Bartonian; biodiversity; biostratigraphy; paleoenvironments; Ligurian Alps.


We present here new quantitative analyses of planktic and benthic foraminifera to assess the impact of the Middle Eocene Climatic Optimum (MECO, ~40 Ma) on these biotic groups studied along a shallow-water succession rich in larger benthic foraminifera (Sealza, Liguria, NW Italy). The MECO is one of the major Eocene global warming events, characterized by ~4–6°C warming, shifts in the global carbon cycle, and rise in atmospheric pCO2. The Sealza succession is interpreted as the product of a drowning ramp influenced by tectonic activity and provides an exceptional chance to compare biotic variations in shallow-water assemblages with deep-water communities across the MECO. In the section, the MECO interval is tentatively constrained by stable isotope oxygen data and calcareous plankton biostratigraphy. The marked decline in abundance of the epifaunal benthic Cibicidoides across the lower-middle part of the MECO suggests a decrease in oxygenation at the seafloor. Further evidence of oxygen depletion is the increase in organic matter content (TOC) of the sediment and the presence of infaunal genera Uvigerina and Bolivina. The planktic foraminiferal assemblages record the MECO warming in the upper water column as the mixed-layer warm index genera Acarinina and Morozovelloides markedly increase in abundance. In the post-MECO interval, here poorly exposed, cooler conditions are indicated by the dominance of the cold-water index genus Subbotina. Remarkably, Acarinina decline in abundance in the upper MECO interval and never recover. The MECO perturbance permanently impacted the benthic and planktic communities at Sealza that exceeded the tipping point to move to a new regime, thus proving the fauna to be not resilient, but also not recording any extinctions.



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Author Biographies

VALERIA LUCIANI , University of Ferrara



MICHELE PIAZZA, University of Genoa



THIERRY ADATTE, University of Lausanne



LUCA ARENA, University of Genoa



BRAHIMSAMBA BOMOU, University of Lausanne



ELIANA FORNACIARI, University of Padua



GIANLUCA FRIJIA, University of Ferrara



LÁSZLÓ KOCSIS, University of Lausanne



ANTONINO BRIGUGLIO, University of Genoa




Agnini C., Muttoni G., Kent D.V. & Rio D. (2006) - Eocene biostratigraphy and magnetic stratigraphy from Possagno, Italy: the calcareous nannofossil response to climate variability. Earth Planet Science Letters, 241: 815-830. doi: 10.1016/j.epsl.2005.11.005.

Agnini C., Fornaciari E., Raffi I., Catanzariti R., Pälike H., Backman J. & Rio D. (2014) - Biozonation and biochronology of Paleogene calcareous nannofossils from low and middle latitudes. Newsletters on stratigraphy, 47(2):131-181.

Agnini C., Backman J., Boscolo-Galazzo F., Condon D. J., Fornaciari E., Galeotti S., ... & Wade B. S. (2021) - Proposal for the global boundary stratotype section and point (GSSP) for the Priabonian stage (Eocene) at the Alano section (Italy). Episodes Journal of International Geoscience, 44(2): 151-173.

Altenbach A.V., Pflaumann U., Schiebel R., Thies A., Timm S. & Trauth M. (1999) - Scaling percentages and distributional patterns of benthic foraminifera with flux rates of organic carbon. Journal of Foraminiferal Research, 29: 173-185.

Barbin V. & Keller-Grünig A. (1991) - Benthic foraminiferal assemblages from the Brendola section (Priabonian stage stratotype area, northern Italy): Distribution, palaeoenvironment and palaeoecology. Marine Micropaleontology, 17(3-4): 237-254.

Behar F., Beaumont V. & Penteado H.L.D. (2001) - Rock-Eval 6 technology: performances and developments. Oil & Gas Science and Technology, 56: 111–134.

Bijl P.K., Houben A.J.P., Schouten S., Bohaty S.M., Sluijs A., Reichart G.J., Sinninghe Damsté J.S. & Brinkhuis H. (2010) - Transient middle Eocene atmospheric CO2 and temperature variations. Science, 330: 819–821. doi:10.1126/science.1193654.

Boersma A., Premoli Silva I. & Shackleton N.J. (1987) - Atlantic Eocene planktonic foraminiferal paleohydrographic indicators and stable isotope paleoceanography. Paleoceanography, 2: 287–331. doi:10.1029/PA002i003p00287.

Bohaty S.M. & Zachos J.C. (2003) - A significant Southern Ocean warming event in the late middle Eocene. Geology, 31: 1017–1020.

Bohaty S.M., Zachos J.C., Florindo F. & Delaney M.L. (2009) - Coupled greenhouse warming and deep-sea acidification in the Middle Eocene. Paleoceanography, 24: 2207. doi:10.1029/2008PA001676,2009.

