Search

There is a growing number of new foraminifera with agglutinated wall types held together by secreted crystallites of high-magnesium calcite that do not fit within the traditional definition of the Miliolida. In this study, we analyzed entire and sectioned foraminiferal specimens frommodern marine sediments collected off the Croatian coast (Adriatic Sea) using an Environmental Scanning Electron Microscope (ESEM) equipped with Energy-Dispersive x-ray-Spectroscopy (EDS). The investigated specimens resemble the miliolid genera Nubeculina Cushman 1924 and Falsonubeculina Amao and Kaminski 2019, but display characteristics of testmorphology and an agglutinated-porcelaneous wall structure that have not been previously observed in similar miliolids. Their wall structure is more like that observed in primitive agglutinated foraminifera such as Lagenammina rather than in true miliolids. New taxonomical inferences regarding the nubeculinid group of genera are discussed.

This work investigates whether the honeycomb worm Sabellaria alveolata (Polychaeta) actively selects foraminiferal tests to build its arenaceous bioconstructions and if the tests are chosen based on a defined criterion. To this purpose, both foraminiferal content and structure of communities were compared across samples of bioconstructions and samples of neighbouring sediment collected from two sites of southern Sicily (Central Mediterranean). Results document a higher concentration of foraminiferal tests within the tubes than in sediment, with a clear preference for biconvex and spherical morphologies. We hypothesize that the high proportion of biconvex and spherical tests in the bioconstruction is probably due to the active selection operated by the polychaete combined with the different buoyancy of foraminiferal tests kept in suspension by the wave motion. Among the grains agglutinated in the tubes, we also observed sporadic specimens of Amphistegina lobifera Larsen, a non-indigenous foraminifer native to the Red Sea.

Investigation of a >6‐km‐thick succession of Cretaceous to Cenozoic sedimentary rocks in the Tajik Basin reveals that this depocentre consists of three stacked basin systems that are interpreted to reflect different mechanisms of subsidence associated with tectonics in the Pamir Mountains: a Lower to mid‐Cretaceous succession, an Upper Cretaceous–Lower Eocene succession and an Eocene–Neogene succession. The Lower to mid‐Cretaceous succession consists of fluvial deposits that were primarily derived from the Triassic Karakul–Mazar subduction–accretion complex in the northern Pamir. This succession is characterized by a convex‐up (accelerating) subsidence curve, thickens towards the Pamir and is interpreted as a retroarc foreland basin system associated with northward subduction of Tethyan oceanic lithosphere. The Upper Cretaceous to early Eocene succession consists of fine‐grained, marginal marine and sabkha deposits. The succession is characterized by a concave‐up subsidence curve. Regionally extensive limestone beds in the succession are consistent with late stage thermal relaxation and relative sea‐level rise following lithospheric extension, potentially in response to Tethyan slab rollback/foundering. The Upper Cretaceous–early Eocene succession is capped by a middle Eocene to early Oligocene (ca. 50–30 Ma) disconformity, which is interpreted to record the passage of a flexural forebulge. The disconformity is represented by a depositional hiatus, which is 10–30 Myr younger than estimates for the initiation of India–Asia collision and overlaps in age with the start of prograde metamorphism recorded in the Pamir gneiss domes. Overlying the disconformity, a >4‐km‐thick upper Eocene–Neogene succession displays a classic, coarsening upward unroofing sequence characterized by accelerating subsidence, which is interpreted as a retro‐foreland basin associated with crustal thickening of the Pamir during India–Asia collision. Thus, the Tajik Basin provides an example of a long‐lived composite basin in a retrowedge position that displays a sensitivity to plate margin processes. Subsidence, sediment accumulation and basin‐forming mechanisms are influenced by subduction dynamics, including periods of slab‐shallowing and retreat.

We formally describe a new agglutinated foraminiferal species belonging to the genus Colominella Popescu, 1998 (Textulariida) recovered in two Pliocene successions of the western Mediterranean region. The formal description of Colominella piriniae n. sp. reported here permits the known stratigraphical and geographical range of the genus, previously limited to the Badenian (middle Miocene) of the Paratethys, to be extended into the Pliocene of the Mediterranean. The present work demonstrates the importance of microstructural studies performed on sectioned specimens in taxonomic assignments and reviews.

