Glomospira kaminskii sp. nov., a new agglutinated Foraminifera from the Paleocene of the Scaglia Rossa Formation, Contessa, Italy

This paper describes two Paleogene deep-water agglutinated foraminiferal species from the Contessa Highway Section of the Umbria–Marche Basin, Italy. The foraminiferal assemblages in the lowermost Paleogene are dominated by opportunistic species belonging to the Reophax group. Previous studies of the agglutinated foraminifera from the Scaglia Rossa Formation have reported hormosinids (Reophax spp.) mostly using open nomenclature. To facilitate the proper species assignment according to accurate species descriptions, we describe the new species Nodulina kuhnti n. sp. and Nodulina eugubina n. sp. Both species are characterized by their more or less straight elongated tests with horizontal sutures, and therefore are best assigned to the genus Nodulina. They constitute a significant component of the benthic foraminiferal assemblage in the stratigraphic interval above the K/Pg boundary.

Deep-sea benthic foraminiferal recolonisation following a volcaniclastic event in the lower Campanian of the Scaglia Rossa Formation (Umbria–Marche Basin, central Italy)

High-resolution Hg chemostratigraphy: A contribution to the distinction of chemical fingerprints of the Deccan volcanism and Cretaceous–Paleogene Boundary impact event

This paper describes two Paleogene deep-water agglutinated foraminiferal species from the Contessa Highway Section of the Umbria–Marche Basin, Italy. The foraminiferal assemblages in the lowermost Paleogene are dominated by opportunistic species belonging to the Reophax group. Previous studies of the agglutinated foraminifera from the Scaglia Rossa Formation have reported hormosinids (Reophax spp.) mostly using open nomenclature. To facilitate the proper species assignment according to accurate species descriptions, we describe the new species Nodulina kuhnti n. sp. and Nodulina eugubina n. sp. Both species are characterized by their more or less straight elongated tests with horizontal sutures, and therefore are best assigned to the genus Nodulina. They constitute a significant component of the benthic foraminiferal assemblage in the stratigraphic interval above the K/Pg boundary.

Morphogroup analysis of benthic foraminifera is a useful tool that reflects the nature of the trophic continuum, and in particular the flux of organic matter to the sea floor and its source. In broad terms, agglutinated benthic foraminifera can be placed in four morphotypes based on their test morphology and feeding preference. Morphotype M1 constitutes tubular suspension feeders that trap food particles carried in suspension. Morphotypes M2 and M3 are the coiled multichambered forms, which are epifaunal detritivores, and M4 is the group of elongated and rectilinear infaunal deposit feeders. Their relative proportions tell us something about flux of particulate organic carbon (POM) to the sea floor and its mode of delivery, which is ultimately a function of water depth, currents, and the amount of surface-water phytoplankton production.To assess the trophic structure of the benthic foraminiferal community across the Cretaceous/Paleogene boundary in the western Tethys, we examined >70 samples from the Scaglia Rossa Formation in Gubbio, Italy. Samples were mostly collected at 10 cm spacing. We also recalibrated the age model for the Scaglia Rossa Formation in Gubbio using the 2020 geologic time scale. In the top two meters of the Maastrichtian, a gradual increase in the proportion of M4 is observed (to ca. 20%) leading up to the K/Pg boundary. These values fall abruptly to 7% in the beds immediately above the boundary clay, with more variable values in the lower Paleocene. This pattern can be interpreted as reflecting a modest but short-lived reduction in the total sea-floor organic flux following the boundary event (but not a “Strangelove Ocean”). Morphotype M1 shows a major reduction above the boundary, and there is a concurrent increase in the M2 morphotype. This implies a reduction in the amount of POM arriving at the sea floor from suspension. The increase in M2 suggests that there was greater influence of organic matter from bacterial sources in the early Paleocene.The recovery of the deep-marine ecosystem was prolonged, with M1 returning to Maastrichtian values approximately 3.4 m above the K/Pg boundary clay. Using our new age model, this is equivalent to 1.8 m.y. after the event. Our findings of a prolonged recovery are in line with the conclusions of nannofossil workers, who estimated that it took approximately 2 m.y. for the marine food web to fully reestablish itself after the K/Pg boundary event.

Summary The calcilutites of the mid-Cretaceous to uppermost Eocene Scaglia Rossa Formation in Italy have previously been interpreted as a continuous sequence of slowly deposited pelagic limestones. However, regional considerations of thickness, sedimentation rates and facies distribution, together with detailed analysis of composition, texture and sedimentary structures suggest that turbidity currents have played an important part in the deposition of, at least, the middle (Maastrichtian) member. Turbiditic calcilutites are very fine-grained and massive, whereas the pelagites are coarser-grained, mottled and bioturbated. There is, however, a continuous gradation of facies and processes between these two end-members, that we believe is applicable to many other modern and ancient deep-water carbonate systems. The common overlap of turbiditic and pelagic processes in fine-grained ‘pure’ carbonates arises partly from their relative lack of flocculation compared with muddier sediments.

The geometry of collisional mountain belts, which were formed at the expense of passive continental margins, is often complex because orogenic structures, such as thrusts and related folds, commonly interfere with pre-orogenic extensional structures, namely, normal faults, resulting in kinematically complex, composite structural assemblages. In these settings, analysis of the relationships between depositional and structural features may provide very useful tools to correctly unravel the local sedimentary and deformational history and relative ages of structures. Analysis of the relationships between minor normal faults and slumps near Frontale in the Umbria-Marche Apennines of Italy made it possible to correctly unravel the local chronology of events and hence to infer the depositional and deformation history of a part of the Upper Cretaceous–Paleogene Scaglia Rossa Formation pelagic basin. The results of this investigation made it possible to ascribe the normal faults to events that predate the construction of the Umbria-Marche mountain belt. Therefore, the normal faults at Frontale are distinct from those that overprint the main compressional structures responsible for the present-day seismicity of central Italy.

