Course Code: GEOG 1231
Divergent and convergent plate margins are both studied in plate tectonics; which is the study of the plates that makeup the lithosphere, their movements and how these movements has influenced changes in the surface’s topography (Strahler, 2011, 389). The driving force that causes these plate movements is the gradual movement of the semi-molten rock that makes up the asthenosphere (Kious, 1996, 28). Features observed at these margins share some similarities but, also vary quite largely. These differences are caused by the different movements displayed at each boundary and the types of plates involved; oceanic or continental.
Divergent plate boundaries are where two plates are moving apart from one another (Ritter, 2012). The topographic features that develop at this boundary are due to extension of the plate boundaries which causes rifting in continental and oceanic crusts (Strahler, 2011, 419). This extension is caused by rising convectional currents from the asthenosphere, which pushes up on the lithosphere and pulls it apart as the currents move laterally. For oceanic plates this process stretches and thins the lithosphere until it eventually splits. This split causes pressure to be released from the super heated rock in the mantle allowing it to melt, rise through the split and cool to form new crust.
Though for continental plates this process is a bit different. Since this plate is much thicker than the oceanic plate the lateral movement of the asthenosphere is not strong enough to split the crust smoothly. Rather the crust is pushed upwards and as it is pulled apart, normal faults form at both sides and the center blocks sink forming a rift valley.
There are several topographical features found at divergent plate margins some of which are due to faulting....