The occurrence of agglutinated foraminiferal specimens belonging to the Badenian (middle Miocene) genus Colominella Popescu, 1998 was recently documented for the first time in a lower Pliocene succession of the western Mediterranean area. Direct comparisons with topotype specimens of Colominella paalzowi (Cushman 1936), sampled in the Badenian type section of Lăpugiu de Sus (Transylvania), show that the Pliocene individuals from the western Mediterranean morphologically resemble the type species C. paalzowi, but they also differ in possessing a longer biserial chamber arrangement with a higher number of internal chamber partitions, in lacking a clear early triserial stage and in having a more complex microstructure of the agglutinated wall, thereby supporting the idea that the Pliocene Mediterranean specimens represent a new, more highly evolved species. The fact that the Pliocene individuals from the Mediterranean appear to be more evolved with respect to the Badenian specimens from Paratethys represents an interesting evolutionary development of the genus Colominella that also permits the known stratigraphical and geographical range of the genus, previously limited to the middle Miocene (Badenian) of the Paratethys, to be extended.

During the Cenozoic, the Friulian-Venetian Basin (FVB, NE Italy) underwent a complex evolution, related to the inherited Mesozoic sea-bottom topography and the load exerted by the main tectonic phases which affected the three surrounding belts: the Dinarides to the east, the Southern Alps to the north and the Northern Apennines to the south-west. The study of the foraminiferal assemblages from over 500 samples collected from 13 key wells provides important constraints on the paleobathymetric changes which occurred into the basin through time. Moreover, the defined bathymetric ranges, together with information on both thickness of the different depositional units and depositional geometries (derived from 2D seismic), were used as input in geohistory analysis in order to reconstruct the subsidence/uplift trends occurred in different sectors of the basin, as a response to collisional tectonics acting along basin boundaries. The collected results show that the overall depositional architecture of the FVB is the result of six main tectono-depositional phases (Lutetian, Chattian, Langhian, Tortonian, Piacenzian and Quaternary) characterised by paleobathymetric variations and subsidence/uplift trends reflecting the change in the tectonic control of the basin and the balance between subsidence and sediment supply. In particular, the easternmost sector of the FVB evolved as a Dinaric foredeep during Lutetian time. Since Chattian time (Cavanella Group), a moderate subsidence phase characterised by faint flexure to the north occurred, which was followed by a Langhian accentuated subsidence phase, consistent with the development of a Southalpine system. The accommodation space was progressively outpaced by the sediment flux during Serravallian-Messinian time as demonstrated by an overall shallowing upward trend recorded in this stratigraphic interval. A new basin configuration occurred during Piacenzian, when a complex geometry was developed due to the concurrent flexural load of the Southern Alps, to the North, and of the Apennines, to the South. Unlike the previous stratigraphic intervals, the Quaternary sedimentary sequence eventually shows a broadly symmetrical geometry with fast and relatively homogeneous subsidence all over the basin, overbalanced by the sedimentary supply. The observed symmetrical subsidence distribution could be interpreted as a consequence of both vanishing tectonic control and increase of sedimentary input related to increasing climatic variability.

In the northern Italian Alps, along the Tagliamento River valley (46°23'49 N, 12°42'51 E), a large deep-seated landslide affects a road tunnel near Passo della Morte, along National Road 52 Carnica. Several secondary phenomena are developing on the unstable slope, as rock block slides and shallow debris slides. This work focuses on the creation of a geological and numerical model able to simulate the displacements of two adjacent and partly superimposed shallow landslides, which are damaging the east entrance of the tunnel. In fact, field surveys and long-term monitoring allowed the geometries and the kinematics of the landslide bodies to be defined with great detail. In this phase, a numerical model is needed in order to evaluate the effectiveness of possible structural mitigation works. The complexity of the landslides dynamics and the different rates of activity suggest to set up a 3D model rather than a 2D one, using the commercial software FLAC3D. A helicopter-borne Light Detection And Ranging (LiDAR) survey allowed to rely on a 1 m Digital Terrain Model (DTM) for surface topography, while several boreholes equipped with inclinometers supported the definition of a 3D sliding surface. However, the high resolution of the input data collides with the necessity of reduce computational time to an acceptable level, thus an interpolation of the spatial data was almost compulsory. Anyhow, the calibrated model of the Passo della Morte landslides, obtained with filtered data, is the starting point for the simulation of different types of possible countermeasure works designed to mitigate landslide risk.

