Which is the best evidence supporting the concept of seafloor spreading?

Asked By: Neeltje Verbeeck | Last Updated: 2nd May, 2020
Category: science geology
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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.

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Subsequently, one may also ask, which of the following provides supporting evidence for seafloor spreading?

Evidence for Sea-Floor 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.

Secondly, what are the evidence of seafloor spreading theory? Seafloor spreading, theory that oceanic crust forms along submarine mountain zones, known collectively as the mid-ocean ridge system, and spreads out laterally away from them.

Hereof, what is paleomagnetic evidence and how does it support the concept that the seafloor is spreading?

The symmetric banding is the result of seafloor spreading on both sides of a mid-oceanic ridge. This explanation of magnetic striping by paleomagnetism convinced scientists that new oceanic crust was being continually formed at mid-oceanic ridges. Seafloor spreading was accepted as a reality.

How did seafloor spreading provide evidence for continental drift?

Seafloor spreading helps explain continental drift in the theory of plate tectonics. When oceanic plates diverge, tensional stress causes fractures to occur in the lithosphere. At a spreading center, basaltic magma rises up the fractures and cools on the ocean floor to form new seabed.

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What are the effects of seafloor spreading?

Mid-ocean ridges and seafloor spreading can also influence sea levels. As oceanic crust moves away from the shallow mid-ocean ridges, it cools and sinks as it becomes more dense. This increases the volume of the ocean basin and decreases the sea level.

What causes seafloor spreading?

Sea-floor spreading is what happens at the mid-oceanic ridge where a divergent boundary is causing two plates to move away from one another resulting in spreading of the sea floor. As the plates move apart, new material wells up and cools onto the edge of the plates.

Where does subduction occur?

Subduction is a geological process that takes place at convergent boundaries of tectonic plates where one plate moves under another and is forced to sink due to high gravitational potential energy into the mantle. Regions where this process occurs are known as subduction zones.

What evidence supports the theory of plate tectonics?

Evidence of Plate Tectonics. Modern continents hold clues to their distant past. Evidence from fossils, glaciers, and complementary coastlines helps reveal how the plates once fit together. Fossils tell us when and where plants and animals once existed.

What is the source of magma for seafloor spreading?

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.

What is the theory of plate tectonics?

From the deepest ocean trench to the tallest mountain, plate tectonics explains the features and movement of Earth's surface in the present and the past. Plate tectonics is the theory that Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core.

What is the importance of convection currents in the theory of plate tectonics?

Convection currents in the magma drive plate tectonics. Heat generated from the radioactive decay of elements deep in the interior of the Earth creates magma (molten rock) in the aesthenosphere. The aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the Earth that extends to 2900 km.

What are the two tectonic plates called?

Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 mi) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium).

What did paleomagnetism give strong evidence for?

Paleomagnetism is the study of the ancient magnetic field of both rocks and the Earth as a whole. Paleomagnetism has provided very strong quantitative evidence for polar wander and continental drift. In this way, rocks provide a fossil compass for the study of the paleomagnetic field of the Earth.

What is the theory of continental drift?

Continental drift was a theory that explained how continents shift position on Earth's surface. Set forth in 1912 by Alfred Wegener, a geophysicist and meteorologist, continental drift also explained why look-alike animal and plant fossils, and similar rock formations, are found on different continents.

What are paleomagnetic fields?

Paleomagnetism (or palaeomagnetism in the United Kingdom) is the study of the record of the Earth's magnetic field in rocks, sediment, or archeological materials. These include biomagnetism, magnetic fabrics (used as strain indicators in rocks and soils), and environmental magnetism.

How is paleomagnetism measured?

  1. "Paleomagnetic measurements are magnetic measurements of rocks. By determining the magnetic intensity and orientation of multiple rock outcrops in an area much can be learned about the formation history, land movement, and geologic structure of the area.
  2. The given value was not understood.

What happens when the magnetic field of Earth is reversed?

During an excursion or a reversal, the magnetic field is considerably weakened and allows many more cosmic rays to reach the surface of the planet. These energetic particles from space can be damaging to life on Earth if too many reach the surface.

What causes slab pull?

Slab pull is that part of the motion of a tectonic plate caused by its subduction. Plate motion is partly driven by the weight of cold, dense plates sinking into the mantle at oceanic trenches. This force and slab suction account for almost all of the force driving plate tectonics.

Where do divergent boundaries occur?

Most active divergent plate boundaries occur between oceanic plates and exist as mid-oceanic ridges. Divergent boundaries also form volcanic islands, which occur when the plates move apart to produce gaps that molten lava rises to fill.

What do subduction zones cause?

Subduction zones are plate tectonic boundaries where two plates converge, and one plate is thrust beneath the other. This process results in geohazards, such as earthquakes and volcanoes.

How many times has the Earth's magnetic field reversed?

The rate of reversals in the Earth's magnetic field has varied widely over time. 72 million years ago (Ma), the field reversed 5 times in a million years. In a 4-million-year period centered on 54 Ma, there were 10 reversals; at around 42 Ma, 17 reversals took place in the span of 3 million years.