Martin Finné
Ancient Civilisations and Climate - a three part movie
My main research focus is about understanding past climate and environmental
variability in the eastern Mediterranean region in general and the Peloponnese, Greece in particular. I am mainly working with the current interglacial period, the Holocene, i.e. the last ~11 000 years. I have mainly work with providing new data about how the climate has varied in the past but I am also interested in asking broader questions about how climate variability and change has affected human societies and the environment they are living in through history of mankind.
I have a PhD in Physical geography from the Department of Physical Geography, Stockholm University. I defended my thesis Climate in the eastern Mediterranean during the Holocene and beyond – A Peloponnesian perspective in 2014. Since November 2015 I work as a researcher within the research project Domesticated Landscapes of the Peloponnese (DoLP) at the Department of Archaeology and Ancient History, Uppsala University. The DoLP project geographically covers a NE-SW transect over the Peloponnese and in time we cover the period from the Neolithic to the Roman period, roughly 7000 years. Within the project I mainly work with available paleoclimate and paleoenvironmental records and with providing new data for areas of the Peloponnese that currently is not covered. Read more about DoLP
To understand how the climate has varied in the past I mainly work with speleothems from caves. Speleothems form slowly in their sheltered environment and can at the same time record information about the surrounding environment within and outside the cave. There is a vast number of different speleothems, such as stalactites, stalagmites, straws, curtains etc., but I mainly work with stalagmites, i.e. speleothems that grow from the floor toward the ceiling.
Stalagmites are formed in limestone areas when water supersaturated with calcite enters a cave void and is forced to release carbon dioxide resulting in the formation of solid calcium carbonate. The stalagmite is formed drop by drop over time. When the stalagmite forms information about the environment is brought in with the drip water and can be trapped in the calcium carbonate matrix when the stalagmite forms. The drip water originally comes from precipitation that, at some point, has fallen above the cave and then percolated through the soil and then the bedrock. Therefore, the drip water can contain tiny pieces of information about precipitation e.g. type and amount and also about conditions and activity in the soil. To get information about the precipitation I analyze stable oxygen isotopes (d18O) and to retrieve information about the vegetation I analyze stable carbon isotopes (d13C) in the growth layers of the stalagmite. I have also been involved in developing a new method to analyze stalagmites to find evidence for cave flooding.
To know when the speleothems have formed I date then using uranium-thorium dating. The method is essentially a radioactive stop-watch that starts counting upon deposition of a layer in the speleothem. The counting is then the radioactive decay of uranium into it daughter thorium which occurs at a known rate. A prerequisite for the method is the fact that uranium is soluble in water and thorium is not. This means that there will be small amounts of uranium in the drip water entering the cave but no thorium, and that uranium can get incorporated into the growing speleothem. The uranium then decays into to thorium. To date the speleothem small samples are collected at a number of levels in the speleothem and then the amount of uranium and thorium is measured using a high-precision instrument, and thus time elapsed since deposition can be calculated.
Currently I am working with speleothems from a cave located in SW Peloponnese. I am also trying to understand what the changes we see in the stable isotopes in the speleothems from the Peloponnese more exactly means in terms of precipitation change e.g. amount and season for rainfall. The overall aim of this research is to try and move from the relative measures we have today (today we can say it was wetter and drier) to more absolute measures of precipitation change. This is an important to be able to better understand how climate change affected people in the past. By knowing more about climate change I think we have better chances of studying and understanding the human decisions that are behind the societal change we can discern in e.g. archaeological material.
Publications:
Weiberg E., Unkel, I., Kouli, K., Holmgren, K., Avramidis, P., Bonnier, A., Dibble, F., Finné, M., Izdebski, A., Katrantsiotis, C., Stocker, S.R., Andwinge, M., Baika, K., Boyd, M., Heymann, C. 2016. The socio-environmental history of the Peloponnese during the Holocene: Towards an integrated understanding of the past. Quaternary
Science Reviews 136, 40-65.
Finné, M., Kylander, M., Boyd, M., Sundqvist, H.S., Löwemark, L. 2015. Can XRF scanning of speleothems be used as a non-destructive method to identify paleoflood events in caves? Journal of Speleology 44, 17-23.
Finné, M., Bar-Matthews, M., Holmgren, K., Sundqvist, H.S., Liakopoulos, I., Zhang, Q. 2014. Speleothem evidence for late Holocene climate variability and floods in Southern Greece. Quaternary Research 81, 213-227.
Weiberg, E., Finné, M., 2013. Mind or matter? People-environment interactions and the demise of early helladic II society in the northeastern Peloponnese. American Journal of Archaeology 117, 1-31.
Finné, M., Holmgren, K., Sundqvist, H.S., Weiberg, E., Lindblom, M. 2011. Climate in the eastern Mediterranean, and adjacent regions, during the past 6000 years - A review. Journal of Archaeological Science 38, 3153-3173.
Finné, M, Norström, E, Risberg, J, Scott, L. 2010. Siliceous microfossils as Late Quaternary paleo-environmental indicators at Braamhoek wetland, South Africa. The Holocene 20, 747-760.
Finné, M., and Holmgren, K. 2010. Climate Variability in the Eastern Mediterranean and the Middle East during the Holocene. In: Sinclair, P.J.J., Nordquist, G., Herschend, F., Isendahl, C., (Eds), 2010. The Urban Mind: Cultural and Environmental Dynamics 2010. Studies in Global Archaeology 15. Uppsala, African and Comparative Archaeology, Department of Archaeology and Ancient History, Uppsala University
Finné, M. 2009. Grottexpedition på Peloponnesos. Grottan 4. In Swedish only