Biodiversity of museum and bulk field samples compared: The Eocene Chiampo sponge fauna, Lessini Mountains, Italy

The sponge body fossils from the Lutetian (Eocene) of Chiampo Valley in north-eastern Italy, Lessini Mountains, exhibit a high diversity. The fauna, comprising 32 species, was recently described in a systematic study based on museum material. Here we compare diversity measures and rank-abundance distributions between the museum material and new material from random surface collection at the original sampling site. Not surprisingly, we find that selectively collected museum material tends to have greater diversity and evenness than bulk field samples. Nevertheless, abundance rank- orders are maintained between samples. Bulk field sampling revealed hexactinellids to be strongly dominant over lithistids, which suggests a deep-water setting of greater than 200 m water depth

Geometry and stratigraphic relationships of lower Oligocene coral reefs in Lumignano (Berici Hills, northern Italy)

The Cliffs of Lumignano (Northern Italy) are a renowned climbing area, set on the steep walls of lower Oligocene limestones of the Castelgomberto formation which are made mainly of coral boundstone. Lumignano lies approximately on the south-eastern margin of a Cenozoic carbonate platform known as the Lessini Shelf, but the depositional environment of coral reefs is still debated, and it is unclear whether it was a Caribbean-type carbonate platform with a lagoon and steep slope, or a carbonate ramp with coral reefs on the mid ramp. We produced a geological map of the Lumignano area, in which five lithofacies are distinguished and mapped within the Castelgomberto formation. Their spatial distribution and main sedimentological characters outline that landward of coral reefs, a high-energy environment was present and was shallower than the reefs. Seaward of coral reefs, coralline algae and marlstones with bryozoans occur, while no evidence of a slope made of coral rubble was found. Hence, the detailed geological mapping and the documentation of the stratigraphic relationships between lithofacies provided a valuable contribution to the understanding of depositional environments of the lower Oligocene Lessini Shelf. This work also suggests elements for a better definition of the Castelgomberto formation, which could be split in members or lithofacies that can be mapped at a reasonably large scale (1:10000). The coralline algal lithofacies of the Castelgomberto formation is locally indistinguishable from the analogous facies of the underlying Priabona formation, but the boundary between these two units is always marked by an unconformity, which is easy to identify and may be used for the lithostratigraphic definition of the Castelgomberto formation

Pre-Alpine and Alpine deformation at San Pellegrino pass (Dolomites, Italy)

In this work, we present the geological map of the San Pellegrino pass, inserted in the spectacular scenario of the Dolomiti region (Southern Alps, Italy), at a scale of 1:10.000 and accompanied by geological cross-sections. The detailed distinction of lithological thin units allowed to achieve a consistent interpretation of the local structural setting by drawing brittle and ductile Alpine tectonic deformations. The differential deformation and structural styles within the geological map are the result of the different rheological nature of volcanic and sedimentary rocks, as well as of the superimposition of compressional Alpine tectonics over Permo-Mesozoic extensional tectonic phases, and consequent reactivation of inherited structures

Update of ichnofaunal units and link with footprint biochrons in the late Palaeozoic to early Mesozoic of the Southern Alps: towards a better correlation with the marine realm

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A continental/siliciclastic to shallow-marine/carbonate system in the Upper Triassic of Dolomites (Travenanzes Formation, northern Italy)

La Formazione di Travenanzes (ex Formazione di Raibl Auctorum) \ue8 una successione mista silicoclastico/carbonatica di ambiente da continentale a marino-marginale e di clima arido che si deposit\uf2 nel Sudalpino orientale durante il Carnico superiore (Tuvalico). La deposizione avvenne in un\u2019area costiera a basso gradiente, alimentata da sedimenti provenienti da rilievi meridionali e aperta verso nord-nordest alla Tetide. L\u2019ambiente deposizionale della Fm. di Travenanzes \ue8 stato ricostruito in Dolomiti ed inquadrato nell\u2019ambito di un sistema di piana alluvionale \u2013 piana costiera inondabile - laguna a sedimentazione carbonatica. La porzione continentale del sistema deposizionale carnico \ue8 costituita da un sistema fluviale di tipo \u201cterminal fan\u201d caratteristico di clima arido con precipitazioni stagionali, dove l\u2019intensa evaporazione ed infiltrazione porta alla diminuzione della portata e delle dimensioni dei canali fluviali verso mare, fino alla totale scomparsa della rete idrografica superficiale in corrispondenza di una piana fangosa costiera, prima della linea di costa. La piana costiera fangosa costituisce la zona di interazione tra sistema continentale e marino, essendo temporaneamente inondata durante le tempeste marine e le piene fluviali maggiori. Localmente il clima arido porta allo sviluppo di una \u201csabkha\u201d costiera con precipitazione di anidrite nodulare e \u201cchicken-wire\u201d, e gesso laminato. La porzione marina del sistema deposizionale carnico \ue8 costituita da piane tidali e lagune poco profonde a sedimentazione carbonatica, caratterizzate da dolomie afanitiche, cristalline, laminate e marnose, organizzate frequentemente in cicli peritidali metrici del tutto simili a quelli della soprastante Dolomia Principale, e subordinate intercalazioni di peliti scure. Distinti modelli di facies possono essere applicati separatamente alla porzione continentale e marina del sistema, ma un modello deposizionale comprensivo dell\u2019intero sistema non \ue8 ancora stato descritto in letteratura. Punto chiave per la sua elaborazione \ue8 la comprensione dei processi deposizionali che avvengono sulla piana costiera inondabile. In conclusione, la Formazione di Travenanzes \ue8 un esempio di sistema a sedimentazione mista di clima arido e di ambiente di transizione continentaleparalico- marino marginale, ed il suo confronto con casi analoghi, antichi e attuali, potrebbe essere utile alla costruzione di un modello deposizionale di validit\ue0 generale e applicabile ad altri casi di studio nella storia della Terra