What are the three evidences of seafloor spreading?

What are the three evidences of seafloor spreading?

Several types of evidence from the oceans supported Hess’s theory of sea-floor spreading-evidence from molten material, magnetic stripes, and drilling samples. This evidence also led sci- entists to look again at Wegener’s theory of continental drift.

Who proved the seafloor spreading?

Harry H. Hess

Why do Tablemounts have flat tops?

Some seamounts are formed from magma rising at a divergent boundary, and as the plates move apart, the seamounts move with them, which can result in a seamount chain. As this happens, the top of the seamount can become eroded flat, and these flat-topped seamounts are then called tablemounts or guyots.

What causes a seamount?

At mid-ocean ridges, plates are spreading apart and magma rises to fill the gaps. Near subduction zones, plates collide, forcing ocean crust down toward Earth’s hot interior, where this crustal material melts, forming magma that rises buoyantly back to the surface and erupts to create volcanoes and seamounts.

What is an example of seamount?

Seamounts are extinct submarine volcanoes that are conically shaped and often flat-topped…. Seamount chains in the Pacific basin tend to be aligned northwesterly, and several chains are intimately associated with fracture zones; the Eltanin Fracture Zone in the southwestern Pacific is an example.

How long does it take a seamount to form?

When they are in an eruptive phase, they can easily grow about 300 meters (1,000 feet) in a few weeks or months, such as Nafanua Volcano on Vailulu’u seamount near Samoa in the Pacific Ocean.

Why are seamounts so productive?

Seamounts have a big effect on the deep-sea environment. They accelerate ocean currents, generate waves, increase upwelling, and amplify tides. These changes improve the food and nutrient supply for filter feeders while removing waste and reducing sediment build-up.

What does Seamount mean?

A seamount is an underwater mountain formed by volcanic activity. Thanks to the steep slopes of seamounts, nutrients are carried upwards from the depths of the oceans toward the sunlit surface, providing food for creatures ranging from corals to fish to crustaceans.

What lives on a seamount?

Tuna and deep-water species, such as alfonsino and orange roughy, grow slowly and the latter can live for 150 years. The seamounts become feeding hotspots and many other animals like cetaceans (whales and dolphins), seabirds, sharks and seals depend on them.

What’s the biggest threat to life on seamounts?

However, the greatest danger from seamounts are flank collapses; as they get older, extrusions seeping in the seamounts put pressure on their sides, causing landslides that have the potential to generate massive tsunamis.

Which sea is the deepest?

Pacific Ocean

Why are most trenches found in the Pacific Ocean?

Why are most oceanic trenches found in the Pacific Ocean? The Pacific Ocean is shrinking and plates are descending below surrounding plates along its edges, hence the creation of trenches.

How deep is an ocean trench?

Deep-sea trench, also called oceanic trench, any long, narrow, steep-sided depression in the ocean bottom in which occur the maximum oceanic depths, approximately 7,300 to more than 11,000 metres (24,000 to 36,000 feet). They typically form in locations where one tectonic plate subducts under another.

Why it is dangerous to live near plate boundaries?

Are They Dangerous Places to Live? Mountains, earthquakes, and volcanoes form where plates collide. If we choose to live near convergent plate boundaries, we can build buildings that can resist earthquakes, and we can evacuate areas around volcanoes when they threaten to erupt.

What natural disasters are caused by plate tectonics?

Events such as earthquakes, volcanoes and tsunamis all result because of plate tectonics.

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