The Alps are the archetypical collisional orogenic system on Earth and yet our understanding of processes controlling topographic growth in the Cenozoic remains incomplete. Whereas ideas and models on the Alps are abundant, data from the foreland basin record able to constrain the timing of erosion and sedimentation, mechanisms of basin accommodation and basin deformation are sparse. We combine seismic stratigraphy, micropaleontology, white mica 40Ar/39Ar, detrital zircon (U-Th)/He and apatite fission track thermochronology to Miocene-Pliocene samples from the retro-wedge foreland basin (Saluzzo Basin in Italy) and to Oligocene-Miocene sedimentary rocks from the pro-wedge foreland basin (Bârreme Basin in France) of the Western Alps. Our new data show that exhumation in the Oligocene-Miocene was non uniform across the Western Alps. Topographic growth was underway since the Oligocene and exhumation was concentrated on the pro-side of the orogenic system. Rapid and episodic early Miocene exhumation of the Western Alps was concentrated instead on the retro-side of the orogen and correlates with a major unconformity in the proximal retro-foreland basin. A phase of orogenic construction is recorded by exhumation of the proximal pro-foreland in both the Central and Western Alps at ca. 16 Ma. This is associated with high sedimentation rates, and by inference erosion rates, and suggests that an increase in accretionary flux associated with the dynamics of subduction of Europe under Adria controlled orogenic expansion in the Miocene.

This study updates the current distribution, range expansion and establishment status of the non-indigenous species Amphistegina lobifera Larsen, 1976 and other foraminifera that are cryptogenic in the Sicily Channel. Prior to this study, amphisteginids were reported from the Levantine Basin, the Central Mediterranean (Tunisia, Malta, Pelagian islands) and the southern Adriatic Sea. Here, we provide new records documenting a north-western expansion in the Central Mediterranean. In summer-autumn 2017 and spring-summer 2018, we collected algae and sediment samples from shallow coastal habitats along the shores of the Maltese archipelago, southern and north-western Sicily, Pantelleria and the Aegadian islands. Analysis of the foraminiferal assemblages showed that A. lobifera is effectively established around Malta and in southern/south-eastern Sicily, and has reached the oceanographic boundary between the Central and Western Mediterranean. Our results also show that the thermotolerant A. lobifera is at an advanced stage of invasion in the Sicily Channel, probably favoured by a recent rise in Mediterranean sea surface temperatures. New species distribution models are provided for the years 2040–2050 and 2090–2100, indicating that the predicted warming trend will facilitate north-westward migration of Mediterranean amphisteginids along the coast of northern Africa into the Alboran Sea, and deep into the Adriatic Sea.

Agglutinated foraminifera from surface sediments of two sites (S1 and E1) in the North Adriatic Sea were investigated in order to detect their test composition and to explore possible links with the surrounding environment. Chemical-mineralogical analyses of the agglutinated tests by scanning Electron Microscopy and Energy Dispersive Spectroscopy, suggest that the chemical composition of the test surfaces generally mirrors the one of the sea-floor sediment. Only some species, as Reophax nana and Leptohalysis scottii exhibit a clear selectivity of the agglutinated grains. In detail, specimens of R. nana from site E1, which is mainly characterized by high hydrodynamic conditions at the sea-floor, show a preferential selection of mineral grains containing high concentrations of Zircon (Zr) and Titanium (Ti) even if these elements occur in very low concentrations in the surrounding sediment. L. scottii exclusively picks mica flakes to build the test. We suggest that the compositional differences recorded in the considered agglutinated foraminiferal tests represent distinctive life strategies in order to live successfully in different environments.

This project was funded by “FAR 2012-2014” grants of the University of Pavia (Italy). The paper focuses on the occurrence of morphologically abnormal specimens of planktonic foraminifera observed over the last 550ky in IMAGES core MD 97-2114 (East of New Zealand, SW Pacific). Abnormal tests occurred throughout the entire record in all the morphospecies characterising the assemblages but were relatively rare, with percentages not exceeding 1.5% of the total assemblage. No mass abnormality events were found. A range of malformations were observed from slight deformity with smaller or overdeveloped chambers to more severe deformity, with misplaced chambers, distorted spirals or double tests forming twinned individuals. They exhibited several different categories of morphological abnormalities, even within the same sample. Test abnormalities were most abundant in the morphospecies Globorotalia inflata, Globigerina bulloides and Orbulina universa and were characterised by a long-term decreasing trend up core with an alternating % abundance pattern at the glacial to interglacial scale between MIS 14 to MIS 8, recording the highest percentages during the interglacials. Normalised total abundance and abnormal abundance curves co-varied very closely for G. bulloides and O. universa, but for G. inflata two opposing excursions were observed during MIS 13 and 6 which may be linked to water column states. Although abnormal numbers were proportionately low, there appears to be a “natural” background number of malformations in the G. inflata population through time. There was no relationship between volcanic ash production and test abnormalities. Postprint

