Markku Oinonen, docent, Director of Laboratory

Throughout the ages, nature has affected human activities. Laboratory of Chronology produces age determinations of past human activities as well as larger dating models and chronologies of past events. Based on philosophy of science cause occurs before effect, therefore timelines give rise to reflections on cause-and-effect relationships. Recent examples of research on interactions between humans and nature are the breakthrough of Vuoksi river and the Northern Hemispheric climate anomaly 1500 years ago and its effects on the lives of Levänluhta people.

In Eastern Fennoscandia human settlements followed the edge of the melting ice cap already over 10000 years ago. In the Middle Holocene 8000-5000 years ago the climate was on average a couple of degrees warmer than today, and at the same time human population in the area was at its highest. Breakthrough of lake Saimaa through Salpausselkä towards Lake Ladoga also dates to this era. As a consequence, Vuoksi river was born and water level of Saimaa fell 4 meters. This environmental disaster affected the area by revealing thousands of square kilometers of land which, by being biodiversically rich, also strenghtened the human settlements in Eastern Finland. By dating the origin of Vuoksi river and the cultural changes of that era, one can consider what kind of effects natural phenomena have on local settlements.

During the Iron age 1700 - 1300 years ago a number of deceased people were sunk into a spring grave in Levänluhta, Isokyrö. The bones of the corpses have stored information about the food they ate through the isotopes of carbon and nitrogen. About 1500 years ago almost the whole Northern Hemisphere was covered by a "mystery cloud", which also dimmed the sun in Mediterranean sea for 18 months. This climate disruption, which can also be seen in tree rings, coincided with Levänluhta burials and therefore might have affected the way these people were living. By combining the radiocarbon datings and isotope determinations from tree rings and from the bones of the corpses, one can speculate about the role of the "mystery cloud" in the temporal changes of how the levänluhta people were living.

Oinonen M, Pesonen P, Tallavaara M (2010) Archaeological Radiocarbon Dates for Studying the Population History in Eastern Fennoscandia. Radiocarbon 52: 393–407.

Tallavaara M, Pesonen P, Oinonen M (2010) Prehistoric population history in eastern Fennoscandia. J Archaeol Sci 37: 251–260.

Pesonen P, Oinonen M, Carpelan C, Onkamo P (2012) Early Subneolithic ceramic sequences in Eastern Fennoscandia - a Bayesian approach. Radiocarbon 54(3-4): 661–676.

Oinonen M, Pesonen P, Alenius T, Heyd V, Holmqvist-Saukkonen E, Kivimäki S, Nygrén T, Sundell T, Onkamo P (2013) Event reconstruction by timing – Massive mid-Holocene lake burst triggered a large-scale ecological and cultural change. Submitted.

Wessmann A et al. (2011) The Levänluhta site – Multidisciplinary research into a unique mystery in Northern European prehistory. Funding decision by Emil Aaltonen foundation for 3-year project 2012–2014.