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The Muschelkalk ((ドイツ語:shellbearing limestone), ''French'': ''calcaire coquillier'') is a sequence of sedimentary rock strata (a lithostratigraphic unit) in the geology of central and western Europe. It has a Middle Triassic (240 to 230 million years) age and forms the middle part of the tripartite Germanic Trias, that give the Triassic its name, lying above the older Buntsandstein and below the younger Keuper. The Muschelkalk ("mussel chalk") consists of a sequence of limestone and dolostone beds. In the past, the time span in which the Muschelkalk was deposited could also be called "Muschelkalk". In modern stratigraphy, however, the name only applies to the stratigraphic unit. ==Occurrence== The name ''Muschelkalk'' was first used by German geologist Georg Christian Füchsel (1722-1773). In 1834, Friedrich August von Alberti included it into the Triassic system. The name indicates a characteristic feature of the unit, namely the frequent occurrence of lenticular banks composed of fossil shells. The Muschelkalk is restricted to the subsurface in most of Germany and adjacent regions as the low countries, the North Sea and parts of Silesia, Poland and Denmark. Outcrops are found in Thuringia, the Harz, Franconia, Hesse, Swabia, and the Saarland and in Alsace. The Muschelkalk was deposited in a land-locked sea which, in the earlier part of its existence, had only imperfect communications with the more open waters of the Tethys Ocean to the south. The basin in which the Muschelkalk was deposited is called the Germanic Basin. Sometimes stratigraphic units with the same age from the Alps, southern Europe and even Asia are called Muschelkalk too. Of course these rocks have little history in common with the central European Muschelkalk except for similarities in fossil content. Closer at hand, the Alpine Muschelkalk differs in many respects from that of Central Europe, and in its characteristic fossil fauna has a closer affinity with the Triassic Tethys realm. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「muschelkalk」の詳細全文を読む スポンサード リンク
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