Chapter 4: When is it Dated? Dating Methods Flashcards
Mention 3 ways in which we (in Canada) usually pinpoint time (abbreviations and tell something about their usage).
BC (Gregorian calendar)
BCE (before common era)
BP (before present, used by scientists)
Mention 4 methods for relative dating we discussed in class; also explain how each method works.
Stratification = using the law of super position
Typology = like goes with like
- artifacts that look similar are likley from the same period.
Seriation = arranging finds in chronological sequence.
- Contextual = arranged in duration, greatest number of artefacts have the shortest duration.
- Frequency = abundance of a certain style.
- Battleship curves can be compared to make a chronological system.
Pollen Dating = Can take the amount of pollen and put it on a graph, relate it to a relative amount of time.
Say of these four methods in which periods in the history of archaeology (see Ch. 2) they were developed?
Methods 1-3 = classificatory historical period (19th century)
Method 4 = around the time of new archaeology (20th century)
What is the difference between relative and absolute dating? Why does relative dating always need absolute dating?
Relative Dating = identify artefacts as older or younger than other artifacts, dates are relative to others. Artifacts are put into sequence (archaeological deposits in a stratigraphic excavation, or artifacts in a typological sequence).
Absolute Dating = dating artefacts at the exact year they were made
Relative needs absolute because it helps give an exact date, need a fixed point
The traditional way of absolute dating is by using historical texts. Mention 2 of the 3 disadvantages of this dating method.
- Chronological system may be incomplete or inaccurate (flawed).
- Individual artefacts in dig need to be related to chronological system.
What is a terminus ante quem, what a terminus post quem? Illustrate each case with an example from archaeology.
Terminus ante quem = imports being made before the date
- Materials of a building (know the building date) must be younger than the building itself.
- Artifacts in a tomb must be before a date.
Terminus Post quem = imports being made after that date.
- Example: A coin found with a certain year on it would be made after that year, used in abundance after the date.
Describe which 3 principles result in the fact that radiocarbon or C-14 can excellently be used for absolute dating.
- Proportion of C-14 in atmosphere is stable because of cosmic radiation.
- Goes into all living organisms: from plants to animals to man.
- When organism die, radiocarbon decreases in a proportioned way; measure the proportion of 14C in any organic remains we can calculate the exact date.
Mention at least 2 advantages, at least 3 disadvantages of radiocarbon dating.
- Is a worldwide dating method
- Covers the last 50,000 years
- Sampling contamination, errors before or after sampling collection.
- Mistakes can be made in laboratories and can affect the sample.
- Cosmic radiation fluctuates, makes us give a standard deviation and an estimate of +/- years, calibrated dates.
Describe the factors that contribute to tree rings being an excellent way of coming to an absolute date.
Each tree gets a new ring every year (with every cycle of
seasons) Varies because:
- Rings become narrower when they are older.
- Growth of tree (and ring) depends on climatic change.
Similar trees in same area produce the same tree ring pattern.
By graphing the thickness between the rings of a tree’s growth sequence and overlapping the graphs with other trees in the area, can work backwards and develop a chronological sequence.
Mention 2 advantages, 3 disadvantages of dendrochronology.
- Covers last 8000 years
- Very detailed: can date a piece of wood within a year
- Not in tropics, so not worldwide
- Can only use wood where there is a long sequence from the present day backwards.
- Sapwood must be there (outer rings).
What is Thermoluminescence dating/how does it work?
Atoms exposed to radiation from decay of radioactive elements in the nearby environment can trap some of the energy. If radiation stays constant, energy will accumulate as a result of exposure.
When sample is heated, the energy is dispersed as TL, radioactive clock is set to zero and energy starts to accumulate again.
Pottery initially had its TL clock at zero when it was kindled and made.
Therefore, if we reheat the object and measure the TL released, we can date the object.
The more TL released, the older the object (because more energy was trapped and had time to accumulate).
What are the 2 advantages, but what is also the big disadvantage of TL?
Advantages:
- Only method of dating inorganic remains (pottery).
- Dating can go beyond 50,000 years.
Disadvantages:
- Less accurate than radiocarbon dating.
Describe at least 4 dating methods which were used to come to the date of the eruption of the island of Thera.
1520 BCE – Thought that the eruption had nothing to do with the destruction of Thera and that it came afterwards.
- Typology: abundance of ceramics of Minoan 1A go with 1520.
1628-1626 BCE – could see a disruption in the tree rings around the area when the eruption took place.
1645-1390 BCE – Ice cores show a short peak of high acidity with two dates: 1645 BCE (wrong) and 1390 BCE.
1627-1600 BCE – used C-14 dating on an olive tree found buried in the ash layer, had a 94.5% accuracy.
Which 4 implications do the usage of new scientific methods have for the chronology of Iron Age Italy?
Must redate the Greek pottery (needs to be more accurate).
Greek colonization was a longer process, started in 9th BCE and took until 7th BCE.
Iron Age starts earlier, changes are less abrupt.
‘Dark Ages’ = transitional period between Bronze and Iron Ages.
What is Magna Graecia?
Greater Greece
