Applying laser scanning technology to studying alluvial flume-bed topography in laboratory conditions

The aim of the research was to compare alluvial bed topography description in laboratory conditions using the “traditional”, currently applicable method with an original approach, based on LiDAR technology. LiDAR application in local scours shape investigation in based on the grounds of introducing the autonomic measuring module, which, placed above the bed on dedicated controllable arrangement of guideways, describes the landform as a cloud of coordinates. The result of the performed experiment was obtainment of point clouds (x, y, z), reflecting the bed shape before and after local scour formation during twenty measurement series with varying hydraulic conditions. Objects of the study were basic geometry properties of the scour hole and its volume. The measurement with laser scanner technology application allowed for obtaining much more accurate results in shorter time, comparison to disc probe survey, and also relatively fast conversion of numerical data into figures. The device equipped with portable computer, precise stepper motors and dedicated software permitted the introduction of automation into laboratory work. The effect is not only measurements accuracy, but also significant acceleration of data gathering. The adopted grid is characterized by significant density, which – in connection with meaningfully high accuracy – allows very precise surface description. Bed shape can be presented in numerical or graphical form. It must be pointed out that disc probe method application would never give such accuracy as in the case of introducing laser scanning technology in similar studies

Migration – Kommunikation – Transfer (Volume 1, Edition 1)

Der Band behandelt Fragen des gegenseitigen Austauschs sowie ethnischer, kultureller und religiöser Verflechtungen der mitteleuropäischen Länder und ihrer Bevölkerung. In zwölf Beiträgen von Archäologen und Historikern der Nikolaus-Kopernikus-Universität Torun spiegelt sich die Komplexität und Vielschichtigkeit dieser Problematik. Damit bilden sie den Auftakt einer neuen Schriftenreihe, die als ein Forum für den Austausch über die neueste wissenschaftliche Forschung zur Geschichte Polens im weit verstandenen mitteleuropäischen Kontext dient. In den jährlich erscheinenden Bänden werden komplexe Themen der Geschichte untersucht. This volume not only focusses on issues on mutual exchange but also on ethnic, cultural and religious ties of the Middle European countries and their citizens. The twelve contributions of archaeologists and historians from the Nicolaus Copernicus University in Toruń reflect the complexity of this issue. The authors therefore kick off a new series of journals which serve as a forum for the exchange on recent research on the history of Poland in the wider sense of the Middle European context. The annually published volume will analyse complex subjects of history

Discovery and preliminary results of research on a logboat from Lake Kromszewickie, Kujawsko-Pomorskie Voivodeship

The paper discusses the discovery of a logboat in Lake Kromszewickie. The description of circumstances of the discovery is preceded by a brief biological and geographical characterisation of the basin and a reference to the findings of archaeological fieldwalking. Further in the article, a detailed description of the site and the discovered object is presented. The dugout, resting at a depth of approx. 7 m, is 4.25 m long and 0.42 m wide. At a short distance from it, a bovine horn and deer antlers were found. Based on the typology by W. Ossowski, it can be carefully assumed that the described logboat matches the characteristics of similar objects from the 14th century

The use of acoustic and magnetic methods in the search for archaeological objects through the example of Lednica lake

Noninvasive surveys and prospections are a new dynamic trend in contemporary archaeology. They represent a trend of multidisciplinary analyses of cultural heritage. Due to limited access to technology, these methods are still not widely used in underwater archaeology, in particular in inland reservoirs. For this reason a team from the Department of Underwater Archaeology of the Institute of Archaeology at Nicolaus Copernicus University in Toruń in cooperation with the Maritime Institute in Gdańsk, the Museum of the First Piasts at Lednica and the Scientific Association of Polish Archaeologists (Warsaw branch), planned and completed a project Kolebka Piastów — archeologiczne prospekcje podwodne w rejonie jeziora Lednickiego in 2017. The project was financed by the Ministry of Culture and National Heritage under the following programme: Cultural heritage, priority: The protection of archaeological monuments. In the course of the project a multibeam probe, a subbottom profiler and a magnetometer were used to conduct surveys. If the conditions and assumptions of the project allowed, a direct underwater verification was conducted. Due to multibeam sonar it is possible to obtain a reliable spatial picture of a lake bottom in high resolution, e.g. 100 or more measurement points for each m2 of the bottom, which enables one to conduct a detailed overview of a surface of the research area and objects lying on it. This method turned out to be the most effective during verification and resulted in the localization of a new medieval bridge in Lednica lake. Using a subbottom sediment profiler is at the moment the only noninvasive method of searching for non-magnetic objects sunk into the bottom. After applying it on a recognized object, such as the Poznań bridge, and after receiving the positive results, it may be assumed — with high probability — that this technology will succeed in the search for other wooden archaeological structures located in subbottom sediments. Magnetometric measurements are the next technology which was used in the researched reservoir. They are indispensable when noninvasive large scale searches of metal objects with magnetic signatures are conducted e.g. the objects made of iron or steel. In the area of Lednica lake several objects with a magnetic signature were localized. In the course of research in Lednica, three types of noninvasive prospections were applied: hydroacoustics (a multibeam probe), seismology (subbottom sediment profiler) and magnetics (Caesium magnetometer). Each of these methods helps to localize other objects and gives very interesting results; however, only after all three have been used is it possible to obtain a precise picture of the bottom of the lake together with anomalies, which to a large extent can have anthropogenic origins. It seems that the future of underwater archaeology is closely related to the described noninvasive surveys. Unfortunately it will be more difficult to achieve in shallow inland reservoirs than in sea waters, where these technologies have already been introduced for some time now

