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12 cze 2024 · The concept of plate tectonics was formulated in the 1960s. According to the theory, Earth has a rigid outer layer, known as the lithosphere, which is typically about 100 km (60 miles) thick and overlies a plastic (moldable, partially molten) layer called the asthenosphere.
Tectonic plates are composed of the oceanic lithosphere and the thicker continental lithosphere, each topped by its own kind of crust. Along convergent plate boundaries, the process of subduction carries the edge of one plate down under the other plate and into the mantle.
1 gru 2021 · Plate tectonics probably began at a global scale during the Mesoarchean (c. 2.9–3.0 Ga), with firm evidence for subduction in older geological terranes accounted for by isolated plate tectonic ‘microcells’ that initiated at the heads of mantle plumes.
17 lut 2023 · Tectonic plates are large, irregular-shaped slabs of rock making up the Earth’s crust and upper mantle. They are found to float on top of a semi-liquid layer of rock called the asthenosphere.
Earth’s lithosphere, or outermost shell, is broken up into large pieces called tectonic plates. These plates move slowly over the asthenosphere, a layer of softer rock below the lithosphere.
Movement of the plates over Earth’s surface is termed plate tectonics. Plates move at a rate of a few centimeters a year, about the same rate fingernails grow. HOW PLATES MOVE. If seafloor spreading drives the plates, what drives seafloor spreading? Picture two convection cells side-by-side in the mantle, similar to the illustration in figure 3.
Harry Hess proposed a new mechanism for continental drift through mantle convection cells, causing seafloor spreading. These ideas were confirmed by magnetic surveys and subsequent research, leading to the theory of plate tectonics.