Borelli C., Cramer B.S. & Katz M.E. (2014) - Bipolar Atlantic deep-water circulation in the middle late Eocene: Effects of Southern Ocean gateway openings. Paleoceanography, 29: 308–327. doi:10.1002/2012PA002444.

Boscolo Galazzo F., Giusberti L., Luciani V. & Thomas E. (2013) - Paleoenvironmental changes during the Middle Eocene Climatic Optimum (MECO) and its aftermath: The benthic foraminiferal record from the Alano section (NE Italy). Palaeogeography, Palaeoclimatology, Palaeoecology, 378: 22–35. doi: 10.1016/j.palaeo.2013.03.018.

Boscolo Galazzo F., Thomas E., Pagani M., Warren C. & Giusberti L. (2014) - The middle Eocene climatic optimum (MECO): A multi-proxy record of paleoceanographic changes in the southeast Atlantic (ODP Site 1263, Walvis Ridge). Paleoceanography, 29: 1143–1161.

Boscolo Galazzo F., Thomas E., Luciani V., Giusberti L, Frontalini F. & Coccioni R. (2016) - The planktic foraminifer Planorotalites in the Tethyan middle Eocene. Journal of Micropaleontology, 35: 79-89.

Boussac, J (1912) - Ètudes stratigraphique sur le Nummulitique alpin. Mémoires pour servir à l'explication de la carte géologique détaillée de la France, 662: 20.

Briguglio A., Seddighi M., Papazzoni C.A. & Hohenegger J. (2017) - Shear versus settling velocity of recent and fossil larger foraminifera: New insights on nummulite banks. Palaios, 32: 321-329.

Briguglio A., Giraldo-Gòmez V.M., Baucon A., Benedetti A., Papazzoni C.A., Pignatti J., Wolfgring E. & Piazza M. (2023) - A middle Eocene shallow-water drowning ramp in NW Italy: from shoreface conglomerates to distal marls. Newsletter on Stratigraphy. doi: 10.1127/nos/2023/0784

Burgess C. E., Pearson P. N., Lear C. H., Morgans H. E., Handley L., Pancost R. D. & Schouten S. (2008) - Middle Eocene climate cyclicity in the southern Pacific: Implications for global ice volume. Geology, 36(8): 651-654.

Campredon R. (1977) - Les formations paléogènes des Alpes Maritimes franco-italiennes. Mémoire hors-série de la Société géologique de France, 9: 1-199.

Coccioni R., Bancalà G., Catanzariti R., Fornaciari E., Frontalini F., Giusberti L., Jovane L., Luciani V., Savian J. & Sprovieri M. (2012) - An integrated stratigraphic record of the Palaeocene-lower Eocene at Gubbio (Italy), new insights into the early Palaeogene hyperthermals and carbon isotope excursions. Terra Nova, 24: 380–386.

Coletti G., Mariani L., Garzanti E., Consani S., Bosio G., Vezzoli G., Hu X. & Basso D. (2021) - Skeletal assemblages and terrigenous input in the Eocene carbonate systems of the Nummulitic Limestone (NW Europe). Sedimentary Geology, 10: 6005.

Corfield R.M. & Norris R.D. (1998) - The oxygen and carbon isotopic context of the Paleocene–Eocene Epoch boundary. In: Aubry M.P., Lucas S. & Berggren W.A. (Eds.) - Late Paleocene - Early Eocene Climatic and Biotic Events in the Marine and Terrestrial Records: 124-137. Columbia University Press, New York.

Coxall H.K., Wilson P.A., Pälike H., Lear C.H. & Backman J. (2005) - Rapid stepwise onset of Antarctic glaciation and deeper calcite compensation in the Pacific Ocean. Nature, 433: 53–57. doi:10.1038/ nature03135.

Cramwinckel M. J., van der Ploeg R., Bijl P. K., Peterse F., Bohaty S. M., Röhl U., Schouten S., Middelburg J.J. & Sluijs A. (2019) - Harmful algae and export production collapse in the equatorial Atlantic during the zenith of Middle Eocene Climatic Optimum warmth. Geology, 47(3): 247–250.

Dallagiovanna G., Fanucci F., Pellegrini L., Seno S., Bonini L., Decarlis A., Maino M., Morelli D. & Toscani G. (2012) - Note illustrative della Carta Geologica Foglio 257-Dolceacqua e Foglio 270 - Ventimiglia. 75 pp. Regione Liguria.

Dawber C.F. & Tripati A.K. (2011) - Constraints on glaciation in the middle Eocene (46–37 Ma) from Ocean Drilling Program (ODP) Site 1209 in the tropical Pacific Ocean. Paleoceanography, 26: 2208. doi:10.1029/2010PA002037.

