Search results for "Calcareous nannofossil"
showing 7 items of 17 documents
Calcareous nannofossil surface sediment assemblages from the SicilyChannel (central Mediterranean Sea): palaeoceanographic implications.
2008
Quantitative analysis of 67 calcareous nannofossil assemblages from surface sediments recovered in a wide area across the Sicily Channel has been carried out in order to improve the interpretation of palaeontological data based on this planktonic group in a key area for Mediterranean palaeoceanographic studies. The investigation focused on three case studies that demonstrate the high potentiality of such a combined approach, taking into account the recent distribution of taxa or groups of taxa on the sea floor and the palaeontological record. The distribution of reworked specimens over the northern Sicily Channel sea floor validates the role of southern Sicily as a source region for reworke…
A high-resolution record of the last deglaciation in the Sicily Channel based on foraminifera and calcareous nannofossil quantitative distribution
2003
Abstract Relative abundance fluctuations in planktic foraminiferal and calcareous nannofossil assemblages are reported on the basis of a high-resolution study of ODP Leg 160 Hole 963D, drilled in the Sicily Strait, near Capo Rossello (southern Sicily). With its 8 m of undisturbed sediments, the core covers the interval from 1.5 to 23 kyr, allowing a 50–100-yr sampling resolution. All the short warm and cold events and sub-events recorded in this time interval in the GRIP Greenland ice core and at several Mediterranean sites were recognized. On this basis, a total number of nine ecozones based on planktic foraminifera and seven ecozones based on calcareous nannofossils were identified. A sho…
The holocene marine depositional event in the historical centre of palermo
2004
Studi recenti hanno indicato come al di sopra della classica sequenza del Quaternario marino della Piana di Palermo ricorra, in alcunisiti del Centro Storico, un limitato spessore di depositi marini di età post-tirreniana. Con lo scopo di precisare l’età di tali depositi sonostate studiate le associazioni di microfossili di campioni provenienti da sondaggi geognostici. Utilizzando lo schema ecobiozonale anannofossili calcarei recentemente proposto per l’ultima deglaciazione nel Mediterraneo centrale (Canale di Sicilia) detti depositi contengononannoflore attribuibili all’Olocene. Un'analisi al radiocarbonio ha confermato tale attribuzione, limitando alla parte bassadell'Olocene la pertinenz…
Millenial-scale paleoenviromental changes in the central Mediterranean during the Last Interglacial: comparison with European and North Atlantic reco…
2010
Abstract The environment of the central Mediterranean Sea is investigated on the basis of high-resolution planktonic foraminifera and calcareous nannofossil data (mean sampling resolutions of about 80 and 160 yr, respectively). MIS 5 is characterized by warm, oligotrophic and stratified waters, while coccolithophore communities developed a vertical zonation that, in today's oceans, is typical of the low-latitude gyres. The temperate-subtropical configuration of planktonic foraminifera and calcareous nannofossil assemblages is repeatedly transformed into a temperate-subpolar one during the suborbital cooling episodes C25-C18. A comparison with European pollen sequences and North Atlantic cor…
HIGH-RESOLUTION PALAEONVIRONMENTAL RECONSTRUCTION OF ODP HOLE 963D (SICILY CHANNEL) DURING THE LAST DEGLACIATION BASED ON CALCAREOUS NANNOFOSSILS
2004
Abstract A palaeoenvironmental reconstruction of Ocean Drilling Program (ODP) Hole 963D (Sicily Channel) has been obtained on the basis of quantitative abundance fluctuations in the calcareous nannofossil assemblages. The studied hole is characterized by a very high sedimentary resolution and covers the last ca. 20 kyr. A new palaeoclimatic curve, based on the Gephyrocapsa muellerae/Upper Photic Zone (UPZ) group ratio, permitted the detection of the rapid climatic fluctuations that characterized the last deglaciation. Cold water masses occupied the Sicily Channel during the glacial period and the Younger Dryas, whereas they were generally warm during the Bolling–Allerod and the Holocene. An…
Integrated stratigraphy of the Oxfordian global stratotype section and point (GSSP) candidate in the Subalpine Basin (SE France).
2014
44 pages; International audience; An integrated biostratigraphic approach, based on ammonites, calcareous nannofossils, dinoflagellates, combined with sedimentology, carbon-isotope and physical stratigraphy, is proposed for the Subalpine Basin (Thuoux and Saint-Pierre d'Argençon sections). Within the expanded marl deposits of the Terres Noires Fm., the Callovian-Oxfordian boundary is particularly well defined by ammonite taxa from different families (i.e. Cardioceratidae, Oppeliidae, Aspidoceratidae and Perisphinctidae), calcareous nannoplankton (first occurrence of large-sized Stephanolithion bigotii) and dinoflagellate cysts (first occurrence of Wanaea fimbriata). This precise biostratigr…
Calcareous Nannofossil Biostratigraphy and Chronostratigraphy of ODP Hole 964D (eastern Mediterranean Sea)
2008
Quantitative analyses of calcareous nannofossil were carried out on sediments from ODP Hole 964D succession, recovered in the Ionian Sea, Eastern Mediterranean. Results show that the sedimentary sequence, spanning from about 3.5 Ma (Early Pliocene) to the Present, has been investigated through an average sampling resolution of less than 30 kyr. The detailed subdivision into 11 biozones makes it possible to recognize chronostratigraphic the boundaries in the Early Pliocene-Middle Pleistocene interval. Finally, two sedimentary gaps, lasting at least 340 kyr and 120 kyr respectively, have been recognized between the Zanclean and Piacenzian and in the lower part of the Early Pleistocene. SHORT …