Chapter 11 Flashcards
What is lithogenous sediment? Where did it originate?
- Sediment from rocks
* Result of weathering and erosion
What is the principal component of most beach sand? Lithogenous
didn’t originate there
How is the lithogenous sediment transported?
Wind and currents
What is calving
Calving-when a piece of the glacier breaks off, forms icebergs
How is lithogenous sediment classified? Include size and sorting.
Grain Size
–Mud –very small (think of flour or powdered sugar)
–Sand-less than 2 mm in size (think of granulated sugar or a sand box)
–Gravel-anything bigger than 2 mm
Streams and lithogenous
- Streams and run-off from continents
* Highest concentrations of lithogenous sediment near the coasts!
Wind and lithogenous
Blows dust and clay sized particles into the ocean
Glaciers and lithogenous
Calving-when a piece of the glacier breaks off, forms icebergs
What is biogenous sediment?
From living organisms or their remains
What is biogenous sediment made of
–Includes shells, bones, coral, skeletal parts
–Includes excretions and secretions
–Fecal Pellets-undigested food, sinks to deep ocean-major food source in the deeper parts of the ocean
What is the chemical make up of a diatom?
Silica
What is a radiolarians made of?
Silica
What is a coccolithophores made of
Calcium carbonate
What is a foraminifera made of?
Calcium carbonate
What is hydrogenous sediment? How are they formed?
Precipitated from seawater. Form as coatings on other particles
Describe manganese nodules
- Black nodules
- Contain Manganese, Iron, copper, cobalt, and nickel
- Form as coatings on other particles
Where are deposits of manganese nodules found?
Manganese (or polymetallic) nodules occur widely on the sediment-covered abyssal plains at depths of 3500 to 6500 m. Origin of Manganese Nodules: Manganese nodules form on the ocean floor by the slow precipitation of metallic minerals extracted directly from seawater or pore waters of the sea-bottom sediments.
What is an oolith? How big are they? How are they formed?
•Tiny spheres of calcite•Precipitate out of seawater
What is cosmogenous sediment?
–Meteorites–Space Dust–Tektites
What is a tektite?
- Form from a rock that was hit by a meteorite, then melted, then cooled back into the rock
- A tektite is not the meteorite, but the rock the meteorite crashed into
What is a neritic? What type of sediment dominates?
relating to or denoting the shallow part of the sea near a coast and overlying the continental shelf.
are dominated by lithogenous sources and are typically deposited quickly.
What is a delta?
Fan shaped deposit formed when a stream enters the ocean and drops all of its sediment
What is a wetland?
•Low-lying, flat areas•Covered with water at least part of year
Define pelagic.
(chiefly of fish) inhabiting the upper layers of the open sea.
What is a calcareous ooze?
Calcareous ooze is a calcium carbonate mud formed from the hard parts (tests) of the bodies of free-floating organisms. Once this mud has been deposited, it can be converted into stone by processes of compaction, cementation, and recrystallization.
Which organisms make up a calcareous ooze? Be sure to look at pictures in book.
foraminifera, coccolithophores
What is the carbonate compensation depth (CCD. How deep is it )
Depth at which calcium carbonate (calcite) dissolves
Average 4500 M
Calcareous oozes dissolve below a depth of _________.
4500 M
What is a siliceous ooze?
Siliceous ooze is a type of biogenic pelagic sediment located on the deep ocean floor. Siliceous oozes are the least common of the deep sea sediments, and make up approximately 15% of the ocean floor. Oozes are defined as sediments which contain at least 30% skeletal remains of pelagic microorganisms
Which organisms compose a siliceous ooze? Be sure to look at pictures in book.
30% silica organisms (diatoms, radiolaria)
Are siliceous oozes inhibited by depth?
no
What kind of ooze would you expect to find in a trench?
Siliceous ooze
Describe the formation of oil and natural gas.
Oil and natural gas were formed from the remains of prehistoric plants and animals—that’s why they’re called fossil fuels. Hundreds of millions of years ago, prehistoric plant and animal remains settled into the seas along with sand, silt and rocks. As the rocks and silt settled, layer upon layer piled up in rivers, along coastlines and on the sea bottom trapping the organic material. Without air, the organic layers could not rot away. Over time, increasing pressure and temperature changed the mud, sand and silt into rock (known as source rock) and slowly “cooked” the organic matter into petroleum. Petroleum is held inside the rock formation, similar to how a sponge holds water.
Over millions of years, the oil and gas that formed in the source rock deep within the Earth moved upward through tiny, connected pore spaces in the rocks. Some seeped out at the Earth’s surface, but most of the petroleum hydrocarbons were trapped by nonporous rocks or other barriers. These underground traps of oil and gas are called reservoirs. Contrary to popular misconception, reservoirs are not underground “lakes” of oil; they are made up of porous and permeable rocks that can hold significant amounts of oil and gas within their pore spaces. Some reservoirs are hundreds of feet below the surface, while others are thousands of feet underground.
What is a reservoir rock?
A reservoir rock is a rock providing a condition to trap oil in porous media. The reservoir rock contains pores and throats, creating flow path and an accumulating system for hydrocarbon and also consist of a sealing mechanism for prohibiting hydrocarbon penetration to surface layers.
What is the exclusive economic zone (EEZ)?
•Extends 200 nautical miles offshore of country•This is the area where a coastal country has jurisdiction for resources (mineral, fuels, and fisheries)
