Unravelling prehistoric plant exploitation in eastern Baltic: organic residue analysis of plant-based materials by multi-method approach
Date
2023-08-31
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Abstract
Käesoleva doktoritöö eesmärk on uurida muinasaegset taimede kasutamist Läänemere idakaldal, keskendudes kahele peamisele taimset päritolu materjalitüübile: vaigulaadsetele materjalidele ja toidutaimedele. Peamised uuendused seisnevad mitmemeetodiliste lähenemisviiside väljatöötamises ja erinevate andmestike tõlgendamises kemomeetriliste ja statistiliste meetoditega.
Vaigulaadsete materjalide koostise kindlakstegemiseks viidi läbi ATR-FT-IR analüüs koos PCA-põhise DA klassifitseerimismudeliga; mis võimaldas proove täpsemalt klassifitseerida ka ruumilisel/ajalisel skaalal. Loodud mudel aitab lihtsustada IR-spektrite tõlgendamist ja vähendada vajadust teha analüüse GC-MSiga.
Taimejäänuste tuvastamiseks kasutati mitmemeetodilist lähenemist, mis hõlmas endas taimede mikrofossiilide uurimist, EA-IRMSi kombineerituna ORA-ga. EA-IRMS võimaldab eristada taimedepõhist ja/või loomset päritolu proove. Taimede mikrofossiilide analüüs ja ORA täiendavad teineteist, võimaldades määrata taimede liike. Korrespondentsanalüüs võrdleb ja näitab kolme meetodi kokkulangevust ning visualiseerib mitmemeetodilise töö tulemusi.
Taimede kasutamises Läänemere idaosa muinasaja materjalis ilmnevad erinevad mustred. Kiviajal kasutati taimi pigem tehnoloogilistel eesmärkidel (neist tehti vaikusid ja liime) kui toiduna. Pronksiajal esines juba enam taimede toiduks tarbimist. Suuremad muutused taimse toidulaua osas leidsid aset rauaajal, mille proovidest paistab mitmekesisem toidutaimedevalik. Põhitoiduks olid C3-teraviljad (näiteks nisu ja oder), kuid C4 taimena tuntud hirsi kasvatamine sel perioodil käesolevas uurimispriikonnas veel ilmselt ei levinud.
This PhD work is aimed at unravelling the plant exploitation in ancient eastern Baltic area with focus on two types of plant-derived materials: resinous materials and dietary plants. The main innovations are developing multi-methodological approaches and interpreting multi-proxy datasets with chemometric and statistical methods. For identifying the composition of resinous adhesives, ATR-FT-IR analysis was conducted in combination with a PCA-based DA classification model for further compositional and spatial/temporal classification. This method can help simplify IR spectra interpretation and reduce the need for GC-MS analysis. For identifying dietary plants, a multi-method approach was applied by plant micro fossil analysis and EA-IRMS combined with ORA. EA-IRMS can provide preliminary origins of samples with plant and/or animal bases. Plant micro fossil analysis and ORA in complementary can identify the species of plant remains. Correspondence analysis further compares and indicates the agreement of three methods and visualizes the correlations between the multi-proxy data The plant exploitation in prehistoric easter Baltic shows different patterns with dedicated multi-method case studies on several Stone Age, Bronze Age and Iron Age sites. In Stone Age, plant exploitation was more technological (adhesives and resinous compounds) than dietary-related. The plant consumption for dietary purposes became more abundant in the Bronze Age. The major changes happened with the Iron Age displaying more diverse plant-based diet with more inclusion of C3 cereals (e.g., wheat and barley), yet the spread and cultivation of C4 millet may not have emerged in this region.
This PhD work is aimed at unravelling the plant exploitation in ancient eastern Baltic area with focus on two types of plant-derived materials: resinous materials and dietary plants. The main innovations are developing multi-methodological approaches and interpreting multi-proxy datasets with chemometric and statistical methods. For identifying the composition of resinous adhesives, ATR-FT-IR analysis was conducted in combination with a PCA-based DA classification model for further compositional and spatial/temporal classification. This method can help simplify IR spectra interpretation and reduce the need for GC-MS analysis. For identifying dietary plants, a multi-method approach was applied by plant micro fossil analysis and EA-IRMS combined with ORA. EA-IRMS can provide preliminary origins of samples with plant and/or animal bases. Plant micro fossil analysis and ORA in complementary can identify the species of plant remains. Correspondence analysis further compares and indicates the agreement of three methods and visualizes the correlations between the multi-proxy data The plant exploitation in prehistoric easter Baltic shows different patterns with dedicated multi-method case studies on several Stone Age, Bronze Age and Iron Age sites. In Stone Age, plant exploitation was more technological (adhesives and resinous compounds) than dietary-related. The plant consumption for dietary purposes became more abundant in the Bronze Age. The major changes happened with the Iron Age displaying more diverse plant-based diet with more inclusion of C3 cereals (e.g., wheat and barley), yet the spread and cultivation of C4 millet may not have emerged in this region.
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Keywords
plants (botany), edible plants, using, prehistory (Estonia), fossils, organic substanses, chemical analysis, Baltic States