Plate tectonics and eustatic sea-level changes have fundamental effects on paleoenvironmental conditions and bio-ecological changes. The Paratethys Sea was a large marine seaway that connected the Mediterranean Neotethys Ocean with Central Asia during early Cenozoic time. Withdrawal of the Paratethys from central Asia impacted the distribution and composition of terrestrial faunas in the region and has been largely associated with changes in global sea level and climate such as cooling associated with the Eocene/Oligocene transition (EOT). Whereas the regression has been dated in the Tarim basin (China), the pattern and timing of regression in the Tajik basin, 400 km to the west, remain unresolved, precluding a test of current paleogeographic models. Here we date the Paratethys regression in Tajikistan at ca. 39 million years ago (Ma), which is several million years older than the EOT (at ca. 34 Ma) marking the greenhouse to icehouse climate transition of the Cenozoic. Our data also show a restricted, evaporitic marine environment since the middle–late Eocene and establishment of desert like environments after ca. 39 Ma. The overall stratigraphic record from the Tajik basin and southern Tien Shan points to deposition in a foreland basin setting by ca. 40 Ma in response to active tectonic growth of the Pamir–Tibet Mountains at the same time. Combined with the northwestward younging trend of the regression in the region, the Tajik basin record is consistent with northward growth of the Pamir and suggests significant tectonic control on Paratethys regression and paleoenvironmental changes in Central Asia.

The effects on calcite dissolution of both oceanic circulation and volcanic ash-fall were evaluated in lower bathyal sediments over the last 550 ka record from core MD 97-2114, recovered on the northern slope (depth of 1936 m, in the Pacific Deep Water, PDW) of the Chatham Rise (east of New Zealand, SW Pacific Ocean). This area has been impacted by changes in glacial/interglacial circulation and ocean chemistry as well as by the explosive volcanic activity of the Taupo Volcanic Zone. Several micro-paleontological dissolution proxies, based on planktonic foraminifera and calcareous nannofossils, were analysed in order to evaluate the calcite dissolution of the deep-sea sediments. These were compared with a couple of proxies of primary productivity (benthic foraminiferal epifaunal/infaunal ratio and δ13Cbenthic foraminifera) and the abundance of volcanic glass. The dissolution proxy data from MD 97-2114 were compared with two nearby ODP sites, ODP 1123 (3290 m deep, bathed by the lower Circumpolar Deep Water, LCDW) and ODP 1125 (1365 m deep, bathed by the Antarctic Intermediate Water, AAIW). The results suggest: (1) the calcite dissolution/preservation cycles at all three core sites show Glacial–Interglacial (G–I) periodicities that match the previously described “Pacific-style” CaCO3 cycles; (2) several short-term dissolution events do not follow this general scheme and occur following tephra deposition. The dissolution related to the tephra deposition seems to have mostly affected calcareous nannofossils, thus we hypothesise that the ash-fall induced a temporary reduction of the surface water pH (below 7.8), which affected the coccolithophores that inhabit the surface waters. (3) Other short-term dissolution events (1000 years) are unrelated to tephra deposition and are possibly driven by the slowing of deep-sea circulation and a reduced Deep Western Boundary Current (DWBC). This lead to the dominance of older, more corrosive Pacific Deep Water (PDW) flowing in to the region, resulting in coeval dissolution episodes at all three core sites (depth range from 1365 to 3290 m).

