Scientific Tools for Probing the Past Sven Isaksson Archaeological Research Laboratory Department of...

Scientific Tools for Probing the Past

Sven IsakssonArchaeological Research LaboratoryDepartment of Archaeology and Classical StudiesStockholm University

Archaeology and Chemistry

Why a little chemistry is useful to archaeologists:

•The archaeological sources are material remains – chemistry is the study of matter and its change

•Material remains are affected by the ravages of time – what is left and how it is preserved

•Man has always made use of matter and changed it; Man – the Chemist

History

C. 1800, first chemical analyses

1896, first physical analyses

1945 New techniques in chemistry, physics and biology

1949, 14C-dating

1970 Increased application in archaeology

1985 Break-through in organic analyses

Established in 1976

Professorship in 1986, first as an adjoining position but later as a regular chair, in laboratory archaeology (swe: laborativ arkeologi)

Since 2005 part of the newly created Department of Archaeology and Classical Studies

Archaeological

Research

Laboratory

Department of Archaeology and Classical Studies

Archaeology OsteoarchaeologicalResearchLaboratory

Classical Studies NumismaticResearchGroup

Archaeological Research Laboratory

Scientific tools are used to probe the archaeological material for more data

5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 4 0 0 4 5 0 5 0 0 5 5 0 6 0 0 6 5 0 7 0 00

1 0 0 %

B e t u l i n t r i m e t h y l s i l y l e t h e r7 3

1 8 9

4 9 6

1 2 93 9 3

4 8 3

2 0 3

4 9 6

4 8 3

1 8 9

+

O

C H 3CH 3

C H 3

C H 3

O

CH 2

C H 3

C H 3

C H 3

S i

C H 3

C H 3

CH 3S i

CH 3 C H 3

CH 3

C H 3

C H 3CH 3

C H 3

m / z

Archaeology! Not Archaeology?

Not science? Science!

The Fate of Finds

•ExcavationSemi-stable equilibriums are broken,

collection, registration

•RecordingCleaning, visual characterization

•ConservationHalt decomposition, extract information-excavation on microscopic level

•StorageKeep, preserve, display

•Scientific analyses?Excavations on molecular or atomic level

The nature of archaeological material

12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.000

100%

IS

C14:0C16-ol

C16:0 C18-olC18:0

1,2-D16

1,3-D16

1,2-D18

1,3-D18

1,2-D20 1,3-D20

T24

T26

T28

T30

Abundance

Retention time

50 100 150 200 250 300 350 400 4500

100%Trioctanoat or Tricaprylin127

57

327

201

O

O

O

O

O

O

CH3CH3

CH3

O

O+

O

CH3

H

327

127

201

500

m/z

Abundance

10.00 15.00 20.00 25.00 30.00 35.00 40.000

100%

Druvvax

Contamination during excavation

Hawaiian Tropic (coconut oil, UV-block).

10.00 15.00 20.00 25.00 30.00 35.00 40.00 0

100% Fettsyror

Monoacylglyceroler Diacylglyceroler

Triacylglyceroler

Labkontamination Mjukgörare från plastpåse

10.00 15.00 20.00 25.00 30.00 35.00 40.000

100%

C12:0

C16:0

C18:1, C18:2

C18:0

Mjukgörarefrån plast

Steroler

Isopropyl-myristat

Contamination during recording

Day Cream (palm-tree oil etc)

8 732

1(a)

95

4

2

7 3

1(b)

Contamination during conservation

ParaffinFrom Aveling 1998

Keeping in museums

Excavated aDNA

mtDNA HTG10 HTG8

Late 1800-tal + - -

Late 1900-tal + + +From Götherström 2001

r = -0,554 p = 0,032

Tid sedan utgrävning (år)

Me

de

lko

lke

dje

län

gd

(A

CL

) h

os

fetts

yro

r

15,4

15,8

16,2

16,6

17,0

17,4

17,8

0 40 80 120 160 200

r = -0,057 p = 0,841

Tid sedan utgrävning (år)A

nd

ele

n o

mä

ttad

e fe

ttsyr

or

(%)

-2

2

6

10

14

18

22

26

0 40 80 120 160 200

Ancient horse DNA from Birka

Alkanoic acids in Norwegian organic residues

Is organic residues better off in the ground than in the museum?!

Analytical techniques

Prospecting

Dating

Characterization

Prospecting

Site locating

Prospecting

Site locating

Site investigating

Prospecting

Site locating

Site investigating

Detecting anomalies from natural background

Prospecting

Site locating

Site investigating

Detecting anomalies from natural background

Geochemical – e.g. phosphate

Geophysical – e.g. slingram, magnetometerand ground penetrating radar

Nutida kyrkan

Modellering efter georadar-prospektering

Gamla Uppsala kyrka

Nutida kyrkan med tolkningen av katedralens utsträckning


Gamla Uppsala kyrka

Undersökningsytorna


Gamla Uppsala kyrka

Reflexer på 0 -0,6 m djup


Gamla Uppsala kyrka

Reflexer på 0,2-0,8 m djup


Gamla Uppsala kyrka



Gamla Uppsala kyrka

Dating

To fix an event along a time axis

Dating


But what event?

