GLY150: INTRODUCTION TO OCEANOGRAPHY University of North Carolina Wilmington

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Lecture Outline

Marine Sediments 

I.  Importance of studying marine sediments

• indicators of past/present ocean chemistry and temperature
• indicators of movements of ocean floor in the context of plate tectonics
• indicators of past/present ocean circulation patterns and sealevel changes

II.  Sediment texture and grain size

• Wentworth grain-size scale
• Hjulstroms diagram
• Maturity

III.  Classification of marine sediments based on composition

• Terrigenous (lithogenous)
  • produced by weathering and erosion of rocks on land

• Biogenic
  • derived from the hard parts of organisms, such as shells and skeletal debris

• Authigenic (hydrogenous)
  • particles that are precipitated by chemical or biochemical reactions in seawater, e.g. manganese nodules

• Comogenous
  • tiny particles that originate from outer space

• Volcanogenic
  • particles that are ejected from volcanoes

IV.  Distribution of sediments

• Continental Shelf

• Deep Sea
  • Turbidites
  • Clays
  • Oozes
    • Calcium Carbonate Compensation Depth

Some useful links relevant to this lecture:
Sediments and Rocks of the Seafloor
Ocean Drilling Program

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