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Author: Admin | 2025-04-28
Volcanoes. But do they have any evidence?Satellites Measure Ground MovementWith the advent of satellite technologies, scientists can now measure precise movements of land on both sides of the plate boundaries. A network of base stations sends signals up to the satellites, which show that the plates are indeed moving, albeit at a snail’s pace of inches per year (about the same pace that fingernails grow).The study of earth movements is technically known as “tectonics,” so the study of plate movements is called “plate tectonics.” (Note that it is no longer accurate to call it “continental drift.” We now know that the ocean floor crust is also moving. In fact, the Pacific, Nazca, Cocos, and Scotia plates are moving even though they consist almost entirely of ocean floor crust. See Figure 1.)But do these plate movements cause volcanoes and earthquakes?--> Figure 1Different Types of Plate Boundaries According to plate tectonics theory, the earth consists of moving plates. At their boundaries, the plates interact in one of four ways, with very different effects. Chemical Tests of Lava Show Ocean Crust Moving Under Continental CrustPerhaps you never realized it, but the earth has two different types of crust. When ocean vessels began sampling the ocean floor in the 1960s, scientists realized how different the ocean crust was from the continents’ crust. If the ocean crust was moving under the continental crust, scientists suspected they might find evidence in the lavas rising up onto the continents’ surfaces.Plate tectonics give us insights as to what likely happened during the global Flood.The differences are very distinct. The continents are made up of many different rock types, but if we were to grind them all up, the average composition would be similar to granite. On the other hand, drilling into the ocean floors has revealed that the oceanic crust beneath the ooze is made up of basalt (dark volcanic rock). Granites contain a lot of silicon and not so much iron and magnesium, whereas basalts contain a lot less silicon but much more iron and magnesium.Cooled oceanic crust is heavier than the hot mantle beneath it. So it tends to sink. The continental crust, in contrast, is much lighter (less dense), so it floats. As a result, the continents “ride” higher than the ocean crust. If they collide, the ocean crust would slide under the continental crust because it is heavier.The high pressure and temperature in a collision would cause a melting reaction that would ultimately send hot magma from the upper mantle toward the surface. Scientists have checked the chemistry of many lavas on the edges of continents and found that they are generally mixtures of ocean basalt rock and continental granitic rocks, producing intermediate rocks
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