The agglutinated foraminiferal content from the last 550 kyr record of the IMAGES core MD 97-2114 (Chatham Rise, New Zealand) was analysed in order to detect the possible linkage existing between the composition of the grains forming the agglutinated tests and the deposition of tephras. The core was collected east of New Zealand, about 680 km from the active Taupo Volcanic Zone (TVZ) located on the North Island, thus it contains numerous macro- and microscopic tephra layers. Scanning Electron Microscopy and Energy Dispersive Spectroscopy analyses were carried out on entire agglutinated foraminifera as well as on sectioned specimens, sampled around and within the tephra layers. The analyses show that the studied foraminifera built structurally complex tests picking and selecting mineral and biogenic particles on the basis of their availability and abundance in the substratum, as well as their composition, size and shape. In most of the studied species, belonging to the order Textulariida, the composition of the agglutinated grains does not change when the deposition of the tephra layer strongly enriched the substratum in volcanic glass shards. Only the species Karreriella novangliae changed significantly its grain composition, mostly selecting volcanic glass fragments to cover the test surface. Nevertheless, the tephra deposition seems to influence the wall microstructure of the agglutinated tests. Textulariid specimens coming from the volcanoclastic layers have a thinner wall which is also characterised by a less abundant calcareous matrix with respect to the specimens sampled above or below the tephra layer. We hypothesise that the volcanic ash deposition probably interfered with the normal agglutinating process by causing the development of more aggressive waters at the sea floor which, in turn, could have induced carbonate dissolution. Our observations therefore suggest that the sediment type of the substratum is not the only controlling factor in the construction of the agglutinated foraminiferal test and grain selection, which appears to be species-dependent.

Larger agglutinated foraminifera resembling the Cretaceous genus Navarella Ciry and Rat 1951 were recently recovered in Thanetian hemipelagites from the Belluno Basin, northeastern Italy. These lituoids first appear in the basal Thanetian (uppermost calcareous nannofossils Zone CNP 8) and become common in the >500 micron washed residue from the uppermost Thanetian. They abruptly disappear at the Paleocene/Eocene boundary, in coincidence with the extinction of Paleocene small benthic foraminifera (the benthic foraminiferal extinction event - BEE). In order to document the internal chamber arrangement and the agglutinated wall microstructure of the Thanetian lituolids and to compare them with similar individuals recovered from the Upper Cretaceous and Danian strata of the same section, the collected specimens were sectioned and analyzed using a Scanning Electron Microscope (SEM), equipped with an energy-dispersive X-ray spectrometer (EDX). Our results show a typical bi-layered wall microstructure in the Thanetian specimens, whereas the older Maastrichtian and Danian specimens, occurring in the same section, display a single, thicker agglutinated wall. The taxonomy of the Italian lituolids is discussed and compared with similar taxa known from the literature. We describe the Thanetian lituolids as the new genus Neonavarella, which shows an apparently identical external morphology to mono-layered Maastrichtian-Danian specimens but differs in the microstructure of the agglutinated test wall that is bi-layered. The finding of new and well-preserved material from the Paleocene Scaglia Rossa beds of Italy helps shed light on the taxonomy of the still poorly known deep-water larger lituolids.

Over 100 cosmopolitan species of deep-sea benthic foraminifera (Extinction Group, Ext. Gp) became extinct during the late Pliocene-middle Pleistocene (3.6–0.55 Ma). Most had elongate, cylindrical tests and terminal apertures with complex modifications. This study provides new hypotheses on the functions of the morphologies that characterised the Ext. Gp and how these features could have been associated with their demise. From our functional morphological analysis we infer that: i) their elongate cylindrical or flabelliform tests, combined with fine perforations and a complex terminal apertural face are indicative of infaunal k-strategists with a low rate of metabolism; and ii) their complex apertural faces may also have been an adaptation for gathering or processing their specific phytodetrital food. We propose three alternative hypotheses for the cause of these extinctions, and where possible test them using our high resolution micropaleontological and geochemical record through the last 1.07 Ma in lower bathyal site MD 97-2114 in the SW Pacific Ocean. Hypothesis 1 is that the Ext. Gp species were unable to adapt to increased variability in the overall quantity or pulsed seasonality of the food supply to the sea floor and were out-competed by opportunistic r-strategist benthic foraminifera. This is supported by the highly variable and increasing abundance of opportunistic foraminifera at our study site during the final phase of the extinction in the mid-Pleistocene Climate Transition, MPT. We doubt however, that there was increased variability in phytoplankton productivity throughout the world's oceans sufficient to bring about the global demise of the Ext. Gp. Hypothesis 2 is that lowered pCO2 during increasingly severe MPT glacials, which coincided with the final phases of the extinction, may have caused the decline and possible loss of the Ext. Gp's phytoplankton food source. Declining pCO2 during Neogene cooling was coeval with declining relative abundance of the Ext. Gp and reticulofenestrid nannofossils, but the final demise of this latter phytoplankton group occurred slightly later than the MPT in our study site and cannot be implicated with the extinction. If this hypothesis has any validity maybe the phytoplankton group left no fossil record. Our third alternative hypothesis is that maybe our Ext. Gp had much common DNA which made them the selective target of pathogens that caused their extinction. This does not easily explain their earlier disappearance at abyssal depths than at bathyal depths in our study region, which can be accommodated by hypotheses 1 and 2.

