Buried amber finds in the coastal deposits of Saaremaa Island, eastern Baltic Sea – their sedimentary environment and possible use by Bronze Age islanders

• Published in: Boreas 2017-10, Vol.46 (4), p.725-736
• Main Authors: Nirgi, Triine, Rosentau, Alar, Ots, Mirja, Vahur, Signe, Kriiska, Aivar
• Format: Article
• Language: English
• Subjects: Amber; Aquatic plants; Archaeological sites; Archaeology; Baltic amber; Biological settlement; Bronze Age; Coastal plains; Coastal zone; Coastal zones; Deposits; Fieldwork; Geochronometry; Historic sites; Holocene; Infrared analysis; Infrared spectra; Infrared spectroscopy; Isotope composition; Isotopes; Marine sediments; Organic matter; Radiocarbon dating; Radiometric dating; Sediments; Seeds; Spectra; Stable isotopes; Stone Age
• ISSN: 0300-9483; 1502-3885
• DOI: 10.1111/bor.12236

Here, we present new sedimentary data of the amber bearing layer from the Holocene coastal plain on the SW Saaremaa Island where amber is not known in sedimentary successions but is common in Stone Age and Bronze Age archaeological sites. A layer of buried organic matter (BOM), sandwiched between sandy coastal deposits and containing pieces of natural amber, was discovered during fieldwork and analysed in detail. Results show that the BOM layer is buried under approximately 90‐cm‐thick sandy coastal deposits and consists of the remains of different coastal plants. Palaeogeographical reconstructions and sediment compositions indicate that the layer was deposited in the coastal zone and buried quickly by sandy marine sediments. According to AMS radiocarbon dating of knotgrass seeds (Polygonum lapathifolium), deposition of the BOM layer took place in the Late Bronze Age; about 2.7–2.5 cal. ka BP. Infrared spectra and isotopic composition of the analysed amber from the BOM layer indicate Baltic amber, also known as succinite. The stable isotope ratio indicates the origin of the amber to be south of Estonia. Therefore, it is proposed that the amber was probably transported to Saaremaa within organic matter (along the main SW–NE orientated current flows) from the SE coast of the Baltic Sea where secondary Baltic amber deposits are known to exist widely. Amber items are common in Late Bronze Age settlement sites and burials in Saaremaa and are considered to originate from present‐day Latvia, Lithuania, Kaliningrad district (Russia) and Poland. The current study shows that during the Late Bronze Age natural amber accumulated in the coastal zone of Saaremaa Island and that the islanders could collect it. Therefore, the possibility exists that some Bronze Age archaeological amber objects could be made of local material as opposed to being a result of trade with southern neighbours, as formerly thought.