Table of Contents
- 1 What is a subsurface topography?
- 2 What type of topography can be seen on the seafloor?
- 3 How is ocean floor topography different from land?
- 4 What are the differences between oceanic and continental crust?
- 5 What are three differences between continental and oceanic crust?
- 6 Are oceans topographic features?
- 7 How are plate boundaries related to the subduction zone?
- 8 What happens when tectonic plates converge in the ocean?
What is a subsurface topography?
Subsurface. Topography. The study of the surface of the ocean floor; topography studies the shape of the land.
What are the two main topography of the ocean floor?
The ocean floor is almost entirely underlain by mafic oceanic crust (mostly basalt and gabbro, as described in more detail below), while the continental slopes are underlain by felsic continental crust (mostly granitic and sedimentary rocks).
What type of topography can be seen on the seafloor?
Science has established that the topography of the ocean floor is similar to the ground topography with features such as valleys, mountains, and plateaus. Three quarters of the Earth consists of ocean water. All these details are incorporated on underwater topography maps.
How does continental crust differ from oceanic crust?
The crust is the outer layer of the Earth. It is the solid rock layer upon which we live. Continental crust is typically 30-50 km thick, whilst oceanic crust is only 5-10 km thick. Oceanic crust is denser, can be subducted and is constantly being destroyed and replaced at plate boundaries.
How is ocean floor topography different from land?
1. In Today’s days, there are separate scales for the ocean and the land topography because Ocean topography is little vaster than the land topography. 2. For example, there will be small Islands which will be shown like a whitish mark instead of the yellowish mark as they are shown in Land Topography.
Why are there straight lines on the ocean floor?
These lines are artifacts of the ocean floor mapping process. Oceanographers use sonar—sound waves—to map the ocean bottom. These sonar readings are typically taken by ships towing submersible devices that send out sound waves.
What are the differences between oceanic and continental crust?
What portions of the seafloor are underlain by continental crust?
The vertical exaggeration is approximately 200 times. The ocean floor is almost entirely underlain by mafic oceanic crust (mostly basalt and gabbro, as described in more detail below), while the continental slopes are underlain by felsic continental crust (mostly granitic and sedimentary rocks).
What are three differences between continental and oceanic crust?
Continental crust is low in density whereas oceanic crust has a higher density. Continental crust is thicker, on the contrary, the oceanic crust is thinner. Continental crust floats on magma freely but oceanic crust floats on magma scarcely. Continental crust cannot recycle whereas oceanic crust can recycle it.
Why is continental crust less dense than oceanic crust?
Continental crust is less dense because of its composition. Continental crust is made up of felsic material (SiO4)– mainly granite. The density of continental crust is 2.9 g/cm^3. Oceanic crust, while thinner, is made of mafic materials (Fe, Mg)– mainly basalt.
Are oceans topographic features?
Ocean and land topography are defined exactly the same way. Both give the height of the ocean or land above the geoid. The geoid is the shape the sea surface would have if all the currents and tides stopped. Tides and currents are the two major factors that contribute to the dynamic topography of the ocean’s surface.
What happens to the continental crust as it stretches and thins?
As the plate stretches and thins, the underlying asthenosphere flows upward and expands like a hot-air balloon, lifting the region to higher elevations. The continental crust breaks along faults, forming long mountain ranges separated by rift valleys.
A plate capped by thin oceanic crust subducts beneath one capped by thick continental crust, forming an accretionary wedge and volcanic arc on the overriding plate. The ocean closes as a continent with thick crust approaches the subduction zone.
Where can you find layers of continental crust?
Similar, but much older, layers are found in NPS sites in the Keweenawan Rift of the Lake Superior region, where divergent plate boundary forces tried, unsuccessfully, to rip the North American continent apart 1.1 billion years ago. Continental crust is thick and buoyant, and therefore sticks up above sea level.
What happens when tectonic plates converge in the ocean?
Sometimes an entire ocean closes as tectonic plates converge, causing blocks of thick continental crust to collide. A collisional mountain range forms as the crust is compressed, crumpled, and thickened even more. The effect is like a swimmer putting a beach ball under his or her belly—the swimmer will rise up considerably out of the water.