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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
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Undersökningsytorna
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 0 -0,6 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 0,2-0,8 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 0,5-1,1 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 0,7-1,3 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 1,0-1,6 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 1,2-1,8 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 1,4-2,1 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 1,7-2,3 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 1,9-2,5 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 2,1-2,8 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 2,4-3,0 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Reflexer på 2,6-3,2 m djup
Modellering efter georadar-prospektering
Gamla Uppsala kyrka
Dating
To fix an event along a time axis
Dating
To fix an event along a time axis
But what event?
Dating
To fix an event along a time axis
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?
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