The Piora Oscillations are two cold periods in the Alpine climate history of the Holocene Epoch. Piora 1-O. is dated by Heinz Zoller and other scientists to -5300 to -5000 conv. BP, calibrated from 4138 ± 113 to 3796 ± 109 BC. Piora 2-O. is dated to -4800 to -4400 conv. BP, calibrated both using OxCal 4.4 (Christopher Bronk Ramsey) from 3569 ±119 to 3081 ±150 BC. It clearly shows up e. g. in the NGRIP and other Greenland Icecores.
The phenomenon is named after the Val Piora (Piora Valley) in Switzerland, where it was first detected.Lamb, pp. 124, 128, 143.
The water level of Lake Constance in the Alps show a considerable history of variations as reconstructed from sediment and pollen analysis. In 5,375 BP (3,375 BCE) there occurred an abrupt rise in lake level at the archaeological site of Arbon-Bleiche 3, indicating a cooling of the temperatures. This caused an abandonment of this prehistoric lake-shore location.
Two stages of Piora Oscillation, Piora 1, and the later Piora 2 are suggested in recent literature. The Piora 2 oscillation, also called Rootmos 2, refers to the transition between Late Atlantic and Subboreal around 3500 BCE. This period also coincides with the transition between the Pfyn and Horgen cultures in Switzerland.Celine Maicher, Matthieu Le Bailly 2024, The impact of climate change upon intestinal parasites in central Europe during the 4th millennium BCE. Quaternary Science Reviews. Elsevier.
See also Bond event 4.2-kiloyear event Bølling–Allerød warming African humid period Older Peron
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