The Northern Apennines provide an example of long-term deep-water sedimentation in an underfilled pro-foreland basin first linked to an advancing orogenic wedge and then to a retreating subduction zone during slab rollback. New palaeobathymetric and geohistory analyses of turbidite systems that accumulated in the foredeep during the Oligocene-Miocene are used to unravel the basin subsidence history during this geodynamic change, and to investigate how it interplayed with sediment supply and basin tectonics in controlling foredeep filling. The results show an estimated ca. 2 km decrease in palaeowater depth at ca. 17 Ma. Moreover, a change in basin subsidence is documented during Langhian time, with an average decompacted subsidence rate, during individual depocentre life, that increased from

Through a multidisciplinary approach based on novel micropaleontological and geochemical analyses, the main paleoceanographic and paleoclimate changes that have influenced the surface- and deep-water circulation in the SW Pacific Ocean (Chatham Rise, eastern New Zealand) during the last million years are reconstructed. This region represents a key area for investigating the climate evolution during the Pleistocene because here the largely wind-driven Antarctic Circumpolar Current interacts with the west Pacific Ocean circulation via the Deep Western Boundary Current, the major source of deep water for the whole Pacific Ocean. To understand coupling or decoupling events between sea surface and bottom waters, a continuous marine sedimentary succession since 1.1 Ma, recovered by the IMAGES (International Marine Past Global Change Study) cruise in the SW Pacific Ocean (Core MD97-2114), has been investigated based on calcareous planktonic and benthic microfossil content and C and O isotope record performed on planktonic and benthic foraminiferal tests. Results show the occurrence of long- and short-term patterns of climate and ocean circulation in the last million years as the result of the interplay of ice-sheet dynamics, surface tropical versus polar water inflow, and trophic status of the surface water. Copyright # 2012 John Wiley & Sons, Ltd.

This paper discusses the Cenozoic interaction of regional tectonics and climate changes. These processes were responsible for mass flux from mountain belts to depositional basins in the eastern Alpine retro-foreland basin (Venetian–Friulian Basin). Our discussion is based on the depositional architecture and basin-scale depositional rate curves obtained from the decompacted thicknesses of stratigraphic units. We compare these data with the timing of tectonic deformation in the surrounding mountain ranges and the chronology of both long-term trends and short-term high-magnitude (‘aberrant’) episodes of climate change. Our results confirm that climate forcing (and especially aberrant episodes) impacted the depositional evolution of the basin, but that tectonics was the main factor driving sediment flux in the basin up to the Late Miocene. The depositional rate remained below 0.1 mm year−1 on average from the Eocene to the Miocene, peaking at around 0.36 mm year−1, during periods of maximum tectonic activity in the eastern Southern Alps. This dynamic strongly changed during the Pliocene–Pleistocene, when the basin-scale depositional rate increased to an average of 0.26 mm year−1 (Pliocene) and 0.73 mm year−1 (Pleistocene). This result fits nicely with the long-term global cooling trend recorded during this time interval. Nevertheless, we note that the timing of the observed increase may be connected with the presumed onset of major glaciations in the southern flank of the Alps (0.7–0.9 Ma), the acceleration of the global cooling trend (since 3–4 Ma) and climate variability (in terms of magnitude and frequency). All these factors suggest that combined high-frequency and high-magnitude cooling–warming cycles are particularly powerful in promoting erosion in mid-latitude mountain belts and therefore in increasing the sediment flux in foreland basins.

