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首页> 外文期刊>Zeitschrift der Deutschen Gesellschaft fur Geowissenschaften: ZDGG >The Muschelkalk Group in the Stratigraphic Table of Germany 2016 (STG 2016)
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The Muschelkalk Group in the Stratigraphic Table of Germany 2016 (STG 2016)

机译：2016年德国地层表中的Muschelkalk群（STG 2016）

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摘要

In the Stratigraphic Table of Germany 2016 (STG 2016, STD 2016) the Muschelkalk Group has been assessed as early Anisian (Bithynian) through early Ladinian (Fassanian). Following decisions of the Permian-Triassic Subcommission (SKPT) in the German Stratigraphic Commission (DSK), the boundaries of the Muschelkalk Group against the Buntsandstein and Keuper groups have been fixed at widespread marker beds that are nearly isochronous. The internal subdivision into the regional geochronological units Folge m1 to m9 is also based on marker beds. The number of Lower Muschelkalk small-scale cycles has been estimated by different authors as 19 to 29. In the STG 2016, 21 cycles of 100 ka duration arc assessed, whereas the numbers of II cycles for the Middle and 38 for the Upper Muschelkalk still require additional research. While marker bed-based boundaries are nearly isochronous, unit boundaries based on facies changes are diachronous on a regional scale: (1) in the eastern part of the basin (Poland), the typical Muschelkalk carbonate sedimentation commences with the Lower Gogolin Formation, time equivalent of the carbonatic Dornburg Subformation (Member) of the Rot Formation (former Myophoria Beds) in the western basin parts, which is overlain by variegated and sandy claystone and hence attributed to the Buntsandstein Group, and (2) in the Polish and northeast German basin parts the carbonatic facies ended already in earliest Ladinian times. In the largest parts of the Central European Basin, the Muschelkalk Group is constituted according to SKPT decisions of seven formations which are mostly delimited by nearly isochronous and widespread marker beds. Identical boundaries of formations and allostratigraphic marker bed-based Folgen (m1 through m9) are favourable for understanding the basin history. Where significant facies changes occur towards the basin margins, regional formations with mostly diachronous boundaries were established, some of which are covering the equivalents of more than one group of the basinal facies. The Muschelkalk Group is biostratigraphically subdivided in biozones by means of cephalopods and conodonts and also by additional invertebrate and vertebrate groups, and palynomorphs. Since no radio-isotopic age determinations (RIA) are available for the Muschelkalk Group itself, all age estimates have to be based on the hypothesis that Muschelkalk sedimentary cycles are caused orbital-climatically and by integration of global RIA into the Muschelkalk succession using biostratigraphic correlations with the Tethyan Triassic. The Anisian-Ladinian boundary, dated in the STG 2016 at ca. 241 Ma, is the only global stage boundary within the Muschelkalk Group, located in the vicinity of the Cycloidesbank in the upper part of the Upper Muschelkalk. In the STG 2016, a maximum estimate of 7 Ma for the Muschelkalk Group was chosen. Additional estimations are discussed which indicate shorter Muschelkalk durations of 5.2 Ma or 4.8 Ma respectively and are nearly consistent with the RIA.

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