methods, where located, typical sedimentation rates, and main features?

  - Lithogenous: from land erosion; biogenous: from marine organisms; cosmogenous: from space; hydrogenous: from chemical precipitation; volcanogenic: from volcanic eruptions.

- What types of organisms produce biogenic sediments?

  - Foraminifera, diatoms, radiolarians.

- What are examples of hydrogenous sediments, how do they form, and where are they likely to be found?

  - Manganese nodules, formed by chemical precipitation, found on abyssal plains.

- What types of sediment (and accumulation rates) are most common on the continental margins? ...versus in deep ocean basins?

  - Continental margins: coarser, faster; deep ocean basins: finer, slower.

- What is the EEZ?

  - Exclusive Economic Zone, extending 200 nautical miles from a country's coast where they have exclusive rights to marine resources.