stratigraphy understanding site deposits. reading the layers
TRANSCRIPT
Layer upon layer…
Stratigraphy represents the depositional history of a site.
Key ideas: Site depth
When do cultural deposits begin or stop as we dig down?
Site integrity Has the site been disturbed and by what?
What it reveals…
Site history Environmental changes Human behaviors
Culturally sterile: without evidence of human activity
Concept review
Principle of superposition Age of each layer/order of each layer
Principle of association Artifacts and strata deposited
together Provenience and context
Where on the site a feature is located or from where an artifact came.
Elements to note Soil composition Soil colors Strata boundaries Moisture Strata lenses
Artifact content Compaction Boundary zones
Strive for clarity and simplicity in graphic representation. It is not necessary or desirable to illustrate every pebble, rock, or root.
Usually best to include a key rather than jumble the drawing with superimposed text.
Field notes
The side walls provide the data. Take note of characteristics. Use a Munsell soil color guide.
Confusion Site formation processes =
taphonomy Human disturbances:
Quarry/mining, storage pits, borrow pits, purposeful restructuring
Bioturbation Worms, crabs, gophers, tree roots,
Environmental flooding, land subsidence, etc
Special cases
Shipwreck The wrecking episode will
dramatically affect site formation. Slow deterioration or rapid destruction?
Environmental conditions will impact deposition and site preservation
The “classic” Disney concept of shipwrecks.
Shipwrecks and underwater archeology will be discussed later in the term.
Intro to Sampling methods(each has statistical merits and drawbacks)
Random Systematic Stratified Combined (ex: stratified random)
Exercise Part 1
Simulated stratigraphic analysis Partners for analysis. Determining order of layers. Asking critical questions about
variations. Interpreting deposits sequentially.
Part II
Hypotheses formation concerning site history.
Developing supporting arguments for conclusions.
Remember
Layers should be described from the bottom up (oldest to newest).
Both human and natural activity at a site should be described whenever possible.
Final products for grading
Written site description and analysis; making a case for your interpretation and generating at least one testable hypotheses.
Stratigraphy model illustration using appropriate scale.