Geo.Alp, Vol. 16 2019 NEW LITHOSTRATIGRAPHIC TERMS USED IN THE GEOLOGICAL MAP OF THE WESTERN DOLOMITES. → Rainer Brandner1 & Alfred Gruber2 1 Institut für Geologie, Universität Innsbruck, Austria; e-mail: [email protected] 2 Geologische Bundesanstalt, Wien, Austria; e-mail: [email protected] The Geological Map of the Western Dolomites is based on the with the Italian national mapping programme CARG. New and new mapping and compilation of the entire sedimentary cover newly defined lithostratigraphic terms are explained below. of the Autonomous Province of Bozen/Bolzano. It was carried Their position is shown in the lithostratigraphic table (Fig. 1). out as part of the project "Geological Base Map of South Tyrol". In the course of this new mapping, new lithostratigraphic terms Werfen Formation: Von Lilienbach (1830) and Peters (1854) wereS introduced,TRATIG RorA conventionalPHIC SC HonesEM redefined,E OF T HacrossE P EtheR MoriginallyIAN T Odescribed UPPE theR "strataTRIA ofS SWerfen"IC SU orC "WerfenCESIO schist"N boundaries of official map sheets. This was not always in line in the type region south of Salzburg. Later, this term was also Heiligkreuz Hospiz Sella - Vallon Ospizio di Santa Croce Lavarella - Settsass 15 Hauptdolomit # # # # # # # # # # # # 21#a # # # 16 Travenanzes Fm Falzarego Mb p Pordoi Fm ! ! ! ! ! ! ! ! # # # # p ! ! ! ! ! ! ! ! ! 26a # # # # 21 u Lagazuoi Mb ! ! ! ! ! ! ! ! u # # # # o 17 n! ! ! ! ! ! ! ! ! r 18 # # # # i o ! ! ! ! ! ! ! ! o Dibona Mb 19 a t ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! r G m ! ! ! ! ! ! ! ! ! - r l o g F 27a b z i b u e 20 e t i a k r u Fedares Member l i g m R i S e 27 H o l 26 e o t D i n m a i o s s p l o 22 a C D u 23 a "Richthofen reef" l o l e St. Cassian Fm r S Rosszähne Fm 23 G 28 7 n r Wengen Fm. 23 e l h 24 29 Marmolada Conglomerate c 31 J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J 34 J J J J J J J J J J RJ oJ sJ eJ nJgaJ rJ teJ n Fm J J J J J J J J J J J J J J J J J Fernazza Gr J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J S 33 J J J J J J J J J J J J J J J J J J Caotico eterogeneo J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J 36 ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 37 J J J J J J J J J J J J J J J J J J ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! J J J J J J J J J J J J J J J J J 30 ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! Acquatona Fm. ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! J J J J J J J J J J J J J J J J J J ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! J J J J J J J J J J J J J J J J J Zoppè Sandstone 38 ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! J TJ sJ chJ aJ mJ inJ J MJ bJ J J J J J J J J ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J J 39 Buchenstein Fm 500 # # # # # # # ¯ # # # # # #41 Moena Fm # # # # # # # Contrin Fm # # # # # # # # # # # # # # 40 # # # # # # # # # #41# a # # # # # # # 4#2 # Morbiac F#m # # # # # # 49 Peres Fm 43 Richthofen Conglomerate ro Oolite C Vo r Mb & Tese en ltag Mazzin c o G V C 50 a en on Upper l B igh Piz da gl. s C e Serla Dolomite g a ad M n Peres Congl. m ia b a G o r a pi M i l P 31 A tro M b t m nd p b Low 250 erophon F r o a er S ¯ Bell az S d erla Do M e en lomite 52 b is O m M o r S b lit 44 an Luc e o ano Mb F 45 n e 46 Fm f 53 Gröden r 47 e 48 W 0 m ¯ FIG. 1: Stratigraphic scheme of the Permian to Upper Triassic succession of the Western Dolomites. Geological Map of Südtirol/Alto Adige, Western Dolomites, 1:25.000 (2019). 47 Geo.Alp, Vol. 16 2019 transferred to the Dolomites and defined here by Bosellini often difficult to identify in individual outcrops, in particular (1968) and Broglio Loriga et al. (1983) as Werfen Formation, if the sequence is disturbed. An easily recognisable criterion subdivided into subformations (members). However, the clearly for mapping in the field is the increase in the terrigenous different facial and lithological development in the type region siliciclastic content, which can be observed in the background in the Northern Calcareous Alps requires a new definition (see sedimentation even in facially different sequences. Both the also Neri (2006). If the term "Werfen" is to be retained, it can only Gastropod