![]() ![]() According to this, the plate boundary along the transform fault is increasingly tilted at depth, so that shearing occurs. Using sophisticated numerical models, the team found an explanation for the phenomenon. The team also detected traces of extensive magmatism at the outer corners of the intersections between transform valleys and the mid-ocean ridges. "In all examples, we could see that the transform valleys are significantly deeper than the adjacent fractures zones, which were previously thought to be simple continuations of the transform valleys," says co-author Prof. The authors of the current study have now looked at available maps of 40 transform faults in all ocean basins. Until now, however, research assumed that the two plates only slide past each other at transform faults, but that seafloor is neither formed nor destroyed in the process. Lars Rüpke from GEOMAR, co-author of the study.Įarthquakes can occur at the transform faults and they leave long scars, so-called fracture zones, on oceanic plates. Because the Earth is a sphere, plate movements repeatedly cause faults that produce these ridge offsets," explains Prof. The individual segments of the ridges each begin or end in an offset at these incisions. They are cut by transverse valleys at almost regular intervals. However, the mid-ocean ridges do not form unbroken lines. "This is the engine that keeps the plates moving," explains Prof. In between, hot material from the Earth's interior reaches the surface, cools down, forms new ocean floor and pushes the older ocean floor apart. They mark the boundaries of the Earth's plates. Even at low resolution, several tens of thousands of kilometres long mid-ocean ridges can be recognised on such maps. Ingo Grevemeyer from GEOMAR, lead author of the study.Ī look at a global overview map of the ocean floors helps to understand the study. However, our analyses show that they are definitely actively involved in shaping the ocean floors," explains Prof. ![]() So far, they have been assigned a purely passive role within plate tectonics. "These are large offsets in the mid-ocean ridges. The continental plate is pushed upward creating mountains like the Andes.Today, five scientists from GEOMAR Helmholtz Centre for Ocean Research Kiel, the Southern University of Science and Technology (Shenzhen, China) and GeoModelling Solutions GmbH (Switzerland) publish a study in the international scientific journal Nature that questions a previous basic assumption of plate tectonics. As the Ocean plate is pushed under the continental plate the sedimentary layers are melted creating volcanos. The resulting subduction zone creates a deep ocean trench and mountains. An example is the Pacific Coast of South America. The most common convergent boundary is where an ocean plate is being pushed under a continental plate. An example is the rift valley of East Africa.Ĭonvergent boundaries occur where two plates are being pushed together. Examples are the mid ocean ridges and Icelandic volcanoes.Īlso because the plates are moving in opposite directions new crust is formed between the two plates. These boundaries produce shield type volcanos that spew out ballistic lava. This pushing creates frequent and severe earthquakes, like the famous San Francisco earthquake.ĭivergent boundaries occur where two plates are being pushed apart as new crust and magma comes to the surface. Transform faults occur where two plates are pushing against each other at a close to a 180 degree angle. ![]()
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