33 research outputs found
New biostratigraphic data from the Early Pleistocene tyrrhenian PALEOCOAST (Western Umbria, Central Italy)
Plio-quaternary marine deposits are largely documented in western Umbria (central Italy), although they still lack biostratigraphic definition. Contrary to published data, Early Pleistocene deposits outcrop more extensively than previously reported in the Orvieto area. A composite biostratigraphic succession, almost continuous from the top of the G. gr. crassaformis Zone to the top of the Gl. cariacoensis Zone, can be reconstructed in offshore clay sections. Nannofossil assemblages and marker events (bmG, tCm, blG, tHs, tlG) from the MNN16a to MNN19e subzones have been documented. Lower shoreface - transition to offshore sections as described, are characterized by poor planktonic assemblages; nevertheless, they are still referable to the same stratigraphic interval. Deposits can be partially inserted into the "Chiani - Tevere" depositional cycle, also documented in this area. Moreover, marine conditions persist in the area from the base of the Gelasian to the top of the Calabrian, and it can be modelled as a peripheral, survival sea-branch, cut-off from the main river supply and from continental influence. However, Zanclean to Piacenzian deposits occur in a small area, localized around the town of Orvieto, so the former distinction of superimposed depositional cycles can only be speculative
Hypogean geology of the Camerano site(Marches, Italy)
The historical Camerano town (Ancona, Central Italy), built on the top of a hill at the rear of the Conero Mt. promontory, holds a broad underground system of remarkable man-drilled caves. Contrary to the roughly total lack of subaerial accessible outcrops, the caves allow to reconstruct the geological evolution and to describe a composite sedimentological and stratigraphic section into Early Pleistocene (Calabrian) marine deposits. The present study is aimed to a better definition of the sedimentological and palaeoenvironmental context for the Camerano area, and also improves the knowledge of the Camerano caves. Sediments are mainly regarded as massive to laminated yellow-brown bioclastic sand and massive grey-green clay couplets, variable in thickness, each couplet showing erosive basal surface and normal gradation, from sand to clay. Plane-parallel lamination, marked by recurring variations in grain size, is referred to “traction carpets”, and the sand horizons are described as carbonatic turbidites with eastern supply (Conero Mt.). Conversely, clay reflects both western river deltas distal supply and local contribution from marine productivity. Along the section, matrix-supported gravel beds also occur made of heterometric clay fragments dispersed into a bioclastic sandy matrix. Described facies only partially insert in the former geological schemes, and offer new insights to the palaeoenvironmental restoration for the Camerano area, which involves a tectonically active Early Pleistocene basin, mainly dominated by clay sedimentation, periodically reached by storm- to seismic-induced carbonatic turbidites. The large clay fragments, matrix-supported gravels probably derive from remobilization of partially lithified deposits along the basin’s flank and represent the distal evolution of west- coming slumps.</p
Late persistence and deterministic extinction of "humid thermophilous plant taxa of East Asian affinity" (HUTEA) in southern Europe
MIDDLE JURASSIC - EARLY CRETACEOUS INTEGRATED BIOSTRATIGRAPHY (AMMONITES, CALCAREOUS NANNOFOSSILS AND CALPIONELLIDS) OF THE CONTRADA DIESI SECTION (SOUTH-WESTERN SICILY, ITALY)
Facies and biostratigraphic analyses of the Contrada Diesi succession, cropping out along the northern slope of Mt. Magaggiaro (Sciacca, SW Sicily), provided new data on the Middle Jurassic-Early Cretaceous pelagic sedimentation in the Saccense domain. The richness in ammonites allowed the identification of Bathonian-Kimmeridgian Biozones and Subzones, while the Tithonian-Valanginian interval was defined mainly by calpionellids and calcareous nannofossils. Facies and microbiofacies analyses of the Jurassic-Cretaceous pelagic sediments of the area, together with ammonite, calpionellid and calcareous nannofossil integrated biostratigraphy, were very effective tools for comparison of biostratigraphic events. Many gaps in sedimentation were recognized, the most important spanning the middle and late Berriasian and part of the early Berriasian. The Contrada Diesi succession provides new litho-biostratigraphic data on the Saccense Domain. It suggests a high degree of internal variability tied to the irregular paleotopography of the carbonate platform substrate (Inici Fm.), derived from Early Jurassic tectonics. Gaps in sedimentation in the Contrada Diesi sections indicate that the environment of the Saccense Domain was characterized by a variable rate of sedimentation and energy changes
MIDDLE JURASSIC - EARLY CRETACEOUS INTEGRATED BIOSTRATIGRAPHY (AMMONITES, CALCAREOUS NANNOFOSSILS AND CALPIONELLIDS) OF THE CONTRADA DIESI SECTION (SOUTH-WESTERN SICILY, ITALY)
Facies and biostratigraphic analyses of the Contrada Diesi succession, cropping out along the northern slope of Mt. Magaggiaro (Sciacca, SW Sicily), provided new data on the Middle Jurassic-Early Cretaceous pelagic sedimentation in the Saccense domain. The richness in ammonites allowed the identification of Bathonian-Kimmeridgian Biozones and Subzones, while the Tithonian-Valanginian interval was defined mainly by calpionellids and calcareous nannofossils. Facies and microbiofacies analyses of the Jurassic-Cretaceous pelagic sediments of the area, together with ammonite, calpionellid and calcareous nannofossil integrated biostratigraphy, were very effective tools for comparison of biostratigraphic events. Many gaps in sedimentation were recognized, the most important spanning the middle and late Berriasian and part of the early Berriasian. The Contrada Diesi succession provides new litho-biostratigraphic data on the Saccense Domain. It suggests a high degree of internal variability tied to the irregular paleotopography of the carbonate platform substrate (Inici Fm.), derived from Early Jurassic tectonics. Gaps in sedimentation in the Contrada Diesi sections indicate that the environment of the Saccense Domain was characterized by a variable rate of sedimentation and energy changes
