Excavation
Mosul University Archaeology
Program
Sunday, May 26, 2013
Overview
• Excavation has become the primary
method of acquiring archaeological data.
• Excavation is inherently destructive.
Thorough documentation will become the
only remaining record of the excavated
material.
• Materials documented and collected are
used as evidence to explain past human
behavior and site formation process.
Sunday, May 26, 2013
Objectives
• In this lecture, you will learn the
following elements of archaeological
method and theory:
– Designing and executing an excavation
– Archaeological recording
– Analyzing stratigraphic, material, and
contextual data
Sunday, May 26, 2013
Key Terms
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•
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•
•
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Stratigraphic relationships
Total excavation
Baulk
Profile & plan
Deposit
Feature
Sunday, May 26, 2013
WHAT IS EXCAVATION?
Sunday, May 26, 2013
Excavation produces data
• Archaeological record is a product of behavioral and
transformational processes, comprised of the materials
within the matrix
• Provenience documents the distribution of material
within the matrix
• Associated materials found in the same deposit are
assumed to be archaeologically related
• Context is the combined analysis of provenience,
association, and matrix
• Data produced by the archaeological record are subject
to interpretation
Photo: Author’s own
Sunday, May 26, 2013
Excavation is destructive
• Majority of archaeological material is below the
surface
• Removal of matrix destroys contextual evidence
• Documentation is the only record for excavated
material
• Total excavation (complete removal) is
generally avoided, but sometimes necessary
Photo: Author’s own
Sunday, May 26, 2013
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Excavation is preservation
• Sites facing human and natural threats can be
preserved in documentation
• Though the archaeological record in its original
form, with proper recording it can be studied in
the future
• But, without site, only documentary evidence can
be used to answer future research questions,
which can be limiting (no more samples)
Photo: Author’s own
Sunday, May 26, 2013
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EXCAVATION
PLANNING
Sunday, May 26, 2013
Where to excavate?
• Locate unexcavated site
based on surface evidence
– Survey
– Remote sensing
• Start new project on
previously investigated site
• Chance find during
commercial investigative
survey
• Rescue of threatened
archaeological material
Photo: Author’s own
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Logistics
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•
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Permissions
Funding
Time
Staing
Research design
– Sampling strategy
Photo: Author’s own
Sunday, May 26, 2013
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Logistics: Permissions
• Permits
– What are the requirements?
– Import/export license for finds & sample
processing outside country
• Laws
– National antiquities/historic preservation laws
– Ownership of materials
– Special treatment of human remains
• Private landowners
– Permission for excavation
– Discuss equipment storage, access, facilities,
maintenance, security
Photo: Author’s own
Sunday, May 26, 2013
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Logistics: Funding
• Understand where your funding originates and the motives
behind it
• Governmental
– Advocacy: promotion of national scientific advancement, investigation
of the past
– Obligation: expansion of infrastructure or utilities
• NGO & University
– Advocacy: promotion of select research projects, advancement of
method, improving knowledge of a time or place
• Commercial
– Obligation: agricultural/industrial/housing expansion
– Advocacy: promotion of research or past, positive public relations
• Private donations
– Advocacy: Individual interest, personal cause
Photo: Author’s own
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Sunday, May 26, 2013
Logistics: Time
• Research project
– Primary purpose is archaeological investigation,
instruction
– Urgency: low, occasionally medium
• Commercial
– Identification of cultural resources prior to
construction
– Urgency: medium
• Rescue
– Material under immediate threat of destruction
– Urgency: high
Photo: Author’s own
Sunday, May 26, 2013
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Logistics: Staing
• Who is recruited is
based on project
goals and finances
• Professionals
– Contractors
– Academics
• Students
– Field school
– Graduate students
• Specialists
• Volunteers
Photo: Author’s own
Sunday, May 26, 2013
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Logistics: Research design
• Determine:
– Purpose
• Research, rescue, or
commercial investigation?
