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Early Miocene volcanic activity and paleoenvironment conditions recorded in tephra layers of the AND-2A core (southern McMurdo Sound, Antarctica)

Sat, 31 Dec 2011 23:00:00 GMT

Title: Early Miocene volcanic activity and paleoenvironment conditions recorded in tephra layers of the AND-2A core (southern McMurdo Sound, Antarctica) Authors: Di Roberto, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Del Carlo, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Rocchi, S.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy; Panter, K. S.; Department of Geology, Bowling Green State University, Bowling Green, OH, 43403, USA Abstract: The ANtarctic geological DRILLing program (ANDRILL) successfully recovered 1138.54 m of core from drillhole, AND-2A, in the Ross Sea sediments (Antarctica). The core is composed of terrigenous claystones, siltstones, sandstones, conglomerates, breccias, and diamictites with abundant volcanic material. In this work we present sedimentological, morphoscopic, petrographic, and geochemical data on pyroclasts recovered from core AND-2A, which provide insights on eruption styles, volcanic sources, and environments of deposition. One pyroclastic fall deposit, 12 resedimented volcaniclastic deposits and 14 volcanogenic sedimentary deposits record a history of intense explosive volcanic activity in southern Victoria Land during the Early Miocene. Tephra were ejected during Subplinian and Plinian eruptions fed by trachytic to rhyolitic magmas and during Strombolian to Hawaiian eruptions fed by basaltic to mugearitic magmas in submarine/subglacial to subaerial environments. The long-lived Mt. Morning eruptive centre, located c. 80 km south of the drillsite, was recognized as the probable volcanic source for these products on the basis of volcanological, geochemical, and age constraints. The study of tephra in the AND-2A core provides important paleoenvironment information by revealing that the deposition of primary and moderately reworked tephra occurred in a proglacial setting under generally open water marine conditions.

Plio-Pliocene high-low latitude climate interplay: a Mediterranean point of view

Tue, 31 Jan 2012 23:00:00 GMT

Title: Plio-Pliocene high-low latitude climate interplay: a Mediterranean point of view Authors: Colleoni, F.; Centro Euro-Mediterraneo sui Cambiamenti Climatici; Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Negri, A.; Universita' Politecnica delle Marche; Marzocchi, A.; Centro Euro-Mediterraneo sui Cambiamenti Climatici Abstract: The high–low latitude climate interplay during the Plio–Pleistocene global cooling is not yet well understood. Insight on the Mediterranean region can provide some clues about past significant climate changes since the basin reflects the climate dynamics of both high-latitude and low-latitude regions, being connected to the North Atlantic and subjected to monsoon influence. Here we shade light on this connection problem by per- forming a spectral analysis on an Eastern Mediterranean stack of planktonic records spanning the last 5 Ma and by further comparing it to North Atlantic and Pacific deep- and surface-water records. Our main conclu- sion is that the Mediterranean detected the main global climate transitions over the last 5 Myr although sapropel depositions indicate that it remained influenced by the African summer monsoon during the whole interval. Our analysis reveals that until 2.2 Ma the Mediterranean planktonic record is driven by re- gional processes dominated by precession. The progressive emergence of the 41-kyr frequency in the Medi- terranean records around 2.8 Ma suggests that, since this date, the Mediterranean was more and more affected by the high-latitude climate dynamics forcing than by the low-latitude one. Moreover, during the ongoing Plio–Pleistocene cooling, the 41-kyr frequency signal in the Mediterranean records anticipated high-latitude deep-water response to the intensification of the Northern Hemisphere Glaciations (NHG) and lagged the signal in tropical latitudes. Finally, toward 1.2 Ma the results suggest that the progressive shift from the 41-kyr to the 100-kyr frequency was led by the northern high latitudes. Overall, our results confirm that the Mediterranean is an ideal site to study the interplay between high and low latitude climates.

