15022018 Flashcards
1st Exam
- Mainly MC
- Fill in the blanks
- SQ
- Review session: Williams 5th floor (get in from back door) 2-3pm
Radiometric Dating (14C)
- “Conventional” radiocarbon dating
- Cheaper
- Need larger sample of material (about 6g of charcoal)
- Larger error ranges - Accelerator mass spectrometry (AMS)
- More expensive
- Can date tiny samples
- Smaller error ranges (+/- 40yrs only)
** ALL radiometric dating is destructive!
> (Entire sample is incinerated)
Obsidian hydration dating
- Obsidian has only ca. 2% water
- When fractured, fractured surface begins to hydrate and develop a crust “hydration band”
- Thickness of hydration band equivalent to time since fractured
> In California, for example, approximately 1 micron of thickness of hydration band is equal to 1000 years - Need lots of samples to get average date
- Advantage is it is inexpensive BUT you need obsidian in your site to use it
Potassium-Argon dating (KAr)
- Based on rate of decay for radioactive isotope of Potassium, Potassium 40 and ratio to Argon which is a byproduct of decay
- Used in volcanic contexts to date ash layers
- Useful for dating very old sites
- Problem is that is has huge error ranges and subsequent eruptions can mess up isotope ratios
Subsistence
= Action or means by which an individual or group supports themselves
- Main focus is on FOOD. What people eat and all that goes into obtaining what they eat
- Can study subsistence DIRECTLY and INDIRECTLY
Direct ways to study subsistence
- Faunal analysis
- Plant remains
- Coprolites
- e.g. Hinds cave, southwest Texas
> Portion of domesticated dog skull recovered from a paleo fetal sample or human coprolite
> Dig skull fragment directly dated with AMS to 9,260 +/- 7- years B.P.
> Mitochondrial DNA (mtDNA) extracted from bone sample
> Shows that sample from Domesticated dog, not wolf or coyote
Indirect ways to study subsistence
- Environmental reconstruction ecofacts, pollen, phytoliths (e.g. in the soil)
- Settlement patterns
> e.g. hunter/gatherers v agriculturalists farmers v fishermen - Technology
- Human skeletal remains:
- Bone isotopes, subsistence stress, nutritional inadequacies, paleopathology
Faunal analysis
Issues:
1. Most animals (ca. 99%) die and do not preserve
2. Preservation is best when ground water is alkaline (non-acidic)
> e.g. limestone
3. Emplacement shortly after death is essential to preservation
Goals:
1. Reconstruction of past human-animal relationship
2. Reconstruction of past (animal) environment
Good faunal analysis requires:
A. Large samples
B. Careful excavation (to avoid bias)
C. Comparative samples