Decarlis A., Maino M., Dallagiovanna G., Lualdi A., Masini E., Seno S. & Toscani G. (2014) - Salt tectonics in the SW Alps (Italy–France): From rifting to the inversion of the European continental margin in a context of oblique convergence. Tectonophysics, 636: 293-314.

De Graciansky P.C., Roberts D.G. & Tricart P. (2010) - The Western Alps, from rift to passive margin to orogenic belt: an integrated geoscience overview. Developments in Earth Surface Processes 14. Elsevier, Amsterdam, 398 pp.

De Rijk S., Jorissen F.J., Rohling E.J. & Troelstra S.R. (2000) - Organic flux control on bathymetric zonation of Mediterranean benthic foraminifera. Marine Micropaleontology, 40(3): 151-166.

D'Onofrio R., Luciani V., Fornaciari E., Giusberti L., Boscolo Galazzo F., Dallanave E., Westerhold T., Sprovieri M. & Telch S. (2016) - Environmental perturbations at the early Eocene ETM2, H2, and I1 events as inferred by Tethyan calcareous plankton (Terche section, northeastern Italy). Paleoceanography, 31(9): 1225–1247.

D’Onofrio R. & Luciani V. (2020) - Do different extraction techniques impact planktic foraminiferal assemblages? An early Eocene case study. Marine Micropaleontology, 155: 0377-8398.

D’Onofrio R., Luciani V., Dickens G.R., Wade B.S. & Kirtland Turner S. (2020) - Demise of the planktic foraminifer genus Morozovella during the Early Eocene climatic optimum: new records from ODP Site 1258 (Demerara rise, Western Equatorial Atlantic) and site 1263 (Walvis Ridge, South Atlantic). Geosciences, 10(3): 88.

D’Onofrio R., Zaky A.S., Frontalini F., Luciani V., Catanzariti R., Francescangeli F. & Jovane L. (2021) - Impact of the Middle Eocene Climatic Optimum (MECO) on foraminiferal and calcareous nannofossil assemblages in the Neo-Tethyan Baskil Section (Eastern Turkey): Paleoenvironmental and paleoclimatic reconstructions. Applied Sciences, 11(23): 11339.

Eder W., Briguglio A. & Hohenegger J. (2016) - Growth of Heterostegina depressa under natural and laboratory conditions. Marine Micropaleontology, 122: 22-43.

Eder W., Hohenegger J. & Briguglio A. (2017) – Depth-related morphoclines of megalospheric tests of Heterostegina depressa d'Orbigny: Biostratigraphic and paleobiological implications. Palaios, 32: 110-117.

Eder W., Hohenegger J. & Briguglio A. (2017) – Test flattening in the larger foraminifer Heterostegina depressa: Predicting bathymetry from axial sections. Paleobiology, 44: 76-88.

Edgar K.M., Wilson P.A., Sexton P.F. & Suganuma Y. (2007) - No extreme bipolar glaciation during the main Eocene calcite compensation shift. Nature, 448: 908–911.

Edgar K.M., Wilson P.A., Sexton P.F., Gibbs S.J., Roberts A.P. & Norris R.D. (2010) - New biostratigraphic, magnetostratigraphic and isotopic insights into the Middle Eocene Climatic Optimum in low latitudes. Palaeogeography Palaeoclimatology Palaeoecology, 297: 670-682. doi: 10.1016/j.palaeo.2010.09.016.

Edgar K.M., Bohaty S.M., Gibbs S.J., Sexton P.F., Norris R.D. & Wilson P.A. (2013) - Symbiont ‘bleaching’ in planktic foraminifera during the Middle Eocene Climatic Optimum. Geology, 41(1): 15-18.

Espitalié J., Deroo G. & Marquis F. (1985) - La pyrolyse Rock-Eval et ses applications. Revue de l’Institut Français du Pétrole, 40: 563–579.

Fornaciari E., Giusberti L., Luciani V., Tateo F., Agnini C., Backman J., Oddone M. & Rio D. (2007) - An expanded Cretaceous–Tertiary transition in a pelagic setting of the Southern Alps (central–western Tethys). Paleogeography and Paleoclimatology, 255: 98–131.

Fornaciari E., Agnini C., Catanzariti R., Rio D., Bolla E.M. & Valvasoni E. (2010) - Mid latitude calcareous nannofossil biostratigraphy and biochronology across the middle to late Eocene transition. Stratigraphy, 7: 229–264.

Frank T.D., Arthur M.A. & Dean W.E. (1999) - Diagenesis of Lower Cretaceous pelagic carbonates, North Atlantic: Paleoceanographic signals obscured. Journal of Foraminiferal Research, 29: 340–351.

Gardin S. & Monechi S. (1998) - Palaeoecological change in the middle to low latitude calcareous nannoplankton at the Cretaceous/Tertiary boundary. Bulletin de la Societé Géologique de France, 5: 709-723.

