Editing Black Forest (section)

== Geology ==
{{more citations needed|date=November 2017}}
[[File:Schwarzwald - Deutsche Mittelgebirge, Serie A-de.png|thumb|upright=1.3|Topography of the Black Forest]]
The Black Forest consists of a cover of [[sandstone]] on top of a core of [[gneiss]] and [[granite]]. Formerly it shared tectonic evolution with the nearby [[Vosges|Vosges Mountains]]. Later during the Middle [[Eocene]] a [[rift]]ing period affected the area and caused formation of the [[Upper Rhine Plain]]. During the last [[glacial period]] of the [[Würm glaciation]], the Black Forest was covered by glaciers; several [[tarn (lake)|tarns (or lakes)]] such as the [[Mummelsee]] are remains of this period.

=== Basement ===
The geological foundation of the Black Forest is formed by the crystalline bedrock of the [[Variscan orogeny|Variscan]] basement. This is covered in the east and northeast by [[Bunter (geology)|Bunter Sandstone]] slabs, the so-called platforms. On the western edge a descending, [[Fault (geology)|step-fault]]-like, foothill zone borders the Upper Rhine Graben consisting of rocks of the [[Triassic]] and [[Jurassic]] periods.

The dominant rocks of the basement are gneiss (ortho- and paragneisses, in the south also [[migmatite]]s and diatexites, for example on the Schauinsland and Kandel). These gneisses were penetrated by a number of granitic bodies during the [[Carboniferous]] period. Among the bigger ones are the Triberg Granite and the [[Forbach Granite]], the youngest is the Bärhalde Granite. In the south lies the zone of Badenweiler-Lenzkirch, in which Palaeozoic rocks have been preserved (volcanite and sedimentary rocks), which are interpreted as the intercalated remains of a [[Continental fragment|microcontinental]] collision. Still further in the southeast (around Todtmoos) is a range of exotic inclusions: [[gabbro]] from [[Häg-Ehrsberg|Ehrsberg]], [[serpentinite]]s and [[pyroxenite]]s near Todtmoos, [[norite]] near [[Dachsberg|Horbach]]), which are possibly the remnants of an [[accretionary wedge]] from a continental collision. Also noteworthy are the basins in the [[Rotliegend]], for example the Schramberg or the Baden-Baden Basin with thick quartz-porphyry and [[tuff]] plates (exposed, for example, on the rock massif of [[Battert]] near Baden-Baden). Thick {{lang|de|rotliegendes}} rock, covered by bunter, also occurs in the north of the [[Dinkelberg]] block (several hundred metres thick in the Basel [[geothermal gradient|geothermal]] borehole). Even further to the southeast, under the Jura, lies the North Swiss Permocarboniferous Basin.

=== Uplift of the mountains ===
Since the downfaulting of the [[Upper Rhine Plain|Upper Rhine Graben]] during the [[Eocene]] epoch, the two shoulders on either side have been uplifted: the Black Forest to the east and the [[Vosges]] to the west. In the centre lies the [[Kaiserstuhl (Baden-Württemberg)|Kaiserstuhl volcano]], which dates to the [[Miocene]]. In the times that followed, the [[Mesozoic]] [[platform (geology)|platform]] on the uplands was largely eroded, apart from remains of Bunter Sandstone and [[Rotliegend|Rotliegend Group]], but it has survived within the graben itself. During the [[Pliocene]] a pronounced but uneven bulge especially affected the southern Black Forest, including the Feldberg. As a result, the upper surface of the basement in the northern part of the forest around the Hornisgrinde is considerably lower. In the central Black Forest, the tectonic [[syncline]] of the Kinzig and Murg emerged.

[[Geomorphology|Geomorphologist]] [[Walther Penck]] regarded the Black Forest as an uplifted [[dome (geology)|geologic dome]] and modeled his theory of [[piedmonttreppen]] (piedmont benchlands) on it.<ref name=Harris1968>{{cite encyclopedia|author-last=Harris|author-first=Stuart A. |title=Treppen concept (penck) |encyclopedia=Geomorphology|series=Encyclopedia of Earth Science|year=1968 |isbn=978-3-540-31060-0 }}</ref><ref>{{cite journal |last1=Spreitzer |first1=H. |date=1951 |title=Die Piedmonttreppen in der regionalen Geomorphologie |jstor=25635740 |journal=[[Erdkunde]] |volume=5 |issue=4 |pages=294–305 |language=de }}</ref>

=== Platform ===
Above the crystalline basement of the Northern Black Forest and the adjacent parts of the Central Black Forest, the bunter sandstone platforms rise in prominent steps. The most resistant surface strata on the stepped terrain of the {{lang|de|[[grinden]]}} uplands and the heights around the upper reaches of the [[Enz]], which have been heavily eroded by the tributaries of the Murg, is the silicified main conglomerate (Middle Bunter). To the east and north are the [[nappe]]s of the Upper Bunter (platten sandstones and red clays). South of the Kinzig the Bunter Sandstone zone narrows to a fringe in the east of the mountain range.

=== Ice age and topography ===
It is considered proven that the Black Forest was heavily glaciated during the peak periods of at least the [[Riss glaciation|Riss]] and [[Würm glaciation|Würm]] glaciations (up to about 10,000 years ago). This glacial geomorphology characterizes almost all of the High Black Forest as well as the main ridge of the Northern Black Forest. Apart from that, it is only discernible from a large number of [[cirque]]s mainly facing northeast. Especially in this direction snow accumulated on the shaded and leeward slopes of the summit plateau to form short cirque glaciers that made the sides of these funnel-shaped depressions. There are still tarns in some of these old cirques, partly a result of the [[wikt:anthropogenic|anthropogenic]] elevation of the low-side lip of the cirque, such as the [[Mummelsee]], [[Wildsee (Ruhestein)|Wildsee]], [[Schurmsee]], [[Glaswaldsee]], [[Buhlbachsee]], [[Nonnenmattweiher]], and [[Feldsee]]. The Titisee formed as [[glacial lake]] behind a glacial [[moraine]].