Midterm Exam #2 Flashcards
Geoarchaeology
study, through application of geological principles and methods, of soils, sediments, landforms and stratigraphy in order to investigate archaeological sites and to answer archaeological questions regarding human activity in the past
Sediments
inorganic and organic component of the earth’s surface deposited by natural processes
Soils
in situ developmental sequences
A Horizon
zone of accumulation and elluviation
B Horizon
zone of deposition/illuviation
C Horizon
Parent material
paleosols/buried A Horizons
Matrix
Physical substance surrounding an archaeological find
Provenance
3D position of an object within the matrix
Association
2/more archaeological items (artifacts, ecofacts, features/fossils) occurring together within the same matrix
Primary Context
context of the original context of the find, undisturbed by any factor
Secondary Context
context the context of a find whose primary context has been disturbed by later activity
Systematic Context
manufacture, use, re-use, and discard
Archaeological Context
artifacts continue to be affected by human action and natural processes
Taphonomy
The study of the processes of site disturbance and destruction
An understanding of site taphonomy can help an archaeologist make an informed and cautious interpretation of the past
How Does a Site Get Interred?
Abandonment and Rotting plant matter
Unconformities
Natural geological deposits separating 2 occupational strata
Indicate abandonment
Silt from a river flood
Windblown sand
Volcanic ash
Site Formation Processes - Natural Transformation
Decomposition
Flooding
Volcanos
Earthquakes
Site Formation Processes - Cultural Transformation
Discarding
Recycling
Curation
Deliberate and Accidental Destruction
Relative Dating Methods
Used to date artifacts, features/geological deposits in relation to 1 another
Absolute Dating Methods
Used to measure how old a specimen/deposit on a fixed calendric system
Complicating Factors - Stratigraphy
Mixing: Digging operations turn dirt over and leave it in place in the deposit created by the digging
Filling: A depositional unit is laid down to alter the original level of the ground
Collection: The acquisition and reuse of ancient objects.
Unconformities: Temporal breaks in the stratigraphic sequence as a result of a change that caused deposition to cease for a period of time
Seriation
chronological ordering of a group of artifacts/assemblages where the most similar are placed adjacent to each other in a series
Battleship Curves:
Frequency seriation: Measures changes in the proportional abundance, or frequency, observed among finds (e.g. counts of tools/ceramic types)
Absolute Dating Method - Historical Objects
Uses objects of known historical age to date other archaeological finds
Doesn’t account for shelf life/reuse - date of manufacture not date of use
Historical documents
Works on: previously documented items
Absolute Dating Method - Dendrochronology
A dating method that matches the annual growth rings of an archaeologically recovered wood sample to an established temporal sequence
Complicating factors: not always annual, not all trees have rings, habitat, old wood problem (only marks day when tree was cut down, doesn’t tell if it was used - cultural use)
Absolute Dating Method - Radiocarbon (C14) Dating
A dating method that uses the decay of carbon-14 to date organic remains
Most commonly used
Complicating Factors: Limited in more recent materials (pollution), only up till 1980
Works on:
Wood, charcoal, ivory, plants, shell, bone, and other organics - anything with significant amount of carbon collectant
Absolute Dating Method - Accelerator Mass Spectrometry (AMS) Dating
A newer, more accurate form of Radiocarbon dating - gives smaller range of date
Accelerates ions to high energies before mass analysis (several percent the speed of light)
Absolute Dating Method - Uranium Series Dating
Measures the decay of uranium isotopes found in calcium carbonate deposits
Uranium (235U and 238U) decays into other isotopes (such as 230Th, thorium).
Works on:
Limestone bedrock, cave deposits (stalagmites, flow stone)
Finds between 50,000 and 1 million years old
Absolute Dating Method - Thermoluminescence Dating
Thermoluminescence dating reheats samples to emit photons
Measures trapped electrons in surrounding radioactive material – annual dose radiation in sediment - to determine calendric age
Only works on objects that were heated in the past, can’t date recent items either
Absolute Dating Method - Optically Stimulated Luminescence (OSL)
Dates soils based on accumulation of trapped electrons
Works for sediments without organic materials
Absolute Dating Method - Potassium-Argon (K-AR) Dating
Uses the rate of decay of a radioactive form of potassium (40K) into argon (40 Ar).- 50,000-2000000000000
Works on: the minerals and rocks surrounding a fossil
Does not date the fossil itself
Absolute Dating Method - Fission-Track Dating
Measures the number of uranium fission tracks in a sample (narrow trails of damage)
Works on:
Volcanic rocks (obsidian, basalt)
Finds between 100,000 and 20 million years old
A working plan for a Research project
Multiple objectives.
Multiple stages.
Logistics.
Budget.
Used as the basis for grants and permits.
In CRM projects, the research design often incorporates recommended courses of action to mitigate damage caused by construction work and other non-archaeological activities
Conservation
process of treating artifacts, ecofacts, and in some cases even features, to stop decay and, if possible, reverse the deterioration process
Approaches to Archaeological Survey - Non-probabilistic (Judgmental)
Targeting of specific areas by the excavator in a non-random manner.
Results cannot be used to generalize
Approaches to Archaeological Survey - Probabilistic (Random) sampling
Uses random sampling techniques.