Anomuran and brachyuran trackways and resting trace from the Pliocene of Valduggia (Piedmont, NW Italy): environmental, behavioural, and taphonomic implications
We report a rich ichnofacies including trackways and a resting trace made by indeterminate anomuran and brachyuran crabs, and other organic sedimentary structures produced by invertebrates. This is the first fossil record of crab trackways and resting trace in a shoreface intertidal environment from the Pliocene sediments of Valduggia area (Vercelli, Piedmont, NW Italy). Behavioural and palaeoenvironmental data allow reconstruction of the possible scenario of the upper shoreface surface in this area of the northern paleo-Adriatic Gulf during the Pliocene. The resting trace is tentatively compared to the rehydrating and respiration behaviour of a semiterrestrial (?Ocypodidae) crab, documented for the first time in the fossil record. A single trackway is tentatively assigned to the locomotion of a land hermit crab, the first such fossil record from the paleo-Mediterranean area. Moreover, among other invertebrate burrows, hypichnal Halopoa cf. H. imbricata is reported in shallow marine deposits for the first time. Palaeontological, petrological, sedimentological, taphonomic, and ethological implications are discussed and compared with neoichnological data. This notable discovery enlarges our scant knowledge on the palaeo-ichnology of decapod crustaceans
the early pleistocene whale fall community of bargiano umbria central italy paleoecological insights from benthic foraminifera and brachyuran crabs
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Late persistence and deterministic extinction of “humid thermophilous plant taxa of East Asian affinity” (HUTEA) in southern Europe
Evidence of Predation on Early Pleistocene Freshwater Ostracods (Umbria, Central Italy)
Although drillholes in modern and ancient ostracods are known, the record is relatively scarce when compared to other taxa, and mainly exist with reference to the marine environment. Moreover, less is known about perforated ostracods, and more generally, about bioerosion in freshwater environments. Traces of predation on freshwater ostracods are reported for the first time in deep-lake deposits belonging to the early Pleistocene Fosso Bianco Unit, and outcropping in the Cava Nuova section (Umbria, central Italy). Deposits are mainly clay to silty clay and sand; the fossil record is sparse, and is mainly comprised of very rare gastropods and bivalves, ostracods and plant remains (leaves, seeds and wood’s fragments). The association of ostracods consists of Candona (Neglecandona) neglecta, Caspiocypris basilicii, Caspiocypris tiberina, Caspiocypris perusia, Caspiocypris tuderis, Caspiocypris posteroacuta, and Cyprideis torosa. The Caspiocypris group, considered to be endemic to the grey clays of the Fosso Bianco Unit, present the majority of specimens affected by predation, with a prevalence of predated female valves and a comparable number of right and left predated valves, while only a few of Candona(N.) neglecta (adult and juvenile) valves are perforated. Traces of predation for nourishment, represented by microborings of different types, were abscribed to the ichnospecies Oichnus paraboloides Bromley 1981, Oichnus simplex Bromley 1981, Oichnus gradatus Nielsen and Nielsen 2001, Oichnus ovalis Bromley 1993, and Dipatulichnus rotundus Nielsen and Nielsen 2001. Microboring affected both adult and juvenile specimens, evidencing prey–predator coexistence in the same environment over a long period of time. This report makes a fundamental contribution to the knowledge of predation in this peculiar confined environment, also suggesting prey–predator relations over a relatively short time interval (80–160 ka)
Early Pleistocene River-Fed Paleocoast in Western Umbria (Central Italy): Facies Analysis and Coastal Models
Pliocene (?)—early Pleistocene shallow marine deposits, varying from gravel to sand to clay, characterize the southernmost sector of the Valdichiana Basin, between Orte and Città della Pieve, across Tuscany, Umbria and Latium (Central Italy). Facies associations, referring to the evolution of a river-fed coast, with a sensible facies heteropy, and a sub-environment articulation, both across and alongshore, have been recently described. Although the main part of the territory responds to a wave-dominated coastal model, a clear fluvial sediment origin and the presence of localized river mouths have also been documented. Nearshore is mainly represented by interbedded sand and gravel beachface to upper shoreface deposits, in which both a mouth bar organization and a lateral distribution of gravel beaches are recognizable. Sediment origins largely depend ondebris flow processes, related to small alluvial fans/fan deltas. In constrained areas, debris flow and current continental deposits occur, referring to coalescent alluvial fans, organized as a smoothly seaward-dipping piedmont band, drained by shallow braided channels. This roughly organized fluvial system feeds a coastal area, with a fandeltabuild-up. The as-described fan delta and beach systems are characterized by a smooth seaward morphology, according to models resembling, on a coast-transverse profile, the shelf-type fan delta. Although the proposed models differ from each other’s, with respect tothe shelf-type one, this is mainly on a lateral facies distribution