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Backman, J.
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Backman, J.
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- PublicationRestrictedChronology of the Lower-Middle Pleistocene succession of the south-western part of the Crotone Basin (Calabria, Southern Italy)(2011-05)
; ; ; ; ; ; ; ; ; ;Capraro, L.; Department of Geosciences, Via Gradenigo 6, I-35100 Padova, Italy ;Massari, F.; Department of Geosciences, Via Gradenigo 6, I-35100 Padova, Italy ;Rio, D.; Department of Geosciences, Via Gradenigo 6, I-35100 Padova, Italy ;Fornaciari, E.; Department of Geosciences, Via Gradenigo 6, I-35100 Padova, Italy ;Backman, J.; Department of Geology and Geochemistry, S-10691 Stockholm, Sweden ;Channell, J. E. T.; Department of Geological Sciences, POB 112120, Gainesville, FL-32611, USA ;Macrì, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Prosser, G.; Department of Geological Sciences, Campus Macchiaromana I-85100 Potenza, Italy ;Speranza, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; ; ; ; Biostratigraphy based on calcareous nannofossils, integrated by magnetostratigraphic, geochronological and isotopic data, allowed establishing a precise chronological framework for the Pleistocene succession within the south-western sector of the Crotone Basin (Calabria, Southern Italy), where the Pliocenee Pleistocene global stratotype section and point is defined, thus demonstrating that sedimentation was quasi-continuous during most of the Lower and Middle Pleistocene. At a large scale, the Pleistocene succession in this sector of the Crotone Basin is characterized by an evident shallowing-upwards trend, showing facies changes from bathyal to shelfal to littoral/continental. However, comparison between adjacent sectors within the investigated area demonstrates that stratigraphic architectures change vastly on very short distances. Our chronological constraints indicate that such changes in sedimentation styles probably occurred in response to differential subsidence rates, which originated tectonically-controlled synsedimentary structures where accommodation space and sediment yield were allotted unevenly. This articulated physiography led to striking differences in the overall thicknesses and organization of Pleistocene stratigraphies and, eventually, to a distinct diachroneity in the first appearance of shallow-marine deposits. In addition, superimposed are complex interplays between regional and local tectonics, eustasy and orbitally-forced climate changes. These interactions have been highlighted by the oxygen isotope stratigraphy established for a part of the studied succession, which is likely to document almost continuously the interval from Marine Isotope Stage (MIS) 26 to MIS 17. In its younger part (post-MIS 17), chronological ties are poor, as the succession is dominated by shallow-water to continental deposits showing a prominent organization into cyclothems. Nevertheless, based on the chronology of the underlying units, it is feasible that basin infill ended during MIS 15-MIS 14 times.265 30 - PublicationRestrictedAn early Eocene carbon cycle perturbation at ~52.5 Ma in the Southern Alps: Chronology and biotic response(2009-05-14)
; ; ; ; ; ; ; ; ; ; ;Agnini, C.; Dipartimento di Geoscienze, Università di Padova, Padua, Italy ;Macrì, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Backman, J.; Department of Geology and Geochemistry, Stockholm University, Stockholm, Sweden ;Brinkhuis, H.; Palaeoecology, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Utrecht University, Utrecht, Netherlands ;Fornaciari, E.; Dipartimento di Geoscienze, Università di Padova, Padua, Italy ;Giusberti, L.; Dipartimento di Geoscienze, Università di Padova, Padua, Italy ;Luciani, V.; Dipartimento di Scienze della Terra, Polo Scientifico Tecnologico, Università di Ferrara, Ferrara, Italy ;Rio, D.; Dipartimento di Geoscienze, Università di Padova, Padua, Italy ;Sluijs, A.; Palaeoecology, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Utrecht University, Utrecht, Netherlands ;Speranza, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; ; ; ; ; At least two transient events of extreme global warming occurred superimposed on the long-term latest Paleocene and early Eocene warming trend in the Paleocene-Eocene thermal maximum (PETM) (or ETM1 ~55.5 Ma) and the Elmo (or ETM2 ~53.6 Ma). Other than warmth, the best known PETM is characterized by (1) significant injection of 13C-depleted carbon into the ocean-atmosphere system, (2) deep-sea carbonate dissolution, (3) strong biotic responses, and (4) perturbations of the hydrological cycle. Documentation of the other documented and suspected "hyperthermals" is, as yet, insufficient to assess whether they are similar in nature to the PETM. Here we present and discuss biomagnetostratigraphic data and geochemical records across two lower Eocene successions deposited on a continental margin of the western Tethys: the Farra and Possagno sections in the Venetian pre-Alps. We recognize four negative carbon isotope excursions within chron C24. Three of these shifts correlate to known or suspected hyperthermals: the PETM, the Eocene thermal maximum 2 (~53.6 Ma), and the informally named "X event" (~52.5 Ma). The fourth excursion lies within a reverse subchron and occurred between the latter two. In the Farra section, the X event is marked by a ~0.6% negative carbon isotope excursion and carbonate dissolution. Furthermore, the event exhibits responses among calcareous nannofossils, planktic foraminifera, and dinoflagellates that are similar to, though less intense than, those observed across the PETM. Sedimentological and quantitative micropaleontological data from the Farra section also suggest increased weathering and runoff as well as sea surface eutrophication during this event.365 36