Oolith and the Campil Members were distinguished be used as in "Werfen Group". This would have the advantage from the Seis Member by the appearance of the first distinct that comparable developments in the Werfen facies (mixed layers of fine-grained sandstone. siliciclastic-carbonatic, cyclical sedimentation in shallow shelf environments with specific faunal developments) could be Peres Formation: The term was introduced by Pia (1937) summarized by the term "Werfen Group". In wide areas of the and extended by Bechstädt & Brandner (1970). It refers to western Tethys, developments in the Werfen facies presently terrigenous clastic deposits with silty, mostly red marls and carry different formation names in different countries. Use of intercalated lenses of conglomerates. In the basin area of the term Werfen Group would mean that units, which in the the Prags/Braies Group, the Peres Formation occurs at three Dolomites are currently defined as members, would become stratigraphic levels (Lower, Middle and Upper Peres Beds in formations (fig. 2). The possibility to map these units, which Bechstädt & Brandner, 1970), which combine to one level on is a basic prerequisite for the term ‚formation‘, is given, and the adjacent Etsch-Gadertal/Adige-Val Badia platform and are mapping has already been carried out on all new map sheets, no longer distinguishable here. The individual designation of albeit using the member classification. Unfortunately, the the three horizons with their conglomerate intercalations (Piz proposal for a new classification could not yet be introduced da Peres Conglomerate, Voltago Conglomerate and Richthofen for the Geological Map of the Western Dolomites, as the editors Conglomerate, according to De Zanche et al., 1992) does not of adjacent geological maps of the CARG project as well as appear useful for the mapping of the entire area and was the client (Geological Survey of South Tyrol) were afraid of a therefore not applied. In the area of the western Etsch/Adige confusion of terms. platform, it is not possible either to distinguish correctly between the various conglomerates. Therefore, the term "Peres For mapping reasons, the "Gastropod Oolith Member" was Formation" was given preference here (Geological Base Map assigned to the Campil Member (in anticipation of the future of the A.P.B., sedimentary cover, 2003, sheets Bozen/Bolzano, formation name) in certain areas, where separation between Eppan/Appiano, Mezzolombardo and Predazzo; unpublished). the two members in the field was not possible. The Gastropod Oolith Member is very variable in the Dolomites and adjacent Schlern Group: This is a collective term for the Upper Anisian areas (see e.g. Venturini et al., 2009, in the Carnic Alps) and is to Lower Carnian carbonate platforms between the Contrin Brandner et al.,2019 S. Lucano-Fm. Cencenighe- Formation Val Badia- Formation Campil- Formation Gastropod. Oolith-Mb. Werfen-Gruppe Seis-Fm.S Andraz-Mb. Mazzin-Fm. A Tesero-Mb. FIG.Tabelle 2: Proposal von for Neri, a new classificationC. (2006), of APAT the Werfen Formation in the Western Dolomites. The introduction of the new term „Werfen Group“ is indicated to have the possibility to include the „Werfener Schichten“ of the type locality in Salzburg with their quite different lithological habit. 48 Geo.Alp, Vol. 16 2019 Formation and the Raibl Group. The newly introduced term volcanites of the Fernazza Formation, overlies the Col Rodela is appropriate in those areas where continuous carbonate Olisthostrom. The area of origin of the gravitational sliding platform developments are present without intercalation of blocks is the transpressive bulging zone in the area of Cima carbonates interfingering with basinal sediments or volcanites. Bocche-Costabella (Doglioni, 1984). This is the case, for example, at the western edge of the Schlern/Sciliar massif or at the northern edge of the Dolomites Raibl Group: The Raibl Group is divided into three formations (Toblach/Dobbiaco sheat). The "Sexten/Sesto Dolomite Group" in the mapped area: Pordoi Formation, Heiligkreuz Formation on the geological map of the Sexten/Sesto Dolomites Nature and Travenanzes Formation. Park 1:25,000 (2004) is equivalent to the Schlern Group.