@article{JaramilloVogelStrasserFrijiaetal.2013, author = {Jaramillo-Vogel, David and Strasser, Andre and Frijia, Gianluca and Spezzaferri, Silvia}, title = {Neritic isotope and sedimentary records of the Eocene-Oligocene greenhouse-icehouse transition the Calcare di Nago Formation (northern Italy) in a global context}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {369}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2012.11.003}, pages = {361 -- 376}, year = {2013}, abstract = {From the Middle Eocene to Early Oligocene, the Earth experienced the most significant climatic cooling of the Cenozoic era. The Eocene-Oligocene transition (EOT) represents the culmination of this climatic cooling, leading to the onset of the Antarctic glaciation and, consequently, to the beginning of the present-day icehouse world. Whereas the response of deep-sea systems to this climate transition has been widely studied, its impact on the shallow-water carbonate realm is poorly constrained. Here, the sedimentary expression of the EOT in two shallow-marine carbonate successions (Nago and San Valentino, northern Italy) belonging to the Calcare di Nago Formation is presented. The chronostratigraphic framework was constructed by integrating litho-, bio-, and isotope-stratigraphic data (C and Sr isotopes), allowing to correlate these shallow-marine successions with pelagic sections in central Italy (Massignano), Tanzania (TOP Sites 12 and 17), and the Indian Ocean (ODP Site 744). Within several sections in northern Italy, including Nago and San Valentino, a Priabonian (Late Eocene) transgression is recorded. Oxygen isotopes of ODP Site 744 show a coeval negative shift of 0.4 parts per thousand., suggesting a glacio-eustatic origin for this transgression. In the Nago and San Valentino sections, no prominent sequence boundary has been detected that would indicate a rapid sea-level drop occurring together with the positive shift in delta O-18 defining the EOT-1 cooling event. Instead, a gradual shallowing of the depositional environment is observed. At TDP Sites 12 and 17, the EOT-1 is followed by a negative shift in delta O-18 of around 0.4 parts per thousand, which correlates with a relative deepening of the environment in the studied sections and suggests a melting pulse between EOT-1 and the Oligocene isotope event 1 (Oi-1). The positive delta O-18 shift related to the Oi-1 translates in San Valentino into a change in carbonate factory from a photozoan association dominated by larger benthic foraminifera, corals, and red algae to a heterozoan association dominated by bryozoans. The same bryozoan fades occurs in several Italian localities near the Eocene-Oligocene boundary. This fades is interpreted to represent an analogue of modern cool-water carbonates and results from a cooling pulse of at least regional scale, associated to the Oi-1 event.}, language = {en} } @article{FrijiaDiLuciaVicedoetal.2012, author = {Frijia, Gianluca and Di Lucia, Matteo and Vicedo, Vicent and G{\"u}nter, Christina and Ziemann, Martin Andreas and Mutti, Maria}, title = {An extraordinary single-celled architect A multi-technique study of the agglutinated shell of the larger foraminifer Mesorbitolina from the Lower Cretaceous of southern Italy}, series = {Marine micropaleontology}, volume = {90-91}, journal = {Marine micropaleontology}, number = {7}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0377-8398}, doi = {10.1016/j.marmicro.2012.04.002}, pages = {60 -- 71}, year = {2012}, abstract = {Orbitolinids are larger foraminifera widespread in Lower Cretaceous shallow-water carbonates of the Tethyan realm. They are among the most important fossil groups used for Biostratigraphy. Despite this and although the structural features of the group have been described in detail, very little is known about the composition of their agglutinated test and the process by which they selected foreign grains. In this study, the test of Orbitolina d'Orbigny, 1850 (subgenus Mesorbitolina Schroeder, 1962) from Aptian shallow-water carbonate deposits of southern Italy has been studied in detail. We combine petrographic techniques (optical microscope and SEM) with energy-dispersive x-ray spectrometry (EDS), electron probe microanalyzer (EPMA), X-ray diffraction and Raman spectroscopy analyses. The results show that the test of Mesorbitolina is composed of carbonate and non-carbonate agglutinated grains with the latter distributed across the test with a specific pattern, moving from the marginal to the central zone. In the marginal zone, non-carbonate grains are found only in the epidermis and along the septa which are composed of quartz, with smaller amounts of illite/muscovite and K-feldspar grains. In the central zone of the test, non-carbonate grains are distributed in two ways. Coarse grains of quartz and K-feldspar are abundant and randomly placed in the endoskeleton embedded in a mosaic of minute carbonate grains. Flat grains, mainly of illite/muscovite constitute the external part of the septa. Our observations indicate that Mesorbitolina did select and place agglutinated grains across its test, mainly according to their shape, whereas it did not select particles according to grain size. The distribution of agglutinated particles according to their mineralogical composition shows some contradictory evidence and therefore, at the moment, grain selection in function of mineralogy cannot be completely confirmed or ruled out. Analogies in the test composition of Mesorbitolina specimens from coeval deposits from different areas of southern Italy indicate that the features of their agglutinated test are typical characters of the genus Mesorbitolina. However, it is still unclear what advantage was obtained by the foraminifer by the described test features.}, language = {en} } @article{BoixFrijiaVicedoetal.2011, author = {Boix, Carme and Frijia, Gianluca and Vicedo, Vicent and Bernaus, Josep M. and Di Lucia, Matteo and Parente, Mariano and Caus, Esmeralda}, title = {Larger foraminifera distribution and strontium isotope stratigraphy of the La Cova limestones (Coniacian-Santonian, "Serra del Montsec", Pyrenees, NE Spain)}, series = {Cretaceous research}, volume = {32}, journal = {Cretaceous research}, number = {6}, publisher = {Elsevier}, address = {London}, issn = {0195-6671}, doi = {10.1016/j.cretres.2011.05.009}, pages = {806 -- 822}, year = {2011}, abstract = {The Upper Cretaceous La Cova limestones (southern Pyrenees, Spain) host a rich and diverse larger foraminiferal fauna, which represents the first diversification of K-strategists after the mass extinction at the Cenomanian-Turonian boundary. The stratigraphic distribution of the main taxa of larger foraminifera defines two assemblages. The first assemblage is characterised by the first appearance of lacazinids (Pseudolacazina loeblichi) and mean-dropsinids (Eofallotia simplex), by the large agglutinated Montsechiana montsechiensis, and by several species of complex rotalids (Rotorbinella campaniola, Iberorotalia reicheli, Orbitokhatina wondersmitti and Calcarinella schaubi). The second assemblage is defined by the appearance of Lacazina pyrenaica, Palandrosina taxyae and Martiguesia cyclamminiformis. A late Coniacian-early Santonian age was so far accepted for the La Cova limestones, based on indirect correlation with deep-water fades bearing planktic foraminifers of the Dicarinella concavata zone. Strontium isotope stratigraphy, based on many samples of pristine biotic calcite of rudists and ostreids, indicates that the La Cova limestones span from the early Coniacian to the early-middle Santonian boundary. The first assemblage of larger foraminifera appears very close to the early-middle Coniacian boundary and reaches its full diversity by the middle Coniacian. The originations defining the second assemblage are dated as earliest Santonian: they represent important bioevents to define the Coniacian-Santonian boundary in the shallow-water facies of the South Pyrenean province. By means of the calibration of strontium isotope stratigraphy to the Geological Time Scale, the larger foraminiferal assemblages of the La Cova limestones can be correlated to the standard biozonal scheme of ammonites, planktonic foraminifers and calcareous nannoplankton. This correlation is a first step toward a larger foraminifera standard biozonation for Upper Cretaceous carbonate platform facies.}, language = {en} }