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The Riss glaciation, Riss Glaciation, Riss ice age, Riss Ice Age, Riss glacial or Riss Glacial (german: Riß-Kaltzeit, ', ' or (obsolete) ') is the second youngest
glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betw ...
of the
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
epoch in the traditional, quadripartite glacial classification of the Alps. The literature variously dates it to between about 300,000 to 130,000 years ago and 347,000 to 128,000 years ago. It coincides with the glaciation of North Germany. The name goes back to and who named this cold period after the river in
Upper Swabia Upper Swabia (german: Oberschwaben or ) is a region in Germany in the federal states of Baden-Württemberg and Bavaria.''Brockhaus Enzyklopädie.'' 19. Auflage. Band 16, 1991, p. 72. The name refers to the area between the Sw ...
in their three-volume work ' ("The Alps in the Ice Age") published between 1901 and 1909.


Boundaries and division

The Riss glaciation was defined by Penck and Brückner as the Lower (''Niedere'') or Younger Old Moraines and Old Terminal Moraines High Terraces (''Jüngere Altmoränen und Alt-Endmoränen-Hochterrassen''). The type locality lies near
Biberach an der Riß Biberach an der Riß ( Swabian: ''Bibra''), often referred to as simply Biberach (), is a town in southern Germany. It is the capital of Biberach district, in the Upper Swabia region of the German state (Land) of Baden-Württemberg. It is calle ...
where the end of the northeastern
Rhine Glacier The Rhine Glacier was a glacier during the last glacial period and was responsible for the formation of the Lake Constance Lake Constance (german: Bodensee, ) refers to three bodies of water on the Rhine at the northern foot of the Alps: Uppe ...
stood. Results gained from over a century of research show that in almost all glacial periods, several ice advances took place. Today it is thought that there were, in all, at least eight to fifteen ice advances. In the Riss stage, too, there were several advances of the ice sheet, so that it can be divided into
interstadial Stadials and interstadials are phases dividing the Quaternary period, or the last 2.6 million years. Stadials are periods of colder climate while interstadials are periods of warmer climate. Each Quaternary climate phase is associated with a Ma ...
s (ice retreats) and
stadial Stadials and interstadials are phases dividing the Quaternary period, or the last 2.6 million years. Stadials are periods of colder climate while interstadials are periods of warmer climate. Each Quaternary climate phase is associated with a Ma ...
s (ice advances), and at least one hitherto unnamed warm period. The present-day division differs from the original Penck classification. The beginning of the Riss ice age, according to the 2002 Stratigraphic Table of Germany, was the end of the Holstein interglacial (known as the Mindel-Riss interglacial in the Alpine Foreland and corresponding to the ''Samerbe'', ''Thalgut'', ''Praclaux'' and ''La Côte''). Its end is the start of the Eem interglacial (Riss-Würm interglacial). It is thus roughly contemporaneous with the
Saale glaciation The Saale glaciation or Saale Glaciation, sometimes referred to as the Saalian glaciation, Saale cold period (german: Saale-Kaltzeit), Saale complex (''Saale-Komplex'') or Saale glacial stage (''Saale-Glazial'', colloquially also the ''Saale-Eiszei ...
of the North German glacial sequence. The Riss is paralleled by
MIS MIS or mis may refer to: Science and technology * Management information system * Marine isotope stage, stages of the Earth's climate * Maximal independent set, in graph theory * Metal-insulator-semiconductor, e.g., in MIS capacitor * Minimally i ...
6, 8 and 10, which would therefore place it about 350,000 and 120,000 years ago. Excluded from the Riss glaciation is the so-called Old Riss (''Ältere Riß''), the time of the greatest ice advance in the Alpine region: today it is referred to as the Haslach-Mindel complex (in Bavaria and Austria), Hoßkirch complex (in Baden-Württemberg) or Great Glaciation in Switzerland. The classification of ice ages in Switzerland varies from that used in the Bavarian and Austrian Alpine Foreland. The glaciation complex between the end of the Holstein and the beginning of the Eem interglacials is referred to as the Penultimate Ice Age and the Great Glaciation. It is divided into two additional interstadials, the so-called Double Holstein Event of Meikirch (''doppelte Holstein-Vorkommen von Meikirch''), which is not identical, however, with the Holstein interglacial. During the period of maximum glaciation, ancient man (
Homo heidelbergensis ''Homo heidelbergensis'' (also ''H. sapiens heidelbergensis''), sometimes called Heidelbergs, is an extinct species or subspecies of archaic human which existed during the Middle Pleistocene. It was subsumed as a subspecies of '' H. erectus'' i ...
– later the
Neanderthal Neanderthals (, also ''Homo neanderthalensis'' and erroneously ''Homo sapiens neanderthalensis''), also written as Neandertals, are an extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ago. While the ...
s) retreated behind the permafrost boundary and, in the warmer periods, spread beyond it to the north and northeast. Not until the Weichsel-Würm ice age did modern Cro-Magnon man settle these regions, in about 40,000 BC.


