Ceiling separator
The term ceiling separator is used in geology , especially in the highly metamorphic gneiss areas of the central Alps in Europe. A ceiling divider separates two tectonic units (ceilings or rock ceilings ). In the Central Alps or the Lepontine , it consists mostly of Mesozoic, highly metamorphic sediments such as quartzites , dolomite or limestone marbles , which are sandwiched between two gneiss layers of pre-Mesozoic age. Such gneiss covers correspond to complex lying folds of sometimes enormous dimensions. A ceiling separator thus serves as a guide horizon for dividing gneiss series into tectonic units (ceilings) lying one above the other or next to one another, because it separates younger series (e.g. Mesozoic dolomites) from older tectonic units (e.g. paleozoic gneiss). While a ceiling separator can grow into massive series on the fold or ceiling forehead, it is often present as a greatly reduced series of a few meters thick along the fold legs. Often these few meters of metamorphic sediments are the only indication of a subdivision of an otherwise homogeneous gneiss series and are therefore of great importance for the tectonic interpretation of highly metamorphic mountain belts. A well-known example is the complex pile of blankets in the region of Ticino (Switzerland) and Piedmont (Italy).
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- Jump up ↑ Alfons Berger, Ivan Mercolli, Martin Engi: The central Lepontine Alps: Notes accompanying the tectonic and petrographic map sheet Sopra Ceneri (1: 100,000). in: Schweizerische Mineralogische und Petrographische Mitteilungen 85, pp. 109–146, Zurich 2005
- ^ Albrecht Steck, Franco Della Torre, Franz Keller, Hans-Rudolf Pfeifer, Johannes Hunziker, Henri Masson: Tectonics of the Lepontine Alps: ductile thrusting and folding in the deepest tectonic levels of the Central Alps. in: Swiss Journal of Geosciences, Springer, Basel, 106/2013, pp. 427–450