Sea floor spreading forms the best evidence for continental drift. Critically discuss this statement. There is lots of evidence to support the theory of continental drift, including Harry Hess’s discovery of sea floor spreading theory. By using sonar, Hess found that oceans were shallower in the middle, allowing him to identify Mid Ocean Ridges. He suggested that at the centre of oceans, molten material would rise from the Earth’s mantle, causing new sea floor to be created, pushing the ocean floor.
He claimed that each of the present continents was once joined together as part of a super continent called Pangea. He believed this because he saw that in certain areas continents would fit together for example the west coast of Africa fits together with the east coast of South America, therefore they must have moved apart from one central mass. Other evidence was shown to back up this theory such as the fact that glacier derived clays are found in all of the continents in Gondwana forming one half of Pangea, as one striations in rocks of Carboniferous age. Presently they cover half the globe but would form a reasonably sized polar ice cap if Wegener’s theory was true and the globe was reconstructed in his image of how it used to be. Despite Wegener having no concrete proof as to why this was the case his theory was proved to be accurate, physicists had believed that the earths crust was far from strong enough to be able to force itself apart.
5. Why is the pattern of alternating reversals of the Earth's magnetic field as recorded in the sea floor rocks such an important piece of evidence for advancing plate tectonics? -It changes the direction of where some materials move so it might help plate tectonics move one way or the other. 6. Describe sea floor spreading and explain why it is an important piece of evidence for advancing plate tectonics.
These are important to prove evolution. Convergent evolution includes three very important parts: (a) common ancestry, (b) speciation, and (c) natural selection. Evidence of a continental drift involvesis marsupials spreading across oceans that did not yet exist, making their travel across vast bodies of land possible. A key examplenother supporter of the a species that experienced continental drift is the Glossopteris. This tree was only able to grow in warm climates and had a seed that could not float, yet fossils of this tree are found in different hemispheres of the world today.
Charles Lyell, a British geologist, reintroduced the idea of uniformitarianism when he published a series of books called Principles of Geology. Only then did people start to seriously consider that uniformitarianism was the way in which the earth was shaped. During the late 20th century, scientists began to challenge uniformitarianism. They believed that catastrophes do, at times, play a major part in shaping the Earth. Today we realize that neither uniformitarianism nor catastrophism completely explains what shapes the Earth.
As well as landforms caused by river processes, such as the Bangladesh Delta – which can be seen via satellite - therefore a major landform. One major piece of evidence in support of a strong relationship between tectonic processes and major landforms on the Earth’s surface is the Mid Atlantic Ridge. The Mid-Atlantic Ridge is an underwater mountain range caused by a diverging tectonic plate along a constructive plate boundary located along the floor of the Atlantic Ocean. The MAR is the longest mountain range in the world, therefore is definitely one of the Earth’s major landforms, and is caused by tectonic activity therefore the relationship between tectonic activity and major landforms reinforced by this evidence. In the North Atlantic, the MAR separates the Eurasian and North American Plates, whereas in the South Atlantic it separates the African and South American Plates, this evidence emphasises the size of the MAR and backs up
A seismometer permits seismologists to produce a map of the Planet’s inner surface. Another device that is used to utilize the measures of earthquakes is a Richter magnitude scale. This device provides figure to the quantity of seismic energy released during an earthquake. The Richter magnitude scale was created in 1935 by Charles Richter (www.geo.mtu.edu/UPSeis/intensity.html). Another way to measure the strength of an earthquake is to use the Mercalli scale.
3. Perform independent research to answer the following questions: Cite resources used o A. What was the size or tons of the object that impacted Earth during the late Mesozoic – often given credit for causing the dinosaur extinction? Discuss where the impact occurred, what size crater was produced, how fast it was traveling, and how did this event impact the Earth? o B.
When magma collides with the ocean water, it solidifies and new crust is formed on the ocean floor. (Tabuck, Lutgens, Tasa 2011, p.49) However, Hess idea of seafloor spreading was not enough to prove it’s validly, until years later when new evidence was revealed. Fred Vine, a Cambridge University Graduate and D.H Mathews discovered that “over periods of hundredths of thousands of years, Earth’s magnetic field periodically reverses polarity.” (Tabuck, Lutgens, Tasa 2011, p.49) During this process the north and the south pole reverse allowing lava to solidify at the crest of an ocean ridge and then magnetizes with the polarity of the existing magnetic field. In other words, magnetic reversal reinforces Hess concept of seafloor spreading which involves the Earth’s magnetic field. Vine and Mathews were able to demonstrate this revelation through a magnetometer which recorded symmetrical magnetic field across the ridges.
The lithosphere is divided into 7 major plates, including the North-American plate, and several minor plates. Between these plates are three different types of plate boundaries: constructive, destructive and conservative. Earthquakes can occur at all three when pressure builds up and is released in one sudden movement. The Earth’s plates move due to convection currents within the mantle in the Earth’s asthenosphere. As heat rises and cools it forces the plates in different directions; either sliding past one another, away or towards each other.