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2021-05-17

What is the evidence for sea floor spreading?

What is the evidence for sea floor 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.

What evidence did the Deep Sea Drilling Project?

It investigated some 624 sites in the Atlantic, Pacific, and Indian oceans, not only revealing the presence of deep ocean salt domes (which themselves may indicate the presence of oil) but also supporting the theory of plate tectonics by providing evidence of continental drift and seafloor renewal.

How did drilling by the Glomar Challenger support seafloor spreading?

Glomar Challenger was made to help Harry Hess with the theory of Seafloor Spreading by taking rock samples confirming that the farther from the Mid-ocean ridge, the older the rock was.

What 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.

Which information did the Glomar Challenger study in 1968?

ANSWER: Glomar Challenger studies about the “age of rocks in various places in the ocean” in 1968. EXPLANATION: Glomar Challenger was a “deep sea research vessel” for marine geology and oceanography studies.

Which is one piece of evidence of seafloor spreading fossil material continent material drilled core samples ocean water samples?

Explanation: Eruptions of molten material, which results in continent material is a piece of evidence of seafloor spreading.

When scientists analyzed drilling samples from the Glomar Challenger study which Discovery did they make about rocks in relation to Mid-Ocean Ridge?

When scientists analyzed drilling samples from the Glomar Challenger study, which discovery did they make about rocks in relation to a mid-ocean ridge? Rocks closer to the ridge are newer.

Are the four major ocean basins connected?

Arctic, the Atlantic, the Indian, and the Pacific. These basins are connected. Explanation: The main oceanic basins in the world are connected to each other, they are: the Arctic, the Atlantic, the Indian and the Pacific.

Is dividing the ocean beneficial?

This is often called the global ocean. The idea of naming and dividing the global ocean is merely a formality used to help people better organize and understand Earth’s major bodies of water. Dividing and naming Earth’s ocean water is helpful in studying ocean characteristics to better understand the Earth.

What are the four major ocean basins?

Historically, there are four named ocean basins: the Atlantic, Pacific, Indian, and Arctic. However, most countries – including the United States – now recognize the Southern (Antarctic) as the fifth ocean basin.

How much of ocean is unexplored?

eighty percent

What is the newest sea creature found?

Scientists have for the first time identified a small gelatinous blob in the deep sea as a new species, using only high-definition underwater cameras. The creature, officially known as Duobrachium sparksae, is a new species of ctenophore, or comb jelly.

What is the evidence for sea floor 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.

How does pillow lava presence in the Central Valley of mid-ocean ridges support the idea of sea floor spreading?

Magma comes out of ocean ridges as pillow lava and forms a new oceanic crust, supporting sea floor spreading. The older crust gets pushed away from the ridge and pushes on to the continents, making them drift.

How are magnetic stripes on the ocean floor are evidence for sea floor spreading?

When lava gets erupted at the mid-ocean ridge axis it cools and turns into hard rock. This creates a symmetrical pattern of magnetic stripes of opposite polarity on either side of mid-ocean ridges. These patterns of stripes provide the history of seafloor spreading.

What is unusual about the magnetic stripes on the ocean sea-floor?

Magnetic Stripes Some stripes have normal polarity and some have reversed polarity. Scientists found that magnetic polarity in the seafloor was normal at mid-ocean ridges but reversed in symmetrical patterns away from the ridge center. This normal and reversed pattern continues across the seafloor.

Where do magnetic anomaly patterns appear on the ocean floor?

Ocean floor stripes Magnetic surveys over the oceans have revealed a characteristic pattern of anomalies around mid-ocean ridges. They involve a series of positive and negative anomalies in the intensity of the magnetic field, forming stripes running parallel to each ridge.

What can be detected by using magnetic anomaly detectors?

Magnetometers are commonly used to search for submarines. Submarines are made mainly from ferromagnetic materials, so their presence in the Earth’s magnetic field will distort that field about them. This is in addition to their inherent remanent magnetisation.

What do marine magnetic anomaly belts run parallel to?

Cards

Term From left to right, correctly label each section of this slice of the Earth. Definition crust, upper mantle, transition zone, lower mantle, liquid outer core, solid inner core
Term Marine magnetic anomaly belts run parallel to: Definition mid-ocean ridges

What property of marine magnetic anomalies proves seafloor spreading?

The magnetic anomalies across a mid-ocean ridge have reversed magnetic norths across different distances away form the mid-ocean ridges and this is explained by sea-floor spreading and how as the sea floor spreads it produces rock and the rock preserves the magnetic field that is apparent at the time of its creation.

How are magnetic anomalies measured at sea?

The intensity can be measured by towing a magnetometer behind a survey ship, or by using an aircraft. The best results will be from deep tows. Measurement from the sea surface or aircraft or spacecraft will record the general features, but smoothing means the results are much worse that from towed ship measurements.

Which process is most responsible for creating the Earth’s magnetic field?

On Earth, flowing of liquid metal in the outer core of the planet generates electric currents. The rotation of Earth on its axis causes these electric currents to form a magnetic field which extends around the planet. The magnetic field is extremely important to sustaining life on Earth.

How is seafloor spreading rate calculated?

It is possible to calculate the spreading rate of one side of a mid-ocean ridge by dividing distance by time (Distance/Time = Rate).

Who is responsible for the theory of seafloor spreading?

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

What is the spreading rate of oceanic ridges per year?

Global spreading rates range from 10 mm (0.4 inch) per year or less up to 160 mm (6.3 inches) per year. Oceanic ridges can be classified as slow (up to 50 mm [about 2 inches] per year, intermediate (up to 90 mm (about 3.5 inches) per year, and fast (up to 160 mm per year).

What is the rate of spreading?

Spreading rates determine if the ridge is fast, intermediate, or slow. As a general rule, fast ridges have spreading (opening) rates of more than 90 mm/year. Intermediate ridges have a spreading rate of 40–90 mm/year while slow spreading ridges have a rate less than 40 mm/year.