Plate tectonics

Plate tectonics

Introduction

Tectonics is that part of geology that studies the nature and causes deformation of rock. Plate tectonics is a unifying global scientific theory which proposes that the deformations of the lithosphere are connected to the internal forces of the earth and that these distortions result in the cutting of the lithosphere in a number of plates. Alfred Wegener proposed in 1912 that if all the known continents were combined into a single supercontinent it would have broken into blocks such rafts drifted away from each other leading to the distribution current continents. Wegener is set aside by scientists of the time because it lacked justification for the movements of said plates. The origin of these movements is now known and argued. It was not until the 1960s that new data particularly from the study of the seabed have helped to build and validate the model of plate tectonics (Korenaga, 2010).

Discussion

Plate Tectonics

Plate tectonics is a scientific theory which describes the large scale motion of the earth's lithosphere. This theory is built on the concept of continental drift which was developed in 20th century. It was accepted by the geo-scientific community after the development of seafloor spreading developed during 1950s and 1960s (Korenaga, 2010). There are many several small and 12 large plates and ones which float and travel independently over the asthenosphere (Valencia, O'Connell, 2009). The major continents which are embedded within them include African, Antarctic and North American plates. Although, the minor plates are smaller in size still they are considered very important when it comes to shaping the earth. Juan de Fuca plate is responsible for the volcanoes which are observed on Pacific Northwest of the United States.

These plates make the outer shell of the earth and are known as lithosphere including the crust and uppermost part of the mantle. Currents in the molten rocks push them like a mixture of conveyer belt in bad shape. Geologic activity curtails from the interaction of the plates where they meet and divide. The movement of these plates includes three types of tectonic boundaries which are:

Divergent, where plates move apart

Convergent, where plates move into one another

Transform, when plates move into one another (Bercovici, 2003).

Figure 1: Plate Tectonics

Divergent

It is common phenomenon that heat flows from the center to the outside of earth which is caused by the radioactive decay of certain chemical elements in the mantle and generates convection cells in the asthenosphere. As a result of this convection, there is a concentration of heat in area where the heated material expands and causes uplift parallel to the oceanic ridge. The concentration of heat leads to a partial melting of the mantle which produces magma (Warren, Hirth, 2006). Product convection in the solid portion of the lithosphere forces that make two plates diverge causing oceanic lithosphere on both sides. Between these two divergent plates, the arrival of magma creates new oceanic crust.

The magma produced by partial melting of the mantle enters the cracks and fractures of the ...