Wegener didn't have an explanation for how continents could move around the planet, but researchers do now. This strong outer layer is called the lithosphere.ĭeveloped from the 1950s through the 1970s, plate tectonics is the modern version of continental drift, a theory first proposed by scientist Alfred Wegener in 1912. The plates act like a hard and rigid shell compared to Earth's mantle. 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. 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. by earthquakes and floods" and went on to say: "The vestiges of the rupture reveal themselves, if someone brings forward a map of the world and considers carefully the coasts of the three. suggested that the Americas were "torn away from Europe and Africa. Kious described Ortelius' thoughts in this way: Abraham Ortelius in his work Thesaurus Geographicus. Abraham Ortelius (Ortelius 1596), Theodor Christoph Lilienthal (1756), Alexander von Humboldt (18), Antonio Snider-Pellegrini (Snider-Pellegrini 1858), and others had noted earlier that the shapes of continents on opposite sides of the Atlantic Ocean (most notably, Africa and South America) seem to fit together.
In 1858 Antonio Snider-Pellegrini created two maps demonstrating how America and Africa continents might have once fit together. The idea of continental drift has been subsumed by the theory of plate tectonics, which explains how the continents move.
The concept was independently and more fully developed by Alfred Wegener in 1912, but his theory was rejected by some for lack of a mechanism (though this was supplied later byArthur Holmes) and others because of prior theoretical commitments. The plate then moves.Continental drift is the movement of the Earth's continents relative to each other, thus appearing to "drift" across the ocean bed. The speculation that continents might have 'drifted' was first put forward by Abraham Ortelius in 1596.The Hotspot then explodes, creating a volcano.Hotspots The hotspot is also known as a magma chamber, it is located in the mantle.Friction builds up between the plates until they snap and cause EARTHQUAKES.Transform – the plates slide past each other, they form faults.Ocean/ocean Formations – island arc, trench.Land/land Formations – Large Mountains (Orogeny).Land/ocean Formations- subduction zone, trench, volcanoes, earthquakes.Mid-Atlantic Ridge it is 40,000 miles long.Ocean/Ocean Formations- ocean ridge, fissures.Divergent Boundaries two plates move apart.Identical magnetism on opposite sides of ridges. This proved that new sea floor was being created at mid-ocean ridges.As new crust is created the iron bearing minerals point to where the magnetic pole is at the time of creation. These new maps showed the different magnetism in different layers of rock.Plate Boundaries and Convection Currents.Rising convection currents will move plates apart (divergent), while sinking convection currents will move plates together (convergent). Since the hotter material deep in the asthenosphere is less dense it will slowly rise, as it reaches the base of the lithosphere it begins to cool, become more dense, and will sink. Convection current/Plate motion Plate motion is thought to be caused by convection currents in the asthenosphere.Seafloor Spreading – new ocean crust is formed at ocean ridges and destroyed at deep sea trenches.This could detect small changes in the magnetic field in rocks and map them. This way stunk because it didn’t accurately map the floor. FINDING EVIDENCE The first way to map the ocean floor used Sonar.History of Plate Tectonics and Alfred Wegener.
0 kommentar(er)
