Sven Isaksson Archaeological Research Laboratory Department of Archaeology

Sven Isaksson Archaeological Research Laboratory Department of Archaeology and Classical Studies Stockholm University Scientific Tools for Probing the Past

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, 14 C-dating 1970 Increased application in archaeology 1985 Break-through in organic analyses

Archaeological Research Laboratory 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

Department of Archaeology and Classical Studies Archaeology Archaeological Research Laboratory Classical Studies Numismatic Research Group Osteoarchaeological Research Laboratory

Scientific tools are used to probe the archaeological material for more data Archaeology! Not science? Not Archaeology? Science!

The Fate of Finds • Excavation Semi-stable equilibriums are broken, collection, registration • Recording Cleaning, visual characterization • Conservation Halt decomposition, extract information -excavation on microscopic level • Storage Keep, preserve, display • Scientific analyses? Excavations on molecular or atomic level

The nature of archaeological material

Contamination during excavation Hawaiian Tropic (coconut oil, UV-block).

Contamination during recording Day Cream (palmtree oil etc)

Contamination during conservation From Aveling 1998 Paraffin

Keeping in museums Ancient horse DNA from Birka Excavated mt. DNA Late 1800 -tal Late 1900 -tal a. DNA HTG 10 HTG 8 + + From Götherström 2001 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, magnetometer and ground penetrating radar

Modellering efter georadar-prospektering Gamla Uppsala kyrka 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

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 Chronological Find combination Dendrochronology Magnetic TRM DRM Radiation damage Fission tracks TL OSL ESR Radioactive decay Conventional 14 C Accelerator 14 C K/Ar Physical phenomenon Hydration Chemical reactions Racemisation Biological growth Lichenometry Material Range (yrs) Sample size artefacts wood 106 104 100 treerings burnt clay sediment 104, or longer cm glass, mineral ceramic, br. stone sediment enamel 102… 107 102… 105 106 103… 106 mm mg…g organic mineral 50 000 70 000 105… 109 10 g mg g obsidian, glass bone, hair lichens mm 102… 106 g

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

Provenance Flint Provenance of 70 % of flint axes identified by trace elements alone Together with archaeological data, e. g. context and date, 95 % identified

Provenance Garnets

Biological origin Squalene Cholesterol Stigmasterol

Biological origin Chemical analyses of: Fats/Oils Waxes Pitches Tars Leather Textile Food Short-chain fatty acids Long-chain fatty acids and MAG Triacylglycerols (TAG) Sterols IR-spectra of organic residues Morphological analyses: Seeds Leather Fur Textile Bone Long-chain ketones and DAG Gas chromatogram of lipid residues Scanning Electron Micrographs of cells from barley and pea in prehistoric food residue

Technology Deposit or Inlay?

Technology Just because its green doesn't mean its bronze (Stjerna 1997)

Technology Symbols or Cymbals: the Fröslunda shields From a sulfide ore - late Bronze Age Hammered 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, a. DNA Kinship a. DNA Migration a. DNA, S- and Oisotopes, trace elements

Living conditions and climate Disease Osteology, a. DNA Climate O-isotopes Vegetation, regional Pollen analysis Vegetation, local Plant macro fossils, organic geochemistry

Facilities • a. DNA laboratory for extraction and PCR, post-PCR laboratory in separate building • Atomic Absorption Spectrophotometer 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 • 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

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 3 D-scanner for both highresolution surface analyses of artefacts and for large-scale 3 D documentation • Preparation and conservation laboratory primarily for metal artefacts • Slingram, Ground-Penetrating Radar and Magnetometer for archaeological prospecting • Spectrophotometers for wetchemical 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

Research programs • Svealand in the Vendel and Viking Period (finished) • Forts and Fortifications in the Mälaren Region AD 4001100 (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