How Did Drilling Samples Show That Sea Floor Spreading Really Has Taken Place?

What is the strongest evidence of seafloor spreading?

Abundant evidence supports the major contentions of the seafloor-spreading theory.

First, samples of the deep ocean floor show that basaltic oceanic crust and overlying sediment become progressively younger as the mid-ocean ridge is approached, and the sediment cover is thinner near the ridge..

Why is seafloor spreading important?

Significance. Seafloor spreading helps explain continental drift in the theory of plate tectonics. … At a spreading center, basaltic magma rises up the fractures and cools on the ocean floor to form new seabed. Hydrothermal vents are common at spreading centers.

Which is one type of evidence that geologists usually study?

Answer. Geologists have used two main types of evidence to learn about Earth’s interior: direct evidence from rock samples and indirect evidence from seismic waves. The geologists are observing rock on Earth’s surface.

What is the average speed of seafloor spreading?

approximately 5 centimeters a yearThe average speed of seafloor spreading is approximately 5 centimeters a year. This growth rate can be compared to the growth rate of human fingernails (Krupicka). The global ridge system consists of oceanic ridges. Seafloor spreading occurs at these elevated oceanic ridges and has high heat flow and volcanism.

What boundaries destroy seafloor?

At convergent plate boundaries, oceanic crust is often forced down into the mantle where it begins to melt. Magma rises into and through the other plate, solidifying into granite, the rock that makes up the continents. Thus, at convergent boundaries, continental crust is created and oceanic crust is destroyed.

Which statement provides evidence that the seafloor is spreading?

Which statement provides evidence that the seafloor is spreading out from both sides of the mid- Atlantic ridge? parallel strips of igneous rock on each side of the ridge show matching reversals of magnetic polarity.

What are three evidences 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.

Where is active seafloor spreading occurring today?

Where is active sea floor spreading occurring today? Seafloor spreading is the movement of old rock that is being pushed by the new young oceanic crust. This would be a divergent since the plates are separating from each other. Active seafloor spreading is occurring at mid-ocean ridges.

Which is the first step in the seafloor spreading process?

A crack forms in oceanic crust. Molten rock rises up through oceanic crust. Molten rock solidifies at the center of the ridge.

How do we know the seafloor is spreading?

The magnetism of mid-ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. … Oceanic crust slowly moves away from mid-ocean ridges and sites of seafloor spreading. As it moves, it becomes cooler, more dense, and more thick.

Where is the youngest material in the seafloor found?

The youngest crust of the ocean floor can be found near the seafloor spreading centers or mid-ocean ridges. As the plates split apart, magma rises from below the Earth’s surface to fill in the empty void.

What process recycles the crust?

Crustal recycling is a tectonic process by which surface material from the lithosphere is recycled into the mantle by subduction erosion or delamination.

How was sea floor spreading tested as a hypothesis?

Sea-floor spreading — In the early 1960s, Princeton geologist Harry Hess proposed the hypothesis of sea-floor spreading, in which basaltic magma from the mantle rises to create new ocean floor at mid-ocean ridges. … A test of the hypothesis of sea-floor spreading was provided by studies of the Earth’s magnetism.

What scientist helped discover the process of seafloor spreading?

Harry H. HessThe seafloor spreading hypothesis was proposed by the American geophysicist Harry H. Hess in 1960.

In which two places do divergent boundaries occur?

Divergent boundaries are typified in the oceanic lithosphere by the rifts of the oceanic ridge system, including the Mid-Atlantic Ridge and the East Pacific Rise, and in the continental lithosphere by rift valleys such as the famous East African Great Rift Valley.