Waalian interglacial

The Waalian interglacial (German: Waal-Warmzeit or Waal-Interglazial) [1] or Waalian Stage was an interglacial period of the Early Pleistocene in north-west Europe. It was preceded by the Eburonian Stage and succeeded by the Menapian Stage. It coincides with part of the much longer Beestonian stage in Britain.[2] It is variously dated by different authorities. Oxford Reference gives 1.3 to 0.9 million years ago[3] and the British Geological Survey 1.6 to 1.36 million years ago.[2] However, the 2020 chart of the international authority on stratigraphic dating, the International Commission on Stratigraphy shows it as c. 1.6 to 1.4 million years ago.[4]

Its name is derived from a major branch of the Rhine delta, the Waal.

Distinguishing features

Unlike later interglacial periods, the Waalian Interglacial had periods of permafrost conditions, making it a "complex stage".[5] The Waalian Interglacial is also distinct from later interglacial periods in that the migration of tree species during this period did not follow a clear pattern of succession (i.e., most of the species that were present at the end of the Waalian were there at the beginning)[5]. In addition, pollen records show that there was a marked decrease in the number of arboreal taxa from earlier Pleistocene periods.[6]

References
  1. Zagwijn, W.H., 1960. Aspects of the Pliocene and Early Pleistocene vegetation in the Netherlands. Mededelingen Geologische Stichting, Serie C-III-l, 5: 178 pp.
  2. "Waalian Stage". British Geological Survey. Retrieved 28 November 2021.
  3. "Waalian". Oxford Reference. Retrieved 28 November 2021.
  4. "Global chronostratigraphical correlation table for the last 2.7 million years v. 2020b". International Commission on Stratigraphy. Retrieved 28 November 2021.
  5. Zagwijn, Waldo H. (1992-01-01). "The beginning of the Ice Age in Europe and its major subdivisions". Quaternary Science Reviews. 11 (5): 583–591. doi:10.1016/0277-3791(92)90015-Z. ISSN 0277-3791.
  6. Hahne, Jürgen; Ellwanger, Dietrich; Stritzke, Rüdiger (2009-04-01). "Evidence for a Waalian thermomer pollen record from the research borehole Heidelberg UniNord, Upper Rhine Graben, Baden-Württemberg". E&G Quaternary Science Journal. 57 (3/4): 403–410. doi:10.3285/eg.57.3-4.7. ISSN 2199-9090.
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