The Evolution of Continental Drift Theory and Researches
Alfred Wegener was born on the 1st of November, 1880 in Germany, Berlin. He went to the University of Berlin and received a PhD in Astronomy. Wegener taught meteorology at Marburg University and later received a professorship in meteorology, 1924. He believed that all the continents were once joined together as one continent called Pangaea, then split away from each other, forming earth as it is today. This was his main theory which he called, Continental Drift. After many of his trips to Greenland and studying the coastline of Africa, Wegener was able to conclude that the sea-floor was made up of puzzle-like pieces which very slowly moved around. They changed from being one single puzzle (Pangaea) to splitting away and forming multiple puzzles (multiple continents).
Wegener published his first book in 1915, The Origin of Continents and Oceans. The book consisted of fossil evidence such as tropical plant life in Greenland that couldn’t have originated there. This supported his theory of Continental Drift by showing evidence of similar plant life in completely different climates and continents. Nobody would expand on this theory until 30 years after his death. His theory changed how scientists previously thought with regards to how the continents were formed and has allowed them to expand on his ideas. Unfortunately, Wegener died on his fourth trip to Greenland when he was caught in a blizzard and froze to death.
Another scientist was Harry Hess. He was a geophysicist and oceanographer born in New York City, 27th of May 1906. He received a bachelor of science degree at Yale University, then a PhD from Princeton. During World War 2, Hess joined the navy and mapped the ocean floor whilst he was there. He led the Mohole Project, the first journey to drill into the Earth’s crust to reach the mantle. In 1946, after World War 2, Hess collected his data and research from his time in the Navy and discovered that hundreds of flat-topped mountains, or sunken islands mapped the Pacific floor.
In 1960, Hess proposed that the movement of the continents was a result of the sea-floor spreading. He also wrote many scientific papers and most famously, The History of Ocean Basins. This book is one of the most important contributions to the idea of plate tectonics and is also evidence for his theory of sea-floor spreading. He explained that molten magma from underneath earth's crust could rise between tectonic plates in the Great Global Rift, an underwater deep canyon. As hot magma cooled in the ocean water, it would expand and move the tectonic plates on either side of it. He had figured this out by using the data he collected whilst he was in the Navy and also afterwards. Sonar-equipped submarines collected profiles of the sea-floor below. The data allowed Hess to create 3D maps of the sea-floor and discover oceanic mountains and ridges. Hess figured out that all continents are attached to tectonic plates and don’t move by themselves but are carried by these tectonic plates. From his research, we’ve been able to learn more about the earth’s crust, what the seafloor is shaped like and how it moves. Hess also was invited to help NASA plan the US space program.
Frederick J. Vine was born in London, 17th of June 1939. He went to Cambridge University and received an undergraduate degree in Natural Sciences and a PhD in Marine Geophysics. He was also a professor for Princeton University and the University of East Anglia. He studied magnetic surveys with another Marine Geophysicist, Drummond (Drum) H. Matthews. Together they created a 3D computer software which calculated the magnetic pulses of the ocean’s surface.
In 1963, Vine & Matthews published a research paper called Magnetic Anomalies over Ocean Ridges. The paper showed proof that Wegener’s first idea of Continental Drift did occur. Their research showed that there are chunks of ocean crust that have magnetised rocks within them. His theory was that mid-ocean ridges had a symmetrical pattern of magnetic reversals. This means that the magnetised rocks change their polarity causing North to change to South and vice versa. With the combination of both Vine’s and Hess’s theories, they were able to conclude that the ocean’s crust acted as a tape recorder for magnetic reversal. In addition to evidence in his research paper, he also examined what is known as the Juan de Fuca Ridge. Vine used a detailed magnetic survey and a map of the ridge to determine that there were magnetic stripes on either side of the ridge in near-perfect symmetry. With this research and evidence, Vine was able to also proved Hess’s theory right. Vine’s theory told us why there were always slight shifts in faults which would later help us to figure out how to predict if and where the continents will move and whether they would ever form into one continent again.
Overall Plate Tectonics is like a jigsaw. There are numerous cracks in the plates, called fault lines which run in between the different plates. When plates collide or shift they release large amounts of energy. This explains the cause of earthquakes, tsunamis, and volcanic eruptions. Tsunamis occur when the plates move or even when an earthquake occurs. The energy released from the crashing plates, displaces water causing a tsunami. Volcanic eruptions occur when the plates crash into each other then pull apart. Hot magma rises at this point, creating the eruption. We can measure earthquakes using a Richter scale which determines the magnitude of the earthquake. Tsunamis are measured by the height of the waves as they peak on shore and by the length it runs up onto land. We can measure volcanoes by using the Volcanic Explosive Index (VEI). It measures the amplitude of the volcanic eruption.
Moreover, we may never be able to accurately predict earthquakes but we can determine the probability of one occurring. Using seismometers, we can test for vibrations underground from seismic waves. By determining the probability of an earthquake occurring we can use warning systems to alert people in the threatened areas. We can potentially predict volcanic eruptions by looking at the past eruptions from the specific volcano. We can also measure the gas emissions because as hot magma rises it releases gases into the atmosphere. They can be measured by satellites or equipment on land. By monitoring these factors, we may be able to determine whether a volcano is about to erupt so the appropriate actions can be taken to minimise their effect. Scientists have figured out how to measure tsunamis by using devices on buoys that record changes in the sea-surface elevation. A more accurate way to predict tsunamis is by using ‘side-looking’ radars that monitor the movement of waves. This can help warn people and get them to safety before it’s too late.
In conclusion, so what is the connection between all scientists? Harry Hess proved Wegener’s Continental Drift theory right. Vine’s explanation of magnetic stripes proved Hess’s seafloor spreading model. Hess and Vine came together to formulate the idea of transform faults.
