Unit 2 - Post-Excavation Flashcards
How can you sort ceramics?
- Estimated Vessel Equivalent (EVE)
- Minimum Number of Vessels (MNV)
- Number of pieces
- Weight
How can you analyse ceramics?
- Organic residue analysis
- SEM
- Use wear analysis
Ceramic CS
- Boscombe Bowman
- Amesbury Archer
- The Companion
- Kingsmead - decorated with cord/platted cord/comb
How can you date metal objects?
- Stratigraphy
- Coins (historic dating)
- Typology & Seriation
- Obsidian Hydration
How can you conserve metal objects?
- Reduce humidity
- Use a dry brush (no liquids)
- Careful treatment to remove corrosion
How can you analyse metal objects?
- SEM
- X-ray
What can you learn from metal objects?
- If it’s been heated, worked, alloyed
- See if several pieces of metal have been joined to create a complex artefact
- Trade, territories, approx dating (coins)
- How it’s been made (crucibles, slag, molds, ridges)
Gundestrup Cauldron CS
- Iron Age
- Denmark
- One of the largest known examples of celtic metalwork art
- Decorated with mythological and ritual scenes
- SEM shows it was built by 3 silversmiths, plates worked when flat and then shaped into curves, silber was slowly heated and then cooled before being shaped
What can you learn from ceramic analysis?
- Form (beaker, plate etc)
- Manufacture (pinch pot, molds etc)
- Material
- Style, decoration
- Status
- Trade
What can you learn from lithic analysis?
- Purpose
- Trade
- Technology
- Manufacture
How can you analyse lithics?
- SEM
- Petrology
- Usewear
- Microwear
- Surface examination
Lithic CS
- Windmill Hill - 95000 pieces of flint
- Hambledon Hill - flint tools
- West Kennet - Stone beads, flint tools
What are the 4 main absolute dating methods?
- Radiocarbon
- Dendrochronology
- Thermoluminscene
- Uranium Series
What is radiocarbon dating?
- All living things absorb carbon
- This decays into 14N after death at a known rate
- Can be calculated to work out time since death
Pros of radiocarbon dating?
- Can date between 200-500000yrs
- Can date all organic materials (bone, shell, plant remains, wood, seeds)
- Accurate
Cons of radiocarbon dating?
- Can only date organic material
- Only accurate between 200-500000yrs
- Samples can be contaminated
- Number of samples should be taken
- Sample
- Calibration is needed at a radiocarbon year does not equal calender year
What is dendrochronology?
- Use of tree rings to date wood
- Compared to a master sequence
Pros of dendrochronology?
- Can tell if something had been renovated
- Accurate - exact date
Cons of dendrochronology?
- Date tree was felled not artefact used
- Growth can vary by climate
- Have to cut into object
- Can’t date if it’s too small or badly damaged
- Need a master sequence
What is thermoluminscene?
- Quartz crystals (found in clay) decay and produce an electric charge at a known rate
- Electric charge is released as light when heated
- Light produced can be measured
What can thermoluminscene be used on?
- Glass
- Burnt flint
- Stone
- Pottery
Pros of thermoluminscene?
- Can date from present - 400000yrs
- Useful for older sites where there are no organic remains
Cons of thermoluminscene?
- Less accurate that C-14 dating
- False readings due to radiation or if initial firing was at a low temp
What is uranium series dating?
- Uranium decays in water at a known rate
- Can be measured to give a date
Pros of uranium series?
- Can date between 50000-500000
- Can date enamel, shell etc
Cons of uranium series?
- Prone to ambiguous results
- Needs a high uranium content
Two types of flora?
- Microfossils
- Macrofossils
Examples of microfossils?
- Diatom
- Pollen
- Phytoliths
What are phytoliths/how are they used?
- Silican from the cells of plants
- Survive well in alkaline soils
- Can be identified to paticular plants
- Can indicate spread of agriculture
What are diatoms/how are they used?
