Question

List three types of evidence for seafloor spreading

Answer 1

Molten material found in the bottom of seafloors indicated underwater eruptions that formed new areas of the seafloor was presented as evidence for seafloor spreading. Due to earths magnetic polarity and its tendency to switch, iron present on the sea floor contained a magnetic record of sea floor expansion progress. Finally, drilling samples obtained in the seafloor indicated the deeper samples of were significantly older than the shallower samples that were brought up.

Answer 2

Seafloor spreading  

• Seafloor spreading is a geological process that involves the gradual addition of new oceanic crust in the oceanic floor while moving older rocks away from the mid-oceanic ridge. In other words it is the process in which the tectonic plates on the oceanic floor move apart from each other.
• The process occurs when the seafloor spreads apart along divergent boundaries and forms the mid-ocean ridge.
• Magma is pushed up through cracks in the crust along the mid-ocean ridge. As the magma is thrust up and hardens it forms the new crust and the ocean floor on both sides of the mid-ocean ridge move outward.

Evidence of seafloor spreading  

1. Rocks near mid-ocean ridge were younger than rock near trenches. Rocks away from the mid-oceanic ridges are relatively older than those near it.  

Additionally, the older rocks are denser and thicker compared to thinner and less dense rocks near the mid-oceanic ridge.

2. Matching bands of magnetic rocks were found on either side the mid-ocean ridge; bands like tree rings - record changes in earth's magnetic field over time.

This means sea floor contains different rocks based on ages and are positioned equally in opposite directions. This indicates that there is constant movement and spreading of rocks on the ocean floor.

3. Earthquake data showed oceanic crust is sinking on to the mantle at trenches.  

Keywords: Seafloor spreading, evidence of seafloor spreading  

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• Seafloor spreading: brainly.com/question/9912731
• Evidence of seafloor spreading: brainly.com/question/9912731

Level: High school  

Subject: Geography  

Topic: Geology  

Sub-topic: Seafloor spreading