The Sardinian Cainozoic rifted basin is a useful model for studying the stratigraphic response to the Oligo-Miocene structural extension in the western Mediterranean because it allows precise observations on the relationship between sedimentation and normal faulting based on outcrops and seismic reflection data. The purpose of this paper, essentially of stratigraphic nature is to propose a chronology as precise as possible of the tectonic events and of the sedimentary formations. Indeed the tectono-sedimentary framework is complex, characterized by an extreme facies variability, from continental to marginal transitional and to marine environments (shallow-water, hemipelagic). Rifting, active calc-alkaline volcanism and sea-level changes caused rapid physiographical evolution, which controlled progressive marine ingression. New chronobiostratigraphical data presented in this paper allow correlating the sequences, defining their environment and depth of deposition and specifying precisely the timing of pre-, syn-, and post-rift stages in the Oligo-Miocene graben system. In southwestern Sardinia during the middle-late Eocene, after the Pyrenean phase, a continental graben (Cixerri), W-E oriented, preceded the Oligo-Miocene extension, which reactivated inherited Eocene and Palaeozoic faults. The calc-alkaline volcanic activity ranging from 32 to 13 Ma, provides a good estimate for the time span of the west-dipping Apenninic subduction responsible for the continental extension and the oceanic accretion in the western Mediterranean. In Sardinia the Oligo-Miocene extensional tectonics started in a continental environment, preceding the earliest calc-alkaline volcanic products (32 Ma). The marine ingression is dated to the late Chattian-Aquitanian interval and corresponds to a rapid deepening of the Oligo-Miocene graben system of tectonic origin. The end of the rifting i.e. the end of normal faulting activity is pre-middle Burdigalian in age. When Sardinia was in the post-rift stage, extension continued until late Burdigalian – Langhian in the Algero-Provençal basin with oceanic accretion and rotation of the Corsica-Sardinia block (CSB).

Diachronous deformation and exhumation of the Dinaric, eastern Southern Alps, and Northern Apennine belts caused a complex pattern of sedimentation and dispersal in the Venetian–Friulian Basin. Our dataset provides, for the first time, a comprehensive picture of the Cenozoic evolution across the whole basin. Growth and erosion of the three chains feeding the Venetian–Friulian Basin are here traced by combination of multiple analytical techniques. We examine the terrigenous and intrabasinal supply to the basin by using arenite petrography (gross composition, heavy minerals) and apatite fission-track analysis framed in an updated stratigraphy. Data come from both outcropping and subsurface Eocene to Pleistocene strata and are compared with the modern river sediments of the study area. On the basis of this approach, we present a schematic temporal and paleogeographic evolution of the Venetian–Friulian Basin from the Eocene to Present. During the Eocene most sediments were derived from erosion of carbonate successions within the growing Dinaric thrust belt to the east, and from its peripheral bulge to the west, where some carbonate factories were active. Oceanic rocks, probably located in the Vardar suture zone to the north, contributed little. Once Dinaric thrusting ceased, most of the detritus was derived from the northern basement of the Austroalpine realm. An abrupt paleogeographic variation caused by activation of southward-verging thrusts in the Southalpine domain occurred during the Serravallian. The drainage divide moved southward and most of the detritus was derived from the basement and related sedimentary covers of the Southern Alps. Sand composition of modern river sediments and of the Plio-Pleistocene deposits indicates that the modern hydrographic pattern of this area was already established in the Pleistocene.

Integrated geohistory analysis performed on high-resolution stratigraphy of Venezia1and Lido1wells (Quaternary^Pliocene interval) and low-resolution stratigraphy of a simulated well extending Lido 1 down to the base of Cenozoic (Palaeocene^Miocene interval) is used to reconstruct the interplay between subsidence and sedimentation that occurred in the Venice area (eastern Po Plain) during the last 60 Myr, and to discuss the relationships between calculated subsidence rates and time resolution of stratigraphic data. Both subsidence and sedimentation are mostly related to the tectonic evolution of the belts that surround the Venice basin, in£uencing the lithosphere vertical motions and the input of clastic sediments through time. In particular, two subsidence phases are recorded between 40^33.5 and 32.5^24 Myr (0.13 and 0.14 mm year � 1 , respectively), coeval with tectonic phases in the Dinaric belt.Vice versa, during the main South-Alpine orogenic phase (middle^late Miocene), quiescence or little uplift ( � 0.03 mm year � 1 ) re£ects the location of the Venice area close to the peripheral bulge of the South-Alpine foreland system. Early Pliocene evolution is characterised by a number of subsidence/uplift events, among which two uplifts occurred between 5^4.5 and 3^2.2 Myr (at � 0.4 and � 0.2 mm year � 1 , respectively) and can be correlated with tectonic motions in the Apennines. During the last million years, the Venice area was initially characterised by uplift ( � 0.6 mm year � 1 rising to � 1.5 mm year � 1 between 0.4 and 0.38 Myr), eventually replaced by subsidence at a rate ranging between 1.6 and 1.0 mm year � 1 up to 0.12 Myr and then decreased to 0.4 mm year � 1 ,a s an average, up to present. Our results highlight that time resolution of the stratigraphic dataset deeply in£uences the order of magnitude obtained for the calculated subsidence rate.This is because subsidence seems to have worked through short-lived peaks (in the order of10 5 years), alternating with

