Mid-German Crystalline High
Encyclopedia
High (tectonics)
A high is in structural geology and tectonics an area where tectonic uplift has taken place relative to its surroundings. Highs are often bounded by normal faults and can be regarded as the opposites of basins. A related word is a massif, an area where relative old rocks layers are found at the...
in the Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
geology of Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
. The high forms a northeast-southwest oriented zone through Germany, but actual rock outcrops
Outcrop
An outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. -Features:Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by a mantle of soil and vegetation and cannot be...
are sparse since Paleozoic basement rocks
Basement (geology)
In geology, the terms basement and crystalline basement are used to define the rocks below a sedimentary platform or cover, or more generally any rock below sedimentary rocks or sedimentary basins that are metamorphic or igneous in origin...
are in most of central Germany overlain by younger sedimentary rock
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
s. The Mid-German Crystalline High crops out in the Odenwald
Odenwald
The Odenwald is a low mountain range in Hesse, Bavaria and Baden-Württemberg in Germany.- Location :The Odenwald lies between the Upper Rhine Rift Valley with the Bergstraße and the Hessisches Ried in the west, the Main and the Bauland in the east, the Hanau-Seligenstadt Basin – a subbasin of...
, the Spessart
Spessart
The Spessart is a low mountain range in northwestern Bavaria and southern Hesse, Germany. It is bordered on three sides by the Main River. The two most important towns located at the foot of the Spessart are Aschaffenburg and Würzburg....
, the northern Vosges
Vosges
Vosges is a French department, named after the local mountain range. It contains the hometown of Joan of Arc, Domrémy.-History:The Vosges department is one of the original 83 departments of France, created on February 9, 1790 during the French Revolution. It was made of territories that had been...
and some small other massifs.
Structure
The Mid-German Crystalline High forms the northern part of the Saxothuringian ZoneSaxothuringian Zone
The Saxothuringian Zone or Saxothuringicum is in geology a structural or tectonic zone in the Hercynian or Variscan orogen of central and western Europe. Because rocks of Hercynian age are in most places covered by younger strata, the zone is not everywhere visible at the surface...
of the Hercynian orogeny. To the northwest it is bounded by the Northern Phyllite Zone (slightly metamorphosed
Metamorphism
Metamorphism is the solid-state recrystallization of pre-existing rocks due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids. Mineralogical, chemical and crystallographic changes can occur during this process...
sediments of mid-Paleozoic age), part of the Rhenohercynian Zone
Rhenohercynian Zone
The Rhenohercynian Zone is in structural geology a fold belt of west and central Europe, formed during the Hercynian orogeny . The zone consists of folded and thrusted Devonian and early Carboniferous sedimentary rocks that were deposited in a back-arc basin along the southern margin of the then...
. 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
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
and early Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
) the Mid-German Crystalline High formed an area were not much deposition took place, perhaps an archipelago
Archipelago
An archipelago , sometimes called an island group, is a chain or cluster of islands. The word archipelago is derived from the Greek ἄρχι- – arkhi- and πέλαγος – pélagos through the Italian arcipelago...
, between two marine or oceanic basins
Oceanic crust
Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium...
(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 ProterozoicProterozoic
The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...
orthogneisses and early Paleozoic volcanic
Volcanic rock
Volcanic rock is a rock formed from magma erupted from a volcano. In other words, it is an igneous rock of volcanic origin...
(amphibolite
Amphibolite
Amphibolite is the name given to a rock consisting mainly of hornblende amphibole, the use of the term being restricted, however, to metamorphic rocks. The modern terminology for a holocrystalline plutonic igneous rocks composed primarily of hornblende amphibole is a hornblendite, which are...
s with MORB-protolith
Protolith
Protolith refers to the precursor lithology of a metamorphic rock.For example, the protolith of a slate is a shale or mudstone. Metamorphic rocks can be derived from any other rock and thus have a wide variety of protoliths. Identifying a protolith is a major aim of metamorphic geology.Sedimentary...
s and tuff
Tuff
Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...
s) and sedimentary
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
(pelite
Pelite
Pelite is old and currently not widely used field terminology for a clayey fine-grained clastic sediment or sedimentary rock, i.e. mud or mudstone. It is equivalent to the Latin-derived term lutite. More commonly, metamorphic geologists currently use pelite for a metamorphosed fine-grained...
s, calcareous schist
Schist
The schists constitute a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a particular form called quartz schist is...
s and marble
Marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...
s) rocks that were metamorphosed at high grade during the Hercynian orogeny (up to amphibolite facies). These rocks were intruded by two generations of plutons: Silurian
Silurian
The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
to Early Devonian (440-400 million years old) granitoid
Granitoid
A granitoid or granitic rock is a variety of coarse grained plutonic rock similar to granite which mineralogically are composed predominately of feldspar and quartz. Examples of granitoid rocks include granite, quartz monzonite, quartz diorite, syenite, granodiorite and trondhjemite. Many are...
s and middle Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
(Hercynian, 340-325 million years old) granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
s.
Literature
; 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 it’s consequences for the evolution of the European Variscides (Mid-German Crystalline Rise), Geologische Rundschau 86, pp. 2-20.; 1990: Geological Atlas of Western and Central Europe, Shell Internationale Petroleum Maatschappij BVRoyal Dutch Shell
Royal Dutch Shell plc , commonly known as Shell, is a global oil and gas company headquartered in The Hague, Netherlands and with its registered office in London, United Kingdom. It is the fifth-largest company in the world according to a composite measure by Forbes magazine and one of the six...
(2nd ed.), ISBN 90-6644-125-9.