Giammarino S., Orezzi S., Piazza M. & Rosti D. (2009) - Evidence of syn-sedimentary tectonic activity in the "flysch di Ventimiglia" (Ligurian Alps foredeep basin). Italian Journal of Geosciences, 128(2): 467-472. doi: 10.3301/IJG.2009.128.2.467.

Giammarino S., Fanucci F., Orezzi S., Rosti D., Morelli D., Cobianchi M., De Stefanis A., Di Stefano A., Finocchiaro F., Fravega P., Piazza M. & Vannucci G. (2010) - Note Illustrative della Carta Geologica d'Italia alla scala 1:50.000 - Foglio "San Remo" n.258- 271. ISPRA - Regione Liguria. 130 pp. A.T.I. - SystemCart s.r.l. - L.A.C. s.r.l. - S.EL.CA., Firenze.

Giorgioni M., Jovane L., Rego E.S., Rodelli D., Frontalini F., Coccioni R., Catanzariti R. & Özcan E. (2019) - Carbon cycle instability and orbital forcing during the Middle Eocene Climatic Optimum. Science, 9: 9357.

Giraldo Gómez V. M., Beik I., Podlaha O. G. & Mutterlose J. (2017) - The micropaleontological record of marine early Eocene oil shales from Jordan. Palaeogeography, Palaeoclimatology, Palaeoecology, 485: 723-739.

Giraldo-Gómez V. M., Mutterlose J., Podlaha O. G., Speijer R. P. & Stassen P. (2018a) - Benthic foraminifera and geochemistry across the Paleocene–Eocene Thermal Maximum interval in Jordan. Journal of Foraminiferal Research, 48(2): 100-120.

Giraldo-Gómez V. M., Beik I., Podlaha O. G. & Mutterlose J. (2018b) - A paleoenvironmental analyses of benthic foraminifera from Upper Cretaceous–lower Paleocene oil shales of Jordan. Cretaceous Research, 91: 1-13.

Gooday A.J. (2003) - Beyond methane: Towards a theory for the Paleocene‐Eocene Thermal Maximum Benthic foraminifera (protista) as tools in deep‐water palaeoceanography: Environmental influences on faunal characteristics. Advances in Marine Biology, 46: 1–90.

Hammer Ø., Harper D.A.T. & Ryan P.D. (2001) - PAST: paleontological statistics software package for education and data analysis. Paleontologia Elettronica, 4(1): 9.

Henehan M. J., Edgar K. M., Foster G.L., Penman D. E., Hull P. M., Greenop R., Anagnostou E. & Pearson P.N. (2020) - Revisiting the Middle Eocene Climatic Optimum “Carbon Cycle Conundrum” with new estimates of atmospheric pCO2 from boron isotopes. Paleoceanography and Paleoclimatology, 35: e2019PA003713.

Hess S. & Kuhnt W. (2005) - Neogene and Quaternary paleoceanographic changes in the southern South China Sea (Site 1143): the benthic foraminiferal record. Marine Micropaleontology, 54(1-2): 63-87.

Hohenegger J., Kinoshita S., Briguglio A., Eder W. & Wöger J. (2019) - Lunar cycles and rainy seasons drive growth and reproduction in nummulitid foraminifera, important producers of carbonate buildups. Scientific Reports, 9(1): 8286.

Holbourn A., Henderson A.S., MacLeod N. & MacLeod N. (2013) - Atlas of benthic foraminifera. London, Wiley-Blackwell, vol. 654.

IPCC, Masson-Delmotte V., Zhai P., Pörtner H. O., Roberts D., Skea J. & Shukla P.R. (2018) Global warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. IPCC Geneva, Switzerland, 2018.

Jorissen F.J., Fontanier C. & Thomas E. (2007) - Chapter seven: Paleoceanographical proxies based on Deep-Sea benthic foraminiferal assemblage characteristics. Developments in Marine Geology, 1: 263–325.

Jovane L., Florindo F., Coccioni R., Dinarès-Turell J., Marsili A., Monechi S., Roberts A.P. & Sprovieri M. (2007) - The middle Eocene climatic optimum event in the Contessa Highway section, Umbrian Apennines, Italy. Geological Society of America Bulletin, 119: 413-427.

Kawagata S., Hayward B.W. & Gupta A.K. (2006) - Benthic foraminiferal extinctions linked to late Pliocene–Pleistocene deep-sea circulation changes in the northern Indian Ocean (ODP Sites 722 and 758). Marine Micropaleontology, 58(3): 219-242.

Kaiho K. (1994) - Benthic foraminiferal dissolved-oxygen index and dissolved-oxygen levels in the modern ocean. Geology, 22(8): 719–722. doi:<0719: BFDOIA>2.3.CO;2.

