Convergentand Divergent Plate Boundaries
Platetectonics is a philosophy or a theory used to explain the earth’slithosphere in a large-scale motion (BBC,par).This theory helps in describing the numerous apparent disparategeological occurrences. It states that the lithosphere of the earthis broken down into many lumps (or plates) which are in continuousmotion whose driving forces are mantle and core (heart flow fromwithin the earth’s interior). This theory is based on continentaldrift theory that was proposed by Alfred Wagener over a century ago.There are four distinct types of plate boundaries. This paperexplains how convergent and divergent plate boundaries can be thoughtof as destructive and constructive plate margins, respectively.
Divergentboundaries are thought of as constructive boundaries [ CITATION DrS09 l 1033 ].They are formed when one plate moves away from another plate thusforming a new ocean floor from the up-surgingmagma which allows the formation of new ocean basin (BBC,par).The ridge is formed at the spreading center as the motion of platestake place, thus making the ocean basin to expand which finally leadsto numerous small volcanic emissions. The magmas that are formed areless dense hot. This is why divergent boundaries are termed asconstructive plate margins.
Convergentboundaries are as well, known as active margins. They are theopposite of divergent boundaries. These boundaries are formed whentwo plates slide towards each other to form either a sub-duction zoneor a continental collision [ CITATION DrS09 l 1033 ].Due to ocean-to-continent motions, the denser oceanic lithosphereplunges under the less dense continent, which causes earthquakes thatmoves up to form a trench [ CITATION DrS09 l 1033 ].As a result, the molten rock rises to form continental volcanoes.Oceanto ocean sub-duction causes a formation of an arc-like trench. Thiswill cause the oceans to close thus destructive boundaries.
BBC.Plateboundaries.Retrieved From web.http://www.bbc.co.uk/bitesize/ks3/geography/physical_processes/plate_tectonics/revision/3/
Steve Ackerman, Dr Ellen Lettvin, Margaret Mooney, Et al. Wisc Education. 12 May 2009. 19 June 2011 <https://cimss.ssec.wisc.edu/sage/geology/lesson2/concepts.html>.