Transcript Archaeological Dating, Survey and Excavation

Archaeological Dating,
Survey and Excavation
Types of Dating Methods
TYPOLOGY AND CROSS-DATING
HISTORICAL DATING
DENDROCHRONOLOGY
SCIENTIFIC DATING TECHNIQUES
ABSOLUTE TECHNIQUES
DERIVATIVE TECHNIQUES
Typology and Cross-Dating
Typology is not, strictly speaking, a dating method, but a
means of placing artefacts into some kind of order.
Typology seeks to identify and analyse changes that will
allow artefacts to be placed into sequences.
These techniques place assemblages of artefacts into
relative order. Petrie used sequence dating to work
back from the earliest historical phases of Egypt into
pre-dynastic Neolithic times, using groups of
contemporary artefacts deposited together at a single
time in graves.
Seriation (Cross-dating) was developed in the USA to
place in order finds from strata or other kinds of
assemblages such as potsherds collected from the
surface of sites.
Historical Dating
Prehistorians sometimes overestimate the accuracy and
detail of frameworks based on historical evidence; in
practice, early written sources may provide little more
information than a scatter of radiocarbon dates. The
extent of documentation varied considerably in
'historical' cultures and the information that survives is
determined by a variety of factors.
E.G. If a context containing burnt debris and broken
artefacts is excavated on a site from a historical period,
it is tempting to search the local historical framework for
references to warfare or a disaster in the region, and to
date the excavated context accordingly.
Dendrochronology
(dendron = tree, chronos = time, logos = word = the
science of): The science that uses tree rings dated to
their exact year of formation to analyze
temporal and spatial patterns of processes in the
physical and cultural sciences.
Dendroarchaeology-The science that uses tree rings to
date when timber was felled, transported, processed, or
used for construction or wooden artifacts.
Example: dating the tree rings of a beam from a ruin in
the American Southwest to determine when it was built.
© 2002 by Henri D. Grissino-Mayer.
Dendrochronology and Cross-Dating
© 2002 by Henri D. Grissino-Mayer.
Absolute Techniques
Radiocarbon dating
Potassium-argon (40K/40Ar) and argon-argon dating
(40Ar/39Ar)
Uranium series dating-decay of uranium to helium/lead.
Fission-track dating-microscopic tracks in glassy material
Luminescence dating-heating of crystalline material.
Electron spin resonance (ESR)-electrons subjected to
radiation then resonate.
Radiocarbon dating
Carbon 14- one peaceful by-product of
accelerated wartime research into atomic
physics and radioactivity in the 1940s. The rate
of decay of 14C, which has a half-life of 5730
(±40) years, is long enough to allow samples of
carbon as old as 70,000 years.
AMS- Accelerator Mass Spectrometry
Potassium-argon (40K/40Ar) and
argon-argon dating (40Ar/39Ar)
Ideal for dating early hominid fossils in East
Africa.
They occur in an area that was volcanically
active when the fossils were deposited between
one and five million years ago.
DERIVATIVE TECHNIQUES
Protein and amino acid diagenesis dating
Bones, teeth and shells contain proteins that break down after death,
and the most commonly investigated products of decomposition are
amino acids. Amino acid racemization dating (AAR) measures changes
between these amino acids' L- and D-forms; their ratio is an indication
of age.
Obsidian hydration dating
Obsidian was a popular alternative to flint for making flaked tools in
many parts of the world. As soon as a fresh surface of obsidian is
exposed, during the process of making it into a tool, a microscopically
thin hydration rim begins to form as a result of the absorption of water.
Archaeomagnetic dating
The position of magnetic North wanders around the North Pole, and
even reverses completely to the South Pole for extended periods on a
geological time-scale. From any reference point its position is
measurable in terms of two components: movement up or down
(inclination or 'dip') and from side to side (declination).
Survey and Excavation
Research Design
Finding Archaeological Sites
Excavation
Types of Sites
Research Design
Design and Formulation
Background Research
Research design
Implementation
Funding
Research team members
Permission
Data Acquisition
Field Research
Conservation
Initial Artifact processing
Processing and
Analysis
Lab analysis
Curation
Interpretation
Final Report
Finding Sites
Accidentally
Iceman-1991
Lascaux
Archaeological Survey
surface survey
subsurface excavation
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stp
auger
bank cuts
Remote Sensing
Ground penetrating radar
magnetic resistivity
Aerial Photography
mounds
crop marks
Satellite Imagery
Geographic Information
Systems (GIS)
Iceman-1991 Austrian/Italian Alps
Ground Penetrating Radar
Magnetic Resistivity
Aerial Photography
Samarra' is a town on the east bank of the middle Tigris in Iraq, 125
km north of Baghdad, Between A.D. 836 and 892 it was the capital
of the Abbasid Caliphs. Samarra’ expanded to an occupied area of 57
km², one of the largest cities of ancient times.
Excavation
Vertical Excavation
Digging limited areas
for info on
stratigraphy and
dating
“Test Trenching”
Area Excavation
Horizontal
excavation
“Block Areas”
Underwater
Tools
Backhoes, Bulldozers
Picks, shovels, trowels
Dental picks, brushes
Recording
Stratigraphy
Vertical Excavation
Area Excavation
Underwater Archaeology
Types of Sites
Habitation Sites
Open campsites
Villages
Caves & Rockshelters
Earthworks
Mounds
Forts
Shell Middens
Ceremonial Sites
Architectural Sites
Burials and Cemetaries
Historic Sites