Dating Flashcards
How do we know about dates of Caesar’s accomplishments?
He wrote letters dated by the year of the consul, which can be compared to the list of consuls
How far back does the list of Consuls extend?
~508BC-1400AD; to Byzantine empire
What kingslists exist?
King lists of Persia, Egypt (Turing Papyrus), and Sumeria
What is the King List of Persia associated with?
Astronomical events; extends to ~800BC
Why are the King Lists of Egypt and Sumeria unreliable?
List reigns of gods, and start way after their civilisation started
What was the theory of origin of civilisation in the Victorian era?
Cultural diffusion occurred from centres of high culture; civilisation diffused outwards from the Fertile Crescent, which are river valleys which periodically flood and deposit fertile silt; regions of the Fertile Crescent were Ancient Egypt (~5000BC), Ancient Mesopotamia (~5300BC), and Sundaland
What was Sundaland?
An area in the South China Sea, which was flooded and covered by rising sea levels, causing sophisticated culture to escape along Asia into the Middle-East, to the hotspots of civilisation
What was the assumption made by Victorian and Edwardian archaeologists about similar structures, objects, etc. found in Britain/ Northern France that were also in Middle-East and Eastern Europe?
Anything found in Britain was assumed to be younger
What is seriation?
A relative, floating dating method; compares age by depth that an object is discovered at; can be combined with comparison of structures
When was radiocarbon dating invented?
~1945AD; known as the radiocarbon revolution
What is the % error of radiocarbon dating?
+-10% error
What is radiocarbon dating?
An absolute dating method; cosmic radiation produces radioactive C-14; animal takes up the different C isotopes; animal dies and so C-14 is no longer replenished; C-14 starts decaying (half life of 5730 years, C-14 –> N-14 (loss of neutron)); C-14: C-12/13 ratio found by measuring emissions of beta radiation/ MS
Why was radiocarbon dating such a revolution?
Disproved theories of high culture in Egypt and Babylonia being origin, as structures from northwest Europe predated those in Asia and Middle-East by centuries/millenia
What are the five types of limitations to radiocarbon dating?
Irregularity of the calibration curve; types of samples; fractionation; reservoir effects; predictable limit of ~50,000 years
Why are there irregularities in the calibration curve?
Plateaus exist, such as during the Dark Ages; a volcanic event affected C-14 content in air; at the beginning of the Cold War there was an increase in radioactivity due to the testing of nuclear weapons; burning fossil fuels dilutes C-14 content as sources are ancient and depleted of C-14
Why do types of samples create limitations for radiocarbon dating?
E.g. corn regrows each year and is used in that year, whilst trees lie around dead for seasons/years without use
What is fractionation?
Lighter isotopes are preferentially absorbed for photosynthesis, diluting C-14 pick-up
How can limitations from fractionation be resolved?
Use C-13: C-12 ratio
What is the reservoir effect?
Molluscs extract carbonate from sea water which is “old” and depleted of C-14, leading to an overestimate of age
What is Sr-isotope analysis?
Sr-86:Sr-87 ratio; old rocks have high ratio, young rocks have old
How can Sr-isotope allow for estimation of an origin of an individual?
Nature of geology influences diet, so can measure Sr isotopes in enamel of skeletons’ teeth
How far back does dendrochronology account for?
Over 26,000 years
How has the analysis of corbelled tombs/ passage graves changed over the centuries?
Corbelled passage-graves were found in Brittany in UK, similar to corbelling found in Greece, such as the Tomb of Atreus. Initially it was thought that the corbelling in the UK was a mimic of those in Greece, as those in Greece were much more sophisticated, being much higher, and the stones were dressed, in addition to the theory of Greek high civilisation being older than UK. With radiocarbon dating, however, was found that those in UK were from 4700BC, about 3000 years before those of Mycenean culture. Thus, a Megalithic culture (associated with introduction of agriculture into NW europe) from northwestern Europe seemed to predate the Bronze Age of Greece
What is an example of how radiocarbon dating and dendrochronology can be used together?
Seahenge: storms in Norfolk stripped away sand and silt, revealing and upside-down tree-looking structure, surrounded by planks. This was presumed to be an excarnation platform. Radiocarbon dating allows identification ~2000 years back, whilst dendrochronology can identify ~9000 BP
