ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Geo.Alp Jahr/Year: 2016 Band/Volume: 013 Autor(en)/Author(s): Kustatscher Evelyn, Bernardi Massimo, Petti Fabio Massimo, Avanzini Marco, Tomasoni Riccardo Artikel/Article: Field trip 2 Late Paleozoic and Mesozoic terrestrial environments in the Dolomites and surrounding areas 71-116 Geo.Alp, Vol. 13 2016 71 - 116 Field trip 2 Late Paleozoic and Mesozoic terrestrial environments in the Dolomites and surrounding areas Evelyn Kustatscher1,2, Massimo Bernardi3,4, Fabio Massimo Petti3,5, Marco Avanzini3 & Riccardo Tomasoni3 1 Naturmuseum Südtirol, Bindergasse 1, 39100 Bozen/Bolzano, Italy; e-mail: [email protected]; 2 Department für Geo- und Umweltwissenschaften, Paläontologie und Geobiologie, Ludwig-Maximilians- Universität and Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Straße 10, 80333 München, Germany; 3 Museo delle Scienze di Trento, Corso del Lavoro e della Scienza 3, 38123 Trento, Italy; e-mail: [email protected], [email protected], [email protected], [email protected]; 4 School of Earth Sciences, University of Bristol, Bristol BS81RJ, UK; 5 PaleoFactory, Dipartimento di Scienze della Terra, Sapienza Università di Roma, P.le Aldo Moro 5, 00185, Roma, Italy. 1 Topics and highlights of the excursion Mojsisovics, 1879, 1882; Mojsisovics et al., 1895; Bittner, 1892; Brack et al., 2005, Mietto & Man- The Southern Alps represent one of the classical frin, 1995; Mietto et al., 2003, 2012). Since 1970, areas for the study of Late Paleozoic to Early the number of studies in petrology, stratigraphy, Mesozoic stratigraphy. Spectacular outcrops sedimentology and palaeontology conducted allow exceptional insights into the genesis of the in the area has increased substantially (Gianolla Permian continental-marine succession, Middle– et al., 2009–2010; Roghi et al., 2014, and refer- Upper Triassic carbonate platforms and Juras- ences therein) and the integration of numerous sic shallow-marine to coastal successions. This well-correlated sections has resulted in a reliable area played an important role in the history of biostratigraphic framework (ammonoids, bivalves, geology: in the 18th century Giovanni Arduino conodonts, sporomorphs) tied to radioisotope introduced in the Venetian and Recoaro Alps the age data and magnetic reversals (especially for subdivisions that now identify the four Erathems the PT-boundary, and the Anisian–Ladinian and (Primary to Quaternary). Déodat de Dolomieu the Ladinian–Carnian boundary intervals; see collected in the Etschtal/Valle dell’Adige the car- Roghi et al., 2014 and references therein). At the bonate rock called in 1792 Dolomie by Nicolas de same time, several studies based on discoveries Saussure (Zenger et al., 1994; Mckenzie & Vascon- made in the area allowed deriving new palaeo- celos, 2009). The granitoid intrusions that meta- ecological and palaeobiological models, which morphosed the Middle Triassic limestone rocks gave new insight of broad evolutionary interest in the area of Predazzo and Passo San Pellegrino (e.g. Schmidt et al., 2006; Posenato et al., 2014; played a major role in the demise, in the early Bernardi et al., 2015). Last but not least, since 2009 19th century, of the Neptunist Theory. Further- the Dolomites are included in UNESCO natural more, since the late 19th century the Southern world heritage list which explecitely acknow- Alps and the Northern Calcareous Alps have been ledges the “spectacular landscapes, which reflect used to define the global Permian–Triassic stratig- the complex geological architecture of the region” raphy and biostratigraphy (e.g., Richthofen, 1860; (Gianolla et al., 2009). 71 Although famous for its Triassic marine basinal 2 Geological and environmental settings and platform successions, the Dolomites include also important non-marine successions. The The stratigraphic framework of the Dolomites Athesian Volcanic Group represents the largest includes Permian to Cretaceous formations (for a and best outcropping lower Permian volcanic more detailed overview see Gianolla et al., 2009), area in Europe. Volcanic rocks are locally inter- although the area is mostly famous for its Triassic calated with sedimentary successions marking successions, making the region a classical study periods of volcanic inactivity. This alternation area for the stratigraphy of this period (see Roghi between radiometrically dated volcanic rocks et al., 2014). The stratigraphic basement is com- and fluvio-lacustrine sedimentary successions posed of lower Palaeozoic rocks, deformed and gives the latter an exceptional time constrain. The metamorphosed by the Carboniferous Variscan early Permian Athesian Volcanic Group is covered