Wegener's Theory Of The Earth Essay

2. Literature Review
2.1 Theoretical Background
2.1.1 The Earth and its Atmosphere

In the early twentieth century, a young German scientist named Alfred Wegener, His theory was motivated by the observation that the continents, particularly South America and Africa, seemed to be pieces of a global jig-saw puzzle that had somehow been pulled apart (Asrat, 2006). He reasoned that all land masses were once connected in a gigantic supercontinent he named "Pangaea". The northern part of Pangea is commonly called Laurasia and the southern part Gondwanaland. A single supercontinent that broke apart to form the modern continents is called the theory of continental drift. He posited that the now separated continents floated and drifted through a highly viscous sea floor. This part of his theory was later proved incorrect but the basic notion of drifting continents was right. Wegener 's problem was in identifying correctly the forces that ripped apart the pieces and in fact keeps them moving.

Other theory which is accepted, that new land was being created on either side of the mid-Atlantic ridge, the so-called "sea-floor spreading"

This system consists of three main arms: the Red Sea Rift; the Gulf of Aden Rift; and the East African Rift which develops through Eritrea, Ethiopia, Kenya, Tanzania, Zambia, Malawi and northern Mozambique floored by a thinned continental crust (Manfred, 2005). The EARS is composed of two rift trends; the eastern and western branches. The western branch develops from Uganda throughout lake Tanganyika, where it joins the Eastern branch, following the border between Rwanda and Zaire. The western branch is, however, much less active in terms of tectonics and volcanism although both branches are seismically and tectonically active