Neogene tectonic and climatic evolution of the Western Ross Sea, Antarctica — Chronology of events from the AND-1B drill hole

Sun, 30 Sep 2012 22:00:00 GMT

Title: Neogene tectonic and climatic evolution of the Western Ross Sea, Antarctica — Chronology of events from the AND-1B drill hole Authors: Wilson, G. S.; Department of Marine Science, University of Otago, PO Box 56, Dunedin, New Zealand; Levy, R. H.; GNS Science, PO Box 30‐368, Lower Hutt, New Zealand; Naish, T. R.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Powell, R. D.; Department of Geology & Environmental Geosciences, Northern Illinois University, DeKalb, IL 60115, USA; Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Ohneiser, C.; Department of Geology, University of Otago, PO Box 56, Dunedin, New Zealand; Sagnotti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Winter, D. M.; ANDRILL Science Management Office, Department of Geosciences, University of Nebraska-Lincoln, Lincoln, NE 68588‐0340, USA; Cody, R.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Henrys, S.; GNS Science, PO Box 30‐368, Lower Hutt, New Zealand; Ross, J.; New Mexico Institute of Mining & Technology, Earth & Environmental Sciences, Socorro, NM 87801, USA; Krissek, L.; Byrd Polar Research Centre, The Ohio State University, Columbus, OH 43210, USA; Niessen, F.; Alfred Wegener Institute, Department of Geosciences, Postfach 12 01 6, Am Alten Hafen 26, D-27515, Bremerhaven, Germany; Pompillio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Scherer, R.; Department of Geology & Environmental Geosciences, Northern Illinois University, DeKalb, IL 60115, USA; Alloway, B. V.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Barrett, P. J.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Brachfeld, S.; Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043, USA; Browne, G.; GNS Science, PO Box 30‐368, Lower Hutt, New Zealand; Carter, L.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Cowan, E.; Department of Geology, Appalachian State University, Boone, NC 28608‐2067, USA; Crampton, J.; GNS Science, PO Box 30‐368, Lower Hutt, New Zealand; DeConto, R. M.; Department of Geosciences, University of Massachusetts, Amherst, MA 01003‐9297, USA; Dunbar, G.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Dunbar, N.; Department of Marine Science, University of Otago, PO Box 56, Dunedin, New Zealand; Dunbar, R.; Department of Environmental Earth System Sciences, School of Earth Sciences, Stanford University, Stanford, CA 94305, USA; von Eynatten, H.; Department of Sedimentology and Environmental Geology, Geoscience Center Göttingen (GZG), Goldschmidtstrasse 3, Göttingen, Germany; Gebhardt, C.; Alfred Wegener Institute, Department of Geosciences, Postfach 12 01 6, Am Alten Hafen 26, D-27515, Bremerhaven, Germany; Giorgetti, G.; Dipartimento di Scienze della Terra, Universita di Sienna, Via Laterina 8, I-53100, Sienna, Italy; Graham, I.; GNS Science, PO Box 30‐368, Lower Hutt, New Zealand; Hannah, M.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Hansaraj, D.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Harwood, D. M.; ANDRILL Science Management Office, Department of Geosciences, University of Nebraska-Lincoln, Lincoln, NE 68588‐0340, USA; Hinnov, L.; Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218, USA; Jarrard, R. D.; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, USA; Joseph, L.; Environmental Studies Program, Ursinus College, Collegeville, PA 19426, USA; Kominz, M.; Department of Geology, Western Michigan University, Kalamazoo, MI 49008, USA; Kuhn, G.; Alfred Wegener Institute, Department of Geosciences, Postfach 12 01 6, Am Alten Hafen 26, D-27515, Bremerhaven, Germany; Kyle, P.; New Mexico Institute of Mining & Technology, Earth & Environmental Sciences, Socorro, NM 87801, USA; Läufer, A.; Federal Institute for Geosciences & Natural Resources, BGR, Stilleweg 2, D-30655 Hannover, Germany; McIntosh, W. C.; New Mexico Institute of Mining & Technology, Earth & Environmental Sciences, Socorro, NM 87801, USA; McKay, R.