Dating


But what event?

The event dated by an analytical technique is not always the same as

the archaeological event…

Dating

Dating

Method Material Range (yrs) Sample sizeChronological

Find combination artefacts 106 -Dendrochronology wood 104 100 treerings

MagneticTRM burnt clay 104, or longer cmDRM sediment

Radiation damageFission tracks glass, mineral 102…107 mmTL ceramic, br. stone 102…105 mg…gOSL sediment 106 mg…gESR enamel 103…106 mg…g

Radioactive decayConventional 14C organic 50 000 10 gAccelerator 14C organic 70 000 mgK/Ar mineral 105…109 g

Physical phenomenonHydration obsidian, glass mm

Chemical reactionsRacemisation bone, hair 102…106 g

Biological growthLichenometry lichens

Characterization

Provenance

Biological origin

Technology

Man

Living conditions and Climate

Provenance

Heterogeneity of the Earths

crust

Materials collected from a

certain deposit may have a

specific composition

Mineral (stone, clay), metal,

slag, glass

ProvenanceFlint

Provenance of 70 % of flint axes identified by trace

elements alone

Together with archaeological data, e.g. context and

date, 95 % identified

ProvenanceGarnets

Biological origin

OH

CH3 CH3

CH3

CH3

CH3

OH

CH3 CH3

CH3

CH3

CH3

CH3

StigmasterolCholesterol

CH3

CH3CH3CH3

CH3CH3

CH3

CH3

Squalene

Biological origin

Chemical analyses of:Fats/OilsWaxesPitchesTarsLeatherTextileFood

Morphological analyses:SeedsLeatherFurTextileBone

Short-chainfatty acids

Long-chainfatty acids and MAG

Long-chainketones and

DAG

Sterols

Triacylglycerols (TAG)

IR-spectra of organic residues Gas chromatogram of lipid residues

Scanning Electron Micrographs of cells from barley and pea in prehistoric food residue

TechnologyDeposit or Inlay?

(Stjerna 1997)

TechnologyJust because its green doesn't mean its bronze

TechnologySymbols or Cymbals: the Fröslunda shields

From a sulfide ore - late Bronze Age

Hammered and annealed – not suitable as cymbals

Flattening of slag inclusions – hammered from a piece 15 cm in diameter

Man

Diet C- and N-isotopes,

trace elements

Breast-feeding N-isotopes

Sex determination Osteology, aDNA

Kinship aDNA

Migration aDNA, S- and O-

isotopes, trace elements

Living conditions and climate

Disease Osteology, aDNA

Climate O-isotopes

Vegetation, regional Pollen analysis

Vegetation, local Plant macro fossils,

organic geochemistry

•aDNA laboratory for extraction and PCR, post-PCR laboratory in separate building•Atomic Absorption Spectrophoto-meter for trace metal element analyses of soil, bone and artefacts•Field-archaeology equipment, incl. sampling probes, field spectrophotometer, metal detector, GPS, total station, photo-tower for analogue or digital cameras•Fourier Transform Infrared Spectrometry for analyses of organic residues and pigments

Facilities

•Freezer-room for the storage of very large samples, e.g. whole graves•Gas Chromatography and Mass Spectrometry for organic residue analyses•GIS computer systems for spatial analyses•Mass Spectrometry for isotope (C, N, S, O) analyses primarily of bone collagen•Microscopes and sample preparation equipment for analyses of archaeo-botanical materials, textiles, etc

•Slingram, Ground-Penetrating Radar and Magnetometer for archaeological prospecting•Spectrophotometers for wet-chemical analyses (e.g. phosphates) •Variable Pressure Scanning Electron Microscope with Energy Dispersive X-ray Spectrometry for microstructure and elemental analyses•X-Ray Diffraction for the analysis of minerals, bones and pigments

Facilities

•Microscopes and sample preparation equipment for microstructure analyses of metals and ceramics•Microwave Accelerated Reaction System for rapid sample preparation, i.e. extracting, digesting, dissolving, hydrolysing or drying organic or inorganic materials•Optical 3D-scanner for both high-resolution surface analyses of artefacts and for large-scale 3D documentation•Preparation and conservation laboratory primarily for metal artefacts

Research programs

•Svealand in the Vendel and Viking Period (finished)

•Forts and Fortifications in the Mälaren Region AD 400-1100 (finished)

•Us and Them – Cultural identity in the Middle Neolithic

•Bread for the dead, bread for the living… Cereal-based food in the Late Iron Age

•By House and Hearth – The chemistry of culture layers as a document of the subsistence of prehistoric man

•Tracing Ancient Vegetable Food – Chemotaxonomy of plant lipid residues

•Gender and Diet in the Neolithic

Scientific Tools for Probing the Past Sven Isaksson Archaeological Research Laboratory Department of...

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