Testing the Evidence

You wouldn’t think it but science is absolutely ridiculous in the way it can investigate a site! I know the CSI Tv show has got a lot of people talking about forensics..I am just not sure how reliable that show is at demonstrating methodologies. What I do know is that Archaeology has a lot to thank science for! Here we will look at how science helps to date objects found on a site

1) Stratigraphy

It’s a mouthful but do try and remember it! This is the examination of the layers of soil in the ground. By testing the soil the archaeologist can identify how old the site might be. Take a look at this diagram

stratigraphyIt’s pretty simple! The soil has been tossed and turned many times over. The soil you are standing on right now is the newest layer and it’s therefore the youngest. But, if you were standing where you are 2,000 years ago for example it was probably very different. So, the earth has layers! Finding an object at the top of the surface would probably indicate it is relatively new, finding it many yards below would then suggest that it is probably much older. Therefore, stratigraphy can identify the age of an object based on the level at which it was found at! Magic!

2) Coins & Pottery

Coins usually have a name or date printed on them. If you were in Rome during the time of the Emperors, coins were stamped with the face of the current Roman Emperor. Pottery likewise can have a name or date displayed on them. Here is an example of a Roman Coin during the time of the Emperor Trajan 98-117 AD. It bears his face along with the quote “Good Health To All”. Trajan was considered a forward thinking Emperor who was concerned with his subject’s welfare.

trajan coin

3) Tree-Ring Dating

Each year a tree grows a ring of new wood. These can be seen in the cross sections of the tree trunk. It is possible to work out how old a tree is by cutting it down and studying the rings (Do not try this yourself!). This is called tree-ring dating or dendrochronology to be scientific! Examining the wooden beams in a building or on a site can allow archaeologists to figure out the age period from when it was created.

tree ring

4) Radiocarbon Dating

EVERYTHING IS MADE OF CARBON!! Did you know that??!! Without it we would not exist! Plants and animals take in what is known as carbon-14 while it is alive. When they die, the carbon begins to decay. Samples of charcoal, wood, animal and human bone, seeds can all be investigated when they are found. The age of the plant, animal, person etc. can be worked out  by calculating how much radiocarbon is left in them.

radiocarbon

How is Evidence Destroyed?

  • Building Works – roads, new offices, clearing land
  • By wars or battles – destruction of vast land, towns and cities
  • Natural disasters – storms and volcanoes can destroy a region along with other natural disasters such as tsunamis or hurricanes

How is Evidence preserved?

  • In tombs – bodies buried in coffins and sealed tombs
  • In the desert – the heat dries out objects which prevents decay
  • In peat bogs – waterlogged bogs can preserve objects
  • Volcanoes – can also preserve as well as damage objects

Summary of what artefacts and remains can tell us?

  Methods of Dating What it tells us
1 Stratigraphy

Coins

Tree-Ring

Radiocarbon

Layers of Soil

Date stamped on it

Age of wood used

Carbon-14 decay

2 Bones and bodies Age of the person

Sickness or cause of death

Lifestyle – hunter etc.

3 Plants and Pollen Type of plants grown

Dating

Forest clearance

4 Pottery Dating

Use of objects

Trading links

For more info on the work of the archaeologist, check out other blogs in this category.

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