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In the Perda S’altari area, north of Fluminimaggiore, black shales of the Silurian Genna Muxerru Formation and limestones of the Devonian Mason Porcus Formation are exposed. The area is strongly tectonized, and poorly preserved fossils occur only in a few outcrops. Graptolites of Telychian and Rhuddanian age have been collected from the shales, whereas conodonts indicate the Lochkovian Icr. postwoschmidti and Ad. transitans zones. The problematic Eurytholia bohemica species is here documented from Devonian rocks for the first time outside the Czech Republic. A gradual transition between the Genna Muxerru Fm. and the Mason Porcus Fm. suggests an update to the lithostratigraphical scheme of the Silurian and Lower Devonian of SW Sardinia.

Vengono descritti gli aspetti geologici, paleontologici, mineralogici e naturalistici dellìarea di Pramosio-Avostanis nelle Alpi Carniche

Guidebook of the field trip in the Carnic Alps

Zieglerodina eladioi (Valenzuela-Ríos) is a small ozarkodinid from the latest Přídolí (Silurian) and the Lochkovian (Lower Devonian), up to now documented only in areas of North Gondwana. Material from Morocco, the Carnic Alps, and Sardinia provide the basis for the seximembrate reconstruction of this conodont species’ apparatus (consisting of P1, P2, M, S0, S1, and S2 elements). The ramiform elements of Zieglerodina eladioi are characterised by an alternate denticulation with spike-like denticles, further confirming the attribution of the species to the genus Zieglerodina.

The Hoher Trieb Formation consists of five well-bedded facies listed below: Facies A: medium dark gray very thick-bedded rudstone and floatstone; matrix consists mainly of grainstone; silicified corals are common among the clasts; Facies B: medium dark gray thin to thick-bedded pack-/grainstone locally showing evidence of tractive structures; Facies C: medium dark gray thin to medium-bedded wackestone; Facies D: black thin to medium-bedded laminated cherts; cherts are also locally present in nodules mainly within facies C; Facies E: black very thin to thin-bedded laminated shales.

The Rauchkofel Formation mainly consists of dark gray to black laminated and well-bedded, partly platy limestones intercalated with black shales and marls of various thickness. Lateral variations are common. Thickness of beds varies from very thin to medium for limestones. Black graptolitic shales with graptolites are more abundant in the lower part of the unit, where they may constitute levels up to 15 cm thick. In the proximal parts of the basin thick to very thick calcarenitic beds and breccias occur more frequently in the upper part of the unit, but in places they may occur also in the lowermost part. A distinct horizon with loboliths is present in the lowermost part of the formation.

The Kellerwand Formation consists of four well-bedded facies listed in order of decreasing abundance. Facies A: medium dark gray, thin to medium-bedded, wackestone to packstone with moderate yellow thin laminae of silt; Facies B: medium dark gray, thin to thick bedded, often fining upward, moderately to well sorted and locally laminated grainstone (from very coarse up to granules to fine-grained) to packstone; Facies C: medium light gray, medium to thick bedded, moderately to well sorted crinoidal-bearing grainstone (biosparite); Facies D: medium dark gray, thick bedded, poorly sorted coral-bearing rudstone with clasts up to about 10 cm of diameter and poorly sorted very coarse to fine grainstone matrix.

The Findenig Formation consists of red to pink nodular centimetric thick beds of mudstone/wackestone, with interlayered millimetric to centimetric red marls, and, at places, some centimetric to decimetric calcarenitic (grainstone) intervals (allodapic layers) and breccia (calcirudite) beds in the upper part of the unit.

Medium dark gray, very thick bedded (more than 10 m), poorly sorted, coral- and stromatoporoid-bearing rudstone and subordinate floatstone with clasts up to ca. 40 cm of diameter and poorly sorted, very coarse to fine grainstone matrix; sometimes rudstone shows a fining upward trend up to grainstone. Sometimes the layer base shows inverse grading with laminated grainstone passing to floatstone/rudstone. However, the deposits are mostly disorganised.

