Foraminiferal record and astronomical cycles: An example from the Messinian pre-evaporitic Gello Composite Section (Tuscany, Italy)

A high resolution bio-magneto and cyclostratigraphical study has been carried out for the first time on Messinian pre-evaporitic marine deposits (Gello Composite Section) from the Volterra Basin (Italy). Since the investigated deposits manifest no evident lithological cyclicity, others records have been used to recognize the vidences of an astronomical periodicity. The distribution curves of planktonic and benthic foraminifera have been used for paleoenvironmental reconstruction. yclostratigraphical analyses have been based on: i) abundance fluctuations of Bolivina and Bulimina among the benthic foraminifera, Globigerinoides, Orbulina and Turborotalita among the planktonics; ii) CaCO3 content changes; and iii) Shannon-Weaver index variations relative to benthic assemblages. As a result, 18 precession-controlled cycles have been recognized. Moreover, the recognition of the C3An.1r, C3An.1n and C3r magnetozone and some biochronohorizons, have allowed the tuning of the studied section with the ATNTS (Astronomical Tuned Neogene Time Scale) using the Laskar 2001 (1,1.2) solution of the insolation curve. This multidisciplinary study strongly supports that the onset of evaporitic deposition in Tuscany and in other circum-Mediterranean type-successions, as the Abad Composite Section (Spain) and the Falconara Section (Sicily), was isochronous

Paleoclimatic changes in the Serravallian record of the Mediterranean area

Planktonic foraminiferal and oxygen isotope records of the astronomically tuned S. Nicola composite section (Tremiti Islands, Mediterranean basin) provide new insight into the paleoclimatic evolution during the Middle to early Late Miocene (between 12.60 and 11.10 Ma). The application of PCA (Principal Component Analysis) to high-resolution data enabled us to examine the interactions among the foraminiferal proxies and to identify a series of paleoclimatic events of long and short duration that took place in the Mediterranean basin during the late Serravallian. The long term trend in PCA-1 score plot shows that the faunal composition of the studied sedimentary record changed significantly at 11.80 Ma. This change coincides with the significant shift from negative to positive loading in PCA-1 and it has been correlated with the onset of the Mi5 event, which in the Mediterranean area is testified by the first influx of neogloboquadrinids. Such a major change is preceded by other minor events at 12.38, 12.21, and 12.00 Ma, which indicate the progressive deterioration from warm to colder climatic conditions. The most evident step coincides with a sharp decrease in abundance of surface species at 12.00 Ma and the relative increase of intermediate species, suggesting a contraction of the habitat of warm faunas and increasingly eutrophic conditions. This cooling (of sea surface water) is also supported by a gradual shift in the bulk δ18O from –2.38‰ (12.374 Ma) to -0.28‰ (11.963 Ma). The comparison between oxygen isotope oscillations and the eccentricity records revealed a good correspondence of the light δ18O values to eccentricity maxima. In addition, the vanishing from the Mediterranean of the neogloboquadrinids between 11.54 Ma and 11.21 Ma has been related to the intensification of monsoon activity with an increase in runoff. This hypothesis is supported by more negative values in δ18O. The Mediterranean results are compared with those from the Equatorial and North Atlantic Ocean. keywords. paleoclimatology, planktonic foraminifera, stable isotope, late Middle Miocene, Mediterranean

In search of the Burdigalian GSSP. New evidence from the Contessa Section (Italy)

The Contessa Section is a reference section for the early Miocene in the Mediterranean. Along this 36 m thick section 115 samples were collected and analysed for an integrated bio-magnetostratigraphic study through the Scaglia Cinerea and Bisciaro formations. Planktonic foraminifera were analysed semi-quantitatively, while calcareous nannofossils were examined using the standard quantitative method. A reliable biozonation for both fossil groups was then accomplished. The paleomagnetic analyses identified a sequence of magnetozones, then correlated with the ATNTS using the calcareous plankton bioevents. The investigated interval extends from foraminiferal Zone P22 (Chattian) to MMi2c (Burdigalian) and from calcareous nannofossils Zone MNP25a to MNN3a, thus from Chron C7An to C5En. Therefore, the section chronologically spans from 24.80 Ma to 18.10 Ma. Three hiatuses were recognised along the section: H1 at 0.63 m from the base (comprising a minimum time interval from 24.36 Ma to 23.38 Ma), H2 at 12.33 m (between 21.80 Ma and 21.35 Ma) and H3 at 34.03 (between 19.21 Ma and 18.40 Ma). All three hiatuses were correlated with regional megahiatuses identified in the North Atlantic Ocean and in the Paratethys area. Furthermore, the First Occurrence of the calcareous nannofossil Helicosphera ampliaperta is recognised within Chron C6An.2n at 19.77 m from the base (6 m above the volcaniclastic Raffaello Level). This event provisionally defines the Aquitanian/Burdigalian boundary according to the literature. Thus, the Contessa Section is a possible candidate for the definition of the Burdigalian Global Stratigraphic Section and Point. Finally, the age of the Raffaello Level (a regional marker horizon for the early Miocene) is discussed in this new integrated stratigraphic framework, falling in Chron C6AAn and dated between 21.09 Ma and 21.08 M

Phosphoinositide 3-kinase signalling in lung disease: leucocytes and beyond

The family of lipid kinases termed phosphoinositide-3-kinase (PI3K) is known to contribute at multiple levels to innate and adaptive immune responses, and is hence an attractive target for drug discovery in inflammatory and autoimmune disease, including respiratory diseases. The development of isoform-selective pharmacological inhibitors, targeted gene manipulation and short interfering RNA (siRNA) target validation have facilitated a better understanding of the role that each member of this family of kinases plays in the physiology and pathology of the respiratory system. In this review, we will evaluate the evidence for the roles of specific PI3K isoforms in the lung and airways, and discuss their potential as targets for novel drug therapies