Gymnasielærerdag 8/ Hvad kan vi lære af effekten af tidligere tiders dramatiske klimaændringer?

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1 Gymnasielærerdag 8/ Hvad kan vi lære af effekten af tidligere tiders dramatiske klimaændringer? Diet of man, aurochs and the earliest cattle in Denmark, evidenced from 13 C and 15 N stable isotopes, indicate a dramatic change in palaeoenvironment due to a relative sea level fall a little after 6000 cal yr BP This sea level change occurred at the Mesolithic/ Neolithic transition contemporary with a rapid change of the coastline during spit and beach ridge formation. Preboreal 11,000 years BP Atlantic 9,000 years BP Havniveau Nanna Noe Nygaard Institut for Geografi og Geologi Warmer Holocene ( ca. 2 o average) resulted in the rapid sea level rise: The Littorina transgressions from c yrs ago. Can we use these events to predict the possible effects of a future sea level rise resulting from global warming and melting of the ice caps? Klima Imperia in N. Italy

2 Isostasi The traditional view of the two cultures Neolithic Mesolithic

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4 Mike Richards % Individer med karierede tænder Tre vanskelige spørgsm rgsmål vedrørende rende neolitiseringen 20 Er den mesolitiske befolkning identisk med den neolitiske? Kan genetiske, miljømæssige og kulturelle påvirkninger p adskilles? 5 0 Meso Tid Neo Neo Jernalder Viking Middelalder Medførte agerbrugets indførsel helbredsmæssige ssige ændringer? Tandreduktion af permanente tænder Jægerstenalder Bondestenalder - 4,91 % Jernalder - 6,90 % Middelalder - 11,99 % AD % Nutidsbefolkning % Sum af kronearealer af hjørnet rnetænder, nder, små kindtænder nder samt 1. og 2. kindtand square mm Tooth crown areas Maxillary teeth

5 Generelle træk: menneske lemmeknogler En mindre nedgang af længden fra Mesolitikum til tidlig Neolitikum. En fortsat forøgelse af længden til mellem og Senneolitikum, til Broncealder? og til et maximum i Yngre Romersk jernalder. En nedgang af længden i Vikingetiden. Det blev fulgt af en forøgelse i Middelalderen. Pia Bennike 2008 Legemshøjde gennem forhistorisk tid, middelalder og nyere tid I Danmark udregnet fra lårbenslængde (Trotter & Gleser 1958) Bennike 1993

6 What forced the Mesolithic Neolithic transition from hunter gatherers to farmers What happened at the Transition to man and dog? The role of climatic and environmental changes Had sea level changes anything to do with it? The earliest cattle domesticated late aurochs? Was the Elm decline a trigger for the first appearance of domestic cow and agriculture in Denmark at around 4000 BC? Were the differentiation and specialization in the Late Ertebølle culture paving the way for introduction of a new cultural époque? Or was the early Neolithic farmers emigrants from the first Near East Farmer immigrants New DNA data from human bones indicate closer connection of the early Neolithic farmers to the Near East population than to the standing Ertebølle population in Denmark Funded by the Carlsberg foundation Project founded by the Carlsberg Nanna Noe Nygaard Department of Geography and Geology, University of Copenhagen, Denmark

7 Urokser Tamokser

8 C years BP δ 13 C Bos primigenius Bos domesticus

9 δ 13 C values on food in open and closed environments (Mikkel Ulfeldt Hede) Gammellyng I Sandhuse II

10 Aurochs DNA from Danish aurochs 11 positive out of 40 tested samples. Range in time from to C yr BP. In total 10 haplotypes are found in the 11 Danish and the 4 English aurochs material. Seven haplotypes are up till now found in the Danish material. Cow Hvad ved vi om klimaet gennem Ældre Stenalder

11 Dorthe Dahl Jensen Dorte Dahl-Jensen et al. Science 282, p , 1998 Temperatur og havniveau gennem 600 myr Efter Marshak 2001 og Ruddiman 2000

12 Havniveau ændringer Nordsø S Storebælt

13 Storebæltskurven Aldrene er i BC kalender år C. Christensen 1997 Eustatic and relative sea level (After A. L. Coe, 2003)

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15 KLINTEBJERG Kattegat Sea Tengslemark 2,5m a.s Højby Sø 5.2m ȧ.s 10m a.s Topography Mikkel U. Hede (KMS G15 03)

16 Sea level, base level and groundwater flow during sea level rise Kattegat Sea (Mikkel Ulfeldt Hede) Tengslemark: Climate and sea level changes recorded in lake sediments Lake Tengslemark Mose Foto: M. Mortensen (Redrawn and modified from M. Mortensen, unpublished data) Climate proxies Lake sediments 14 C datings Sea level changes Correlation/ice cores Palaeoecology Pollen analyses Diatoms analyses

17 Transition between marine and lake deposits Lake Marine Transition Tengslemark Littorina transgression reconstructed from cored profiles and TS Freshwater Lake Beach Sea barriere Brackish fjord (Mikkel Ulfeldt Hede)

18 14 C dates Tengslemark geochemistry and sediment accumulation rates wt%

19 Sediment deposition and sea level (W.F.Rudimann) (Modified Berner&Raiswell 1984) Model Anoxic Marine Brackish water Brak Oxic normal marine Fresh water Fersk

20 Pollen and geochemistry Ivy Misteltoe (Morten F.Mortensen) Grass-covered beach meadows with summer cattle

21 Elme fald 3965 BC 3895 cal. yr. BC 4700 cal. yr. BC TS % TOC TOC % TS depth (cm)

22 Late Mesolithic forest cover Early Neolithic beach meadows Boreal/Early Atlantic mammal diversity in the Åmose basin c. 9,000 BP Late Atlantic mammal diversity in the Åmose basin c. 6,000 BP 20,82 20,17 23,26 23,56 22,53 22,53 23,57 23,44 22,17 21,79 23,84 22,35 24,44 25,35 20,45

23 1. The Littorina transgression could directly be detected m above present day sea level on NW Sjælland by increasing TS and TOC values. 2. The salt water input occurred either as wash over pulses or by influence of salty ground water Former sea 3. The contemporary rise in sea and ground water level meant renewal of a number of shallow inland lake basins by rising lake levels and transgression of the rim of the lakes and low laying, grass and herb covered suitable areas for foraging. 4. Regression during late marine highstand created new marine foreland overgrown with beach meadows; a perfect location for cattle breeding. Lille Vildmose 5. During this a large regression raised bog new spit and beach ridge systems rapidly developed, closing fjords and lagoons by sediment fill resulting in restricted water circulation and loss of marine mollusc and fish species. 8 m above Sea leavel sea level 8 m above present day

24 Present day sea level 0 m N Lille Vildmose

25 Lille Vildmose: Airborn laser scanning image of the spit and beach ridge systems Lille Vildmose Spit ridge succession

26 Beach ridges Swales/Dobbe Ridge/Ribbe

27 Bos primigenius/taurus 15N/14C years BP Sjælland δ 15 N/time C Years BP ,00 3,50 4,00 4,50 5,00 5,50 6,00 6,50 7,00 7,50 8,00 delta 15 N Bos primigenius Bos taurus

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