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Maffioli, P.; Università Milano-Bicocca, Dipartimento di Scienze Geologiche e Geotecnologie, Piazza della Scienza 4, I-20126 Milano, Italy; Magens, D.; Alfred Wegener Institute, Department of Geosciences, Postfach 12 01 6, Am Alten Hafen 26, D-27515, Bremerhaven, Germany; Millan, C.; Byrd Polar Research Centre, The Ohio State University, Columbus, OH 43210, USA; Monien, D.; Alfred Wegener Institute, Department of Geosciences, Postfach 12 01 6, Am Alten Hafen 26, D-27515, Bremerhaven, Germany; Morin, R.; US Geological Survey, Mail Stop 403, Denver Federal Center, Denver, CO 80225, USA; Paulsen, T.; Department of Geology, University of Wisconsin, Oshkosh, 800 WI 54901, USA; Persico, D.; Departimento di Scienze della Terra, Universita di Parma, Parco Aeres delle Scienze, 157 Parma, Italy; Pollard, D.; Earth and Environmental Systems Institute, 2217 Earth-Engineering Science Bldg, University Park, PA 16802, USA; Raine, J. I.; GNS Science, PO Box 30‐368, Lower Hutt, New Zealand; Riesselman, C.; Department of Marine Science, University of Otago, PO Box 56, Dunedin, New Zealand; Sandroni, S.; Dipartimento di Scienze della Terra, Universita di Sienna, Via Laterina 8, I-53100, Sienna, Italy; Schmitt, D.; Department of Marine Science, University of Otago, PO Box 56, Dunedin, New Zealand; Sjunneskog, C.; Antarctic Marine Geology Research Facility, Department of Geology, Florida State University, Tallahassee, FL 32306, USA; Strong, C. P.; GNS Science, PO Box 30‐368, Lower Hutt, New Zealand; Talarico, F.; Dipartimento di Scienze della Terra, Universita di Sienna, Via Laterina 8, I-53100, Sienna, Italy; Taviani, M.; CNR, ISMAR — Bologna, Via Gobetti 101, I-40129 Bologna, Italy; Villa, G.; Departimento di Scienze della Terra, Universita di Parma, Parco Aeres delle Scienze, 157 Parma, Italy; Vogel, S.; Department of Geology & Environmental Geosciences, Northern Illinois University, DeKalb, IL 60115, USA; Wilch, T.; Albion College, Department of Geology, Albion, MI 49224, USA; Williams, T.; Columbia University, Lamont-Doherty Earth Observatory, Palisades, NY 10964, USA; Wilson, T. J.; Byrd Polar Research Centre, The Ohio State University, Columbus, OH 43210, USA; Wise, S.; Antarctic Marine Geology Research Facility, Department of Geology, Florida State University, Tallahassee, FL 32306, USA Abstract: Stratigraphic drilling from the McMurdo Ice Shelf in the 2006/2007 austral summer recovered a 1284.87 m sedimentary succession from beneath the sea floor. Key age data for the core include magnetic polarity stratigraphy for the entire succession, diatom biostratigraphy for the upper 600 m and 40Ar/39Ar ages for in-situ volcanic deposits as well as reworked volcanic clasts. A vertical seismic profile for the drill hole allows correlation between the drill hole and a regional seismic network and inference of age constraint by correlation with well‐dated regional volcanic events through direct recognition of interlayered volcanic deposits as well as by inference from flexural loading of pre‐existing strata. The combined age model implies relatively rapid (1 m/2–5 ky) accumulation of sediment punctuated by hiatuses, which account for approximately 50% of the record. Three of the longer hiatuses coincide with basin‐wide seismic reflectors and, along with two thick volcanic intervals, they subdivide the succession into seven chronostratigraphic intervals with characteristic facies: 1. The base of the cored succession (1275–1220 mbsf) comprises middle Miocene volcaniclastic sandstone dated at approx 13.5 Ma by several reworked volcanic clasts; 2. A late-Miocene sub-polar orbitally controlled glacial–interglacial succession (1220–760 mbsf) bounded by two unconformities correlated with basin‐wide reflectors associated with early development of the terror rift; 3. A late Miocene volcanigenic succession (760–596 mbsf) terminating with a ~1 my hiatus at 596.35 mbsf which spans the Miocene–Pliocene boundary and is not recognised in regional seismic data; 4. An early Pliocene obliquity-controlled alternating diamictite and diatomite glacial–interglacial succession(590–440 mbsf), separated from; 5. A late Pliocene obliquity-controlled alternating diamictite and diatomite glacial–interglacial succession (440–150 mbsf) by a 750 ky unconformity interpreted to represent a major sequence boundary at other locations; 6. An early Pleistocene interbedded volcanic, diamictite and diatomite succession (150–80 mbsf), and; 7. A late Pleistocene glacigene succession (80–0 mbsf) comprising diamictite dominated sedimentary cycles deposited in a polar environment.

