Penninic
The Penninic is one of the main geological units of the Alps. Most of its rocks belonged to the Tethys deposit area , the northwestern tip of which lay in the Jura (206 - 144 mya ) between the European continental crust and the Apulian continental plate , which is part of the African continent . During the folding of the Alps , the rocks of the Penninic were pushed together and pushed far north and west onto the European continental margin. This is how the Pennine blankets were created from the Penninic .
Structure and rock content
In the structure of the Alps, the Penninic lies above the Helvetic (sheared sediments of the European continent) and below the Eastern / Southern Alps (components of the upper continental plate).
The rocks of the Penninic can be divided into three parts: Upper, Middle and Lower Penninic, which in turn consist of a complicated, deformed stack of tectonic nappes that can be traced back to a common area of origin. Also in use is the equivalent division into North, Middle and South Penninic, alternatively also High, Middle and Low Penninic.
Upper Penninic (Piedmont Zone)
The rocks of this unit come from the Piedmont-Ligurian Ocean, an oceanic sub-basin of the Tethys directly in front of the edge of the Apulian plate. The Upper Penninic or High Penninic ( Piedmont , Liguria ) include the southern Penninic ophiolites , which occur together with Bündner schists and radiolarites (a typical deep sea sediment). Another characteristic of the rock Penninikums is the helminthoids - flysch . The ophiolites are the remains of a larger ocean that have not fallen victim to subduction , so they are of great importance as evidence of the existence of oceanic lithospheric material . Such larger opholite masses also form some peaks in the Alps, the most famous being the Großglockner in the Hohe Tauern in Austria. The rocks of the Préalpes and the tectonic mélange of the Matreier scale zone also belong to the Upper Penninic .
Middle Penninic (Briançonnais Zone)
The rocks of the Middle Penninic come from a high area in the Alpine Ocean called Briançonnais. It represented a "continental" high zone, while the southern Piedmont zone and the northern Valais zone were deeper sedimentation areas. The exact geological position of Briançonnais is still the subject of research. The origin of the remains of a terran or the former eastern tip of today's Iberian Peninsula is discussed . It is clear that the Briançonnais threshold separated the Walliser Trough (Valais zone) in the north from the Piedmont Ocean in the south.
The Middle Penninic contains crystalline ceilings , coal-bearing layers from the Paleozoic Era (Houillière zone) and Mesozoic sedimentary ceilings sheared off from them , consisting of sandstones, claystones and limestone sands (in the Valais trough) and shallow marine limestone and marls (on the Briançonnais threshold).
Lower Penninic (Valais Zone)
The Lower Penninic contains, among other things, oceanic sediments and ophiolites, Bündner schists and the Rhenodanubian flysch . Today it is regarded as the remnant of an accretion wedge from the North Penninic Valais Ocean , which is open to the Atlantic , in which rocks from the ocean and from the outermost edge of the European continent are mixed with one another. Limestone and clay slate of the Lower Penninic now form the mountains between Brig and Prättigau .
The deepest units of the Penninic nappes, classically classified as part of the Penninic, contain rocks that originate from the transition between the ocean and the outer areas of the European continental shelf . Today they are summarized under the name Subpenninikum.
Tectonic structure
As a medium-sized unit between the Adriatic Upper Plate and the European Lower Plate, the Penninic as a whole is often heavily tectonically stressed. In contrast to the Helvetica, not only the sedimentary overburden, but also the crystalline basement was included in the overburden tectonics. Typical of its construction are large, lying folds with gneiss cores and the frequent, large-scale shearing of the sedimentary cover from its original base, especially on Evaporite series from the Triassic . The sheared sediments were generally moved further north than their sub-stock, leaving the crystalline basement in the south. Narrow remnants of sediment make it possible to differentiate between the various ceiling units.
At a late stage of the Alpine orogeny, the Penninic was pushed back south and southwest onto the Southern Alpine at the Periadriatic Seam , so that the pile of nappies was folded in a complicated way. In addition, there was a deep bulge in Ticino . The entire Penninic was raised up to 16 km in a north-south trending structure, the Lepontine Cathedral . For this reason, the units of the deep peninsula are exposed there on the surface.
On the Pennine ceiling pile of Switzerland and France in the area which is Dent Blanche a great rest ostalpiner rocks preserved, the Dent Blanche ceiling . Around the border between Switzerland and Austria, the Pennine nappes are almost completely covered by the Eastern Alpine nappes. They only appear in the Pennine flysch of the flysch zone accompanying the northern edge of the Alps and in some tectonic windows in the east ( Gargellen window , Engadine window , Tauern window and Rechnitz window ).
