Tectonic Plates and Ocean Floor Features

Flashcards covering vocabulary related to tectonic plates, ocean floor features, and sediment types.

Lithosphere

The outermost structural layer of the Earth, consisting of the crust and the upper rigid mantle.

Asthenosphere

The layer beneath the lithosphere that exhibits plasticity (the ability for solid to flow).

Continental Crust

Thick and less dense.

Oceanic Crust

Thinner but more dense.

Ring of Fire

volcanically active area around the Pacific ocean known for earthquakes and volcanic eruptions.

Hot Spot

where volcanic activity can occur away from plate boundaries due to a magma chamber near the surface.

Transform Boundary

Type of plate boundary that is not associated with volcanic activity.

Ridge Push

warmer, newer rock at a mid-ocean ridge cools and pushes the plate away from the rift.

Slab Pull

The force exerted by a subducting plate as it pulls the rest of the plate along with it.

Subduction

one tectonic plate being drawn under another at a convergent plate boundary.

Continental Margin

The region where the land meets the ocean.

Continental Shelf

The gently sloping edge of the continent beneath the ocean.

Seamount

volcanic mountain; rises at least 1 km above the ocean floor.

Atoll

intermediate stage In the erosion of islands; Lagoon + reef is usually present.

Abyssal Plain

Flat, deep areas of the ocean.

Mid-ocean Ridge

underwater mountain chain formed at a divergent plate boundary.

Deep Ocean Trench

steep depression in the ocean floor formed at a subduction zone.

Nodule

lump of minerals found in abyssal plains; formed from dissolved minerals (precipitate).

Biogenic Sediments

Sediments that originate from the remains of living organisms.

Foraminifera shells leave what biogenic substance in the sediment?

Calcium Carbonate

Silica

biogenic substance left by radiolarian and diatom shells.

Robotic ROV

A smaller, unmanned submersible used for deep-sea exploration.

Guyot

flat topped eroded structure (former seamount, Island, atoll) underwater.

What are the 3 types of plate boundaries?

Convergent- come together

Divergent - come apart

Transform- slide past each other

Which substance would I find below 5 km, calcium carbonate or silica?

Silica because calcium carbonate at that point would be dissolved back into the deep ocean water.

Radiolarians, and diatoms shells leave what biogenic substance in the sediment?

Silica

2 types of oozes

Calcareous and siliceous

What are the 3 sources of sediments that are found on the ocean floor?

1. Inorganic: rock particles (rivers, icebergs, meteorites, volcanic activity)

2. Biogenic: made by living things (plankton)

3. Chemical Deposits- minerals from from the water precipitate - eg. Nodules

How does a submarine canyon form and where would I find one?

Found in the continental shelf, erosion by turbidity currents create deep V-shaped valleys carved by sediment flows and underwater landslides. found at edge of continental shelf.

List and briefly describe the 3 parts of the continental margin

1. Continental Shelf - gently slopes away from the shoreline from the continent, relatively flat

2. Continental Slope - sharp quick drop from continental shelf to the ocean floor

3. Continental Rise: Sediment pile at the bottom of the continental slope.

What are the 2 parts to the Ocean Floor?

Continental Margin and Deep Ocean Basin

What does SONAR stand for and what is it used for?

Sound, Navigation and Ranging- It is the sending and receiving of sound waves to determine the depth of the ocean bottom.

Bathyscaph

Piloted, free-moving, has its own life support system and power

Bathysphere

piloted by a person but attached to a surface ship for support and power.

1st largest ocean

Pacific Ocean

2nd largest ocean

Atlantic Ocean

3rd biggest ocean

Indian Ocean

4th biggest ocean

Southern Ocean

5th biggest ocean

Arctic Ocean

What is subduction? And what type of plate boundary would it happen at?

When a tectonic plate is drawn under another tectonic plate.  This would happen at a convergent boundary that has at least one oceanic plate.

Which causes of plate motion are at work at a subduction zone?

Sinking part of the Convection currents and slab pull

Which causes of plate motion would be at work at a divergent plate boundary?

Rising part of Convection Currents and Ridge Push

What are the 3 causes of tectonic plate motion?

Convection currents/cells in the asthenosphere

Ridge push 

Slab Pull

Which type of boundary forms an ocean trench?

Convergent - with at least one oceanic plate (subduction zone).

Which main type of boundary is NOT associated with volcanic activity?

Transform (where they slide past each other) e.g. California.

Which type of convergent boundary would result in an island arc? (a line of volcanic islands?

Oceanic-Oceanic-  islands would run parallel to the trench e.g. Mariana

Which type of convergent boundary would result in mountain building?

Continental- Continental, (Collision) e.g. Himalayan

Which type of crust does not subduct, and why?

Continental- it is NOT very dense and very thick

What are the 3 types of convergent boundary interactions?

Oceanic plate- Oceanic plate

Oceanic Plate- Continental Plate

Continental Plate- Continental plate