Il contributo dei pozzi perforati dalla Regione Lombardia alla conoscenza del Pleistocene lombardo

Wed, 31 Dec 2008 23:00:00 GMT

Title: Il contributo dei pozzi perforati dalla Regione Lombardia alla conoscenza del Pleistocene lombardo Authors: Scardia, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Muttoni, G.; Università di Milano Abstract: Facies analysis applied to several up to 220-m-deep cores, taken by Regione Lombardia in the central-northern Po Plain, allowed to recognize an overall regressive sequence consisting of cyclotemic shallow marine and ﬂuvial-deltaic deposits overlain by distal to proximal braidplain sediments. Magnetostratigraphy, coupled with calcareous nannoplankton biostratigraphy, was used to date marine and ﬂuvial-deltaic sediments to the early Pleistocene and continental sediments to the middle–late Pleistocene. Sediment accumulation rates were of ~0.3-0.4 mm/yr in the early Pleistocene, whereas an overall reduction in sediment accumulation rates to ~0.06-0.08 mm/yr, associated to relevant unconformities, characterized the middle-late Pleistocene. Stratigraphic evidences from petrographic, sedimentologic and palynologic analyses highlight in the Regione Lombardia cores a drastic reorganization of vegetational, ﬂuvial, and Alpine drainage patterns, associated to a sequence boundary termed the “R surface”. The “R surface”, seismically traceable across the Po Plain subsurface, was constrained magnetostratigraphically to the first prominent Pleistocene glacio-eustatic lowstand of marine isotope stage (MIS) 22 at 0.87 Ma at the end of the Mid-Pleistocene Revolution, when climate worsened globally and locally caused the onset of the first major Pleistocene glaciation in the Alps. Most marine deposits in the cores lie above sea level highstands of corresponding age, suggesting that they have been uplifted. In order to estimate the observed rock uplift, sediments were back-stripped to elevations at times of deposition (expressed in meters above current sea level) by applying a simple Airy compensation model. The correlation of the isostatically corrected sedimentary facies to a glacio-eustatic reference curve obtained from classic oxygen isotope studies highlights a positive elevation mismatch (rock uplift) in the range of 70-120 m, which occurred after the onset of the major Pleistocene glacial-interglacial cycles at rates of at least 0.15-0.09 mm/yr. Although the driving forces of the observed rock uplift cannot be unambiguously identified, but its timing of onset after the beginning of the major Pleistocene glacial-interglacial cycles and the low seismicity observed in the most of the Regione Lombardia area seem to point to an isostatic readjustment of the chain probably due to the long-term erosional removal of sediments during major Pleistocene glacial advances.

Late Matuyama climate forcing on sedimentation at the margin of the southern Alps (Italy)

Wed, 31 Dec 2008 23:00:00 GMT

Title: Late Matuyama climate forcing on sedimentation at the margin of the southern Alps (Italy) Authors: Scardia, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Donegana, M.; CNR-IDPA; Muttoni, G.; Università di Milano; Ravazzi, C.; CNR-IDPA; Vezzoli, G.; Università di Milano-Bicocca Abstract: The Pleistocene history of climate control on sedimentation in the Southern Alps-Po Plain system, northern Italy, was reconstructed using an integrated magnetostratigraphic, palynological, and petrographical approach on a 47-m-deep core. The core mainly consists of lacustrine sediments pertaining to the Bagaggera sequence, deposited at the foothills of the Southern Alps during the late Matuyama subchron (0.99–0.78 Ma). At that time, climate worsened globally and locally it caused the progradation of an alluvial fan unit onto the nearby Po Plain, triggering lake formation by damming of a tributary valley. These new data are used in conjunction with data from the literature to highlight and track the effects of climate forcing on sedimentation during the late Matuyama subchron in different orographic and geodynamic settings of the Southern Alps-Po Plain system as part of the greater Alpine area. We found that the episodes of alluvial fan and braidplain progradation observed in the southern foreland of the Alps during the late Matuyama global cooling seem broadly synchronous with the deposition of most of the so-called Günz and Älterer Deckenschotter deposits in the northern forelands of the Alps as well as with the first major waxing of the Alpine valley glaciers, possibly around the Marine Isotope Stage 22 (~0.87 Ma).