Kiessling W., Smith J.A. & Raja N.B. (2023) - Improving the relevance of paleontology to climate change policy. Proceedings of the National Academy of Sciences, 120(7): e2201926119

Lamb J.L. & Miller T.L. (1984) - Stratigraphic Significance of Uvigerinid Foraminifers in the Western Hemisphere. University of Kansas Paleontological Institute, Lawrence, 100 p.

Lanteaume M. (1968) - Contribution à l'étude géologique des Alpes Maritimes franco-italiennes. Mémoires puor servir à l’explication de la Carte Géologique détaillée de la France, 1-405.

Less G., Özcan E., Papazzoni C.A. & Stockar R. (2008) - The middle to late Eocene evolution of nummulitid foraminifer Heterostegina in the Western Tethys: Acta Palaeontologica Polonica, 53: 317-350.

Less G. & Özcan E. (2012) - Bartonian-Priabonian larger benthic foraminiferal events in the Western Tethys. Austrian Journal of Earth Sciences, 105(1): 129-140.

Lirer F. (2000) - A new technique for retrieving calcareous microfossils from lithified lime deposits. Micropaleontology, 46: 365–369.

Loeblich Jr A.R. & Tappan H. (1988) - Foraminiferal genera and their classification. Springer, 2045 pp.

Loeblich A.R. & Tappan H. (1994) – Foraminifera of the Sahul shelf and Timor Sea. Cushman special publications, 661 pp.

Luciani V., Giusberti L., Agnini C., Backman J., Fornaciari E. & Rio D. (2007) - The Paleocene–Eocene Thermal Maximum as recorded by Tethyan planktonic foraminifera in the Forada section (northern Italy). Marine Micropaleontology, 64(3): 189–214.

Luciani V., Giusberti L., Agnini C., Fornaciari E., Rio D., Spofforth D.J.A. & Pälike H. (2010) - Ecological and evolutionary response of Tethyan planktonic foraminifera to the middle Eocene climatic optimum (MECO) from the Alano section (NE Italy). Palaeogeography, Palaeoclimatology, Palaeoecology, 292: 82–95. palaeo.2010.03.029.

Luciani V. & Giusberti L. (2014) – Reassessment of the early–middle Eocene planktic foraminiferal biomagnetochronology: new evidence from the Tethyan Possagno section (NE Italy) and Western North Atlantic Ocean ODP Site 1051. Journal of Foraminiferal Research, 44: 187–201.

Luciani V., Dickens G.R., Backman J., Fornaciari E., Giusberti L., Agnini C. & D'Onofrio R. (2016) - Major perturbations in the global carbon cycle and photosymbiont-bearing planktic foraminifera during the early Eocene. Climate of the Past, 12: 981–1007. doi. org/10.5194/cp-12-981-2016.

Luciani V., Fornaciari E., Papazzoni C.A., Dallanave E., Giusberti L., Stefani C. & Amante E. (2020) - Integrated stratigraphy at the Bartonian–Priabonian transition: Correlation between shallow benthic and calcareous plankton zones (Varignano section, northern Italy). The Geological Society of America Bulletin, 132: 495–520.

Maino M. & Seno S. (2016) - The thrust zone of the Ligurian Penninic basal contact (Monte Fronté, Ligurian Alps, Italy). Journal of Maps, 12: 341-351.

Marini M., Patacci M., Felletti F., Decarlis A. & McCaffrey W. (2022) - The erosionally confined to emergent transition in a slope‐ derived blocky mass‐ transport deposit interacting with a turbidite substrate, Ventimiglia Flysch Formation (Grès d’Annot System, north‐ west Italy). Sedimentology, 69: 1675-1704.

Marshall J.D. (1992) - Climatic and oceanographic isotopic signals from the carbonate rock record and their preservation. Geological magazine, 129(2): 143-160.

Messaoud H.J., Thibault N., Bomou B., Adatte T., Monkenbusch J., Spangenberg J.E., Aljahdali H.M. & Yaich C. (2021) - Integrated stratigraphy of the middle-upper Eocene Souar Formation (Tunisian dorsal): implications for the middle eocene climatic optimum (MECO) in the SW Neo-Tethys. Palaeogeography, Palaeoclimatology. Palaeoecology, 581(10): 110639.

Methner K., Mulch A., Fiebig J., Wacker U., Gerdes A., Graham S.A. & Chamberlain C.P. (2016) - Rapid Middle Eocene temperature change in western North America. Earth and Planetary Science Letters, 450: 132-139.

Morelli D., Locatelli M., Corradi N., Cianfarra P., Crispini L., Federico L. & Migeon S. (2022) - Morpho-Structural Setting of the Ligurian Sea: The Role of Structural Heritage and Neotectonic Inversion. Journal of Marine Science and Engineering, 10(9): 1176.

