Archaeology Field Methods

Archaeological Field Methods

Archaeological Field Methods: Part I: Before Excavation

IntroductionSurveyRemote SensingMappingSurface Collections

Before the Fieldwork Begins

• Permission or access to lands • Necessary Research Permits• International preparations if

necessary• Talk to local community• Prepare laboratory processing space• Prepare adequate artifact storage

space

Preliminary Research

• Research any previous archaeology of the region

• Consult historical record (written records, old maps, etc.)

• Understand the landscape

Preliminary ResearchPortion of a Sanborn Fire Insurance Map from 1884 showing Charles Bierbauer's West Utica Brewery on Edwards Street next to "J. B. Goodliff Malt Ho. Old. Vacant."

Archaeological Field Survey

Archaeological survey is the process of locating and initially evaluating sites in a given area.

Archaeological Field Survey

Some sites are found by accident, such as Lascaux.

Archaeological Field Survey

Most site survey is project-related.

Methods of Survey

Transects

Transects may be a better survey strategy in a landscape covered with dense vegetation.

Methods of Survey

Grid

1 km grid squares placed over the Tell Hisban, Jordan Valley

Archaeological Sampling

Various techniques are employed during many phases of archaeological investigation to select a sample of the universe of potential data.

Archaeological Sampling Strategies

Judgmental sampling: sampling where you believe (based on judgement) sites will be found

Probabilistic sampling: using a form of scientific randomization

Archaeological Sampling Strategies

Probabilistic sampling: first, grid off your entire area for analysis (this is the basis for the sampling)

• Simple Random sampling: random selection of squares from entire area• Systematic sampling: sample every nth square• Stratified Random sampling: divide (stratify) total area into different subsections, randomly sample within each• Stratified Unaligned sampling: random sample taken within each predefined grid square

Survey Information RecoveryObservation: identify location of artifacts on the surface

Surface Collection: analyze types and quantities of artifacts in different places

Survey data obtained from the Hungarian Copper Age site of Körösladány 14

Survey Information Recovery

Subsurface Sampling:Shovel Test Pits: small

Test Units: larger, square

Survey Information Recovery

Subsurface Sampling:Post-Hole Diggers

Augers

A Bucket Auger

Archaeology and Remote Sensing

Anything that helps us learn what is on or in the ground without having to dig, or even be present.

Aerial photographyShowing prehistoric enclosure under fields in Cornwall, England

Archaeology and Remote Sensing

Satellite Data: can “see” what is not visible, e.g. through dense forests.

Infrared Imaging (NASA)

Maya region, Petén, Guatemala

Ground Truthing of Archaeological Sites

Archaeology and Remote Sensing

Satellite Data: can highlight ancient features such as roads

Infrared Imaging (NASA)Chaco Canyon Area, NM

Archaeology and Remote Sensing

Ground Penetrating Radar

Possible Fortification DitchesSingle GPR Profile, Bunker Hill

Six 20 m long GPR profiles showing possible fortification ditches from the Revolutionary War battle, Bunker Hill

National Monument, Mass.

Archaeology and Remote Sensing

Magnetometry

Filtered magnetic susceptibility data revealing linear trends possibly

representing structures and garden plots at Escondido Pueblo, NM

Archaeology and Other Modern Technology

Global Positioning Systems (GPS)Reads signals bouncing off several satellites to give exact locations in latitude/longitude or other coordinates.

Geographic Information Systems (GIS)Computerized ways of making maps of different features that can be overlain to show relationships of natural and cultural features through time.

Archaeological Mapping

Tape and Compass

Simple and inexpensive, but less accurate than other techniques

Archaeological Mapping

Total Station and Prism

Total Station measures angle distance to a prism

Archaeological Mapping

GPS Mapping

Good for larger-scale maps, not as precise as Total Station Mapping

Archaeological Mapping

What Gets Recorded

•Landscape Features•Site Locations•Architecture•Excavations

All based on Site Datum

After Mapping the Site

Site-level Surface Collections

Can help determine where to dig within a site

Archaeological Field Methods: Part II: Excavation

Provenience and StratigraphyExcavation LevelsExcavation TechniquesArtifactsNote Taking

Provenience

Must control 3-D space while conducting archaeological investigations.

Stratigraphy: Understanding Vertical Space

Law of Superposition: Earliest strata are typically the deepest

Stratigraphy: Understanding Vertical Space

Law of Archaeology: Strata will not necessarily be horizontal, or even straight across!

Excavation Levels

Natural or Stratigraphic Levels: Excavation reverses the natural order of deposition by proceeding downwards one stratum at a time.

Contoured Arbitrary Levels: The archaeologist picks an arbitrary depth (5 cm, 10 cm, etc.) to which the entire unit is excavated, paralleling the natural slope of the ground surface.

Simple Arbitrary Levels: Levels are defined by arbitrary depths below datum. When a level is completed, all four corners and the center of the unit will be the same depth below datum.

Combined Natural and Arbitrary Levels.

Excavation Techniques: Horizontal or Vertical?

Vertical Excavations:

•Smaller-sized, deeper pits, aimed at recovering diachronic information

•Typically start with small test-pits, 1x1m or 2x2m

Channel Islands, Santa Cruz Island, CA

Excavation Techniques: Horizontal or Vertical?

Probably not Approved by OSHA!

Excavation Techniques: Horizontal or Vertical?

Horizontal Excavations: •Larger, more exposed areas, aimed at recovering synchronic information

Roman Settlement, Vignale III R11522, Italy

Excavation Techniques: Horizontal or Vertical?

Trench Excavations:

•Quick exposure of small horizontal area

•Exposes stratigraphy through sidewalls

Caerleon Legionary Fortress, Roman Era, U.K.

Excavation Techniques: Tools of the Trade

Small Tools:

•Trowel•Tape Measures•Files•Root Clippers•Nails and String•Line Level/Plumb Bob•Dental Picks•Brushes

Excavation Techniques: Tools of the Trade

Larger Tools:

•Spade•Shovel•Pickaxe•Large Clippers•Dustpan•Whisk Broom•Buckets•Wheelbarrow•30m Tape Measure•Screens

Excavation Techniques

Excavations range from careful trowel and brush work to the use of backhoes.

Trowel excavation of Native American site, Morro Bay, CA versusBackhoe removal of topsoil, Yarra Yarra Catchment Area, WA

Excavation and Recovering Artifacts in the Field

Many artifacts are recorded in situ (in their original location) before removal from excavation

Foundation Floor with Artifacts, Historic Bishop Ranch House, Clark County, NV

Excavation and Recovering Artifacts in the Field

Architectural and other features are recorded

Early medieval oven or kiln, Leicester, UK

Excavation and Recovering Artifacts in the Field

Many artifacts are recovered through screening

Screening muddy soilDry screening

Excavation and Recovering Artifacts in the Field

Water-screening

Often must bring soil to a source of water

Excavation and Recovering Artifacts in the Field

Flotation: Recovering tiny artifacts through specialized water-screening

•Tiny Artifacts•Carbon•Botanicals

Low-tech and High-tech

Fish scales, e.g.

Note-Taking in the Field

Forms: ensure archaeologists record consistent information for the following…•Features (within or cross-cutting units)•Levels (within units, complete a new form with each new level)•Units (fill out when excavation unit is complete)•Profile/Plan maps (profile all stratigraphy, draw plan maps of the base of all excavation levels)•Photo/Video Logs (document all finds and levels)