The Mid-German Crystalline High (or Mid-German High) is a structural high in the

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

geology of

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

. The high forms a northeast-southwest oriented zone through Germany, but actual rock outcrops are sparse since Paleozoic basement rocks are in most of central Germany overlain by younger

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

s. The Mid-German Crystalline High crops out in the Odenwald, the

Spessart Spessart is a '' Mittelgebirge'', a range of low wooded mountains, in the States of Bavaria and Hesse in Germany. It is bordered by the Vogelsberg, Rhön and Odenwald. The highest elevation is the Geiersberg at 586 metres above sea level. Ety ...

, the northern

Vosges The Vosges ( , ; german: Vogesen ; Franconian and gsw, Vogese) are a range of low mountains in Eastern France, near its border with Germany. Together with the Palatine Forest to the north on the German side of the border, they form a single ...

and some small other massifs.

Structure

The Mid-German Crystalline High forms the northern part of the Saxothuringian Zone of the

Hercynian orogeny The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan'', comes f ...

. To the northwest it is bounded by the Northern Phyllite Zone (slightly

metamorphosed Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...

sediments of mid-Paleozoic age), part of the Rhenohercynian Zone. Southeast of the Mid-German High lies a zone where early to mid-Paleozoic sediments of the Saxothuringian Basin crop out, metamorphosed during the Hercynian orogeny. Supposedly, during the mid-Paleozoic ( Devonian and early Carboniferous) the Mid-German Crystalline High formed an area were not much deposition took place, perhaps an

archipelago An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster, or collection of islands, or sometimes a sea containing a small number of scattered islands. Examples of archipelagos include: the Indonesian Arc ...

, between two marine or oceanic basins (the Rhenohercynian Basin to the north, the Saxothuringian Basin to the south). Some authors assume the northern basin's oceanic crust subducted beneath the Mid-German High.

Lithologies

The zone consists of Proterozoic

orthogneiss Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures an ...

es and early Paleozoic

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

( amphibolites with MORB-

protolith A protolith () is the original, unmetamorphosed rock from which a given metamorphic rock is formed. For example, the protolith of a slate is a shale or mudstone. Metamorphic rocks can be derived from any other kind of non-metamorphic rock and ...

s and

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock ...

s) and

sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

(

pelite A pelite ( Greek: ''pelos'', "clay") or metapelite is a metamorphosed fine-grained sedimentary rock, i.e. mudstone or siltstone. The term was earlier used by geologists to describe a clay-rich, fine-grained clastic sediment or sedimentary rock, ...

s, calcareous

schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes ...

s and

marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphose ...

s) rocks that were metamorphosed at high grade during the Hercynian orogeny (up to

amphibolite facies Amphibolite () is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase feldspar, but with little or no quartz. It is typically dark-colored and dense, with a weakly foliated or schistose (flak ...

). These rocks were intruded by two generations of plutons: Silurian to

Early Devonian The Early Devonian is the first of three epochs comprising the Devonian period, corresponding to the Lower Devonian series. It lasted from and began with the Lochkovian Stage , which was followed by the Pragian from and then by the Emsian, ...

(440-400 million years old)

granitoid A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quartz- ...

s and middle Carboniferous (Hercynian, 340-325 million years old)

granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...

s.Oncken (1997); Franke (2000)

Notes

Bibliography

*; 2000: ''The mid-European segment of the Variscides: tectonostratigraphic units, terrane boundaries and plate tectonic evolution'', in: (''eds.''); ''Orogenic Processes, Quantification and Modelling in the Variscan Belt'', Geological Society of London, Special Publications 179, pp. 35-61. *; 1997: ''Transformation of a magmatic arc and an orogenic root during oblique collision and its consequences for the evolution of the European Variscides (Mid-German Crystalline Rise)'', Geologische Rundschau 86, pp. 2-20. DOI: 10.1007/s005310050118 *; 1990: ''Geological Atlas of Western and Central Europe'', Shell Internationale Petroleum Maatschappij BV (2nd ed.), {{ISBN, 90-6644-125-9. Geology of Germany Hercynian orogeny Geology of Europe

Structure

Lithologies

See also

Notes

Bibliography