A small collection of echinoderm holdfasts from the Ludlow Cardiola Formation of the Carnic Alps (Austria) contains a wide range of morphologies as a response of environmental adaptation. In general, the holdfasts have a globous and massive dome-like profile with several processes arranged in a sub-radial disposition, so to create a sort of “star-like” outline. A small central depression is common but not present on all specimens. The distinctive holdfasts are preserved in an iron-rich phase, documenting a substitution that has also affected other non-echinoderm calcareous material.

The Carnic Alps correspond to the non- to low-metamorphic portion of the Variscan substratum of the Southern Alps, and display an Upper Ordovician to Upper Carboniferous succession that represents the best preserved example of Variscan succession within the Alps. The Pragian to Frasnian stratigraphic interval is characterized by the differentiation of the basin in shallow water, including carbonate buildups, and pelagic parts, and the so-called ‘transitional facies’ represent a sort of ‘connection’ between these two parts. We analyzed the depositional evolution of the basin through these facies because they 1. reflect well the depositional dynamics; 2. are datable using conodonts, unlike the shallow water units; 3. are less subject to tectonic elisions/repetitions than the basinal units. We performed geological mapping, measured stratigraphic sections of all the units and dated by conodonts all the lithostratigraphic transitions, in order to infer the lateral correlations throughout the basin, also supported by some marker beds/levels. The depositional environments of the different units have been recognized. The main aspects of the basin evolution can be summarized as follows. A transgression between the uppermost Lochkovian and the basal Pragian drowned the first patch reefs recorded in the Carnic Alps. The margin was ramp-type until the Emsian with patch reefs and shoreface deposits distally passing to tempestite and pelagic sediments. During the Emsian, a by pass slope margin separating the shallow water and the basin started to develop as shown by the increasing amount of gravitative driven deposits that persisted until the lower Famennian. In the lower Givetian the gravitative-driven deposits show their maximum progradation on top of the basinal deposits. From the Frasnian, a transgression, possibly enhanced by extensional or transtensional tectonic activity, led to progressively drowning of the carbonate buildups. The depositional evolution appears to follow the supra-regional eustatic trends until the Frasnian. From the Frasnian, the evolution differentiates from the eustatic supra-regional trends, suggesting the importance of a local tectonic control.

A small collection of echinoderm holdfasts from the Ludlow Cardiola Formation of the Carnic Alps (Austria) contains a wide range of morphologies as a response of environmental adaptation. In general, the holdfasts have a globous and massive dome-like profile with several processes arranged in a sub-radial disposition, so to create a sort of 'star-like' outline. A small central depression is common but not present on all specimens. The distinctive holdfasts are preserved in an iron-rich phase, documenting a substitution that has also affected other non-echinoderm calcareous material.

Situato circa a metà della strada che congiunge Paularo a Pontebba, il Passo del Cason di Lanza è lo spartiacque tra il Torrente Pontebbana, che scorre a est per gettarsi nel Fella presso Pontebba, e il Rio di Lanza che, unendosi a ovest al Rio Cercevesa presso Ramaz, dà origine al torrente Chiarsò. Secondo la tradizione popolare il nome deriva dalle lance che si rinvenivano, assieme ad altre armi, in quest’area, testimonianze della vittoriosa battaglia che le truppe della Repubblica Veneta, aiutate da volontari friulani, combatterono contro i turchi nell’estate del 1478. La Valle del Rio di Lanza e la testata di quella del Torrente Pontebbana sono una tra le più interessanti aree naturalistiche della Regione. La diversità degli ambienti naturali che caratterizza i dintorni del Cason di Lanza è legata alle particolari condizioni geologiche di queste valli. Antiche rocce formatesi nei mari del Paleozoico affiorano diffusamente e conservano importanti testimonianze della vita che popolava quei mari centinaia di milioni di anni fa: i fossili.

The Global Stratotype Section and Point (GSSP) of the Silurian/Devonian boundary, Lower Devonian Series and Lochkovian Stage was formally placed in 1977 at Klonk, in the Czech Republic, at the first appearance of the graptolite Uncinatograptus uniformis uniformis (Přibyl). However, since then, correlation of this limit has been often hampered in carbonate facies where graptolites are uncommon or totally absent. A large calcareous deposition occurred at the Silurian/Devonian boundary along the northern and peri-Gondwana margin, thus representing an ideal location to select and test a possible additional biostratigraphic marker of the limit among conodonts. The first appearance of Caudicriodus hesperius almost simultaneously at the base of the Devonian in Bohemia, the Carnic Alps, Sardinia, Morocco and elsewhere indicates that this taxon is the conodont that best approximates the beginning of the Period. The first or last appearance of other species (e.g., Ozarkodina confluens, Zieglerodina klonkensis, Z. remscheidensis and Caudicriodus woschmidti) may help to recognise the boundary as well.

