ArchaeologyMethod and Practice

ARCHAEOLOGY

1. Locating Sites

2. The Excavation

3. Investigating the Evidence

4. Dating Methods

LOCATING SITES

• How do we know where to find archaeological sites?

• Sometimes they are obvious (eg. Colosseum)

• However, most are found by chance.

Chance vs Investigation

• Chance finds are common, lost sites may be exposed by natural elements such as weather, or by human activity such as farming, construction, warfare, fishing, dredging etc.

• Eg. Pompeii was found when a drain was constructed in late 1500’s.

LOCATING SITES

In 1974, workers digging for a village water project in China found some strange pottery items. Their discovery led to the unearthing of the great Terracotta Army.

• Investigation is actively looking for a site. There are several methods used by archaeologists.

• Written Documents: old maps, ancient texts

• Scientific Methods: Aerial photography, Surveying, Satellite imagery, Photographic Probes.

• Trial Trenches: usually 1m by 1m “test” pits across a site.

LOCATING SITES

Satellite Imagery of Angkor Wat temple complex, Cambodia

EXCAVATION

What happens on a dig?

• The excavation is a process of recovering, collecting and recording information.

• There are many steps to the process of excavation. Once a site has been located and a decision is made to excavate, the site director selects a team of experts.

Some experts used on a dig:• Cartographer• Anthropologist• Epigrapher• Architect• Botanist• Numismatist

• Geochemist• Radiologist• Climatologist• Zoologist• Pathologist• Papyrologist

EXCAVATION

Title Job Description

Director Supervises dig, maintains site records.

Assistant Director Care and allocation of equipment. Finance.

Site Supervisor Responsible for specific section of the site. Labelling of artefacts and recording relevant

information.

Diggers Unearth items, clear soil from around artefacts.

Recorders Record position of artefacts, enter details in a log.

Measurers Record location of artefact at the site, measure dimensions.

Washers Wash artefacts.

Sifters Sift excavated dirt to locate small finds.

Photographers Record finds and strata profiles.

Surveyors Survey the site, draw up layout of site.

Lab Experts Preserve / repair artefacts.

Illustrators Scale drawings of artefacts.

The Excavation team

EXCAVATIONMethods of Excavation:

a) Grid Excavation• This is where the site is divided into squares of boxes in

a given size. Each square is numbered and then excavated leaving a wall (called a baulk) in between.

• Each baulk provides a vertical record of the layers that have been dug through. The layers are called strata and each one is labelled with everything found in them.

BAULK

Profile of a Baulk

EXCAVATION

b) Open-area excavation

This is where the site is uncovered layer by layer. Different strata are not revealed.

STRATIGRAPHY

• Generally, a site depends on the principle of Stratigraphy; That each settlement on a site will leave a layer of debris. Normally, the oldest strata will be the deepest.

• Stratigraphy can become very complex, due to movements of the earths crust and intrusions (such as wells or pits).

EXCAVATION

• Archaeologists follow three basic stages of investigation.

• The archaeologist asks question at each stage of the investigation to determine the relevance and reliability of the evidence.

INVESTIGATING THE EVIDENCE

Stage 1:OBSERVATION

Collection of information. - Where was it located? - Who used it? - Purpose / function?

Stage 2:CLASSIFICATION

& RECORDING Place objects in correct context Record important information. - Is it authentic? - What can be learnt from it? - Does it relate to other evidence?

Stage 3:INTERPRETATION

Draw conclusions by looking at the evidence and studying patterns that may emerge.

DATING THE PAST

HistoricalTimes

Prehistory & History

Prehistory = before civilisation (writing)

History = Since Writing

Historical Dating

• The measurement of time

• Calendars have been used based on natural events, eg. sun and moon, Ancient Egyptians based time on the annual flooding of the Nile.