Makes generalizations derived from the sample based on mathematical models
Simple Random Sampling
Simplest form of probabilistic sampling
Stratified Random Sampling
Used when the survey area isn’t geographically uniform
Systematic Sampling
Choose 1 unit at random, and then selects others at equal intervals from the 1st one
Systematic Unaligned Sampling
Combines the characteristics of simple random sampling and systematic sampling into a single strategy
Problems With Sampling
Sample fraction
Surface visibility – shovel testing
Deeply buried sites
Accessibility
Results – density of sites only
Locating Sites - Traditional Methods
Check old maps, aerial photographs
Talk to local people
Pedestrian survey - look for surface artifacts, check exposures, dig shovel tests
Locating Sites - Problems
Prior experience
Emphasis on highly visible sites
Judgemental (usually)
Failure to include all areas used by people
Landscape change? Culture change?
Biased sample of sites
Basic Types of Archaeological Survey - Reconnaissance Survey
preliminary examination of a survey area
Basic Types of Archaeological Survey - Intensive Survey
systematic, detailed field survey that covers an entire area
Methods to Ground Survey
Quadrants
Transects
Opportunistic sampling
Surface Sampling Methods - Surface Collection
Gathers representative samples of artifacts from the surface
Subsurface Sampling Methods
Shovel Tests: Shallow holes of a proscribed size and depth are made with a shovel
Auger/Core Borer: Hand-operated/power tool
Backhoe Testing
Mapping: Geographic Information Systems (GIS)
Revolutionized the storage and display of cartographic data
Uses GPS (Global Positioning System) data to render points, lines and polygons in 3D space
2 Types - Mapping: Geographic Information Systems (GIS)
Total station
Base station and handheld receiver
Remote Sensing
The non-destructive techniques used to generate archaeological data without excavation
The science of identifying, observing, interpreting and measuring objects or surfaces without coming into direct contact with them
The use of some form of electromagnetic energy to detect and measure characteristics of an archaeological target (your textbooks definition)
Aerial Remote Sensing Methods - Google Earth (GE)
You’d be surprised how many sites have been found on Google Earth! There are even crowdsourcing projects to look at Google Earth imagery and find sites
Aerial Remote Sensing Methods - Aerial Photography
Look for shadow Marks, crop marks, soil marks, among other things
Can also use infrared, false color photographs, muti-spectral imagery, etc.
Aerial Remote Sensing Methods - Non-photographic methods
Satellite Sensor Imagery
Aircraft-Borne Sensor Imagery
Sideways-Looking Airborne Radar (SLAR)
LiDAR
LANDSAT 7
Satellite launched in 1999
Single nadir-pointing instrument
Sun-synchronous
Orbits 705 km above the earth, with a swath width of 185 km
Revisits the same area every 16 days, generating 250 images per day
8 bands
Band 6 is thermal infrared
Band 8 is panchromatic
Infrared Satellite Imaging
Most satellites have multiple bands that capture different wavelengths
Visual
Infrared
Multispectral
Computer programs can create false color images of particular bands
ERDAS
ArcGIS
Hidden features may become visible
Changes in vegetation, crop marks
LiDAR Mapping
Light Detection and Ranging (LiDAR)
Pulsing laser (usually mounted on an aircraft) – short wavelength in narrow beams
Measures distance based on the time it takes for a pulse of light to reach the target and return
Ground-Penetrating Radar
Non-invasive survey
Radar pulses are sent into the earth. These are reflected at different rates depending on the density of sub-surface features
Creates a 3D subsurface “map”
Gradient Magnetometry
Measures near-surface magnetic fields. Looking for differences in magnetism in the subsurface strata
Relatively wide application: Measures magnetic anomalies caused by human activity
What does magnetometry data look like?
Intense dipoles (neg and positive, black and white) are usually metal objects.
Hearths usually appear as circular, less intense areas of high magnetism
Soil Restivity
instrument passes current through the soil
measures electrical resistance caused by buried artifacts and features
presence of ground water and compaction of soil can affect results
Benefits of Remote Sensing
Archaeological excavation is destructive
Remote sensing can help plan excavation strategies
Consultation
Aboriginal Consultation Office
Project specific consultation
Mandate process, steps
Alberta Culture, Multiculturalism and the Status of Women
Site specific consultation for Historic Resources
Typically the HRV 4cs
Obtain Permissions
First Nations communities
Permit from government agencies
Permission from land owner
Deciding What to Dig
Research question?
Resources available and other logistical considerations?
Nature of the site and the deposits?
Deciding How to Dig
Research question?
Resources available and other logistical considerations?
Establish the nature of the site
Establish site’s horizontal limits
Establish the site’s vertical limit
Testing
tests of varying sizes
distributed along the main axes of the grid
excavated in various ways
matrix may be screened or trowel sorted
Then excavation
Controlling Horizontal Space
Cartesian coordinate system–Two- or three-dimensional grid
Datum– a reference point for a grid or a map.
Site datum–A stable , arbitrary reference point.
Grid unit–A specific square on the Cartesian coordinate system
Controlling Vertical Space
Levels are used to divide up vertical space
1. Natural levels – based on stratigraphy
2. Artificial levels – based on an arbitrary measurement
Documentation
All deposits must be recorded in 3 dimensions.
Plans and profiles
Levels
Point-plotting of special finds
Photographs
Special Excavation Issues
Occasionally archaeologists face unexpected and exciting challenges that require special excavation techniques
Fragile Objects
Burials
Structures and Pits
Methods: Vertical Trenches/Testing
Used on mounds/temples, deep deposits
Reveals the full sequence of occupation/construction.
Strategically placed to reveal the maximum amount of information
Methods: Horizontal (Area) Excavation
Block excavations – bigger windows
Establishes a grid over a selected large area of the site
Uses the grid to establish horizontal spatial controls through the excavation of individual units within the grid
