Dating an archaeological find 2013

What’s the time ?What’s the date?

The date we are concerned with is used to identify time and its passing.

• c

What year is it?

• 2013 BC• 2013 BCE• 2013 AD• 2013 CE• 1434 AH

Archaeological Dating

• Provides the age of an artefact.• Identifies the chronological order of the stages

of development of a site since its beginning.• Chronology is the science of arranging past

events in the order that thy occurred.

Quick overview of dating

• Dating methods provide either “Absolute dates” or Relative dates”.

• Absolute dating • provides a specific date for the artefact – documents with

dates, coins, etc.

• Relative dating • relative dating is based on the idea that an artifact is older

or younger in relation to something else.• It only gives you a rough idea (approximation) of the date -

pottery sequences, an artefact found on the same strata as artefacts that can be absolutely dated.

Dating Methods

• Dating methods can be divided into three types:

• Historical• Archaeological • Scientific

Historical Methods

• Relies on written sources to determine a time frame. Anything before writing about 3,500 BC is prehistory and requires one of the other forms of dating.

Archaeological Method

Attempts to establish the sequence (chronology) of human occupation until recent times. Stratigraphic, typology and seriation dating are examples of archaeological method.

STRATIFICATION

• Records the occupational sequence of a site through observing successive layers of strata.

• Each layer (strata) is a different time period.

• The deeper you find an object the older it should be.

TYPOLOGY• Placing similar objects in chronological order. • Artefacts from each period have distinctive

features. • Sequence is determined by type and style –

from simple to complex.

SERIATION DATING, aka Flinders Petrie Seriation

• Form of typological dating

• Arranged all objects from graves in topological sequence.

• Then arranged groups of similar finds in a succession or serial order

Scientific Methods

Using scientific tests on objects to determine their age, it is often more precise and accurate than other traditional methods.

Two examples of scientific methods are Radio Carbon 14 dating and tree ring dating.

Radiocarbon 14 • C-14 dates organic material between

400 years ago to 5,000 years.

• All things living absorb Carbon-14, a radioactive isotope of carbon.

• The C-14 starts to decay after death at a constant rate.

• The radioactive emissions of carbon can be measured so the time of death can be deduced.

• This applies to all organic materials – paper, leather, bone, pollen, blood residues, resins, wood, peat, hair, soil, etc.

An introduction to Carbon Dating Archaeology

http://www.youtube.com/watch?v=2Ipa9uhyRoU&feature=related

Why is this cartoon incorrect?

Tree ring dating: Dendrochronology

• Dendrochronology is the dating of past events through the study of tree rings patterns.

• Generally each year the tree grows is marked by a growth ring.

• Each growth ring (thickness) reflects the climate conditions of that year.

• Working backwards with modern timber it is possible using overlapping sequences to determine the age of ancient timber structures.

Three Age System

• Archaeological method based ancient technology.

• Ages: • Stone (early, middle, late)• Bronze (early, middle, late)• Iron (early, middle, late)

Thermoluminescence Dating(aka T L dating)

In a no more than a half page explain what this scientific method measures and how this provides a date.

• TL dating measures inorganic material such as pottery. It is more accurate than typology and can date material up to 35,000 (some believe 200,000) years old.

• There is a small amount radiation in the crystal structure of rocks. With decay small amount radiation is released freeing electrons. These electrons are released and therefore measured if heated.