- Microscopic single celled plants
- Found in wet conditions
- Very sensitive to change in local water
- Hard outer shell survive well in alkaline or anaerobic conditions
- Ca be used to infer deforestation or pollution
- Can indicate where water used to be
What is pollen/how is it used?
- survives well - especially in wet, acidic conditions - hard outer shell
- Relative quantities provide record of environmental change
- Pollen dating - pollen zones defined according to relative amounts of each species
- Can also be dated with C-14 dating
- HOWEVER naturally moves and spreads from original site
What are macrofossils?
- Visible to the naked eye
- Seeds
- Fruit
- Flowers
- Seeds
Otzi - Macrofossils
- Lumps of birch funfus threaded and attatched to clothing
- Bitchbark container with maple leaves in
- Einkern grass on cape
- Grass in shoes
- Sloe berries found by him
Pros of wood
- Survives on wet or dry sites and in carbonised form
- Possible to indentify species with microscope
- Dendrochronology
- Physical evidence for structures, artefacts, carpentry
- Keeps form and detail when wet
Cons of wood
- Wood from dry areas often warped or distorted
- Decay once removed from water
- Can only freeze dry small artefacts
- Treatment of large artefacts is time consuming
What is fauna?
Animals
What are the two types of fauna?
- Micro
- Macro
What are the two examples of microfauna?
- Beatles
- Molluscs
What are/how do we study beatles?
- found in nearly all environments
- Outershell resistance and varies between species - allows indentification
- Changed very little over time so easy to compare
- Tells us about ground surface conditions, vegetation, climate, plant resources
What are/how do we study molluscs?
- Different species have paticular vegetation habits
- Sieved out of soil, indentified and record
How can we count macrofauna?
- Number of Indentified Specimens (NISP)
- Height - bias towards animals with heavier bone s
- Min. number of indiviuals (MNI)
What can we learn from macrofauna?
- Hunting
- Agriculture
- Ritual feasting
- Season
- Environment
- Trade/travel
- Butchery
What are the 5 main relative dating techniques?
- Historic
- Stratigraphy
- Typology
- Seriation
- Obsidian hydration
What is TPQ?
- The earliest possible date an event may have happened
What is TAQ?
- The latest possible date an event may have happened
Pros of historic dating?
- gives a general time period - good starting point
- gives an idea as to how far down you have to dig
Cons of historic dating?
- stratifgraphic layers can have a large time range
- no exact date
- cultural/natural transforms
- objects could be out of place relative to whole site
What is the Law of Superposition?
Layers further down will be older
Pros of dating using stratigraphy?
- Fast
- Can date whole layer
- Shows order or deposits and suggests relationships
- Inexpensive
Cons of dating using stratigraphy?
- can have large time frame
- cultural and natural transforms
What is typology?
- classifying artefacts into types based on shape, surface and raw material
- then placed into a typological sequence
Pros of typology?
- can get an idea of how artefacts may have changed over time
Cons of typology?
- can’t tell how long between the styles of overlap between each
- trends can return
- doesn’t tell you how long it took for changes to occur
- can vary depending on location and culture
What is seriation?
when artefacts from a number of different sites (in the same culture) are placed into chronological order
What are the pros of seriation?
- useful at sites where there are large quanities of artefacts of the same style
- battleship curve shows when and for how long an artefact was used for
Cons of seriation?
- can only be used to provide an exact date if elements of the sequence are tied to historic data
- sequences can be wrong
- assumes all artefacts are phased in gradually whilst others phase out
- basing dates on a few isolated artefacts can cause errors
What is obsidian hydration?
- obsidian aborbs water at a known rate when broken
- this can be measured to give a date
pros of obsidian hydration?
- can compare to other sites
- can give a relative date - more specific
- one of the cheaper lab methods
cons of obsidian hydration?
- speed of hydration varies with local climate and chemical makeup of obsidian
- can only date between 100-100000 yrs
- has a saturation point of 3.5%
- has to be broken
- could be out of historical context
- obsidian is only found in certain places
