20 Marker Planning Prior to Write Up:
To what extent does plate tectonic theory help in understanding the development of
landforms associated with plate movements?
Plate tectonic theory is the unifying framework for explaining anomalous geomorphological
processes that occur in the lithosphere, such as sea floor spreading, earthquakes,
volcanoes, and tectonically induced islands or rift valleys. To a large extent, theories
regarding convergent, divergent, collision and conservative plate boundaries are crucial to
understanding the unique geological formations at each margin. However it remains
important to consider outside factors like coastal and marine erosion, as well as sea level
rise, that may affect the landform’s characteristics, such as gradient, or other outstanding
theories such as the “hot spot” theory.
Firstly, Plate tectonic theories, namely that of convergent plate boundaries, allows
geographers to gain an insight into how islands (tectonic landforms) are created, despite
their anomalous position, and the fact that there is no correlation between islands when
studying only the lithosphere. The theory of convergent plate boundaries suggests that,
within the asthenosphere, magma cyclically cools and condenses, travelling in either the
west or east direction, before eventually reaching the subduction zone. The lithosphere’s
lower temperature, as it is at the surface, and subsequent high density, allows it to be pulled
into the mantle and reheated. Because of this, the melted lithosphere becomes lighter, and
rises, penetrating the stretched crust of the subduction zone, forming volcanic islands in an
arc shape. Conclusively, this theory provides substantial understanding for how volcanic
islands form, and furthermore, it can be found when looking at the igneous, condensed
basalt that island chains like the Galapagos islands, situated around the convergent plate
boundary of the Nazca and Cocos plates, are composed of. The very existence of igneous
rock, by definition, proves that magma must have reached the surface in order to cool and
condense, forming this particular igneous rock. Therefore, this coincides with the belief that,
to a large extent, plate tectonic theories are crucial to understanding the consequential
landforms that occur above the lithosphere of the Earth.
However, critics may argue that the existence of volcanic islands instead suggests that plate
tectonic theory, while comprehensive, doesn't fully account for all volcanic phenomena. This
undermines the complexity of Earth's structure, and the need to consider additional
complimentary theories like mantle plumes, which are crucial to understanding the formation
of landforms. As an example the Galapagos islands are potentially not a formation caused
by Magma at a convergent boundary (as theorised by the tectonic plate theory), but rather
they form due to the theory of “hot spots, which are areas believed to have magma “plumes”
due to increased heat from primordial or radiogenic sources. These plumes of magma rise
as thermal “diapirs” (intrusions in brittle layers of the mantle) from the outer core
boundary,into the lithosphere, causing volcanism at the surface, and the arise of lava
through the lithosphere onto the surface, before cooling and condensing into igneous rock
based islands. This can be evidenced by the fact that, instead of forming on what is
To what extent does plate tectonic theory help in understanding the development of
landforms associated with plate movements?
Plate tectonic theory is the unifying framework for explaining anomalous geomorphological
processes that occur in the lithosphere, such as sea floor spreading, earthquakes,
volcanoes, and tectonically induced islands or rift valleys. To a large extent, theories
regarding convergent, divergent, collision and conservative plate boundaries are crucial to
understanding the unique geological formations at each margin. However it remains
important to consider outside factors like coastal and marine erosion, as well as sea level
rise, that may affect the landform’s characteristics, such as gradient, or other outstanding
theories such as the “hot spot” theory.
Firstly, Plate tectonic theories, namely that of convergent plate boundaries, allows
geographers to gain an insight into how islands (tectonic landforms) are created, despite
their anomalous position, and the fact that there is no correlation between islands when
studying only the lithosphere. The theory of convergent plate boundaries suggests that,
within the asthenosphere, magma cyclically cools and condenses, travelling in either the
west or east direction, before eventually reaching the subduction zone. The lithosphere’s
lower temperature, as it is at the surface, and subsequent high density, allows it to be pulled
into the mantle and reheated. Because of this, the melted lithosphere becomes lighter, and
rises, penetrating the stretched crust of the subduction zone, forming volcanic islands in an
arc shape. Conclusively, this theory provides substantial understanding for how volcanic
islands form, and furthermore, it can be found when looking at the igneous, condensed
basalt that island chains like the Galapagos islands, situated around the convergent plate
boundary of the Nazca and Cocos plates, are composed of. The very existence of igneous
rock, by definition, proves that magma must have reached the surface in order to cool and
condense, forming this particular igneous rock. Therefore, this coincides with the belief that,
to a large extent, plate tectonic theories are crucial to understanding the consequential
landforms that occur above the lithosphere of the Earth.
However, critics may argue that the existence of volcanic islands instead suggests that plate
tectonic theory, while comprehensive, doesn't fully account for all volcanic phenomena. This
undermines the complexity of Earth's structure, and the need to consider additional
complimentary theories like mantle plumes, which are crucial to understanding the formation
of landforms. As an example the Galapagos islands are potentially not a formation caused
by Magma at a convergent boundary (as theorised by the tectonic plate theory), but rather
they form due to the theory of “hot spots, which are areas believed to have magma “plumes”
due to increased heat from primordial or radiogenic sources. These plumes of magma rise
as thermal “diapirs” (intrusions in brittle layers of the mantle) from the outer core
boundary,into the lithosphere, causing volcanism at the surface, and the arise of lava
through the lithosphere onto the surface, before cooling and condensing into igneous rock
based islands. This can be evidenced by the fact that, instead of forming on what is
