Natural Sciences and Geoinformatics Together Give a Clue about the Past

Location of study areas: Narva-Luga Klint Bay, Tallinn city centre and Ruhnu
Island; and apparent land uplift (relative to rising sea level) isobases (Ekman, 1996). Source: Merle Muru doctoral thesis
Location of study areas: Narva-Luga Klint Bay, Tallinn city centre and Ruhnu Island; and apparent land uplift (relative to rising sea level) isobases (Ekman, 1996). Source: Merle Muru doctoral thesis

In the Baltic Sea region, many Stone Age shore-connected settlement sites have been found, which are presently located far from the seashore. The post-glacial land uplift has caused this situation.

Recently, geographer and specialist in geoinformatics at the University of Tartu, Merle Muru (PhD), defended her doctoral thesis[1], where she used data from natural sciences and the methods of geoinformatics to prove archaeological hypotheses about Stone Age settlement patterns and preferred settlement locations, specify the period of shore-bound habitation and adaption of Stone Age people on different types of coasts in Estonia and adjoining areas.

Muru said that these kinds of studies and new information help us to understand our prehistory and cultural heritage. “Where did people live during the Stone Age? Without this knowledge, we would be in the dark,” she explained.

Toes in the Water

In her thesis, past sea level changes and palaeolandscapes around Stone Age settlement sites in Narva-Luga lowland, Tallinn city centre and on Ruhnu Island were reconstructed in order to define the location of the settlements compared to their contemporary shoreline and coastal setting. The geographic information system approach was used for palaeogeographical modelling based on the spatio-temporal correlation of datasets originating from several natural science and archaeological research disciplines.

“With our workgroup that consists of geologists, geographers and archaeologists we carried out geological corings and looked for sediments that indicate past coastal environments, and defined the ages of these. I put this sediment data together with archaeological findings onto the map and to the models and reconstructed the past sea level changes and shoreline configuration. This enabled us to describe the lifestyle and adaptions of the Stone Age human community,” she described.

Palaeogeographical reconstructions show that in Narva-Luga area, hunter-fisher-gatherer settlements were located on the shores of a large lagoon, which existed there ca 7,000–5,000 years ago. On Ruhnu Island, hunting and fishing camps were established directly in the beach zone, only a few metres above sea level at about 7,200 and 6,200 years ago. Similarly, in Tallinn, 5,000 years ago, a camp was established on the beach of the wide palaeo-bay, the shore of which crossed the city centre at that time.

“People literally lived toes-in-the-water, and Narva lagoon reflects that they preferred shores with calm water. The studies about Tallinn and Ruhnu show that for hunting and fishing camps they used open shores as well and adapted to higher waves,” she noted.

The reconstructions showed that this settlement pattern changed ca 4,700 years ago, when areas away from the coast were chosen for habitation, indicating a shift in subsistence strategy towards farming.

Palaeogeographical reconstructions of Narva-Luga Klint Bay. a) The Litorina Sea at the beginning of the transgression and the earliest known Stone Age sites in the area at c. 8.0 cal. ka BP. b) The Litorina Sea after the transgression and the beginning of the coastal settlement at. c. 7.0 cal. ka BP. c) The Litorina Sea lagoon environment and hunter-fisher-gatherers’ coastal settlements c. 6.0 cal. ka BP. d) The Post-Litorina Sea, overgrowing of the lagoon and Neolithic farmers’ riverbank settlements c. 4.5 cal. ka BP. Source: Merle Muru’s thesis

Palaeogeographical reconstructions of Narva-Luga Klint Bay. a) The Litorina
Sea at the beginning of the transgression and the earliest known Stone Age sites in thearea at c. 8.0 cal. ka BP. b) The Litorina Sea after the transgression and the beginning of
the coastal settlement at. c. 7.0 cal. ka BP. c) The Litorina Sea lagoon environment and
hunter-fisher-gatherers’ coastal settlements c. 6.0 cal. ka BP. d) The Post-Litorina Sea,
overgrowing of the lagoon and Neolithic farmers’ riverbank settlements c. 4.5 cal. ka
BP. Source: Merle Muru’s thesis

 

Important for Knowing the Future

What is more, knowing the sea level changes of the past gives knowledge about the future— the sea can change similarly. “Since the last Ice Age, the territory of Estonia has been rising, but the global sea level has done the same. We are now approximately at the zero-point. The rising of land has become slower and the rising of the sea level has accelerated. How fast are we going to lose coastal regions? Using our knowledge about the past sea level changes, we can predict the future better,” Muru explained.

She also noted that Estonian northern and western coasts are changing differently because of the prevailing winds and different land uplift rates. “Signs of past storms are recorded in sediments. When we learn to read these, better forecast of future storms is possible,” she said, and added that Estonia is a good place for testing and developing the methods for modelling coastal changes, because its coastline is long and variable.

Muru and her colleagues continue palaeogeographical reconstructions of Stone Age settlement sites in Hiiumaa, Saaremaa and Jägala, to find more data about past sea level changes.

Furthermore, in her thesis, Muru reconstructed the coastlines for known archaeological sites, but it also works vice versa—she reconstructs the past coastlines for archaeologists to know where to go and look for new findings.

Aivar Kriiska, professor of laboratory archaeology at the University of Tartu, said that the value of the collaboration lies in interdisciplinarity. “It is not usual, that all partners benefit from collaboration, but for us, it works. connecting data and methods of archeology, geology, and geography we have reached to scientific discoveries of both human and natural history,” he explained and added that multiproxy of collaborative research, but also accuracy and cooperation during the whole research is the basis of new quality.

[1] Merle Muru, Doctoral Thesis, 2017, (sup) Raivo Aunap; Alar Rosentau, GIS-based palaeogeographical reconstructions of the Baltic Sea shores in Estonia and adjoining areas during the Stone Age, University of Tartu, Faculty of Science and Technology (old), Institute of Ecology and Earth Sciences, Tartu University. URL: http://www.geograafia.ut.ee/et/uudised/merle-muru-doktoritoo-kaitsmine-senati-saalis

This article was funded by the European Regional Development Fund through Estonian Research Council.