• Based on written documents. (After 3500 B.C)

• Most used is based on Christ’s life. AD (anno Domini,) and BC (Before Christ)

DATING THE PAST

DATING THE PAST

Relative vs Absolute Dating Methods

• Relative Dating = Gives a general idea of the time period an artefact comes from. Often dated through chronological sequence (in relation to something else)

• Absolute Dating = Gives an absolute date in

calendar years (also called scientific dating)

Lower Palaeolithic(Earliest Old Stone Age)

Middle Palaeolithic(Middle Old Stone Age)

Upper Palaeolithic(Latest Old Stone Age)

Mesolithic(Middle Stone Age)

Neolithic (New Stone Age)

Copper Age

Bronze Age

Iron Age

The Three Age System:

Stone, Bronze, Iron

1,000 BC

10,000

30,000

2 Million

100,000

9,000

5,000

3,000

DATING THE PASTRELATIVE DATING TECHNIQUS

TYPE? DESCRIPTION? USES?

1. Stratigraphic

2. Typology

3. Seriation

4. Three Age system

The study of layers in the earth (strata). The oldest is at the bottom.

Classifying objects according to their characteristics. Compare scientifically dated objects.

The arrangement of artefacts in a chronological sequence.

3 stages of technological development by humans – Stone age, Bronze age and Iron Iron age,

Grid excavation. Sites where geological change is noted. Inside test pits.

Items found in large quantities eg.pottery

Artefacts found in large quantities – similar uses to typology dating

Anything made by humans out of stone, copper, bronze or iron.

Typology of Turkish Pipes

DATING THE PASTAbsolute Dating Methods

1. Radiocarbon Dating

• All living things absorb isotope carbon-14 from the atmosphere.

• At the point of death this process ceases.

• C-14 begins to decay at a known rate > 5730 years half is decayed (“half life”)

• By measuring the amount of C-14 left in an organism, scientists can tell when it died, therefore its age.

• Dates expressed in + or – BP. That means: something could be 2000 years + or – 100 years

• Limit is 50, 000 years.

How C14 Dating Works

DATING THE PASTAbsolute Dating Methods

2. AMS Dating

• Recent development in radiocarbon dating

• Can date very small amounts of material containing C-14

• Will extend radiocarbon dating back to 100,000 years

• First absolute dating method used in Rock Art. (pigments of paint from ochre trees or charcoal)

DATING THE PAST

Absolute Dating Methods

3. Tree-Ring Dating (Dendrochronology)

• Dates timber objects

• Counting the growth rings of a tree

• Most species ring annually or every two years.

• Comparing overlapping trees (in age) can reveal a continuous sequence for thousands of years.

Dendrochronology(Tree Ring Dating)

DATING THE PAST

Absolute Dating Methods

4. Thermoluminescence Dating

• Used to date pottery and clay that has been fired

• Clay gives off radiation. This displaces electrons which become trapped in the structure of the clay.

• When re-heated, electrons go back to original positions, giving off light. The light is measured to determine age of the clay since firing.

• Dates to 35,000 years

DATING THE PASTAbsolute Dating Methods

5. Potassium-Argon Dating

• Used to date volcanic rock

• Similar to radiocarbon dating

• Volcanic rock contains potassium-40 which converts to argon-40 as it ages.

• Half life of 1.3 billion years

• Useful in dating fossil remains (human and other) embedded in volcanic rock.

Which Dating Method?CHOOSE THE METHOD OF DATING FOR THE FOLLOWING, AND STATE WETHER IT IS A RELATIVE OR ABSOLUTE DATING METHOD.

1. Inscription on a stone wall2. Stone tool from Africa found without any other material3. Human remains found in a tomb4. Wooden beam found as part of Viking ship5. A glass bottle found during an excavation6. The Great Pyramid in Giza7. Aboriginal rock art painting8. Piece of charred bread from stomach of a bog body9. A group of stone tools varying in style10.A collection of pottery from a site in Athens11.Single pottery piece from Sparta12.A bronze axe from Italy13.Papyrus paper from Ancient Egypt14.A fossil of a hominid jaw from East Africa15.A coin found at Byblos in Lebanon16.Seed residue from a stone hand axe

Research and explain how the following dating methods work

• Carbon 14 (radiocarbon) dating

• Potassium – Argon dating

• Dendrochronology

• Thermoluminescence dating