Mueller P., Maino M. & Seno S. (2020) - Progressive deformation patterns from an accretionary prism (Helminthoid Flysch, Ligurian Alps, Italy). Geosciences, 10(1): 26

Murray J.W. (2006) - Ecology and Applications of Benthic Foraminifera. Cambridge University Press, 426 pp.

Oehlert A.M. & Swart P.K. (2014) - Interpreting carbonate and organic carbon isotope covariance in the sedimentary record. Nature Communications, 5(1): 4672. doi: 10.1038/ncomms5672.

Papazzoni C.A. & Sirotti A. (1995) - Nummulite biostratigraphy at the Middle/Upper Eocene boundary in the Northern Mediterranean area. Rivista Italiana di Paleontologia e Stratigrafia, 101: 63-80.

Papazzoni C.A., Cosovic V., Briguglio A. & Drobne K. (2017) - Towards a calibrated larger foraminifera biostratigraphic zonation: Celebrating 18 years of the application of shallow benthic zones. Palaios, 21: 1-5.

Pearson P.N., Shackleton N.J. & Hall M.A. (1993) - Stable isotope paleoecology of middle Eocene planktonic foraminifera and multispecies isotope stratigraphy, DSDP Site 523, South Atlantic. Journal of Foraminiferal Research, 23: 123-140.

Pearson P.N. & Palmer M.R. (1999) - Middle Eocene seawater pH and atmospheric carbon dioxide concentrations. Science, 284(5421): 1824-1826.

Pearson P.N., Ditchfield P.W., Singano J., Harcourt-Brown K.G., Nicholas C. J., Olsson R.K., Shackleton N. J. & Hallk M.A. (2001) - Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs, Nature, 413, 481–488, doi:10.1038/35097000.

Pearson P.N., Olsson R.K., Hemblen C., Huber B.T. & Berggren W.A. (2006) - Atlas of Eocene Planktonic Foraminifera. Cushman Special Publication, Department of Geology East Carolina University, Greenville, 513 pp.

Perch-Nielsen K. (1985) - Cenozoic calcareous nannofossils. In: Bolli H.M., Saunders J.B., Perch-Nielsen K. (Eds), Plankton Stratigraphy: 427-554. Cambridge University Press, Cambridge.

Peris-Cabré S., Valero L., Spangenberg J. E., Vinyoles A., Verité J., Adatte T., Maxime Tremblin M., Watkins S., Sharma N., Garcés M., Puigdefàbregas C. & Castelltort S. (2023) - Fluvio-deltaic record of increased sediment transport during the Middle Eocene Climatic Optimum (MECO), Southern Pyrenees, Spain. Climate of the Past, 19(3): 533–554.

Perotti E., Bertok C., D'Atri A., Martire L., Piana F. & Catanzariti R. (2012) - A tectonically induced Eocene sedimentary mélange in the West Ligurian Alps, Italy. Tectonophysics, 568: 200-214.

Premoli-Silva I. & Jenkins D.G. (1993) - Decision on the Eocene-Oligocene boundary stratotype. Episodes Journal of International Geoscience, 16(3): 379-382.

Premoli-Silva I., Wade B.S. & Pearson P.N. (2006) - Taxonomy, biostratigraphy, and phylogeny of Globigerinatheka and Orbulinoides. In: Pearson P.N., Olsson R.K., Huber B.T., Hemleben C. & Berggren W.A. (Eds) - Atlas of Eocene Planktonic Foraminifera: 169-212. Cushman Foundation.

Proto Decima F. & Bolli M.H. (1970) - Evolution and variability of Orbulinoides beckmanni (Saito). Eclogae Geologicae Helvetiae, 63: 883-905.

Quillévéré F. & Norris R. (2003) - Ecological development of acarininids (planktonic foraminifera) and hydrographic evolution of Paleocene surface waters. In: Wing S.L., Gingerich P.D., Schmitz B., Thomas E. (Eds) - Causes and consequences of globally warm climates in the Early Paleogene: 223-238. Geological Society of America Special Paper.

Raven J., Caldeira K., Elderfield H., Hoegh-Guldberg O., Liss P., Riebesell U. & Watson A. (2005) - Ocean acidification due to increasing atmospheric carbon dioxide. The Royal Society, 60 pp.

Rego E.S., Jovane L., Hein J.R., Sant'Anna L.G., Giorgioni M., Rodelli D. & Özcan E. (2018) - Mineralogical evidence for warm and dry climatic conditions in the Neo-Tethys (eastern Turkey) during the middle Eocene. Palaeogeography, Palaeoclimatology, Palaeoecology, 501: 45-57.

