What Is The Molten Material That Rises From The Mantle?

What are the 4 evidence of continental drift?

They based their idea of continental drift on several lines of evidence: fit of the continents, paleoclimate indicators, truncated geologic features, and fossils..

What is a deep canyon on the ocean floor called?

The answer is that the ocean floor generally does not just keep spreading. Instead, the ocean floor plunges into deep under-water canyons called deep-ocean trenches. At a deep-ocean trench, the oceanic crust bends downward.

What happened to old oceanic crust as new molten material rises from the mantle?

What happens to old oceanic crust as new molten material rises from the mantle? The molten material spreads out, pushing older rock to both sides of the ridge. It sinks down due to density. It gets evaporated.

What happens to magma that rises through cracks on the sea floor?

The process is called sea-floor spreading. Ridges form along cracks (divergent boundaries) in the oceanic crust (Molten rock (magma) rises through these cracks and pushes to both sides. When it cools, it forms new oceanic crust. The old crust is pushed away and new crust takes over.

Is it true that a deep ocean trench is an underwater mountain?

A deep-ocean trench is an underwater MOUNTAIN. Molten material erupts INSIDE the central valley of mid-ocean ridges. The farther from a mid-ocean ridge a rock sample is taken, the YOUNGER the rock is. Sea-floor spreading occurs at MID-OCEAN RIDGES.

What is the name for the constant production of new ocean floor?

In 1960 Hess suggested that a process called sea-floor spreading contiually adds new material to the ocean floor. In sea-floor spreading, the sea floor spreads apart along both sides of a mid-ocean ridge as new crst is added.

What is the process by which the ocean floor sinks beneath a deep ocean trench and back into the mantle?

At some points, the oceanic crust bends downward and forms a deep-ocean trench. Then the oceanic crust sinks back into the mantle through a process called subduction. … Subduction allows part of the ocean floor to sink back into the mantle over tens of millions of years.

What is the evidence of seafloor spreading?

Several types of evidence supported Hess’s theory of sea-floor spreading: eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves. This evidence led scientists to look again at Wegener’s hypothesis of continental drift.

What is the cause of seafloor spreading?

Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor. Eventually, the crust cracks.

What do you call the process where new material is continually added to the ocean floor?

In 1960, Hess proposed a radical idea. He suggested that a process he called sea-floor spreading continually adds new material to the ocean floor. In sea-floor spreading, the sea floor spreads apart along both sides of a mid-ocean ridge as new crust is added. … This material hardens to form the rock of the ocean floor.

How is the ocean floor like a giant conveyor belt?

Thermohaline Circulation Currents slowly turn over water in the entire ocean, from top to bottom. It is somewhat like a giant conveyor belt, moving warm surface waters downward and forcing cold, nutrient-rich waters upward.

Which is the best evidence that two continents were once connected?

Wegener then assembled an impressive amount of evidence to show that Earth’s continents were once connected in a single supercontinent. Wegener knew that fossil plants and animals such as mesosaurs, a freshwater reptile found only South America and Africa during the Permian period, could be found on many continents.

Which part of the ocean floor is the flattest?

abyssal plainAnswer and Explanation: The flattest part of the ocean floor is called the abyssal plain and is often found next to a continent.

Is sonar a device that scientists use to map the ocean floor?

In the mid-1900s, scientists mapped the mid-ocean ridges using sonar. Sonar is a device that bounces sound waves off underwater objects and then records the echoes of these sound waves. The mid-ocean ridges curve along the sea floor, extending into all of Earth’s oceans.

How is Earth’s crust like a conveyor belt?

The Earth is a dynamic or constantly changing planet. The thin, fragile plates slide very slowly on the mantle ‘s upper layer. This sliding of the plates is caused by the mantle’s convection currents slowly turning over and over. This overturn is like a conveyor belt that moves the plates of the crust.

What is it called when the ocean floor sinks into the mantle?

The process by which the ocean floor sinks into the mantle is called Subduction ..

What are the three types of seafloor spreading?

There are three types of plate-plate interactions based upon relative motion: convergent, where plates collide, divergent, where plates separate, and transform motion, where plates simply slide past each other.

What happens to the ocean floor in deep ocean trenches?

Ocean trenches are steep depressions in the deepest parts of the ocean [where old ocean crust from one tectonic plate is pushed beneath another plate, raising mountains, causing earthquakes, and forming volcanoes on the seafloor and on land.