exam 2 - marine sediments Flashcards
(46 cards)
Why do we study marine sediments?
- Understand past climate to predict changes
- Impact of seafloor habitat on fisheries and marine life
- Pollution patterns & mechanisms for healthy coasts
- Safely route cables & install offshore structures
- Extract seabed resources
- Understand Earth’s environmental systems
To understand the impact of seafloor habitat on Fisheries and marine organisms.
How do we study marine sediments?
- Sediment grab and various sampling methods: Gravity corer, Piston corer, Drilling, Dredging.
- look at the bottom with ROV and Video Cameras.
Look at the bottom using Remotely operated vehicles and Video cameras.
list three drilling projects and what type of drilling used
1968: Deep Sea Drilling Project - USA - Glomar Challenger.
83 - JOIDES Resolution (’85) - 20 countries - rotary drilling
- 2003 integrated drilling program USA and Japan 2466m
2003: Integrated Ocean Drilling Program - Led by USA and Japan.
What kind of sediments are down there?
Terrigenous, Biogenous, Hydrogenous, Cosmogenous.
How are terrigenous marine sediments transported to the ocean?
by Rivers, wind, glaciers, and gravity. rafting is a major vector.
Composition of terrigeneous marine sediments
Mainly quartz, with sizes ranging from boulders to clay.
Desribe where terrigeneous sediments are derived from.
Lithogenous (rock) - Worn down by weathering processes. (water, temperature extremes, chemicals) - freezing and heating cycles.
Distribution of neritic marine sediments
Neritic deposits along continental margins and near islands. Beaches
Continental shelves
Turbidites
Glacial deposits
Major uses of terrigenous marine sediments
- only significant seabed mining. 2. aggregate in concrete 3.Sand and Gravel for construction and mining, 4. beach renourishment. 5.sometimes containing valuable minerals.
what are Biogenous marine sediments?
Hard part remnants of living organisms that settle to the bottom.(algae to whales)
what is Siliceous Ooze made up of and where is it found?
Made up of critters with silica quartz; SiO2 in their shells, found in nutrient-rich areas.
Uses of Siliceous Ooze
Soil conditioner, filters, abrasives, and optical quality glass. space shuttle tiles.
what are Radiolarians?
Single-celled organisms with silica shells that settle to the bottom when dead. pseduopodia to capture food.
Calcareous Ooze
Made up of organisms with calcium carbonate shells,
Major uses of Calcareous Ooze
Chalk and Limestone for agricultural and construction purposes.
Coccolithophores
Plants with calcium carbonate shells, significant for global climate impacts.
Foraminifera
Single-celled (animals) organisms with multichambered calcium carbonate shells.
How is Transport to the seafloor sped up for biogeneous sediments? State normal time to sink and sped up time.
Tiny remains take years to sink 20-50 years; cocepods fecal pellets speed up the process to 2 week.
what are the two Biogenous ooze Energy Resources
Petroleum formed from buried remains of biogenous oozes. and methane hydrates
Hydrogenous marine sediments formation
Chemical reactions within seawater cause some minerals to become solids
Needs a change in conditions – temperature, pressure, or addition of other chemicals
Manganese nodules
Rounded lumps of manganese and other metals found on the deep ocean floor. contain many rare earth minerals. 5-20cm. grow at 1cm/ million years. found in deep ocean.
Uses of Manganese nodules
Used in steel alloys, electrical wiring, and various industrial applications.
describe Evaporite formation and what are some types.
an evaporite is a salt deposit. Form from evaporation of water, leaving salts behind. Halite and gypsum
Phosphate formation and where they are found.
Coatings on rocks on the continental shelf and banks shallower than 1000 m.
Phosphates valuable as fertilizers
