We present trace metal geochemistry and stable isotope records for the middle Eocene Alano di Piave section, NE Italy, deposited during magnetochron C18n in the marginal Tethys Ocean. We identify a ...∼500 kyr long carbon isotope perturbation event we infer to be the middle Eocene climatic optimum (MECO) confirming the Northern Hemisphere expression and global occurrence of MECO. Interpreted peak climatic conditions are followed by the rapid deposition of two organic rich intervals (≤3% TOC) and contemporaneous positive δ13C excursions. These two intervals are associated with increases in the concentration of sulphur and redox‐sensitive trace metals and low concentrations of Mn, as well as coupled with the occurrence of pyrite. Together these changes imply low, possibly dysoxic, bottom water O2 conditions promoting increased organic carbon burial. We hypothesize that this rapid burial of organic carbon lowered global pCO2 following the peak warming and returned the climate system to the general Eocene cooling trend.
A ca. 950 m thick succession that was continuously cored in 1971 in Venice has been revisited, in order to reconstruct the environmental history of the Venice area since about 2.15 Ma. Magnetic ...polarity stratigraphy, integrated with refined calcareous nannofossil biostratigraphy, provides a firm chronostratigraphic framing of the succession. In order to improve the chronological resolution, we derived astrochronological refinements in the lower Pleistocene sapropel-bearing interval by a comparison with other time-correlative sections in the Mediterranean. The pollen record is used as a proxy of climatic changes and as an indirect tool in the chronological reconstruction in the upper part of the succession. The following history has been inferred: (1) in the late Gelasian (late Pliocene), the depositional area was a strongly subsiding shelf which shoaled to near sea level; (2) following a hiatus of a minimum duration of 0.2 Myr, encompassing most of the Olduvai Subchron, the shelf rapidly drowned to bathyal depths over the early Pleistocene (biozones MNN 19a to 19e: from 1.947 Ma to 0.96 Ma). This interval was characterized by starved sedimentation (less than 10 cm/kyr), represented by hemipelagic muds interbedded with sapropel layers; (3) during most of biozone MNN19f (
Pseudoemiliania lacunosa Zone, 0.96–0.42 Ma) a thick package of turbidites was laid down as a result of massive terrigenous input from the eastern Southern Alps; (4) later, in the middle part of Chron 1n (Brunhes), deltaic sedimentation, primarily related to the progradation of the paleo-Po system, led to the progressive infill of the basin. This progradational episode was a major building phase, and ended with the first appearance of continental sediments, tentatively correlated with marine oxygen isotope substage 8.4; (5) the upper part of the succession shows a cyclic organization, with an upward increasing amount of marginal-marine and subaerial deposits. In this interval the Venice area was below sea level during glacioeustatic highstands but became emergent during subsequent major glacioeustatic lowstands. Pollen data support an overall good correspondence of continental sediment packages of sequences with glacial conditions and of maximum flooding intervals with interglacial conditions.
The Monte San Nicola area (Southern Sicily) offers a spectacular exposure of open-marine sediments that were employed in 1998 for defining the Global Stratotype Section and Point (GSSP) of the ...Gelasian Stage (Upper Pliocene). After the lowering of the Pliocene/Pleistocene boundary to ca. 2.6 Ma in 2010, the Gelasian GSSP has been redefined as the base of both the Pleistocene Series and the Quaternary Period, which increased its importance and visibility within the scientific community. However, documentation on the Monte San Nicola reference section is still sparse. In the light of its renewed status, we decided to undertake a complete revision of the Gelasian Stage in its type area, in order to evaluate whether the succession of bio- and magnetostratigraphic events that are expected to occur in the interval of relevance are represented adequately in the local record. The results of our investigation demonstrate that the Monte San Nicola succession spans continuously from the upper Piacenzian to the lower Calabrian, and is therefore suitable to host the Unit Stratotype, or even the Astronomical Unit Stratotype, of the Gelasian Stage.
•Two sections from the Monte San Nicola area (Sicily) were studied.•The “Type” section (Gelasian Stage GSSP) suffers from local tectonic disturbances.•The undisturbed “Mandorlo” section offers a detailed biomagnetostratigraphic record.•Astronomical tuning further proves that the section is complete and continuous.•The Mandorlo section may host the Astronomical Unit-Stratotype of the Gelasian.