Rio D., Fornaciari E. & Raffi I. (1990) - Late Oligocene through early Pleistocene calcareous nannofossils from western equatorial Indian Ocean (Leg 115). In: Duncan R.A., Backman J., Peterson L.C., et al. (Eds) - Proceedings of the ODP, Scientific Results: 175-235. Ocean Drilling Program, College Station.

Rögl F & Spezzaferri S. (2002) - Foraminiferal paleoecology and biostratigraphy of the Mühlbach section (Gaindorf Formation, lower Badenian), Lower Austria. In: Weinmann A., Krapf A. & Kroh A. (Eds) - Serie A für Mineralogie und Petrographie, Geologie und Paläontologie, Anthropologie und Prähistorie: 23-75. Annalen des Naturhistorischen Museums in Wien.

Roslim A., Briguglio A., Kocsis L., Ćorić S. & Gebhardt H. (2019) - Large rotaliid foraminifera as biostratigraphic and palaeoenvironmental indicators in northwest Borneo: An example from a late Miocene section in Brunei Darussalam. Journal of Asian Earth Sciences, 170: 20-28.

Russo B., Ferraro L., Correggia C., Alberico I., Foresi L.M., Vallefuoco M. & Lirer F. (2022) - Deep-water paleoenvironmental changes based on early-middle Miocene benthic foraminifera from Malta Island (Central Mediterranean). Palaeogeography, Palaeoclimatology, Palaeoecology, 586: 110722.

Savian J. F., Jovane L., Trindade R.I.F., Frontalini F., Coccioni R., Bohaty S.M., Wilson P.A., Florindo F. & Roberts A. (2013) - Middle Eocene Climatic Optimum (MECO) in the Monte Cagnero Section, Central Italy. Latinmag Letters, Special Issue, (3): 1-8.

Schmiedl G., Mackensen A. & Müller P.J. (1997) - Recent benthic foraminifera from the eastern South Atlantic Ocean: dependence on food supply and water masses. Marine micropaleontology, 32(3-4): 249-287.

Schrag D.P., Depaolo D.J. & Richter F.M. (1995) - Reconstructing past sea surface temperatures: Correcting for diagenesis of bulk marine carbonate. Geochimica et Cosmochimica Acta, 59: 2265–2278. doi:10.1016/0016-7037(95)00105-9.

Schweizer M., Pawlowski J., Kouwenhoven T. & Van Der Zwaan B. (2009) - Molecular phylogeny of common cibicidids and related Rotaliida (Foraminifera) based on small subunit rDNA sequences. Journal of Foraminiferal Research, 39(4): 300-315.

Seddighi M., Briguglio A., Hohenegger J. & Papazzoni C. A. (2015) - New results on the hydrodynamic behaviour of fossil Nummulites tests from two nummulite banks from the Bartonian and Priabonian of northern Italy. Bollettino della società paleontologica italiana, 54(2): 103.

Sen Gupta B.K. & Machain-Castillo M.L. (1993) – Benthic foraminifera in oxygen-poor habitats. Marine Micropaleontology, 20: 3-4.

Serra-Kiel J., Hottinger L., Caus E., Drobne K., Ferrández C., Jauhri A.K., Less Gy., Pavlovec R., Pignatti J.S., Samsó J.M., Schaub H., Sirel E., Strougo A., Tambareau Y., Tosquella J. & Zakrevskaya E. (1998) - Larger Foraminiferal Biostratigraphy of the Tethyan Paleocene and Eocene. Bulletin de la Société Géologique de France, 169: 281-299.

Sexton P.F., Wilson P.A. & Norris R.D. (2006) - Testing the Cenozoic multisite composite δ18O and δ13C curves: new monospecific Eocene records from a single locality, Demerara Rise (Ocean Drilling Program Leg 207). Paleoceanography, 21: 2019. doi:10.1029/2005PA001253.

Shi J., Jin Z., Liu Q., Zhang R. & Huang Z. (2019) - Cyclostratigraphy and astronomical tuning of the middle Eocene terrestrial successions in the Bohai Bay Basin, Eastern China. Global and Planetary Change, 174: 115-126.

Sinclair H.D. (1997) - Tectonostratigraphic model for underfilled peripheral foreland basins: An Alpine perspective. The Geological Society of America Bulletin, 109: 324-346.

Sluijs A., Zeebe R.E., Bijl P.K. & Bohaty S.M. (2013) - A middle Eocene carbon cycle conundrum, Nature Geoscience, 6(6): 429–434. doi:10.1038/NGEO1807.

Speijer R.P. (1994) - Extinction and recovery patterns in benthic foraminiferal paleocommunities across the Cretaceous/Paleogene and Paleocene/Eocene boundaries. Utrecht University Repository, 1-191 pp.