– Time constraint
– Funding and budget
– Available resources
(laboratories, storage, data
management) and specialists
– Preservation requirements
• Design:
– Sampling strategy
• Excavation units,
• Artifact collection methods,
• Types of environmental,
geological, chemical
samples
• Absolute dating methods
– Investigation goals
– Data processing time frame
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Sunday, May 26, 2013
EXCAVATION
PROCESS
Sunday, May 26, 2013
Excavation Process
• Pre-excavation
– Research design
– Sampling strategy
– Grid layout
– Unit placement
– Surface clearance
– Spoil heap
– Facilities
organization
• Excavation
– Digging technique
– Seeing
stratigraphic
changes
– Collection
methods
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Sunday, May 26, 2013
Pre-ex: Grid layout and unit placement
• Define datum point, then set base line
– Base on known geodetic points if available
– Measuring from one base line reduces error
– Try to use immovable grid points to prevent
shifting
• Lay out grids
– Digitally: EDM or theodolite
– Manually: hand tapes (beware of slope to
avoid error)
• Establish site coordinate system
• Place units, cut trenches
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Photo: Author’s own
Sunday, May 26, 2013
Pre-ex: Grid layout
Set datum point and
baseline, then triangulate
rest of grid using tapes
B
A
S
E
L
I
N
E
datum point
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Pre-ex: Cutting trenches
Photo: Author’s own
Sunday, May 26, 2013
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Pre-ex: Surface clearance
• Determine depth of modern surface
• If surface truncated or shallow turf, remove
manually
• Machinery can be used to remove deep modern
deposits, concrete surfaces
• Once archaeological surface exposed, remove
remaining topsoil with sharp trowel strokes
Photo: Author’s own
Sunday, May 26, 2013
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Pre-ex: Facilities
• Organize the site:
– Spoil heaps
– Pathways
– Recording area
• Protected area to store
records, supplies, finds/
samples
– Rest area
• Protected area for breaks,
meals, escaping elements
– Toilet
• Private area, away from site
• Maintain cleanliness
Photo: Author’s own
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Sunday, May 26, 2013
Health and Safety: Site maintenance
Photo: Author’s own
Sunday, May 26, 2013
• Set spoil heap away from trenches
• Establish direct barrow paths and
walkways
• Never sit on trench edges or step
on edge to enter/exit unit
• Shore up unit walls during deep
soundings
• Use hard hats and high-visibility
jackets
• Keep string lines low and visible
• Use flagging tape on protruding
pegs, nails
• Keep a stocked first-aid kit
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Health and Safety: Personnel care
• Communicate!
• Know your physical
limits
• Take frequent breaks
• Drink water, eat right
• Lift with knees, not
back
• Wear proper attire,
prepare for the
elements
Photo: Author’s own
Sunday, May 26, 2013
Photo: Author’s own
Excavation: Dig Tools
Pick: to excavate deep passes
Spade: to edge units, cut through turf
Shovel: to remove large amounts of spoil
Barrow: to carry large amounts of spoil
Trowel: primary tool, used for everything
Leaf: detailed trowel-work
Brush: to remove fine particles from solid
features
• Pan: to remove small amounts of spoil
• Sift: to separate
•
•
•
•
•
•
•
Photo: Author’s own
Sunday, May 26, 2013
Excavation: Good digging habits
• Work from known to
unknown
• Move side to side,
working backwards
• Minimum contact with
surface: crouch
• Never walk over area
just cleaned
• Brush stones/surfaces,
not soil
• Clean up loose often
• Communicate!
Photo: Author’s own
Sunday, May 26, 2013
27
Good habits
Crouching
Working in one direction
Cleaning up loose
YES
Photo: Author’s own
Sunday, May 26, 2013
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Excavation: Bad digging habits
•
•
•
•
•
•
•
•
Using wrong tools
Improper dress
Working in circles
Ignoring your
neighbor
Walking over a cleaned
area
Sitting in trench
Smoking in trench
Digging without
purpose! Be aware
Bare feet
NO!!
Photo: Author’s own
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Y
Bad habits
Sitting on unit edge
YES
NO!!
Crouching
YES
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Photo: Author’s own
Sunday, May 26, 2013
Bad Habits
Digging without purpose
NO!!
Photo: Author’s own
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Bad Habits
Sitting on surface
NO!!
Photo: Author’s own
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Bad habits
Using equipment inappropriately
NO!!
Photo: Author’s own
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Excavation: Stratigraphic changes
Photo: Author’s own
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Color
Texture
Compactness
Moisture level
Inclusions
Layer thickness
Horizon transition
Finds
Relationships with
other strata
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Sunday, May 26, 2013
Excavation: Artifact/ecofact collection
• Hand collection in trench
• Sifting
Photos: all Author’s own
– Using screen for finds
• Flotation
– Using water to separate
ecofacts and tiny finds
from soil
• Block lift
– Removing a whole find and
surrounding matrix in an
entire unit when it is too
delicate to excavate in the
field
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Sunday, May 26, 2013
Excavation: Sampling
• Samples are only as
good as the quality of
collection
• Process in a timely
manner
• Types:
–
–
–
–
Geomorphology
Carbon
Microbotanical
Phosphate
Photo: T. Parno
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RECORDING
Sunday, May 26, 2013
Recording Methodology
• Registers
• Photographs
• Drawings
– Plans
– Profiles
• Data management
– Databases
– Geographic
Information
System
Photo: Author’s own
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Sunday, May 26, 2013
Recording: Registers
• Stratigraphy
• Features &
structures
• Artifacts
– Batch collection
– Small finds
• Samples
• Photos
• Drawings
• Basic information:
– Stratigraphic
context
– Location
– Elevation
– Description
– ID of excavator
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Sunday, May 26, 2013
Recording: Field notebooks
• Each excavator
should keep a
personal notebook
• Can keep track of
deposits being
excavated
• Write down
changing
interpretations
• Keep track of levels,
drawings, photos
Photo: Author’s own
Sunday, May 26, 2013
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Recording: Photographs
• More flexible than drawing, can capture a variety of angles,
color, texture
• Subjective, altered dramatically by light, angle
• Uses:
– Document context and stratigraphic relationships
– In situ finds, features
– Demonstrate relationship among diferent excavation units
• At very least, take photos at the start of a new layer
• Always take photos at end of the day, even when midcontext
Photo: Author’s own
Sunday, May 26, 2013
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Recording: Photographs
• Film can be used, but digital
cameras more popular, easier,
and less expensive to process
• Method:
– Clean area, spray if contexts are diicult
to see
– Remove non-archaeological material
– Place scales along features
– Place N arrow in correct direction
– Reduce shadow
– Get elevated
– Take both color and B&W
– Bracket exposure (-1, 0, +1)
– Use wide-angle lens if available
– Document day, direction, contexts,
features, photographer in register
Sunday, May 26, 2013
Photo: T.Fowler
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Recording: Photography
Photo: T.Parno
Sunday, May 26, 2013
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Recording: Spatial record
• Horizontal and
vertical position of
features and finds
• Documented with
depths and
triangulation,
manually with tapes
or digitally with
EDM, etc.
