Options
Università degli Studi di Palermo, Dipartimento di Geologia e Geodesia, Via Archirafi 22, 90134 Palermo, Italy
2 results
Now showing 1 - 2 of 2
- PublicationRestrictedVariability in the vertical structure of the water column and paleoproductivity reconstruction in the central-western Mediterranean during the Late Pleistocene(2008-09)
; ; ; ; ; ; ; ;Incarbona, A.; Università degli Studi di Palermo, Dipartimento di Geologia e Geodesia, Via Archirafi 22, 90134 Palermo, Italy ;Di Stefano, E.; Università degli Studi di Palermo, Dipartimento di Geologia e Geodesia, Via Archirafi 22, 90134 Palermo, Italy ;Sprovieri, R.; Università degli Studi di Palermo, Dipartimento di Geologia e Geodesia, Via Archirafi 22, 90134 Palermo, Italy ;Bonomo, S.; Università degli Studi di Palermo, Dipartimento di Geologia e Geodesia, Via Archirafi 22, 90134 Palermo, Italy ;Censi, P.; Università degli Studi di Catania, Dipartimento di Scienze Geologiche, C.so Italia 155, 95129 Catania, Italy ;Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Spoto, S.; Università degli Studi di Catania, Dipartimento di Scienze Geologiche, C.so Italia 155, 95129 Catania, Italy; ; ; ; ; ; A sedimentary sequence spanning Marine Isotope Stage (MIS) 6 to MIS 2 in core LC07, recovered in the central Mediterranean, has been investigated in order to produce a high-resolution paleoceanographic reconstruction. The changes in productivity deduced from calcareous plankton relative abundances and independently confirmed by the BaXS fluctuations are linked to the stability of the water column which is mainly controlled by the water mass temperature. During glacial intervals, productivity was generally enhanced. Oligotrophic and warmer water masses with a deepened seasonal thermocline can be inferred for most of MIS5. The magnetic properties of the sediment show increased occurrences of North Africa dust in the central Mediterranean during cold phases, likely as a consequence of a more efficient erosive process triggered by southward displacement of the intertropical convergence zone. Although increases in both productivity and Saharan dust occurred during cold periods, the atmospheric inputs do not seem to contribute significantly to the fertilization of primary producers. A Shannon Index curve has been used to tentatively synthesize the variations of calcareous nannofossil assemblages through the last 150 kyr. The assemblage diversity sharply increased coincident with the transition from the penultimate glacial to the last interglacial, subsequently low diversity was gradually reached again in the last glacial.230 43 - PublicationRestrictedOrbital variations in planktonic foraminifera assemblages from the Ionian Sea during the Middle Pleistocene Transition(2013)
; ; ; ; ; ; ;Incarbona, A.; Università degli Studi di Palermo, Dipartimento di Scienze della Terra e del Mare, Via Archirafi 22, 90134 Palermo, Italy ;Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Di Stefano, E.; Università degli Studi di Palermo, Dipartimento di Scienze della Terra e del Mare, Via Archirafi 22, 90134 Palermo, Italy ;Ippolito, G.; Università degli Studi di Palermo, Dipartimento di Scienze della Terra e del Mare, Via Archirafi 22, 90134 Palermo, Italy ;Pelosi, N.; Consiglio Nazionale delle Ricerche, Istituto per l'Ambiente Marino Costiero, Calata Porto di Massa, Interno Porto di Napoli, 80133, Naples, Italy ;Sprovieri, R.; Università degli Studi di Palermo, Dipartimento di Scienze della Terra e del Mare, Via Archirafi 22, 90134 Palermo, Italy; ; ; ; ; The Middle Pleistocene Transition (1.2-0.7 Ma) is the most recent re-organization of the global climate system which includes variations in the frequency and amplitude of glacial/interglacial cycles, increased ice sheet volume, sea surface temperature cooling and a significant drop in the CO2 atmospheric levels. Here we present high-resolution planktonic foraminifera data (mean sampling resolution of about 780 years) from core LC10 recovered in the Ionian Sea (eastern Mediterranean), between 1.2 and 0.9 Ma. Selected taxa, among them G. ruber, T. quinqueloba and G. bulloides, show significant periodicities that can be associated to orbital cycles, mainly precession and obliquity. The planktonic foraminifera based paleoclimatic curve exhibits a cooling linear trend that can be associated to similar phenomena observed in the North Atlantic. On the other hand, we refer to the influence of the North African Monsoon the occurrence of two peaks of the low-salinity tolerant species G. quadrilobatus that fall in coincidence of sapropel layers. Finally, we discuss the distribution pattern of N. pachyderma sinistral coiling, with peaks up to about 20% between MIS 30 and 28, and compare it to middle-late Quaternary records of the Sicily Channel and western Mediterranean.195 32