Planktonic foraminifera as proxies of the Holocene climatic variability (Tyrrhenian, Mediterranean Sea)

• Main Authors: Bonfardeci A., Caruso A., Cosentino C., Scopelliti G.
• Other Authors: Gilbert, A, Yanko-Hombach, V, Bonfardeci, A., Caruso, A., Cosentino, C., Scopelliti, G.
• Format: Book Part
• Language: English
• Published: 2017
• Subjects: Planktonic foraminifera; stable isotopes; millennial-scale climatic variability; southern Tyrrhenian; Holocene; ice core; NGRIP
• Online Access: http://hdl.handle.net/10447/264731; http://www.avalon-institute.org/inqua/pdf/Proceedings_IGCP 610_2017.pdf

Introduction. The focus of this study is the paleoclimatic reconstruction of the southern Tyrrhenian between ~9.2 and 2.9 ka, through the study of planktonic foraminiferal assemblages and stable isotopes, and comparing data with other coeval intervals. Several authors have studied the climatic sensitivity of Holocene planktonic foraminifera in different parts of the Mediterranean. Planktonic foraminifera produce good records of Holocene climatic variability, especially as regards the suborbital events such as Bond events (Bond et al., 1997) and other cooling/warming oscillations. Therefore, the obtained eco-biostratigraphy has allowed us to analyze how climatic forcing influenced sea surface temperature (SST) and water column structure during the Holocene in this sector of the southern Tyrrhenian Sea. Methodology. A sedimentary core (196 cm long) was collected in the Gulf of Palermo at the base of the upper continental slope (990 m bsl) and sub-sampled every 2 cm. Micropaleontological and geochemical analyses were performed on 98 samples, and three AMS 14C dates were determined. Micropaleontological analyses consisted of qualitative and quantitative characterization of the planktonic foraminiferal assemblages, in the size fraction greater than 125 μm. Geochemical analyses were performed on 8–10 specimens of Globigerina bulloides. Results. The calibrated AMS 14C ages, together with planktonic foraminiferal fluctuations and G. bulloides oxygen isotope records, were used to develop an age model of the studied interval. In order to obtain additional age control points, the studied records were also tuned to the NGRIP δ18O (GICC05) (Svensson et al., 2008) and GISP2 ice core temperature (Alley, 2000) records. Twenty species and eco-morphotypes were recognized in the planktonic foraminiferal assemblage and grouped depending upon their climatic and feeding affinity. The warm-water species, minus the typical cold-water species, were used to obtain the paleoclimatic curve, whilst the herbivorous/ carnivorous ratio has ...