Bridge crossing to Ledniczka island. Preliminary research results

Advanced noninvasive research carried out in “The cradle of the Piasts: archaeological underwater prospections in the area of Lednickie Lake” (“Kolebka Piastów archeologiczne prospekcje podwodne w rejonie Jeziora Lednickiego”) project, provided a new collection of artefacts and archaeological sites. In the first stage of the project an archive research was carried out and it showed that there are 61 archaeological sites of different character and chronology in the close proximity to the lake. In the further part of the project, non-invasive research with the use of a magnetometer, a multibeam sonar and a subbottom profiler were conducted. This stage of the project was possible due to cooperation between the team from the Maritime Institute in Gdańsk, which was conducting hydroacoustic research, and underwater archaeologists. In the course of the survey of bathymetric anomalies between Ledniczka island and the west coast of the lake, construction elements were identified. Therefore, the terrain between an island and the mainland was thoroughly searched in order to verify the object which was found. During the search of the bottom by the divers in the designated place, more horizontal structural elements were identified. Localizing vertically impaled wooden constructions identified as piles, was the key point. These elements confirm that in the described place, there was a third bridge on Lake Lednica. Samples for dendrochronological and radiocarbon dating were collected from the P1, P4, P5 piles and V object. Only the sample from object V was suitable for dendrochronological dating, as it did not contain a sapwood layer. As a result it was possible to determine the date when the tree was cut, i.e. after 1293, hence most probably at the turn of 13/14th centuries [Ważny 2017]. Sample wood from pile 1 was subject to radiocarbon dating and the 1085±30 BP date was obtained. After calibration it can be said that it is 68.2% probable that the analyzed material comes from 900–993 (900–922: 22.3%; 948–993: 45.9%). Whereas it is 95.4% probable that it comes from 894–1016 (894–932: 30.5%; 937–1016: 64.9%) [Goslar 2017]. In conclusion, it can be said that during the research, the relics of the bridge leading from the mainland to Ledniczka island located on the W–E axis were localized. The crossing is located at the narrowest place between an island and the mainland. This is around 100 meters and this is the probable length of the bridge. On the basis of the variety in the degree of wood conservation, as well as diverse shapes of the construction elements, and especially the obtained dates from the radiocarbon and dendrochronological datings, it can be assumed that there are two bridge crossings which date to the 10th century and the turn of the 13th and 14th centuries. During the 2017 research season an interesting discovery was made. After several seasons of underwater works, a new object was localized and identified as bridge relics. It shows the great archaeological potential of Lednica Lake and how the use of new noninvasive methods can lead to spectacular discoveries. The bridge relics were only identified on the surface level, therefore it is difficult to draw far-reaching conclusions. However, dendrochronological dating makes it possible to determine the origins of the bridge to the 13th/14th century. Militaria found near the bridge are also from this period. The C14 date, which estimates the age of one of the piles for the 2nd half of the 10th century, is very interesting. It can indicate that there were two bridges with different chronology. However, in order to confirm this, further excavation works must be conducted

Manufacture technology of early medieval sword and hammer axe from the relics of the bridge leading to the Ledniczka island on Lake Lednica in the light of archaeometallurgical investigations

