MNS 307 Lecture 7: Sediments Lecture Notes
Document Summary
9:05 am: classify sediments, calcareous and siliceous sedimentary particles, biogenous and lithogenous sediments, isotopes, seabed resources (methane hydrate) Thinnest layers at spreading centers (newer, not enough time for layer to form) Formed by particles settling on the seafloor. Particles are all different sizes, leaving gaps between them. Provide a history of what has lived and died over them, and important for understanding earth"s past. Big steel bag dragged along bottom to collect rocks. Spring loaded metal claw (like a claw machine) Good for muddy sediments close to the surface. Sinking rates do not equal deposition rate. Clay - 47000 days (won"t get there) Particles probably stick together and settle in aggregates. Neritic sediments accumulate much faster than pelagic sediments. River estuaries (where saltwater and freshwater meet): 800,000 cm/1,000 years. Sediment thickness is governed by age and supply/loss. Gulf of mexico: 200 million years old. From a terrestrial sources (pre-existing rock): lithogenous.