Results are presented of a quantitative biostratigraphic study of the calcareous nannofossils from the upper Miocene Metochia section (Gavdos Island, Greece) located in the eastern Mediterranean. The ...study allows the completion of the calcareous nannofossil Zonal Scheme for the Mediterranean Neogene. Parts of the scheme have already been proposed earlier for the Pliocene-Pleistocene (Rio et al. 1990b) and for the latest Oligocene to early late Miocene (Fornaciari and Rio 1996, Fornaciari et al. 1996). The Metochia section proved to be a suitable section for high-resolution biostratigraphic studies. It has a detailed planktonic foraminiferal biostratigraphy and a robust chronology based on the astronomical calibration of the sedimentary cycles (Krijgsman et al. 1995, Hilgen et al. 1995). Age estimates for the nannofossil biohorizons recognized in the section were obtained through direct correlation to this astrochronology. Five out of seventeen biohorizons were selected for biostratigraphic purposes and to define the (sub)zonal boundaries. They are (in stratigraphic order): LO (Last Occurrence) of Discoaster hamatus Martini and Bramlette 1963, equivalent to the base of Subzone MNN10a, dated at 9.53 Ma; FCO (First Consistent Continuous Occurrence) of Discoaster pentaradiatus (Tan 1927) Bramlette and Riedel 1954, equivalent to the base of Subzone MNN10b, at 9.37 Ma; PB (Paracme Beginning) of Reticulofenestra pseudoumbilicus (Gartner 1967) Gartner 1969, equivalent to the base of Zone MNN11a, at 8.76 Ma; FO (First Occurrence) of Amaurolithus spp. (A. primus (Bukry and Percival 1971) Gartner and Bukry 1975), equivalent to the base of Subzone MNN11b, at 7.42 Ma, and FO of Nicklithus amplificus (Bukry and Percival 1971) Raffi Backman and Rio 1998, equivalent to the base of Subzone MNN11c, at 6.69 Ma. We compared our biochronology with data available from other Mediterranean sections (Sprovieri et al. 1996, Negri et al. 1999, Negri and Villa 2000, Bonomo 2001), and with the nannofossil biochronology from low-latitude oceanic reference sections (Raffi et al. 1995, Backman and Raffi 1997). Our results evidence differences and similarities: some of the recently proposed events in the Tortonian-Messinian (e.g., FO and FCO of Reticulofenestra rotariaTheodoridis 1984, FO of Amaurolitus delicatus Gartner and Bukry 1975) proved not to be reliable and do not improve the biostratigraphic resolution by calcareous nannofossils in the time interval under consideration. On the other hand, the five selected biohorizons can easily be reproduced elsewhere in the Mediterranean, and are considered useful for correlations to the extra-Mediterranean realm.
Esta pesquisa se propõe a analisar as formas através das quais a franquia de videogames Sid Meier s Civilization (1991-) lida com a História. Trabalhando com referenciais do campo dos game studies em ...perspectiva interdisciplinar, tentei construir uma compreensão da História encontrada nos jogos, concentrada, principalmente, em permanências identificáveis ao longo de seus 30 anos de existência. Meus três principais objetivos foram: propor a compreensão dos jogos da franquia como histórias – isto é, como obras que apresentam teses acerca da experiência humana em perspectiva diacrônica; questionar abordagens que limitam a interpretação desses jogos à sua natureza enquanto obras especificamente estadunidenses; e posicioná-los como herdeiros de uma tradição de pensamento histórico que remonta pelo menos ao Iluminismo.
This research aims to analyze the ways through which the Sid Meier s Civilization videogame franchise deals with History. Drawing from the field of game studies in an interdisciplinary manner, I have tried to build an understanding of the History found in the games, focusing mainly in constants found throughout it s 30 years of existence. My three main objectives were: to propose the understanding of the franchise s titles as histories – that is, as works that present theses about the human experience in diachronic perspective; to question approaches that limit the interpretation of these games to their nature as specifically U.S. American works; and to position them as heirs to a tradition of historical thinking that goes back at least to the Enlightenment.
The aim of this study was to evaluate the effect of a new treatment for refractory congestive heart failure (CHF) on brain natriuretic peptide (BNP) plasma levels and hydration station.
The study was ...aimed at evaluating the effects of the combination of high-dose furosemide and small-volume hypertonic saline solution (HSS) in refractory CHF patients.
A total of 94 patients (34 women/60 men) with refractory CHF (age 55 to 80 years) were enrolled. They had to have an ejection fraction <35%, serum creatinine <2 mg/dl, blood urea nitrogen <60 mg/dl, a reduced urinary volume, and a low natriuresis (<500 ml/24 h and <60 mEq/24 h, respectively). Patients were divided (double-blind) into two groups: group 1 (18 women/30 men) received an intravenous furosemide (500 to 1,000 mg) plus HSS twice a day in 30 min. Group 2 (16 women/30 men) received an intravenous bolus of furosemide (500 to 1,000 mg/twice a day) alone, for four to six days. At entry, body weight, blood pressure, heart rate, and laboratory parameters were checked during hospitalization; BNP levels were measured on admission, 6 and 30 days after discharge, while on admission and 6 days after, impedance plethysmography was performed. The HSS group received 120 mmol of Na intake versus 80 mmol in non-HSS group. Fluid intake of 1,000 was given to both groups.
