Marine Geology and Geological Oceanography Quiz

Unit 1: Introduction to Marine Geology/Geological Oceanography

• Course Introduction: The course covers marine geology, geological oceanography, and paleoceanography.
• Definitions: Marine geology examines the characteristics and history of the Earth's sea-covered parts. Geological oceanography studies the history and tools of marine geology, including paleoceanography. Paleoceanography studies the history of the oceans in the geological past.
• History of Geological Oceanography: The study of the oceans' history and geological processes.
• Tools of Geological Oceanography: Instruments and techniques used in the field.

Marine Geology and Geological Oceanography

• Scope: The study of the character and history of the Earth's water-covered portions, from coastal areas to deep-sea trenches and abyssal plains.
• Processes: Geological processes shaping ocean floors, oceans' water, and climate.
• Extends beyond the water: The study also includes uplifted marine sediments, plate tectonics, ophiolites, and paleoclimates.

Ocean as a Punch Bowl

• Bowl: Ocean basins. Shaped by plate tectonics and modified by weathering, erosion, and sediment deposition.
• Punch: Water, dissolved particles (living and non-living, e.g., silt, bacteria, whales).

Marine Geology vs. Geological Oceanography

• Interchangeable use: Often used interchangeably, but sometimes distinguished based on origin:
  • Geologists interested in oceans versus oceanographers interested in geological processes.
  • Interests and areas of focus: Geology or oceanography?

Interests in Marine Geology/Geological Oceanography

• Marine Geology: Plate tectonics, volcanoes, earthquakes, minerals, rocks, and terrigenous sediments.
• Geological Oceanography: Physical, chemical, and biological processes (biogeochemistry). These processes affect geology (mineral precipitation, sedimentation, diagenesis) and climate.

Time Scales of Interest

• Geological Oceanography: Primarily focused on the present and near future (modern sedimentation, coastal processes, biogeochemical cycles, and climate).
• Marine Geology: Examines oceanographic processes extending further back in time, becoming the domain of geologists.
• Marine Geology limitations: Primarily interested in the last ~175 million years.

Marine Geology vs. Land Geology

• Historical Focus: Land-based geologic studies have historically been more common due to practical logistics.
• Limited Seafloor Data: There is a scarcity of older seafloor data.
• Logistics: Doing geology on land is practically easier than in the more challenging ocean environment.

Other Differences Between Marine and Land Geologists

• Data Access: Marine geologists rely more on remote sensing and satellite data due to accessibility constraints that limit direct sampling.
• Tools and Techniques: Multi-beam technology, sonar, and underwater vehicles are increasingly used.

Geological Oceanographers vs. Other Oceanographers

• Pecking Order: Geological oceanographers are often seen as having a lower standing compared to other oceanographers (physical, biological, chemical).

Paleoceanography

• Definition: The study of the history of oceans in the geologic past, relating to circulation, chemistry, biology, geology, and patterns of sedimentation and productivity.
• Applications: Provides a critical time dimension for understanding past climates and allowing for predictions of future climates. Using past climates, current climate models can be tested.

Early Exploration Stage

• HMS Beagle (1831-1836): Darwin's voyage.
• Polar Research (e.g., ships "Erebus" and "Terror"): Depth soundings.

The First Oceanographic Expedition

• Challenger Expedition (1872-1876): A significant step in early oceanography. Sir John Murray—a key figure in Marine Geology—recognized marine sediments, deep-sea oozes, and plankton assemblages

After the Early Periods

• 70 Years Later (post-Challenger): Continental drift was initially disputed. Oceanography technology was still expensive and funding was a limitation.
• Early 20th Century: Linking research to national interests/pride to gain funding and propel oceanographic work.
• WWI: Restored German pride via acoustic profiling.
• WWII: Acoustic sounding improved to detect submarines to use its technology in topographic mapping.

1950s-1960s

• Marine Explosion Seismology: Use of explosives and studying sediments (Replaced by air-guns later). Discovery of fracture zones.
• Isotope Use: Paleotemperature analysis, highlighting Cesare Emiliani's role as a paleoceanographer.

1970s-Present

• Deep Ocean Drilling: The Glomar Challenger and Joides Resolution enabled deep-sea core sampling, significantly advancing paleoceanography.
• International cooperation: Large international programs for multi-year research became more common.
• Submarine Technology: Underwater vehicles and satellites aided exploration and remote-sensing.
• Computer Modeling: Advanced computer models help study and understand complex ocean processes.

Deep Ocean Drilling Project (DOCP)

• Glomar Challenger (1968): Pioneering research ship.
• Joides Resolution: Later vessel for deep-sea core sampling.

International Ocean Discovery Program (IODP)

• From 2013: Continuation of deep-sea core sampling—using the Joides Resolution and Chikyu to sample deep-sea cores.

Modern Oceanographic Research

• International Cooperation: Increased international collaboration due to the high cost of modern oceanographic research.
• Modern Tools: Underwater vehicles (submersibles, ROVs, AUVs), satellite remote sensing, supporting technologies are crucial.

Collecting Samples of Sea Floor

• Early Bottom Dredges: Scraped sediments in wire/canvas bags.
• Grab Samplers: Took "bites" out of the seafloor to collect sediments.
• Gravity Corers: Used weighted core barrels to drive the core into the seafloor.
• Piston Corers: Can collect much longer cores than gravity corers by freely falling.

Remote Sensing Methods:

• Altimeters: Measure altitude above the sea surface—crucial in geophysics and geology.
• Optical Sensors: Use light's spectrum for photography to capture information about coastlines, sediments, and shallow water features.
• Other Sensors: Methods measure ratios of wavelengths to assess water contents (suspended sediments, dissolved matter, chlorophyll).

Sounding Equipment: Studying the Sea Bed

• Single Beam Echo Sounding: Maps along straight lines.
• Side-Scan Sonar: Provides scans in two or more swaths to visualize wider areas.
• Synthetic Aperture Sonar (SAR): Multiple sonar data recordings allowing a more detailed representation of the bottom than single-beam sonar.
• Multi-Beam Echo Sounders (MBES): Provide a wide range of swaths and a more complete mapping of the bottom.

Seismic Surveys

• Sound Source: Usually air-guns—generating strong, low-frequency sounds that penetrate deeper into the seafloor
• Acoustic Receivers (Streamers): Measure signals that are reflected off various layers in the ocean floor.

Supporting Technologies

• GPS: Geographic Positioning System – crucial for knowing the location of ocean floor measurements.
• Computer Modeling: Analysis and modeling of seismic signals and other oceanographic data, including modeling of past climates.
• Isotopic Analysis: To determine past climates and other ecological information.
• Sediment Traps/Buoys: Monitoring and collecting physical properties of the sea bottom and biological communities within it.

Test your knowledge on marine geology and geological oceanography with this insightful quiz. Explore key concepts, historical expeditions, and tools used in the field. Discover how these disciplines interrelate and their significance in understanding ocean processes.