Dahmeland
The Dahmeland is a historical landscape in central Brandenburg and in the southeast of Berlin . The name-giving element is the river Dahme . The landscape is characterized by the contrast between the abundance of water and wet lowlands on the one hand and the dry and barren sandy soils that predominate over long stretches on the other . Although it is located directly at the gates of Berlin, the landscape is only sparsely populated. Large parts of the Dahmeland are protected within the Dahme-Heideseen nature park .
Geography and geology
Demarcation
The Dahmeland has no sharp boundaries, either in terms of natural or cultural landscape. For practical reasons, the northern part of the Dahme-Spreewald district is usually equated with the Dahmeland. Historically, however, both the southern parts of the Berlin district of Treptow-Köpenick and the western part of the Oder-Spree district that drains away from the Dahme belong to the Dahmeland. On the other hand the northwestern part of the district Dahme-Spreewald already on the plateau of Teltow , from which the Dahmeland is bounded to the west. The northern border of the historical landscape can be drawn with the confluence of the Dahme into the Spree at the old town of Köpenick . In terms of natural landscape, the border here lies in the middle of the Berlin glacial valley . Especially in the east, the Dahmeland merges into the landscapes to the east without any recognizable border. The Beeskower Platte and the Rauenschen Berge are no longer included in the Dahmeland. The Dahmeland can be relatively sharply delimited in the southeast, as the Dahme around Märkisch-Buchholz and the Spreewald near Neuendorf am See come close to each other within a few kilometers. The Krausnicker Mountains adjoining to the west also form a striking border between Dahmeland and Spreewald. The exact demarcation to the southeast is again fuzzy, since the upper reaches of the Dahme with the town of the same name are not included in the Dahmeland. Here the Dahme itself forms the border between the Fläming southwest and the Lausitz south of the Dahmeland. The southwest border of the Dahmeland is only north of Golßen , in the Baruther glacial valley .
Settlements
Due to the predominance of poor, nutrient-poor sandy soils, most of the Dahmeland is only sparsely populated. Only the northern part experienced a significant increase in population with the strong growth of Berlin from the end of the 19th century. This mainly affected the towns on the Berlin – Görlitz railway line . So did King Wusterhausen , with about 34,000 inhabitants of the currently most populous place in 1900 only one-tenth of today's population. Also Eichwalde , Zeuthen and Wildau , all located along the railway line, experienced a strong increase in population. The most important place up to 1900, the town of Mittenwalde , already located on the Teltow , was not on the railway line and lagged behind the other places in its development. Also south of Königs-Wusterhausen the most populous communities are lined up on the railway line: Bestensee and Groß Köris . All other places in Dahmeland have remained small rural communities to this day. Teupitz and Märkisch Buchholz in the southern part of the Dahmeland have city rights, but like all other communities are rural. With fewer than 800 inhabitants, Märkisch Buchholz is even one of the smallest cities in Germany.
Geology, geomorphology and soils
The Dahmeland owes its creation to the repeated advances of the Scandinavian inland ice during the Quaternary Ice Age . So there are almost exclusively glacial and post-glacial deposits on the earth's surface. All elements of the Glacial series can be found in the Dahmeland .
Pre-Quaternary Deposits
Deposits that are older than the younger Tertiary (or Neogene ) are almost irrelevant for Dahmeland; but they are common in the deeper underground. The only exception is the Mittenwalde salt dome, the top of which is less than a hundred meters below the surface of the earth. Unlike in Sperenberg , however, the surface of the earth is not reached.
Deposits from the Miocene are widespread in Dahmeland, but mostly covered by the Ice Age sediments. In a few places, however, they are directly on the surface of the earth or are found under an overburden that is only a few meters thick. However, all near-surface deposits are not in their original position, but have been compressed by the pressure of the Quaternary ice advances and are mostly in a higher position than their original position. The best known is the occurrence of Miocene brown coal near Schenkendorf , which was mined in the second half of the 19th century. The resulting mine buildings shape the townscape to this day.
