Michael Friedrich

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We built a floating, 1382-ring pine chronology covering the radiocarbon age interval of 12,000 to 10,650 BP. Based on the strong rise of ∆ 14 C at the onset of the Younger Dryas (YD) and wiggle-matching of the decadal-scale ∆ 14 C fluctuations , we can anchor the floating chronology to the Cariaco varve chronology. We observe a marine reservoir correction(More)
We present OKEANOS, a distributed service-based agent framework implemented in Java, in which agents can act autonomously and make use of stationary services. Each agent's behaviour can be controlled individually by a rule-based knowledge component, and cooperation between agents is supported through the exchange of messages at common meeting points (agent(More)
Precise and direct dating of the Minoan eruption of Santorini (Thera) in Greece, a global Bronze Age time marker, has been made possible by the unique find of an olive tree, buried alive in life position by the tephra (pumice and ashes) on Santorini. We applied so-called radiocarbon wiggle-matching to a carbon-14 sequence of tree-ring segments to constrain(More)
The Greenland Stadial 1 (GS-1; ~12.9 to 11.65 kyr cal BP) was a period of North Atlantic cooling, thought to have been initiated by North America fresh water runoff that caused a sustained reduction of North Atlantic Meridional Overturning Circulation (AMOC), resulting in an antiphase temperature response between the hemispheres (the 'bipolar seesaw'). Here(More)
High-quality data from appropriate archives are needed for the continuing improvement of radiocarbon calibration curves. We discuss here the basic assumptions behind 14 C dating that necessitate calibration and the relative strengths and weaknesses of archives from which calibration data are obtained. We also highlight the procedures, problems, and(More)