Online Earth Science Final Exam Study Guide (GEOL 1401)

  • Continental Margins and Ocean Basin Floor:

    • Continental Shelf: The submerged border of a continent, it is relatively shallow, and is rich in marine life due to ample sunlight penetration.

    • Continental Slope: This is where the continental shelf drops off into deeper water, marked by steep slopes, and includes important geological and hydrological features.

    • Continental Rise: Formed by sediment accumulation from the continental slope, it leads down to the ocean floor, characterized by a more gentle slope.

    • Abyssal Plain: These are flat, level areas of the ocean floor that lie between the continental rise and mid-ocean ridges, often covered by sediment which can be several kilometers thick, and are among the Earth's most remote ecosystems.

    • Deep Sea Trenches: The ocean's deepest parts, formed by tectonic plate subduction, they represent some of the most extreme environments on Earth, home to unique organisms adapted to high pressure and cold temperatures.

  • Guyot vs. Volcanic Seamount:

    • Guyot: Flat-topped underwater mountains formed from volcanic activity, they have eroded over time and often emerge as islands.

    • Volcanic Seamount: Similar to guyots but without the flat top, these underwater mountains rise from the ocean floor and can form new islands over geologic time scales.

  • Seafloor Sediments:

    • Comprised of various types, such as terrigenous (from land), biogenous (from organisms), authigenic (formed in place), and cosmogenous (from space). Each type has distinct characteristics and plays a role in the marine ecosystem and geological processes.

  • Fossil Fuels (Coal, Oil, and Natural Gas):

    • Coal: Formed from ancient plant materials under heat and pressure over millions of years.

    • Oil: Created from microscopic marine organisms that are buried under sediment and transformed over time.

    • Natural Gas: Often found in association with oil, primarily consists of methane and results from the same processes as oil, making it a valuable energy source but also a significant greenhouse gas.

    • These resources are classified as nonrenewable because they take millions of years to form and are being consumed at a much faster rate than they are naturally replenished.

  • Fossil Fuel Extraction and Environmental Concerns:

    • Extraction methods vary: coal mining, oil drilling, and hydraulic fracturing for natural gas come with their own ecological impacts, like habitat destruction, water pollution, and contribution to climate change through greenhouse gas emissions.

  • Coal Variations:

    • Types include lignite, sub-bituminous, bituminous, and anthracite, with anthracite being the hardest and cleanest-burning coal, while lignite is the lowest rank and most polluting.

    • In the U.S., sub-bituminous coal is more abundant than anthracite, which is less common, highlighting regional variations in coal deposits.

    • Industries are implementing technology such as scrubbers and carbon capture to mitigate air pollutants during combustion.

  • Oil Variations:

    • Different types include gasoline, kerosene, diesel, and various petrochemical products, each with specific uses from fuel for vehicles to lubrication.

  • Natural Gas:

    • Natural gas is formed primarily from the activity of bacteria decomposing organic matter and is considered cleaner than other fossil fuels, but significant methane emissions can occur during extraction and transportation leading to concerns about its impact on global warming.