The ontogeny of the Lochkovian conodont species Ancyrodelloides carlsi (Boersma) is demonstrated thanks to a rich population from Morocco. The studied sample includes elements at various growth stages from juvenile to gerontic. The data are confirmed by several elements in collections from several localities in the Carnic Alps (Italy and Austria). The absence of terraces at every stage of growth and the presence of a strong denticulated lateral process confirms the generic attribution of the species to genus Ancyrodelloides. Comments on the apparatus are provided. The geographical distribution of the species, limited to Europe and the Mediterranean region, challenges its stratigraphic value for long distance correlations.

The Rio Malinfier West section in the central Carnic Alps provides important data on the evolution of the Lochkovian (Lower Devonian) sedimentary basins of the Variscan belt. An exposure of about 100 m documents five lithostratigraphic units (Alticola, Rauchkofel, Nolbling, La Valute and Findenig formations) spanning in age from the latest Silurian to the Early Devonian. The complex structural setting of the section results from a main fault dividing the succession in two separate segments. A precise lithological characterization was carried on at a macro- and micro-scale. Macrofauna includes, among others, abundant cephalopods and crinoids (loboliths). The biostratigraphic assignment to the uppermost Silurian-lowermost Devonian (Lochkovian) was possible basing on a moderately abundant conodont fauna, that provided thirty-two taxa belonging to thirteen genera, among which the new species Zieglerodina schoenlaubi. The Rio Malinfier West section testifies that a differentiation between shallow and deep water parts of the Devonian basin was already present during Lochkovian times, prior to the establishment of the conditions enabling the colonization of the well-known upper Lower-Middle Devonian reef buildings.

A trace fossil assemblage from the Silurian (Llandovery) black shales of the Genna Muxerru Formation is reported for the first time. The ichnofossil record is abundant, well-preserved and comprises Alcyonidiopsis, Cochlichnus, Phymatoderma, Planolites (large morphotype), Planolites (rough morphotype) and a ‘Small chondritid’. Sedimentological and ichnological evidence indicates that the bioturbated black shales were deposited in outer shelf (or deeper) settings with severe depletion in oxygen. The seafloor provided a high food supply for the infauna. The palaeoenvironment of the Genna Muxerru Formation is an ancient analogue of modern oxygen-minimum zones. Burrow fills are apparently massive in macroscopic view, whereas observations under the petrographic and stereoscopic microscope show that a lifestyle dominated, i.e. that of pellet-filling sediment-feeders. As such, the Genna Muxerru Formation provides not only a new ethologic reference for low-oxygen settings but also a methodological benchmark for ichnological analysis of black shales. Bioturbation in black shales may be commoner than expected but its recognition requires microscopic observation.

In the Carnic Alps, located across the border between Italy and Austria, several sections span the Silurian/Devonian boundary in different sedimentary settings, from very shallow water to moderately deep shelf. All studied sections yielded conodonts and based on the first and last occurrences of the conodont taxa in the upper part of the Upper Oul. el. detortus Zone and in the lower part of the I. hesperius Zone a detailed conodont biostratigraphic framework was able to be constructed for this interval. Comparison of data from different depositional settings demonstrates that, although the majority of species are documented everywhere in the Carnic basin, a few taxa, mainly represented by coniforms, are limited to shallow water, whereas others, mainly ozarkodinids, occur only in open sea deposits.

In Sardinia (Italy) two sections, located in the southeastern part of the island, expose the Devonian/Carboniferous Boundary: the Monte Taccu Section and the Bruncu Bullai section. Both expose limestones from the middle Famennian to the lower Tournaisian Siphonodella jii Zone. The limestone sequence is interrupted by a thin level of shales representing the Hangenberg Event. Data on conodont biostratigraphy and magnetic susceptibility across the Devonian/Carboniferous Boundary are here summarised and reviewed.