Sequence and extent of the Riss glaciation

At the beginning of the Riss ice age almost all of today's river valleys were created. The glaciation of the Alps, even before the Holstein interglacial and towards the end of the major glaciations, resulted in glaciers advancing in several phases far into the Alpine Foreland, further than all other known ice sheet advances, and the main glaciers had established themselves along today's river valleys. During the Riss, glaciers advanced into the Bavarian and Austrian Alpine Foreland probably four times. The first two advances have not been confirmed with certainty because they are overlaid by the two stadials at the end of the Riss glaciation that extended well to the north. The ice sheet advances of the cold period were mostly well beyond the glacial lake of the previous ice sheet. In most areas, the Riss
terminal moraine A terminal moraine, also called end moraine, is a type of moraine that forms at the terminal (edge) of a glacier, marking its maximum advance. At this point, debris that has accumulated by plucking and abrasion, has been pushed by the front edge ...
s have formed as low embankments, for example in the area of the
Inn Glacier The Inn Glacier (german: Inn-Gletscher), also called the Inn Valley Glacier (''Inntal-Gletscher''). was the ice age glacier of the Alpine river, the Inn. Originating in the Swiss Upper and Lower Engadine (in the present canton of Graubünden), it ...
, the Isar-Loisach Glacier, the
Iller Glacier The Iller (; ancient name Ilargus) is a river of Bavaria and Baden-Württemberg in Germany. It is a right tributary of the Danube, long. It is formed at the confluence of the rivers Breitach, Stillach and Trettach near Oberstdorf in the Allg� ...
, and in the area of the western
Rhine Glacier The Rhine Glacier was a glacier during the last glacial period and was responsible for the formation of the Lake Constance Lake Constance (german: Bodensee, ) refers to three bodies of water on the Rhine at the northern foot of the Alps: Uppe ...
. In the type region in Biberach there is a clear, but rather atypical double moraine ridge, also atypical is the double terrace here, which is probably due to heavy erosion as the meltwater runoff moved from the and Altmühl valley into the present day Danube valley, a process that took place during the Riss glaciation. The double ridge of the type region (''Doppelwallriß'', with an outer and inner ridge) is a result of two superimposed sequences of glacial deposits which indicates that the Riss was subdivided into at least two stadials. In the west the
Rhône Glacier , french: Glacier du Rhône, it, ghiacciaio del Rodano , photo = Ghiacciaiorhone.jpg , photo_caption = View towards the Tieralplistock , type = Valley glacier , location = Furka Pass, Valais, Switzerland , coords ...
covered large parts of the
Swiss Plateau The Swiss Plateau or Central Plateau (german: Schweizer Mittelland; french: plateau suisse; it, altopiano svizzero) is one of the three major landscapes in Switzerland, lying between the Jura Mountains and the Swiss Alps. It covers about 30% of ...
and reached as far north as the northern Folded Jura and as far south as
Lyon Lyon,, ; Occitan: ''Lion'', hist. ''Lionés'' also spelled in English as Lyons, is the third-largest city and second-largest metropolitan area of France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of th ...
. To the northeast, it transitioned without any sharp demarcation into the Linth Glacier and
Reuss Reuss may refer to: * Reuss (surname) *Reuss (river) in Switzerland *Reuss (state) or Reuß, several former states or countries in present-day Germany, and the Republic of Reuss * Reuss Elder Line and Reuss Younger Line The Principality of Reus ...
- Aare Glacier; only the
Napf The Napf is a mountain on the border between the Swiss cantons of Bern and Lucerne. With an altitude of , it is the summit of the Napfgebiet (Napf region), the hilly region lying between Bern and Lucerne. It is counted geologically as part of th ...
area remaining ice-free. Further to the northeast, the Reuss-Aare Glacier combined with the Rhine glacier. This extended north beyond the present-day
River Danube The Danube ( ; ) is a river that was once a long-standing frontier of the Roman Empire and today connects 10 European countries, running through their territories or being a border. Originating in Germany, the Danube flows southeast for , ...
to the area of the
Swabian Jura The Swabian Jura (german: Schwäbische Alb , more rarely ), sometimes also named Swabian Alps in English, is a mountain range in Baden-Württemberg, Germany, extending from southwest to northeast and in width. It is named after the region of ...
. In Bavaria, the Riss moraines form a little subdivided countryside without bogs and lakes, where they are not covered by the younger deposits of the
Würm glaciation The Würm glaciation or Würm stage (german: Würm-Kaltzeit or ''Würm-Glazial'', colloquially often also ''Würmeiszeit'' or ''Würmzeit''; cf. ice age), usually referred to in the literature as the Würm (often spelled "Wurm"), was the last g ...
. The gravels associated with the Riss moraines form the present high terraces of the Danube tributaries. During the Riss, the
Salzach The Salzach (Austrian: �saltsax ) is a river in Austria and Germany. It is in length and is a right tributary of the Inn, which eventually joins the Danube. Its drainage basin of comprises large parts of the Northern Limestone and Central ...
and Dachstein glaciers were somewhat smaller than during the
Günz The Günz is a river in Bavaria, Germany. It is formed near Lauben by the confluence of its two source rivers: the Östliche Günz (eastern Günz) and the Westliche Günz (western Günz). It is approx. long (including its western source riv ...
and
Mindel glaciation The Mindel glaciation (german: Mindel-Kaltzeit, also ''Mindel-Glazial'', ''Mindel-Komplex'' or, colloquially, ''Mindel-Eiszeit'') is the third youngest glacial stage in the Alps. Its name was coined by Albrecht Penck and Eduard Brückner, who na ...
s,In the area of Straßwalchen the Riss edge and terminal moraines of the Irrsee Glacier lie at a height of 500–, The Mindel moraines at around  m. GKÖ 64 ''Straßwalchen'' und 65 ''Mondsee''. the latter extending in each case to the Hausruck and Kobernauß Forest ridge (subalpine molasse).


References


Literature

* * . * (3 volumes)


External links


''Stratigraphische Tabellen des Bayerischen Geologischen Landesamtes.''
Ad hoc AG Geologie der Staatlichen Geologischen Dienste (SGD) and the BGR
''Riss-Kaltzeit.''
GeoDZ online lexicon {{DEFAULTSORT:Riss glaciation Pleistocene events Ice ages Geology of the Alps