Cliff ceilings
High and Middle Penninic sediments have been sheared from their crystalline bedrock and pushed far to the north. Today they exist as tectonic cliffs isolated from the rest of the Penninic . The nappes of the Préalpes lie on the tectonically deeper Helvetian nappes , in the far north even on molasses that have been driven over . Here, ultrahelvetian sediments, which are highly stressed tectonically, form the mediating layer between the Préalpes and their sub-camp.
The cliff covers form a long series of individual occurrences that stretch in a wide arc between the east of Lucerne ( Mythen cover ) in Switzerland to Annecy in France ( Annes cover ). The largest contiguous deposits are two large, on the eastern tip of Lake Geneva merging units: in the southwest of the Chablais Préalpes , south of Lake Geneva in Chablais , and in the northeast the Préalpes Romandes in the Friborg Alps .
The préalpes are divided into the following units from bottom to top:
- the Niesen Nappe , which only occurs in the Préalpes Romandes and forms the southernmost unit of the cliff cover there
- the Préalpes Médianes , they are divided into the Préalpes Plastiques (especially soft, plastic flysch rocks) and the overlying Préalpes Rigides (especially hard, rigid limestones)
- the breccia cover , which occurs only on the southern part of the Préalpes Médianes
- the Nappe Supérieure , it is subdivided once more into the Gets-Blanket, the Simmen-Blanket, the Dranses-Blanket and the Gurnigel-Blanket.
Occurrence
Larger parts of the Alpine region consist of Penninic rocks, especially in the western Alps and the Swiss Alps. The western Alps south of the Rhone - Simplon line consist almost exclusively of rocks from the Penninic, which are in front of external crystalline massifs and tectonically deformed overburden to the west. In the Swiss area, the areas south of the Aar massif and north of the Periadriatic Seam are included in the Penninic. In the cliff ceilings east of Lucerne and in the Dent Blanche ceilings, the Penninic remains of the unity of the Eastern Alps are deposited here. The west alpine Penninikum dips below the east alpine near Liechtenstein and Graubünden . East of the Rhine, the Penninkum is almost completely covered by the Eastern Alpine nappes.
In the Eastern Alps it is only accessible in some areas under these ceilings on the surface. The Penninic nappes include the flysch zone (sandstone zone ) that accompanies the northern edge of the Alps in Bavaria and Austria for long stretches. In the Alps themselves, the Penninic appears with crystalline rocks in geological windows , for example in the Gargellen window in Vorarlberg , in the Engadine window that extends as far as Prutz in Tyrol ; in the Tauern window between Brennerfurche and Liesertal and in the Rechnitz window at the east end of the Alps.
Origin of name
The expression Penninikum is derived from the Pennine Alps , whose name comes from the Latin names Mons Penninus or Summus Penninus for the Great St. Bernard Pass and Vallis Pennina ( Vallis Poenina ) for the upper Rhone Valley (corresponds roughly to today's canton of Valais ) derives. Originally the name may have related to a Celtic or pre-Celtic word for pass or mountain (cf. Gaelic ben , Welsh pen ), which later referred to a Celtic and then a Roman deity ( Iupiter Penninus , with the following reference to the Punier ( Poenus ) Hannibal also Iupiter Poeninus ).
See also
literature
- Manfred P. Gwinner: Geology of the Alps. Stratigraphy, paleogeography, tectonics . 2nd Edition. Schweizerbart'sche Verlagbuchhandlung, Stuttgart 1978, ISBN 3-510-65315-7 .
- Stefan M. Schmid , Bernhard Fügenschuh, Eduard Kissling, Ralf Schuster: Tectonic map and overtall architecture of the Alpine orogen . In: Eclogae geologicae Helvetiae . tape 97 , 2004, ISSN 0012-9402 , p. 93–117 ( unibas.ch [PDF]).
- Reinhard Schönenberg, Joachim Neugebauer: Introduction to the Geology of Europe (= Rombach University Paperback . Volume 18 ). 4th, revised edition. Rombach, Freiburg (Breisgau) 1981, ISBN 3-7930-0914-9 , pp. 185 ff .
- Heinz Veit: The Alps. Geoecology and Landscape Development (= UTB. Geosciences, Ecology, Biology . Volume 2327 ). Ulmer, Stuttgart 2002, ISBN 3-8001-2788-1 .
Individual evidence
- ↑ Jon Mosar: The Prealps. (No longer available online.) Institutes of Geology and Paleontology at the University of Lausanne, archived from the original on November 25, 2011 ; Retrieved February 7, 2010 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ “ Livy already contradicts the absurd derivation of the name from the Puners (XXI, 38) . At the height of the pass was a temple in which a god Peninus or Penninus was worshiped by the natives. This name is derived from the Celtic word Penn or Pinn - de tip. The Romans made it into a Jupiter Penninus and mons Jovis (hence Mont Joux ). “C. Ludwig Enoch Zander: Hannibal's campaign across the Alps. Göttingen 1828, p. 25