Orogeny (Brixen Quarzphyllite), covered by the by the late Permian fluvial Gröden/Val Gardena first erosive event, the Waidbruck Conglomer- Sandstones. During the Triassic non-marine suc- ate (Avanzini et al., 2007, 2012, 2013). An early cessions are rare. Terrestrial sediments can be Permian (trans-)tensional rifting resulted in an found locally in the coastal Early Triassic Werfen important volcanic activity that accumulated Formation, the middle Anisian Piz da Peres For- massive volcanic successions (Athesian Volcanic mation and Richthofen Conglomerate, subaerial Group); during the periods of quiescence fluvio- settings of the middle Ladinian magmatic event lacustrine sediments deposited in small, local and the middle–late Carnian paralic Travenanzes basins (Avanzini et al., 2007, 2013; Morelli et al., Formation. During the Early Jurassic the typical 2007; Marchetti et al., 2015). The middle Permian shallow-water limestones of the Calcari Grigi is missing due to an important unconformity, Group locally developed coastal facies that record while the late Permian is mostly represented by terrestrial biota. fluvial red beds of the Gröden/Val Gardena Sand- stone (Massari & Neri, 1997). A marine transgres- This excursion will take us to some of the most sion from the East covered the area and triggered interesting outcrops of non-marine environ- the accumulation of shallow marine evaporites ments in the Dolomites and surrounding areas. and carbonates (Bellerophon Formation). The This includes the late Permian Gröden/Val Gar- end-Permian mass extinction and its aftermath dena Sandstone of the Bletterbach gorge, the (Benton & Twitchett, 2003) are represented by the Middle and Late Triassic successions of the storm-dominated, shallow marine carbonate and Etschtal/Valle dell’Adige and Nonstal/Val di Non terrigenous deposits of the basalmost Werfen For- (Bad Gfrill/Bagni di Caprile, Gampenpass/Passo mation (e.g., Farabegoli et al., 2007). The strong Palade, Mt. Roen) and the Lower Jurassic suc- tectonic activity of the Anisian basins (especially cessions of the famous Lavini di Marco dinosaur to the east) and emerged areas (especially to the tracksite, near Rovereto. These sections, most of west) (Bosellini, 1968), subjected the area to sev- which intensively restudied in the last years by eral emersion episodes and a differential subsid- the authors of this guide, yielded well preserved ence (De Zanche et al., 1992, 1993; Gianolla et al., plant remains, diverse tetrapod footprints as well 1998a). These sequences are marked by subaerial as insect traces giving important insights into the unconformities, and formed by continental con- paleoenvironmental and climatic conditions at glomerates, shallow-water terrigenous-carbon- the paleotropics during the late Palaeozoic and ate deposits and finally deep-water sediments or Mesozoic. prograding carbonate platforms. During the early This field trip guide has been compiled by the Ladinian, the subsidence slowed down and the authors based on personal data and observations isolated nuclei expanded to large, up to thousand but is largely based on several key publications of meters thick, platforms (Schlern/Sciliar Dolomite, the same authors plus co-authors, namely: Avan- Bosellini, 1984) while in the basins tens of metres zini et al. (1997, 2002a, 2013), Gennaro (2007), of nodular-cherty limestones formed (Buchen- Petti et al. (2013), Roghi et al. (2014). stein/Livinallongo Formation). During the middle 72 Geo.Alp,Vol.13 2016 Ladinian a violent massive intrusive and effusive Bletterbach Gorge we will follow the evolution magmatic activity in the Predazzo and Monzoni of this sector of the Alps from the uppermost area formed locally subaerial areas, huge hetero- portion of the Athesian Volcanic Group (Auer/ geneous megabreccia bodies (Caotico Eteroge- Ora Formation; early Permian) to the Gröden/Val neo), pillow lavas and hyaloclastites. After the Gardena Sandstone (late Permian) fluvial depos- magmatic activity, the carbonate production its. During the second day we will move up from restarted with a widespread progradation (Cas- the Permian formations (Lana neighbourhood) sian Dolomite) and a high basinal sedimentation to the Middle Triassic of the Gampenpass/Passo rate (St. Cassian/San Cassiano Formation). Later, Palade observing a nearly complete stratigraphic the basins were filled by mixed terrigenous- succession. During several stops on the road from carbonate deposits (Heiligkreuz Formation) that Lana to the pass (S.S. 238) we will see the different register several moist phases and yielded some of members of the Induan-Olenekian marine Wer- the oldest known amber with inclusions of micro- fen Formation,