Coupled Greenhouse Warming and Deep Sea Acidification in the Middle Eocene

Wed, 31 Dec 2008 23:00:00 GMT

Title: Coupled Greenhouse Warming and Deep Sea Acidification in the Middle Eocene Authors: Bohaty, S. M.; School of Ocean and Earth Science, National Oceanography Centre, Southampton, UK; Zachos, J. C.; University of California, Santa Cruz, USA; Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Delaney, M. L.; University of California, Santa Cruz, USA Abstract: The Middle Eocene Climatic Optimum (MECO) is an enigmatic warming event that represents an abrupt reversal in long-term cooling through the Eocene. In order to further assess the timing and nature of this event, we have assembled stable isotope and calcium carbonate concentration records from multiple Deep Sea Drilling Project and Ocean Drilling Program sites for the time interval between ~43 and 38 Ma. Revised stratigraphy at several sites and compilation of δ18O records place peak warming during the MECO event at 40.0 Ma (Chron C18n.2n). The identification of the δ18O excursion at sites in different geographic regions indicates that the climatic effects of this event were globally extensive. The total duration of the MECO event is estimated at ~500 kyr, with peak warming lasting <100 kyr. Assuming minimal glaciation in the late middle Eocene, ~4 to 6ºC total warming of both surface and deep waters is estimated during the MECO at the study sites. Maximum warming at ~40.0 Ma also coincided with a world-wide decline in carbonate accumulation at sites below 3000 m depth, reflecting a temporary shoaling of the calcite compensation depth. The synchroneity of deep-water acidification and globally extensive warming makes a persuasive argument that the MECO event was linked to a transient increase in atmospheric pCO2. The results of this study confirm previous reports of significant climatic instability during the middle Eocene. Furthermore, the direct link between warming and changes in the carbonate chemistry of the deep ocean provides strong evidence that changes in greenhouse gas concentrations exerted a primary control on short-term climate variability during this critical period of Eocene climate evolution.

Sedimentation and aspects of glacial dynamics from physical properties, mineralogy and magnetic properties at ODP Sites 1166 and 1167, Prydz Bay, Antarctica

Mon, 31 Dec 2007 23:00:00 GMT

Title: Sedimentation and aspects of glacial dynamics from physical properties, mineralogy and magnetic properties at ODP Sites 1166 and 1167, Prydz Bay, Antarctica Authors: Forsberg, C. F.; Norwegian Geotechnical Institute, P.O. Box 3930 Ullevaal Stadion, N-0806 Oslo, Norway; Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Grützner, J.; University of Bremen,; Venuti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Solheim, A.; Norwegian Geotechnical Institute, P.O. Box 3930 Ullevaal Stadion, N-0806 Oslo, Norway Abstract: Trough mouth fans are formed by aggradation of glacial debris flows from sediment deposited by fast flowing ice streams extending to the shelf edge. We here present investigations at two sites, ODP Site 1166 on the shelf and ODP Site 1167 drilled on the Prydz Channel Fan in order to contribute to the understanding of Neogene ice flow patterns in Prydz Bay. The mineralogy, wt.% > 63 μm, physical and magnetic properties were analyzed. The mineralogy of Neogene strata at Site 1166 can be correlated to nearby ODP Site 742 drilled during Leg 119. Moreover an increase in the shear strength of the sediments (Leg 119 load event 3) is found both at Site 1166 and Site 742. This load event probably indicates that the oldest glacial configuration involved thicker glaciers than the later ones. The results from Site 1167 show that there has been a significant change in the provenance of the sediments during the past 2 million years. The greatest change occurred at about 1.13 Ma and implies a shift in the glacial configuration in Prydz Bay with a greater contribution of material from western parts of the drainage basin during the deposition of Unit II (> 1.13 Ma; 217–435 mbsf) at Site 1167 on the Prydz Channel Fan.