Dwa egzemplarze wczesnośredniowiecznej broni odnalezione w reliktach mostu wiodącego na wyspę Ledniczkę na jeziorze Lednica zostały poddane nieinwazyjnym badaniom archeometalurgicznym. Przeprowadzone analizy pozwoliły na ustalenie metod fabrykacji oręża oraz określenie materiałów, które wykorzystano do jego wykonania. Oba przedmioty są wyrobami kompozytowymi odkutymi ze stopów żelaza o różnych właściwościach. Zarówno miecz, jak i czekan były bogato zdobione metalami żelaznymi i nieżelaznymi. Wykonane badania pozwoliły w większości na odtworzenie pierwotnego wyglądu tych ornamentów.Two early medieval weapons discovered within the relics of the Ledniczka bridge on Lake Lednica were subjected to non-invasive archaeometallurgical investigations. The conducted analyses allowed to determine the methods of their manufacture, as well as the characteristics of materials that were used in their making. Each specimen was a composite product forged from iron alloys of varying properties. Both the sword and the hammer axe were richly decorated with ferrous and non-ferrous metals. The research allowed in most parts to recreate the original appearance of these ornaments

Medieval wicker fish trap ('wiersza') from the area of the west bridge in Ostrów Lednicki

In the 2015 season, the underwater research in Lake Lednica focused on further exploration of two exploration plots of the Poznań bridge — 7 in the XCV area and 5 in the XCIII area and on the opening of a trial trench in the area of Ostrów Lednicki island. During the exploration of plot 5 in the XCIII zone, the wicker object in a radiating out shape was localised. Because of its archaeological value and the need of further exploration, the object was excavated and handed over to the Museum of the First Piasts at Lednica for preservation. The excavated object is probably a trap, a type of fish trap called ‘wiersza’ (a wicker fish trap). During examination of the object and cleaning after excavation, a great number of animal bone remains were collected and analysed. They almost exclusively came from fishes. In the bone material, the remains of several fishes were found: a catfish, eight perches, a pike, the fishes of the Cyprinidae family, including at least two roaches, as well as three remains of a pig. In the case of a catfish and the perches there were elements from all parts of the skeletons, while several bones belonged to two roaches and there was one pike tooth. The latter element was probably included in the assemblage accidentally. The conducted analysis shows that the catfish with SL (standard length) 70–75 cm and the perches, in most cases the large ones with SL=35–45 cm, were trapped in the fish trap. It is, however, not certain whether the roaches caught in the trap or had earlier been caught by predatory fish or fishes found in the trap. It is suspected that a phalanx and two ribs of a young pig, which probably come from the same animal, are the remains of a fishing bait placed in the wicker fish trap. Radiocarbon dating of the organic material which the object was made of indicates that it was placed after the bridge was no longer in use, probably in the late 12th or the early 13th century. For unspecified reasons the described wicker fish trap was not emptied and was left among the relics of the early medieval bridge. The discovery of the remains of the wicker fish trap and the analysis of its contents brought new information about one of the ways of fish harvesting used by the inhabitants of the area of Lake Lednica and its efficiency

Early medieval fishery of the inhabitants at Ostrów Lednicki based on underwater survey materials

Połów ryb był jednym z powszechnych sposobów pozyskiwania pożywienia we wczesnym średniowieczu. Znaczenie tego pokarmu rosło wraz z upowszechnianiem się chrześcijaństwa i wymogiem przestrzegania postów. Stąd także w przypadku mieszkańców Ostrowa Lednickiego rybołówstwo musiało być powszechną i codzienną praktyką zdobywania pożywienia. Dzięki wieloletnim podwodnym badaniom archeologicznym prowadzonym w jeziorze pozyskano zbiór ponad 30 przedmiotów identyfikowanych jako narzędzia związane z rybołówstwem. Natomiast analiza szczątków kostnych znalezionych podczas badań lądowych dała możliwość rekonstrukcji składu gatunkowego ryb i preferencji kulinarnych mieszkańców Ostrowa Lednickiego we wczesnym średniowieczu. Pozwala to, w oparciu o dane z obydwu obszarów badań, rekonstruować ów ważny fragment życia wczesnośredniowiecznych mieszkańców okolic jeziora Lednica, jakim było rybołówstwo.Fishery was one of the common ways of obtaining food in the early Middle Ages. The importance of this element grew along with the spread of Christianity and the requirement to observe fasts. This way of obtaining food must have been common for the inhabitants of Ostrów Lednicki as well. A collection of more than 30 objects identified as fishing equipment was obtained through years of underwater archaeological research. The analysis of skeletal remains found during land surveys has provided an opportunity to reconstruct the composition of fish species and culinary preferences of the inhabitants of Ostrów Lednicki in the early Middle Ages. By combining these two types of sources, it is possible to reconstruct that part of the life of early medieval people which was made up of fishery