Theories about the origin of the Earth| How Earth came into existence
The Earth came into being around 4.54 billion years ago. In general, the theories about the origin of the Earth and Solar System can be divided into two groups: (i)…
How old is our Earth| How do we know the age of the Earth?
Age of the Earth The age of the Earth as determined by the current method of radiometric dating is about 4600 million years. Before the discovery of radiometric dating, several…
What is physical geography? Different subfields of Physical Geography
Physical Geography Definition Before going to the definition of physical geography, let’s have a brief introduction to Geography and its branches. Geography is a branch of natural science, devoted to…
Common radiometric methods to determine the absolute age of the geologic material
What is radioactive decay? Radioactive elements continuously release their protons and neutrons and form new daughter products. The radioactive elements are often known as the “parent”, and the element resulting…
Interior Structure and Composition of the Earth
The knowledge about the interior structure and composition of the earth has a long history. Before seismic tomography, scientists knew very little about the interior of the Earth. The study…
The process of convection in Mantle
The mantle is a layered part of the earth, which is located just beneath the crustal layer of the earth. The Earth’s crustal surface (lithosphere) rides atop the asthenosphere. The…
What is Isostasy
Isostasy C.E Dutton, in 1889, suggested that a gravitational balance exists between the elevated masses (i.e. continents) and ocean basin of the earth’s crust. It is believed that the lithosphere…
Theory of the Continental Drift
The theory of continental drift was presented by a German geologist, Alfred Wegener in 1910. He suggested that at the beginning of the Mesozoic era (200 million years ago), all…
Theory of Plate Tectonics (tectonic theory)
The theory of Plate Tectonics has evolved from Harry Hess’s concept of “seafloor spreading”. He proposed this concept in the early 1960s. Hess’s hypothesis was accepted when Vine and Mathews…
Convection current in the mantle
The flow of high heat associated with oceanic ridges proves the existence of “Convection Currents in the Mantle”. These currents are believed to be responsible for the movement of crustal…