The German Outwash Terraces and the Astronomical Theory of the Ice Age

Abstract

THE revision of the astronomical theory of the Ice Age, usually associated with the names of Adhemar and Croll, and its recasting in a form which seems to show considerable correspondence with the observed facts of geology,¹ has led Prof. Soergel to attempt an interpretation, in terms of this theory, of the complex terrace system of certain German rivers. The Köppen-Wegener curves for the secular variation in summer sunshine for latitudes 55°–65° show four well-marked double minima, corresponding to the four ice ages of the Alps, Günz, Mindel, Riss and Wiirm, and three intervening periods of variable but on the whole warmer conditions, supposed to be identical with the interglacial periods. The double character of the minima and the excessive length of the middle interglacial period give some grounds for confidence, for it will be remembered that Penck established on geological evidence a double maximum for the Würm Ice Age and proved that the Mindel-Riss Interglacial Period was several times as long as those which preceded and followed it.

Die Gliederung und absolute Zeitrechnung des Eiszeitalters.

Von Prof. Dr. W. Soergel. (Fortschritte der Geologie und Paläontologie, Heft 13.) Pp. vi + 125–251 + 3 Tafeln. (Berlin: Gebrüder Borntraeger, 1925.) 8.25 gold marks.