Two sections of Epiligurian sediments (Northern Apennines, Italy) covering the chronostratigraphic interval from the Middle Eocene to the Lower Miocene were analyzed for their foraminiferal content. Several specimens belonging to 25 selected species of agglutinated foraminifera were analyzed using the energy-dispersive x-ray spectrometry (EDS) method. The collected data show how these species are selective in composition, size, and shape of the agglutinated grains and cement composition. Test microstructures can be subdivided into four groups: A relationship between test microstructure and paleobathymetric conditions for the Monte Piano Marl, Ranzano Sandstone, and Antognola Marl Formations was observed. An almost exclusive presence of agglutinated taxa showing microstructures I and II characterized the “facies varicolori” of the Monte Piano Marls (lower-middle bathyal depths, from 2000 m to 1000 m). A sharp increase in species showing microstructures III and, subordinately, IV characterized the overlying lithostratigraphic units (“facies grigia” of the Monte Piano Marls, Ranzano Sandstones and Antognola Marls) whose paleobathymetry decreases upwards (middle-upper bathyal up to slope/shelf break from 1000 to 200 m).

International audience; The high-resolution, multi-proxy investigation of microfossil and isotopic data from Shatsky Rise (ODP Site 1209B, NW Pacific Ocean) is presented to evaluate the potential of calcareous nannofossil assemblages as dissolution and paleoproductivity proxies over the last 450 lea. To identify the best nannofossil index to evaluate dissolution (in particular, under polarized light microscope), we calculate and compare the different nannofossil and planktonic foraminiferal dissolution-indices from our original dataset The results demonstrate that the most reliable and reproducible nannofossil dissolution index is the Nannofossil Dissolution Index (NDI) proposed by Marino et al. (2009), particularly for records prior to 250 ka. The NDI data from the studied Site 1209B represent evidence of preservation maxima mainly during deglaciations, whereas dissolution peaks are recorded at the onset of glacial phases or during severe interglacials. These fluctuations are demonstrated to be basin-wide features in the Pacific. The synchronous timing in the fluctuations of the preservation indices, which consistently lagged behind the oxygen isotope cycles, clearly demonstrates the basin-wide changes in the ocean chemistry during the glacial interglacial transitions. The Mid-Brunhes Dissolution Event, which was recorded in the Western Pacific at depths below the lysocline at the Marine Isotope Stage (MIS) 11, is not detectable at our relatively shallower site. At the studied site, the intervals of high productivity generally coincide with the time of good preservation and light carbon-isotope values and vice versa. Therefore, carbonate undersaturation and changes in ocean chemistry (carbonate ion concentration) rather than the variations in the organic carbon flux appear to have controlled the pattern of CaCO3 preservation. In addition to the characterization of the dissolution proxies, changes in the calcareous nannofossil assemblages were used to evaluate the primary productivity fluctuations at the mid-latitudes of the NW Pacific over the last 450 ka. The results highlight a general decrease of paleoproductivity during the entire time period as well as shorter glacial/interglacial fluctuations from the base-core upwards. We interpret these features to be variations in the thermocline and nutricline dynamics related to the northward migration of the Kuroshio Extension, which was triggered by the Mid-Brunhes Event and may have caused deepening of the thermocline/nutricline at the site. The spectral and wavelet analyses performed on the microfossil database prove that the variations in paleoproductivity and carbonate dissolution over the last 450 ka were primarily driven by the glacial interglacial variability (100 ka periodicity) and by the obliquity-controlled changes. (C) 2012 Elsevier B.V. All rights reserved.

A planktonic foraminiferal zonal scheme is proposed for the internal basinal successions of the Monferrato and Northern Apennines (late Bartonian-early Serravallian). This scheme is based on a synthesis of quantitative analyses performed on the foraminiferal assemblages from 30 stratigraphic sections, cropping out over a distance of 300 km, between the Piedmont and the Northern Apennines. The proposed zonal scheme represents the synthesis, with minor changes, of the biozonations proposed by Novaretti et al. (1995) and Mancin and Pirini (2001) with the addition of unpublished data from some new sections, spanning a broader temporal and geographical range. With respect to the previous regional and standard biozonations, this scheme shows a better biostratigraphical resolution resulting from the replacement of missing or unreliable standard bioevents with new “reproducible” and reliable regional biohorizons. These new events are: LO of muricate species, which identifies the top of the Acarinina spp....