An updated stratigraphy of the Rauchkofel Boden Section, a classical reference section for the Carnic Alps that exposes rocks from the Katian (Upper Ordovician) to the Pragian (Lower Devonian) is here presented, following latest developments in conodont taxonomy and biostratigraphy, as well as in chrono stratigraphy, and the recent introduction of a new lithostratigraphic outline of the Carnic Alps. The original conodont collection of the '70s and ’80s was restudied and complemented by a detailed resampling in order to achieve a more precise conodont biostratigraphic assignment. Twenty-five conodont Zones are now documented. The lithostratigraphy is precisely fixed to the new lithostratigraphic scheme of the Pre-Variscan sequence by definition of seven distinct formations. Finally, the position of chronostratigraphic boundaries is discussed.

The main conodont zonation schemes for the Pridoli and the Lochkovian presents some problems that make difficult their use in several geographical areas. Data from several sections in Sardinia and the Carnic Alps not only allow to built a regional zonation scheme for these areas, but also suggest possible solutions of global validity. In the Carnic Alps and Sardinia, the Přídolí is subdivided into three zones: Eosteinhornensis s.l., Lower and Upper detortus. The latter results after the subdivision of the former detortus Zone on the basis of the Last Appearance Datum of some coniform species (Dapsilodus obliquicostatus, Coryssognathus dubius and Panderodus recurvatus) that became extinct almost simulta-neously in the latest Přídolí. Daps. obliquicostatus is chosen as the marker, being the most common and easily identifi-able species. In the Lochkovian six zones are discriminated: Hesperius, carlsi, transitans, eleanorae, trigonicus and pan-dora β. The hesperius Zone, which includes the postwoschmidti subzone in its upper part, is expanded to include most of the eurekaensis zone of the "global" scheme, because the marker Oz. eurekaensis is not present. The carlsi Zone corre-sponds to the upper part of the eurekaensis Zone and to the lower part of the former mid-Lochkovian delta Zone (= omoalpha Zone). The rest of the Middle Lochkovian is subdivided into the three zones (transitans, eleanorae and trigonicus) already proposed in Nevada and Spain, followed by the pandora β Zone. All the zones are discussed and checked for their applicability in other palaeogeographical regions.

A small collection of echinoderm holdfasts from the Ludlow Cardiola Formation of the Carnic Alps (Austria) contains a wide range of morphologies as a response of environmental adaptation. In general, the holdfasts have a globous and massive dome-like profile with several processes arranged in a sub-radial disposition, so to create a sort of ‘star-like’ outline. A small central depression is common but not present on all specimens. The distinctive holdfasts are preserved in an iron-rich phase, documenting a substitution that has also affected other non-echinoderm calcareous material.

The new genus Walliserognathus is described to host the species posthamatus (Walliser). The genus is monospecific. The shape of P1 and P2 elements of Walliserognathus posthamatus, characterized by a small platform along the whole elements, and its stratigraphic distribution limited to the Ancoradella ploeckensis Zone suggest that the species may have been the bridge in the phylogenesis from Wurmiella to Polygnathoides.

The Vinz Formation consists of four well-bedded facies listed in order of decreasing abundance. Facies A: well bedded medium dark gray, medium to thick bedded, poorly sorted coral- and stromatoporoid-bearing rudstone (more rarely floatstone) with clasts up to about 10 cm of diameter and poorly sorted very coarse to fine grainstone matrix; sometimes rudstone shows a fining upward trend up to grainstone; Facies B: medium dark gray, thin to medium bedded, wackestone to packstone with moderate yellow thin laminae of silt; Facies C: medium dark gray, thin to thick bedded, often fining upward, moderately to well sorted locally laminated grainstone (from very coarse up to granules to fine-grained) to packstone; Facies D: rare medium light gray, medium to thick bedded, moderately to well sorted crinoidal-bearing grainstone with sparite cement.

An overview of the geological evolution of the Carnic Alps during the Palaeozoic is presented: the Variscan sequence, the Permo?Carboniferous sequence and the basal part of the Alpine sequence were deposited between the Late Ordovician and the Middle Triassic.