ИСТИНА

Palaeosoils of buried historical agricultural fields, as well as Stone (ca. 3100 BC) and Bronze Age (ca. 700 BC) settlement sites were studied in northern Estonia using a set of archaeological, palaeobotanical and geoarchaeological methods, including sedimentological and soil geochemical analyses, AMS radiocarbon and luminescence dating, and ground penetrating radar study. The National Geographic Society funded the research. According to radiocarbon dates, this area was used for slash-and-burn agriculture from ca. 2000 BC until ca. 1400 AD. Fields were arranged on top of the mid-Holocene coastal landform system, consisting of seaward‑dipping beach deposits and covered by coastal dunes, which developed during the coastal retreat at ca. 5500–5000 BC. Sandy palaeosoils of agricultural fields are characterized by low organic C content, depleted P, Sr and Fe concentrations, and well-developed soil profiles suggesting podzolisation. Palynological and phytolith analyses showed that wheat, barley, rye, millet and perhaps hemp or hops were grown there. Up to 3-m-thick layers of dune sand covering the fields accumulated rather quickly and were probably not related to intensive agricultural land use. According to the combined luminescence age, based on seven datings, this took place around 1524–1581 AD. The development was most likely caused by catastrophic deforestation due to tree felling and/or forest fires, followed by reactivation of old dune sands. It is possible that the complete destruction of forests in the area was the result of the raid or siege of the nearby town and castle of Tallinn by the troops of the Grand Duchy of Moscow during the Livonian War (1558–1583) between 1560 and 1577 AD.