Magpie Ice Age
The deposits of the first ice advances during the Elster Ice Age can reach thicknesses of more than 100 meters in the subsoil of the Dahmeland. They become particularly powerful when filling glacial channels . There is a clear dichotomy: gullies in the northern part of the Dahmeland are only slightly widespread and relatively little cut into their surroundings, while in the south they are significantly deeper and more extensive. The magpie temporal sediments consist mainly of glacial till and paragraphs of proglacial lake . But there are also meltwater sands and gravels. Outside the gullies there is almost no Elsterzeit deposits. Due to the overlay with the also very thick Saale-period sediments, there are certainly no Elster-period deposits directly on the earth's surface. The upper edge of the Elsterzeit deposits also shows no relation to the surface of today's Dahmeland.
Saale ice age
The thickness of the deposits of the Saale Ice Age is greater than that of the older sediments of the Elster Ice Age as well as those of the younger Vistula Ice Age. With a thickness of 20 to 50 meters (and more) they are widespread almost everywhere. Most of the time it is sandy meltwater deposits that are covered by a mighty glacial till. However, there are also repeated fine-grained ice reservoir deposits . In several places the Saale-time deposits even penetrate the Vistula-time and are directly or at least very close to the surface of the earth. In the places where ice reservoir deposits can be found near the surface of the earth, they were mined in several clay pits in the 19th and 20th centuries and burned into bricks.
Since the deposits of the younger Vistula Glacial Period are relatively thin, today's large relief was created as early as the Saale Ice Age. This applies to both the extensive lowlands and most of the high areas.
Deposits of the Eem warm period following the Saale glaciation have been proven by drilling in several places in the Dahmeland. They are small basins that have been filled with lake sediments and peat . In a clay pit near Töpchin around 1900, when the Saale-period reservoir clays were excavated, Eem-period sediments were also exposed on the surface of the earth. However, the information is no longer available.
Vistula ice age
During the Vistula Ice Age, the Dahmeland was last covered and decisively shaped by the Scandinavian inland ice. The glacier on the southern edge of the area at the Brandenburg ice rim location reached its maximum extent to the south. The youngest ice has not reached the Fläming and the Lausitz border wall. The peripheral location is marked south of Teupitz and on the Krausnicker Mountains by well-developed terminal moraines . They consist mainly of sand and gravel. The typical sand areas of the Dornswalder Heide and the Brand (municipality of Halbe ) are located south to south-west of the terminal moraines . They were created by deposits of meltwater that emerged from the inland ice. The Sander roof to the south to the Baruther glacial valley , in which the meltwater flowed further west. Between Massow and the Krausnicker Mountains, terminal moraines and sand are almost completely absent for about 10 km from west to east, so that there the Baruther glacial valley merges into the northern, lower backland, mostly without a sharp border. The Dahme later used this gap to turn it north.
Almost simultaneously with the terminal moraines and sand, numerous glacial channels formed under the ice north of the ice edge . They run from north to south or from northeast to southwest. When the inland ice melted, blocks of dead ice were retained in the gullies, which later became the numerous lakes that characterize the Dahmeland to this day. Most of the lakes in Dahmeland lie within the channels.
According to the Glacial Series model, extensive ground moraines are to be expected north of the terminal moraines . However, this only applies to a limited extent to the Dahmeland. On the one hand, the landscape of the Dahmeland is usually much deeper than the Baruther glacial valley. With the meltdown, the glacial current from the Baruther Valley quickly shifted to the north and buried the landscape for the most part with meltwater sands. Extensive glacial valleys formed between the Baruther and Berlin glacial valleys . On the other hand, dominates on the manner of islands rising out of the ground moraines Urstromtalungen plates not the boulder clay . Due to the short-term ice cover, it is very thin (often less than 2 m) and sandy. He is missing for a long time. On the plateaus, which are actually ground moraines, there are long stretches of sand from the advance phase of the Vistula-age ice or, where these are also missing, even older deposits from the Saale-age.
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