Cretoxyrhina mantelli was a large pelagic lamniform shark geographically widespread during the Late Cretaceous, and well known because of several nearly complete skeletons from the Western Interior Seaway of North America. Here we report 15 partial skeletons belonging to lamniform sharks from the ‘lastame’ lithozone of the Upper Cretaceous Scaglia Rossa Formation of the Lessini Mountains (northeastern Italy). Seven partial but articulated skeletons include tooth sets that allow a confident attribution to Cretoxyrhina mantelli based on dental morphologies. We review the taxonomic history of C. mantelli, evidencing that the taxon was erected by Agassiz (1835) and tracing back four of the original syntypes. Based on calcareous plankton biostratigraphy, the rock in which the Italian skeletal remains are embedded is constrained to the middle-upper Turonian. Total length estimates of the specimens suggest that the sample includes the largest specimen of Cretoxyrhina mantelli (615–650 cm estimated total length) known to date. The placoid scale morphology indicates that C. mantelli most likely was a fast swimmer with a similar ecology as the extant white shark, Carcharodon carcharias. The associated skeletal elements of the specimens represent large chondrichthyan deadfalls and the cadavers decayed on the seafloor where they remained exposed for several months, as indicated by bioerosional traces, some of which are interpreted as a product of bone-eating worm activities and other bioerosional traces with Gastrochaenolites-like structure. The Cretoxyrhina mantelli remains described herein provide new information about the ʻlastameʼ vertebrate assemblage, which seemingly was strongly dominated by chondrichthyans, especially lamniform sharks.

ABSTRACTA review of the remains of mosasaurine mosasaurs from the upper Campanian–Maastrichtian of Italy is provided. The first discoveries of mosasaur material from Italy are represented by a series of isolated teeth from the Scaglia Rossa Formation north of Vittorio Veneto (late Campanian). These teeth show some similarities to Prognathodon, Liodon, and Eremiasaurus, but are not identical and probably represent a new taxon. A partial mosasaur skull found south of Reggio Emilia in 1886 is potentially a new species of Mosasaurus, although more material is needed to support this possibility. This specimen is temporarily referred to M. cf. hoffmanni. A second fragmentary mosasaur skull was accidentally discovered in 1892 north of Verona during the demolition of a school (inside one of the building stones). Based on its general morphology, size, and dentition, this second specimen can be considered as very closely related to M. hoffmanni, but its older age (early–middle Maastrichtian) suggests that it likely represents a new species of Mosasaurus. We refrain from erecting new taxonomic names for these specimens pending the discovery of new, more complete material upon which satisfactory diagnoses can be based. The paleobiogeographic distribution of Mosasaurus hoffmanni, M. cf. hoffmanni, M. beaugei, Liodon, and Prognathodon is reviewed briefly.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at http://www.tandfonline.com/UJVP.

First associated tooth set of a high-cusped Ptychodus (Chondrichthyes, Elasmobranchii) from the Upper Cretaceous of northeastern Italy, and resurrection of Ptychodus altior Agassiz, 1835

An expanded Cretaceous−Tertiary transition in a pelagic setting of the Southern Alps (central-western Tethys)

Earthquakes are widely recognized as triggers for turbidites, submarine debris flows and slumps. In tectonically active areas, surprisingly small changes in stress can trigger seismic events, implying that past sea level changes may be important in controlling the timing of seismicity and the occurrence of turbidites. We apply this idea in an analysis of turbidites from the upper Cretaceous–Paleocene Scaglia Rossa Formation of the Umbria‐Marches region of Italy. These turbidites are composed of resedimented foraminiferal tests derived from fluidizing deep‐water (∼1500 m), pelagic sediments; seismic triggering is the most likely triggering mechanism given this setting and composition. The timing of these turbidites (and associated synsedimentary slumps), constrained by biostratigraphy and magnetostratigraphy, reveals an unusual, non‐random temporal pattern that appears to correlate well with proposed eustatic fluctuations. This correlation between turbidites and eustatic fluctuations leads us to suggest that stress and pore fluid pressure changes associated with changing sea level may trigger periods of increased seismicity in the geological past.

Modern convergent zones at tropical latitudes are characterized by subduction of carbonate sediment. Although carbonate response to deformation is different from clay, they are commonly treated as having a similar rheology. This approximation, though, is inadequate since carbonate behavior is complicated by cementation and pressure solution. Our goal, here, is to focus on the deformation of carbonate sediment in the footwall of a major fossil thrust zone and compare it with a possible scenario in a modern environment. The focus area is the Monti Sibillini Thrust, in the Umbria-Marche sector of the Northern Apennines where the pelagic, Late Eocene-Oligocene carbonates of the Scaglia Cinerea Formation are underthrusted beneath the late Cretaceous-Middle Eocene Scaglia Rossa Formation. The data collected during this meso-structural study allowed for an interpretation of the temporal and spatial relationships between the observed deformation structures (S-C deformation bands, shear veins and stylolites). These results allow the development of a dynamic model for the deformation. The proposed model explains the observed features through cycles of fluid-pressure build up, hydraulic fracturing, and consecutive collapse, producing pressure-solution and stylolitization.

A revision of the Upper Cretaceous shark Ptychodus mediterraneus Canavari, 1916 from northeastern Italy, with a reassessment of P. latissimus and P. polygyrus Agassiz, 1835 (Chondrichthyes; Elasmobranchii)

The Bonarelli Level and other black shales in the Cenomanian-Turonian of the northeastern Dolomites (Italy): calcareous nannofossil and foraminiferal data