Speijer R.P. & Schmitz B. (1998) - A benthic foraminiferal record of Paleocene Sea level and trophic/redox conditions at Gebel Aweina, Egypt. Palaeogeography, Palaeoclimatology, Palaeoecology, 137(1-2): 79-101.

Spofforth D.J.A., Agnini C., Pälike H., Rio D., Fornaciari E. & Giusberti L. (2010) – Organic carbon burial following the middle Eocene climatic optimum in the central western Tethys. Paleoceanography, 25: A3210. doi: 10. 1029/2009PA001738.

Spötl C. & Vennemann T.W. (2003) - Continuous-flow IRMS analysis of carbonate minerals. Rapid Communications in Mass Spectrometry, 17: 1004–1006.

Szarek R. (2001) - Biodiversity and biogeography of recent benthic foraminiferal assemblages in the south-western South China Sea (Sunda Shelf). PhD thesis, Christian-Albrechts Universität Kiel, Germany, 273 pp.

Thomas E. (2007) - Cenozoic mass extinctions in the deep sea: What perturbs the largest habitat on Earth? In: Monechi S., Coccioni R. & Rampino M.R. (Eds) - Large Ecosystem Perturbations: Causes and Consequences: 424: 1-23. Geological Society of America Special Paper. doi: 10.1130/2007.2424(01).

Thomas E. & Gooday A. J. (1996) - Cenozoic deep-sea benthic foraminifers: tracers for changes in oceanic productivity? Geology, 24(4): 355-358.

Toffanin F., Agnini C., Fornaciari E., Rio D., Giusberti L., Luciani V., Spofforth D.J.A. & Pälike H. (2011) – Changes in calcareous nannofossil assemblages during the Middle Eocene Climatic Optimum: clues from the central-western Tethys (Alano section, NE Italy). Marine Micropaleontology, 81: 22–31.

Toffanin F., Agnini C., Rio D., Acton G. & Westerhold T. (2013) – Middle Eocene to Early Oligocene calcareous nannofossil biostratigraphy at IODP Site U1333 (equatorial Pacific). Micropaleontology, 59: 69–82.

Van der Zwaan G. J. (1982) - Paleoecology of late Miocene Mediterranean foraminifera. PhD Thesis, Utrecht University, Netherland, 199 pp.

Van der Zwaan G. J., Jorissen F.J., Verhallen P.J.J.M. & Von Daniels C.H. (1986) - Atlantic-European Oligocene to recent Uvigerina: taxonomy, paleoecology, and paleobiogeography. Utrecht University Repository, 35: 7-20.

Van der Zwaan G. J., Jorissen F. J. & De Stigter H.C. (1990) - The depth dependency of planktonic/benthic foraminiferal ratios: constraints and applications. Marine Geology, 95(1): 1-16.

Van der Zwaan G.J., Duijnstee A.I., Den Dulk M., Ernst S.R., Jannink N. T. & Kouwenhoven T.J. (1999) - Benthic foraminifers: proxies or problems? A review of paleocological concepts. Earth-Science Reviews, 46(1-4): 213-236.

Varrone D. (2004) – Le prime fasi di evoluzione del bacino di avanfossa alpino: la successione delfinese cretacio-eocenica, Alpi marittime. PhD Thesis (unpublished), University of Torino.

Villa G., Fioroni C., Pea L., Bohaty S. & Persico D. (2008) – Eocene–late Oligocene climate variability: calcareous nannofossil response at Kerguelen Plateau, Site 748. Marine Microplaeontology, 69: 173–192.

Wade B. S. (2004) - Planktonic foraminiferal biostratigraphy and mechanisms in the extinction of Morozovella in the late middle Eocene. Marine Micropaleontology, 51(1-2): 23-38.

Wade B. S., & Kroon D. (2002) - Middle Eocene regional climate instability: Evidence from the western North Atlantic. Geology, 30(11): 1011-1014.

Wade B.S. & Bown P.R. (2006) - Calcareous nannofossils in extreme environments: the Messinian salinity crisis, Polemi Basin, Cyprus. Palaeogeography, Palaeoclimatology, Palaeoecology, 233(3-4): 271-286.

Wade B., Pearson P. N., Berggren W. A. & Pälike H. (2011) - Review and revision of Cenozoic tropical planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale. Earth Science Reviews, 104: 111–142. doi: 10.1016/j.earscirev.2010.09.003.

Young J.R., Bown P.R. & Lees J.A. (2017) - Nannotax3 Website. International Nannoplankton Association, available at:, accessed 21st Apr 2017.

Zachos J.C., Pagani M., Sloan L.C., Thomas E. & Billups K. (2001) - Trends, rhythms, and aberrations in global climate 65 Ma to present. Science, 292: 686–693.






Received 2023-05-16
Accepted 2023-09-14
Published 2023-10-17