The groups were similar for clinical characteristics. A significant increase in daily diuresis and natriuresis was observed in HSS group, p < 0.05. The BNP values showed significant intragroup and intergroup differences, 6 and 30 days after treatment. The patients from the HSS group reached a better hydration state than the non-HSS group after six days. In addition, the HSS group showed a significant reduction in hospitalization time and readmission rate.
Our data show that the HSS group reached dry weight more rapidly, a significantly faster reduction in BNP levels, shorter hospitalization stay, and lower incidence in readmissions in the 30-day study period.
The Lower Pliocene succession of the Crotone Basin (Calabrian Arc, Southern Italy) is mainly comprised of blue-grey marly clay with good magnetic properties. Here the bio-magnetostratigraphic data ...indicate a mean sedimentation rate of about 12–15cm/kyr. Around 3.7–3.6Ma a major change in the sedimentation regime occurred: the blue-grey hemipelagic marls grade rapidly into silty marls with a significant increase in the terrigenous fraction and with abundant siliceous remains throughout the whole interval. Magnetic properties of these sediments are very poor, but an integrated calcareous plankton biostratigraphy (foraminifera and nannofossils) infers a high average sedimentation rate (about 50–60cm/kyr). The abrupt onset of this sedimentation regime in the Crotone Basin is contemporaneous with a major unconformity already recognized in the northern sector of the basin, part of a major reorganization phase in the whole Apenninic–Maghrebid Chain known as “Globorotalia puncticulata event”. Reports of coeval siliceous sediments in other marginal basins of the Apennines (Southern Calabria, Southern and Northern Apennines) suggest that this “siliceous event” might have been regionally extensive, having important palaeoceanographical implications. We infer that the “siliceous event” is characterized by a combined tectonic- and climate-induced change in palaeoceanographic conditions. The tectonic triggering factors may have been linked to two synchronous events in the Tyrrhenian–Apennine system: 1) the shortening event also known as “G. puncticulata event”, and 2) the coeval opening of the Vavilov Basin in the Tyrrhenian Sea which yielded profound influences in terms of physiography and characteristics of the Crotone Basin. The consequent uplift of the Southern Apennines would have increased sediment supply and availability of silica, resulting in eutrophication and enhanced silica preservation. Strong winter mixing and possibly upwelling conditions could have increased primary productivity during heavy isotope stages Gi4, Gi2 and MG8, at the onset of the “siliceous event”. This important event, lasting from ca. 3.6Ma to ca. 3.2Ma, would have recorded a peculiar transitional period before further climatic deterioration and more drastic palaeoceanographic changes occurred around 3.1Ma, leading to cyclic sapropel deposition in the whole of the Mediterranean sea.
•We present new bio-magnetostratigraphic data obtained in the Crotone Basin.•The data show a major change in the sedimentation regime in the late Early Pliocene.•Around 3.7–3.6Ma “siliceous” sediments started to deposit in the basin.•This “siliceous event” is coeval with a major reorganization in the Apenninic chain.•This event is probably regional and was triggered by tectonic and climatic factors.
Pronounced warming negatively impacts ecosystem resilience in modern oceans. To offer a long‐term geological perspective of the calcareous plankton response to global warming, we present an ...integrated record, from two Tethyan sections (northeastern Italy), of the planktic foraminiferal and calcareous nannofossil response to the Eocene Thermal Maximum 2 hyperthermal (ETM2, ∼54 Ma). Our study reveals pronounced changes in assemblage composition and a striking dwarfing of planktic foraminiferal tests of up to 40% during the event, impacting both surface and deeper dwellers. The increased abundance of small placoliths among calcareous nannofossils is interpreted as community size reduction. Literature and our foraminiferal size data from Sites 1263 and 1209 (Atlantic and Pacific Oceans) highlights that the pronounced dwarfism is restricted to the Tethyan area. The ETM2 is characterized by warm sea surface temperatures as indicated by our δ18O data, but this warming is of global extent and cannot explain the unique dwarfism. Excluding evolutionary modifications, other potential drivers of dwarfism (eutrophication, deoxygenation, metabolic adaptation) cannot explain the exceptional dwarfism by themselves. The smallest sizes are in close temporal association with peaks in volcanic derived Hg/Th‐Hg/Rb recorded just before and at the ETM2 which could not have been brought into our sections through weathering. In contrast, size reductions are absent below and above the ETM2 at Hg peaks where δ18O data do not show warm conditions. We speculate that the local input of toxic metals from submarine volcanic emissions could have acted synergistically to warming, causing the unique dwarfism.
Key Points
Calcareous plankton size in the Tethys during the Eocene Thermal Maximum 2 (ETM2) reveals marked dwarfism
Pronounced dwarfism was restricted to the Tethyan area, highlighting the importance of local signals in interpreting hyperthermals
Calcareous plankton were highly unstable across the ETM2 but ultimately resilient
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