Glacial Erratic Boulders (Geschiebe) – Witnesses of the Ice Age from the North
Ice ages have occurred several times in the geological history. The most recent glaciation took place in the Pleistocene, with the entire Nordic area covered by snow and ice that was comparable to today’s Antarctic
A characteristic legacy of the glaciers are, in addition to moraines, Sander areas, Osern, and Sölle, the rocky beaches of the Baltic Sea with their Till cliffs. Characteristic of this deposit is the lack of stratification and mixing of all grain sizes from the finest particles to the so-called boulders, which can cover several cubic meters. A characteristic of slings are glacier scratches, which are caused by mutual friction of the rocks during their transport.
Research in Glacial Erratic Boulders and the Neighbouring Geoscientific Disciplines
The importance of Glacial Erratic Boulders lies mainly in the fact that they are often the only and thus irretrievable documents of the former cover of Northern Europe. Accordingly, the Nordic Geology is the main concern of the research in Glacial Erratic Boulders. Significant parts of the geological history of Baltoskandia and Northern Germany can only be determined by studying the sediment. The latter also contributes significantly to an expansion of our knowledge of the geology of the Baltic Sea subsoil.
Today’s glacial zones are also to be included in the studies, whereby the methods developed in the Nordic glaciation area, e.g. have a special significance for Antarctic research. For this continent, which is almost 98% covered in ice, information about the geological structure and the ice movement can be obtained from the peripheral shovels. As the Antarctic runoff pattern shows, there are no longer distances there than were detected on Nordic pushovers (up to 1500 km of transport).
Paleontology is one of the oldest areas within biology research. Many fossil groups have been known in the first place through the discovery of fossils and have in some cases become very important guiding fossils (for example Chitinozoa, Ostracoda, Trilobita). In addition, there are forms that have not yet been found in the upcoming.
In the field of mineralogy and petrography, research into bedding has led to the discovery of the largest copper ore deposit in Europe in Outokumou, Finland. Since the distribution of debris is subject to certain laws, they are arranged according to the glacier course in so-called. Streufächern. When tracing such a scatter fan, one can therefore determine the source of a load.
Interesting, if not in economic terms, are gold finds that are screened by gravel miner in gravel washing plants. The largest aggregates found so far measure several cm.
Sedimentology studies on sedimentology and offshore geology cover two interlocking areas. It deals with statistical investigations on the regional and stratigraphic characterization of moraines and in the case of the Rhine also on river history. In the case of the Rhine, a progression deviating from the present situation could be detected by sediment examination.
Research in Glacial Erratic Boulders – the mother of quaternary geology
The beginnings of the research date back to well into the 17th century. Already in 1606 H.R.Räßmann described some moraines in the Swiss area. In the following period, some scientists postulated that in the Quaternary a different climate prevailed. Finds of mammoth and forest elephant are considered evidence of this. The decisive question about the origin of the rocks answered the identification of sedimentary rocks from Mecklenburg and Pomerania with the pending Orthocerenkalk from southern Sweden. This was the home of the attachment clarified. Von Ahrenswald (1775) set up a first flood hypothesis for their transport. In 1790, G.A. von Winterfeld postulated the first drift hypothesis, which Charles Lyell 1835 underpinned with the actuality principle. George Cuvier set up his theory of the torrent flood (Rollsteinflut).
The absence of any marine fossils in the tills and the presence of large clods (up to 50-80 million m3) made both theories unreliable. On November 3, 1875, at the meeting of the German Geological Society, the Swede Otto Torell founded the Inlandice-Theory, represented by ice-skinned shell limestone from Rüdersdorf near Berlin, which could be inspected during a previous excursion. With the now finally implemented Northern European Inland Theory, the foundation stone was laid for the quaternary geology, so that the research on attachment, which finally led to the glacial theory, got the name “Mother of Quaternary Geology”.
If you would like further information on the genesis of Inlandice-Theory, please refer to the publication by Karlheinz Kaiser (1975, german) [Eiszeitalter u. Gegenwart Vol. 26].