A Record of Antarctic Climate and Ice Sheet History Recovered

Sun, 31 Dec 2006 23:00:00 GMT

Title: A Record of Antarctic Climate and Ice Sheet History Recovered Authors: Naish, T.; Antarctic Research Centre, Victoria University of Wellington, New Zealand, and Geological and Nuclear Sciences, Lower Hutt, New Zealand; Powell, R.; Department of Geology and Environmental Geosciences, Northern Illinois University, DeKalb; Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Harwood, D.; ANDRILL Science Management Office; Kuhn, G.; Department of Marine Geophysics, Alfred Wegener Institute, Bremerhaven, Germany; Niessen, F.; Department of Marine Geophysics, Alfred Wegener Institute, Bremerhaven, Germany; Talarico, F.; Dipartimento di Scienze delle Terra,Università di Siena, Siena, Italy; Wilson, G.; Department of Geology, University of Otago, Dunedin, New Zealand Abstract: Antarctica’s late Cenozoic (the past ~15 million years) climate history is poorly known from direct evidence, owing to its remoteness, an extensive sea ice apron, and an ice sheet cover over the region for the past 34 million years. Consequently, knowledge about the role of Antarctica’s ice sheets in global sea level and climate has relied heavily upon interpretations of oxygen isotope records from deep-sea cores. Whereas these isotopic records have revolutionized our understanding of climate-ice-ocean interactions, questions still remain about the specific role of Antarctic ice sheets in global climate. Such questions can be addressed from geological records at the marine margin of the ice sheets, recovered by drilling from floating ice platforms [e.g., Davey et al., 2001; Harwood et al., 2006; Barrett, 2007].

The middle Eocene climatic optimum (MECO) event in the

Sat, 31 Dec 2005 23:00:00 GMT

Title: The middle Eocene climatic optimum (MECO) event in the Authors: Jovane, L.; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143, Rome, Italy; Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143, Rome, Italy; Coccioni, R.; Istituto di Geologia e Centro di Geobiologia, Università degli Studi di Urbino “Carlo Bo”,; Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143, Rome, Italy; Marsili, A.; Istituto di Geologia e Centro di Geobiologia, Università degli Studi di Urbino “Carlo Bo”,; Monechi, S.; Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via La Pira 4, 50121,; Roberts, A.; National Oceanography Centre, Southampton, University of Southampton, European Way,; Sprovieri, M.; Istituto Ambiente Marino Costiero (CNR), Calata Porta di Massa (Interno Porto di Napoli), Abstract: We report a high-resolution paleomagnetic investigation constrained by new qualitative and semi-quantitative analyses of planktic and benthic foraminifera, nannofossil assemblages, integrated with oxygen and carbon isotope measurements, for the middle Eocene Scaglia limestones of the Contessa Highway section, central Italy. Calcareous plankton assemblages enables recognition of several biostratigraphic events from planktic foraminiferal Zone P11 to the lower part of Zone P15 and from calcareous nannofossil Zone NP15 to the upper part of Zone NP17, which results in refinement of the magnetobiostratigraphy of the Contessa Highway section. Correlation of the paleomagnetic polarity pattern with the geomagnetic polarity timescale provides a direct age interpretation for strata around the middle Eocene Scaglia limestones of the Contessa 2 Highway section, from Chrons C21n (47 Ma) through to Subchron C18n.1n (38.5 Ma). Bulk carbon isotope values indicate a distinct carbon isotopic shift at 40 Ma that is interpreted to represent the first evidence in the northern hemisphere of the middle Eocene climatic optimum that has recently been observed as a stable isotope anomaly in multiple records from the Indian-Atlantic sector of the Southern Ocean. This should demonstrate a global response of carbon cycle to the proposed transient increased pCO2 levels during the late middle Eocene and a consequent global CO2-driven climate change.