Geology Interview Preparation Guide

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The earth has only very recently been accurately dated. Until astonishingly recently, the earth was thought to be anywhere between a few hundred thousand and a few million years old. Now it is thought that the Earth is 4.6 billion years old, and was formed by interstellar dust coming together and being attracted to an increasingly strong gravitational force. Incidentally, life is thought to have arisen relatively early in the earth's existence - just 3.5 - 4 billion years ago!

Usually the triangulation method is used, making three measurements, and then using simple geometry/maths to locate the positioning.

Over time it developed an atmosphere that changed in time as liquid water gathered on the surface of the earth and created an atmosphere with clouds of water and levels of certain gases that protected the planet below and made it the temperature that it is, which is obviously fit for life as we can tell by looking around us.

The earth has changed massively since it was formed. Earth was a ball of rock that was hit and changed by loads of impacts and meteor impacts.

Factors such as the volume and surface area of the lake together with average wind speed and temperature at the surface are the factors that can be used to work out how much evaporation there is at the surface.

Specifically gases that are found in the magma correspond to having been formed at pressures many times greater than those in the outer core have, and rather therefore indicate that it was formed elsewhere.

Minerals or small particles of rocks, become rocks through pressure and temperature, often deep inside the earth’s core, or simply through pressure for instance on the seabed.

Wherever many small things become something big it is usually through compression, temperature, or pressure.

The opposite process - large things being worn into smaller particles - usually comes through another sort of force. Either weathering, erosion - action by wind, rain, and water - is responsible.

Gradually many rocks are eroded by movement of ice and water over them or the wind action also to become finer and finer and form little grains - e.g. of sand or of soil.

Various ways and techniques can be used. With many mountains, the rock in the mountain can be sampled and then a dating technique applied to find the age.

For instance, radiometric dating may be used to find the age of the rock. These techniques exploit the half-life of naturally occurring radioactive isotopes of elements present in tiny quantities to help work out how old something is.

With some mountains other techniques may be used, for instance at a plate boundary scientists may be able to wind back time to work out when the plates must have collided and formed mountain ranges such as the Himalayas.

Limestone is formed from pressure applied over time to dead creatures in the sea. Oil is formed because of sedimentary processes and which is one of the most important resources.

Fossils are created amongst periods of rock formation, and caused by the gradual accumulation of sediment over millions of years at the bottom, most commonly, of the seabed.