Ocean Bathymetry Overview

Questions and Answers

What is bathymetry and what are the four main methods that scientists use to study bathymetry?

Bathymetry is the study of the ocean floor, including ocean depth and features. The four main methods are Multibeam Sonar, Side-scanning Sonar, Satellite Altimetry, and Seismic Profiling.

What is multibeam sonar?

Multibeam sonar utilizes multiple frequencies of sound to generate detailed images of the ocean floor.

What is side-scanning sonar?

Side-scanning sonar generates detailed images of the ocean floor by towing a sonar instrument behind a survey ship.

What is satellite altimetry?

Satellite altimetry measures the variation of ocean surface elevation caused by gravitational attraction, mimicking the shape of the seafloor. Signup and view all the answers

What is seismic profiling?

Seismic profiling uses multiple frequencies of sound to gain information about sub-surface materials and layers below the seafloor. Signup and view all the answers

What does the hypsographic curve illustrate about Earth's surface?

The hypsographic curve illustrates the relationships between the height of land and the depth of the oceans using bathymetric and topographic data. Signup and view all the answers

What are the average and maximum depths of the ocean?

Most of the ocean is between 3 and 6 kilometers deep, with the maximum depth at the Mariana Trench, which is 11 kilometers. Signup and view all the answers

What are continental margins?

Continental margins are the edges of the continents where Earth's crust transitions from continental to oceanic crust. Signup and view all the answers

What are passive continental margins?

Passive continental margins are areas not associated with a plate boundary. Signup and view all the answers

What are active continental margins?

Active continental margins are associated with a plate boundary, which can be convergent or transform. Signup and view all the answers

Match the following continental margin features:

Continental Shelf = Shallow area near the shore Shelf Break = Point where the continental shelf meets the continental slope Continental Slope = Steep slope leading down to the ocean floor Continental Rise = Gentle slope from the continental slope to the deep sea floor Signup and view all the answers

What are submarine canyons?

Submarine canyons are deep valleys cut into the continental shelf created by turbidity currents. Signup and view all the answers

What are deep-sea fans?

Deep-sea fans are created at the base of the continental slope by turbidity currents and consist of layers of graded bedding. Signup and view all the answers

What are turbidity currents?

Turbidity currents are underwater currents flowing swiftly downslope due to the weight of sediment they carry. Signup and view all the answers

What is graded bedding, and how does it form?

Graded bedding refers to layers created by turbidity currents that settle and form turbidite deposits. Signup and view all the answers

Why are the abyssal plains so flat?

Abyssal plains are flat due to the slow settling of fine sediments that fill depressions and irregularities on the ocean floor. Signup and view all the answers

Why are a majority of the world's trenches found in the Pacific Ocean basin?

Trenches are primarily formed in tectonic settings conducive to their formation, such as subduction zones. Signup and view all the answers

Study Notes

Ocean Bathymetry

Bathymetry studies the ocean floor, examining depth and features analogous to terrestrial topographic maps.
Key methods for studying bathymetry:
- Multibeam Sonar: Uses multiple sound frequencies to create detailed images of the ocean floor over a wide strip (up to 60 km).
- Side-Scanning Sonar: Towed behind a ship, it maps ocean floors in swaths, filling in gaps directly beneath the instrument.
- Satellite Altimetry: Measures ocean surface elevation variations due to gravitational attraction, reflecting the seafloor’s shape.
- Seismic Profiling: Employs sound frequencies to analyze sub-surface materials and seafloor layers.

Hypsographic Curve

Combines bathymetric and topographic data to depict relationships between Earth's land heights and ocean depths.

Ocean Depths

Average ocean depth ranges between 3,000 and 6,000 meters (3 to 6 kilometers).
The Mariana Trench is the deepest point, measuring 11,022 meters (11 kilometers).

Continental Margins

Continental margins transition from continental crust (granite) to oceanic crust (basalt).
Classified as active (associated with a plate boundary) or passive (not associated with a plate boundary).

Continental Margin Features

Key features include:
- Continental shelf
- Shelf break
- Continental slope
- Continental rise

Submarine Canyons

Submarine canyons, cutting into the continental shelf, are formed by turbidity currents, which are underwater landslides of sediment.

Deep-Sea Fans

Created at the base of continental slopes by turbidity currents, deep-sea fans comprise graded bedding layers and contribute to the continental rise.

Turbidity Currents

Fast-moving underwater currents that flow downslope due to the weight of carried sediments.

Graded Bedding

Layers formed from turbidite deposits created by turbidity currents.

Abyssal Plains

Very flat seabed formed by slow deposition of fine sediments over time, which fills in depressions and irregularities.

Oceanic Trenches

Majority located in the Pacific Ocean basin, linked to the tectonic activity conducive to their formation.
Pacific Ring of Fire: Volcanic region encircling the Pacific Ocean, notable for frequent earthquakes and volcanic eruptions.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the fascinating world of ocean bathymetry, focusing on methods like multibeam sonar, side-scanning sonar, and satellite altimetry. Learn how these techniques help map the ocean floor and understand its features. Delve into the significance of the hypsographic curve and the average depths of oceans.