• Visually represented
in plans and profiles
Photo: MF Lane 2011
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Photo: Author’s own
Sunday, May 26, 2013
Recording: Drawings
• Plan: horizontal
space
• Profile: vertical space
• Not artistic, but
subject to
archaeological
interpretation of
drawer
• Better than photos
for defining limits
contexts
Photo: Author’s own
Sunday, May 26, 2013
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Drawing: Plan
• Used to document
distribution of
contexts, features,
finds
• Drawn after
removal of each
context
• Typically 1:20 scale
Photo: Author’s own
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Sunday, May 26, 2013
Drawing: Plan
• Method:
– String measuring tape from base line
– Mark unit edges
– Use plumb-bob with tapes or planning frame to
locate and draw contexts, features, finds; make sure
tapes/frame are level
– Label with corresponding recording numbers
– Take elevations, mark on plan
Photo: Author’s own
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Sunday, May 26, 2013
Drawing: Plan
Lay tape and string
from base line
Place planning frame along tape
Photo: Author’s own
Sunday, May 26, 2013
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Drawing: Plan
Place planning frame on
each meter mark.
Each string marks 20 cm
plumb
bob
Use plumb bob to follow
the feature.
tape
planning
frame
Use strings as guide.
Draw what’s inside each box.
20cm
1m
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Sunday, May 26, 2013
Drawing: Plan
Image: T.Parno
Sunday, May 26, 2013
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Drawing: Profiles
• Used to document stratigraphy
• Subject is trench wall or bisected
feature baulk
• Plot all profiles on plans
• Typically 1:10 scale
Photo: Author’s own
Sunday, May 26, 2013
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Drawing: Profiles
• Method:
– Set two stakes at each end of section
– Tie string between stakes and then level
– Secure measuring tape under string, also level
– Measure distance from string to top and bottom of layer to determine
depth, repeat across section face
– Constantly check string line is taut and level
– Determine elevation of string to provide depths of layers
Take elevation on string
when finished
Measure distance from
string to stratum
Sunday, May 26, 2013
Leveled string
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Image:: adapted from WikiCommons
Drawing: Profile
Image: T.Parno
Sunday, May 26, 2013
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Matrix description
• Color
– Munsell chart
• Sediment grain size
– Clay, silt, sand
• Inclusions
– Stones (size, shape)
– Charcoal (flecks,
fragments, pieces)
Photos: all Author’s own
Sunday, May 26, 2013
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Feature description
• Always consider
relationship between
matrix and feature
• Cuts and Infilled features
– Ditches, post holes
• Structures/architecture
– How do elements fit together?
– Stone, brick, timber
• Burials
Photo: all Author’s own
– Record and photo in situ
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Sunday, May 26, 2013
Recording: Data management
Image: A.McCreery
• Computers
– Storage of all recorded
data
• Databases
– Images
– Artifacts
– Samples
• Geographic Information
System (GIS)
Image: AROURA Project
Sunday, May 26, 2013
– Finds recording
– Elevations
– Photos
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Evidence analysis
• Consider deposits, finds, and stratigraphic
relationships for each context AND the unit as
a whole
• Should be an evolving process
• Constantly reevaluate original theories
• Look at other trenches
• Discuss with other excavators
Photo: Author’s own
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Sunday, May 26, 2013
Conclusions
• Archaeology is inherently destructive,
but can produce new data for future
study
• Take into account the logistics and
evaluate available resources and
personnel when developing a research
design prior to excavation
• Recording evidence is the most
important aspect of excavation
Sunday, May 26, 2013
Further Reading
• T. Hester, H. Schaffer, K. Feder (2009) Field Methods
and Archaeology. Walnut Creek: Left Coast Press.
• B.A. Kipfer (2006) Archaeologist’s Fieldwork
Companion. London: Blackwell.
• S.Roskams (2001) Excavation. Cambridge:
Cambridge University Press.
• C. Renfrew and P. Baun (2012) Archaeology:
Theories, Methods, and Practice. London: Thames &
Hudson.
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Sunday, May 26, 2013