Seriation sequence dating Sexchatsms
The rest of the dates lying between 500,000 years to 90,000 years are done through relative dating techniques and hence are very tentative.
Before we go into these methods of dating it will be important to understand how the glacial/interglacial chromometer is applied in practice.
The enormous amount of water trapped in the land borne ice caused severe lowering of the sea level exposing land bridge between many islands and their adjoining main lands.
In many favourable coasts these ancient beaches have been found and named corresponding to the Alpine glacial order.
The calendar is a product of our civilization which measures the past in such units as years, month and days.
All these periods of glacial advances were not of equal intensity neither were the intervening warm periods of the same type.Measuring tangible objects must have been there since the prehistoric period, but time being not tangible requires conceptualization.In pre-literate societies one can often come across dating the age of an individual in reference to a memorable natural event.There are a large number of scientists working in various natural science disciplines to obtain a calendar year estimate for these events or even to date given prehistoric objects.The dates obtained through these allied agencies and expressed in units of years are termed as absolute or chronometric dates.We shall briefly enter into all these dating techniques just for a basic awareness of the beginner, because in most cases these principles and actual working are very much outside the area of interest of average prehistorians: One of the simplest approaches to chronology is based on the principle that the lowest layer in any natural process of deposition is older than the ones above it (provided there has been no disturbance).The youngest phenomenon under the same logic will be represented by the topmost layer.There are several synonyms used for each of these names in different parts of Europe, Asia and Americas but to avoid complications we will use the Alpine names only.The estimation of dates of 5 million to 500,000 years is done through a radio-active isotope disintegration technique known as Potassium- Argon method while dates upto 90,000 years are done by a similar method based on Carbon isotopes.The glaciations which descended down from the North Pole accompanied glaciers of all glaciated mountains gliding down to lower plains.In Europe the glaciers have been identified by giving them names of rivers on the Alps.