Found 23 Articles for Theories & Models in Geography

Plate tectonics is a unifying, integrated and holistic theory that deals with the whole mechanism of evolution, nature and motion of the plates and their resultant reactions. This theory describes and explains Evolution and development, decay and death of continents and oceans. Origin of endogenetic forces and related landforms. Origin and distribution of earthquakes, volcanism and fold mountains. Movements of Plates Thermal convective current originating from mantle-core boundary is the source for the movement of the plates. Rising and laterally spreading outflowing thermal convective current causes the plates to diverge, whereas laterally inflowing and sinking thermal convective current ... Read More

Paleomagnetism helps to investigate the past direction, magnitude, and polarity of the earth's magnetic field, since during the formation of rocks, they lock in the record of the direction and intensity of the magnetic field. Paleomagnetic data has played an instrumental role in deciphering the history of our planet, giving supporting evidence for continental drift and global and regional plate tectonics. Historical background Geophysicists who specialize in paleomagnetism are called paleomagnetists. In 1849, French physicist Achilles Delesse observed that certain minerals in rocks positioned themselves in line with the earth’s magnetic field, in a way that tiny compasses ... Read More

Scientists and philosophers all over the Earth from time to time, on unravelling the mystery of the Origin and evolution of our Solar system in general and our Earth in particular propounded various theories, hypotheses and concepts. Apparently, there is no consensus among the scientists about the origin of solar system and our Earth. Nevertheless, they safely concluded that the Earth would have been formed by the same process as the Solar system. Historical Background In earlier days, religious believes were prevailed to reason out the origin of Solar System. Notably, Archbishop Usher, the Prussian priest opined that the Earth ... Read More

The relationship between limited resources and a growing population interests many geographers, which centres on the human-environment relationship over space and time. Among them, Malthusian theory aims to explain the contradictory nature of the exponential population growth rate and the arithmetic food supply growth rate. Historical Background In the year 1798, the English economist and demographer named Thomas Robert Malthus proposed his theory of population growth in his book titled "Essay on the Principle of Population". He was the first to propose a systematic theory of population. He believed that without any stern limits, the limited food ... Read More

The word "geopolitics" refers to the change in the political records of the world due to its geographical attributes. This theory opines that history without geography was mere narrative and that since every event occurred at a particular time and place, with history and geography respectively, should never be separated. Historical Background Many political thinkers have undergone several analyses of the spatio-temporal characteristics of the geopolitical history of the world. The renounced American strategist Alfred Thayar Mahan was the first to hypothesise the conflict between land and sea power in his famous work, "The Influence of Sea Power upon History". ... Read More

If the present growth trends in world population, industrialization, pollution, food production, and resource depletion continue unchanged, the limits to growth on this planet will be reached sometime within the next one hundred years. The most probable result will be a rather sudden and uncontrollable decline in both population and industrial capacity. Historical Background Many academicians approached world political leaders and expressed the future threats that would arise due to the implications of an increasing population, which were initially neglected. A group of international economists, scientists, philosophers, and geographers founded The Club of Rome in 1968, and ... Read More

Migration can be broadly divided based on two analytical models: the macro and the micro analytical models. Some of the prominent models involved in macroanalysis include the Ravenstein model (Gravity Model), the Zipf model (Model of Least Effort), and the Stouffer model (the Intervening Opportunity Model). The major microanalytical model is Lee’s model. Definitions by Various Organizations The Multilingual Demographic Dictionary, in collaboration with the International Union for the Scientific Study of Population (IUSSP), describes migration as a form of spatial mobility, involving change in the usual place of residence, which implies a movement beyond an administrative ... Read More

The term "Isostasy" is derived from the Greek word "Isostasios", which means the state of being in balance. (equipoise). This doctrine states that the less dense materials of the Earth surface (SIAL) must float over the denser magma (SIMA) of the Earth's interior. Historical Background This phenomenon was initially observed by Pierre Bouguer during his expedition to the Andes (1735-45). He wondered that the mountain has a large mass but, comparatively, has less gravitational attraction. About a century later, similar discrepancies were observed by Sir George Everest (then Surveyor General of India) in the survey of the Great Himalayas. ... Read More

The theory of Growth Pole & Growth Centre has been proposed by French economists Francois Perroux and Boudeville respectively, with a view to resurrecting the French economy with propulsive growth in a short span of time. This concept acknowledges the preeminence of industrialization as the only and sole basis of economic development. The main idea was to initiate economic development in the backward regions by making investments at focused points or in certain areas, from which the development was supposed to diffuse to the whole region. Historical Background The Growth Pole Theory was originally proposed by Francois ... Read More

Geosyncline theory was a primary theory of the Earth until the discovery of seafloor spreading and the advent of plate tectonic theory in the 1960s. The Geosyncline theory explains the formation of tertiary fold mountains such as the Great Himalayas, The Atlas, The Alps, The Rockies and the Andes Cordillera. According to this theory, sediments from the continents gradually reach the long, narrow, and shallow water depressions through rivers. These water depressions are generally bordered by forelands. Because of the earth's constantly changing nature as a result of land compression, those sediments rise as fold mountains. Historical background ... Read More