What Drives Plate Motion, and How Fast Do Plates M.How Can You Tell One Mineral From Another?.Plates on opposite sides of the inactive part of a fracture zone move together, as one plate. Further, in Wilson’s model, slip occurs only along the segment of the fracture zone between the two ridge segments (figure above c). Clearly, the movement direction on the active portion of the fracture zone must be opposite to the movement direction that researchers originally thought occurred on the structure. Mid-ocean ridges and transform margins have shallow earthquakes (usually less than 30 km deep), in narrow bands close to plate margins. With this idea in mind, he drew a sketch map showing two ridge-axis segments linked by a fracture zone, and he drew arrows to indicate the direction that ocean floor was moving, relative to the ridge axis, as a result of sea-floor-spreading (figure above b). These segments were linked (not offset) by fracture zones. Wilson proposed that fracture zones formed at the same time as the ridge axis itself, and thus the ridge consisted of separate segments to start with. Natural or human-made structures that cross a transform boundary are offset split into pieces and carried in opposite directions. One of the most famous transform plate boundaries occurs at the San Andreas fault zone, which extends underwater. Tuzo Wilson, began to think about fracture zones in the context of the sea-floor-spreading concept. Two plates sliding past each other forms a transform plate boundary. The distribution of movement along fracture zones remained a mystery until a Canadian researcher, J. Volcanic activity is normally not present. are locations of recurring earthquake activity and faulting. slide past each other at transform boundaries creating strike-slip faults. The portions of fracture zones that extend beyond the edges of ridge segments, out into the abyssal plain, are not seismically active. Transform plate boundaries are such boundaries along which two plates slides past each other and thus by doing so creates fissures and cracks inside earths. Transform Plate Boundary: Locations where two plates slide past one another. The theory of plate tectonics explains processes in the geosphere that are. Earthquakes, and therefore active fault slip, occur only on the segment of a fracture zone that lies between two ridge segments. But when information about the distribution of earthquakes along mid-ocean ridges became available, it was clear that this model could not be correct. A transform boundary is formed when tectonic plates slide horizontally and parts get stuck at points of contact. In other words, they imagined that a mid-ocean ridge initiated as a continuous, fence-like line that only later was broken up by faulting. Originally, researchers incorrectly assumed that the entire length of each fracture zone was a fault, and that slip on a fracture zone had displaced segments of the mid-ocean ridge sideways, relative to each other. These belts, or fracture zones, lie roughly at right angles to the ridge segments, intersect the ends of the segments, and extend beyond the ends of the segments. *”Physical Geology” by Steven Earle used under a CC-BY 4.0 international license.When researchers began to explore the bathymetry of midocean ridges in detail, they discovered that mid-ocean ridges are not long, uninterrupted lines, but rather consist of short segments that appear to be offset laterally from each other (figure above a) by narrow belts of broken and irregular sea floor. west coast (Steven Earle, “Physical Geology”).Īs we will see in the next section, earthquakes are common along transform faults, as the two plates slide past each other.
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