Palaeoenvironmental reconstruction of the Oligocene Afales Basin, Ithaki island, western Greece

Abstract

Assemblages of benthic foraminifera from one clastic succession in the Afales Basin (Ithaki Island, western Greece) were investigated to reconstruct palaeoenvironmental conditions during the Oligocene. The section consists of alternating hemipelagic marls and detrital deposits, designated as flysch-like beds, attributed to biostratigraphic Zones P20 and P21. Planktic percentages are mostly high (66-80%). Benthic foraminiferal assemblages comprise calcareous and agglutinated taxa (up to 15%). The prevalence of epifaunal foraminifera indicates good ventilation of the bottom water resulting from basin morphology, which enabled the undisturbed flow of water throughout the basin. Palaeodepth estimates imply bathyal deposition, from about 800 to 1200 m deep. The benthic foraminiferal fauna is of high diversity along the section, as is expected in deep marine environments. The abundances of the most common foraminiferal taxa (Cibicidoides spp., Oridorsalis umbonatus, Gyroidinoides spp., Stilostomella spp., Nodosariidae, Nuttallides umbonifera) are quite variable and imply generally oligotrophic to mesotrophic environmental conditions with variable organic flux.

Response of large benthic foraminifera to climate and local changes: Implications for future carbonate production

“…Their broad geographic, taxonomic and morphological diversity is evidence of their ability to adapt and prevail in almost all marine ecosystems (Förderer et al ., 2018). This aspect alone allows them to be used in interpretation and reconstruction of modern and palaeoenvironments (Duchemin et al ., 2005; Drinia, 2009; Reymond et al ., 2011b, 2013b; Narayan et al ., 2015; de Jesus et al ., 2020), thus lending themselves as ideal vessels of geochemical proxies (Curry & Matthews, 1981; Rae, 2018) and bioindicators of coastal pollution (Frontalini & Coccioni, 2011; Pati & Patra, 2012; Suokhrie et al ., 2017; Ben‐Eliahu et al ., 2020). Specifically, the relative proportion of functional groups [large benthic foraminifera (LBF), small heterotrophic and opportunistic] of foraminifera has been established as a powerful bioindicator tool (for example, the FORAM Index) for monitoring the health of coral reefs in terms of nutrient loading (Hallock, 2000a, 2012; Prazeres et al ., 2020a).…”

Paleoenvironmental and stratigraphic investigations of the foraminiferal fauna from the Karpatian (Lower Miocene) Garáb Schlier Formation of the Mátraverebély-122 (Mv-122) borehole (North Hungary)

“…It can be used to estimate the paleobathymetric evolution at a locality. The data were interpreted according to Spezzaferri and Ćorić (2001) and Drinia (2009). These methods are based on recent analogs; thus they include a margin of error.…”

Deep-water paleoenvironmental changes based on early-middle Miocene benthic foraminifera from Malta Island (Central Mediterranean)

“…Data from : Alavi, 1988;Corliss, 1991;Kaiho, 1994Kaiho, , 1999Schmiedl et al, 1997;Fontanier et al, 2002;Spezzaferri et al, 2002Spezzaferri et al, , 2013Murray, 2003Murray, , 2006Rögl and Spezzaferri, 2003;Schmiedl et al, 2003;De Man, 2006;Kouwenhoven and van der Zwaan, 2006;Jorissen et al, 2007;Martins et al, 2007;Oblak, 2007;Russo et al, 2007;Abu-Zied et al, 2008;Drinia, 2009;Melki et al, 2009;Alve, 2010;Ied et al, 2011;Grunert et al, 2012;Rai and Singh, 2012;Sgarrella et al, 2012;Singh et al, 2015;Patarroyo-Camargo and Martinez-Rodriguez, 2013;Székely et al, 2017;Drinia, 2018;Milker et al, 2019;Pascual et al, 2020;Pérez-Asensio et al, 2020. The ecological meaning of the different taxa is reported in the section 3.2, Table 1.…”