Eocene and early oligocene micropaleontology and paleoenvironments in SE Umbria, Italy

Nocchi, Marisa; Parisi, Guido; Monaco, Paolo; Monechi, Simonetta; Madile, Marina

doi:10.1016/0031-0182(88)90154-x

Cited by 37 publications

(28 citation statements)

References 41 publications

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“…Dinoflagellate cyst zones in Priabona are from (1) Brinkhuis (1994). Red star indicates the position of the Eocene-Oligocene boundary in Priabona, as it was defined in Massignano (GSSP; Nocchi et al, 1988;Premoli Silva and Jenkins, 1993). B) Stratigraphy of the Massigano section displaying the dinoflagellate cyst biostratigraphy of (2) Brinkhuis and Biffi (1993).…”

Section: Facies Evolutionmentioning

confidence: 99%

“…Based on dinocyst stratigraphy the coolest interval corresponds to the bryozoan beds in Priabona and therefore in San Valentino, giving additional constrains that a sea-surface cooling occurred coevally with the development of bryozoan beds in northern Italy. The star marks the stratigraphic position of the Eocene-Oligocene boundary in Priabona, as it was defined in Massignano (GSSP; Nocchi et al, 1988;Premoli Silva and Jenkins, 1993). (1) Local disappearance of the dinoflagellate Hemiplacophora semilunifera, which corresponds to subtropical taxa.…”

Section: Change In Nutrient Supplymentioning

confidence: 99%

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Bryozoan beds in northern Italy as a shallow-water expression of environmental changes during the Oligocene isotope event 1

Jaramillo‐Vogel

Bover‐Arnal

Strasser

2016

Sedimentary Geology

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Shifts in carbonate-producing biotic communities in the geological record provide evidence of past environmental changes in the neritic realm. The shallow-marine Calcare di Nago Formation exposed in the San Valentino section (northern Italy) covers the Late Eocene and Earliest Oligocene. The succession is characterized by the occurrence of light-dependent biota such as coralline algae and larger benthic foraminifera. In the uppermost part of the section, however,\ the fossil association is dominated by bryozoans, which are filter-feeder organisms. This ca. 12 m thick interval locally contains up to 86% bryozoans, while coralline algae as well as larger benthic foraminifera are absent. Coralline algae and nummulitid foraminifera recover in the upper part of the bryozoan beds, whereas orthophragminids do not recover. The gradual disappearance of larger foraminifera and coralline algae within the bryozoan-dominated deposits is coeval with a pronounced positive shift in δ 13 C. Based on its biostratigraphic position, this positive shift is interpreted to be linked to the positive shift in δ 13 C recognized in deepsea records shortly above the Eocene-Oligocene boundary, which in turn is associated to the positive shift in δ 18 O leading to the Oi-1 (Oligocene isotope event 1) cooling phase. Total phosphorus content increases in the bryozoan beds, suggesting enhanced nutrient supply to the neritic ecosystem. This phosphorous peak is coeval with the globally recognized increment in ocean productivity around the Oi-1 and δ 13 C positive shift. Thus, disappearance of light-dependent biota and the dominance of bryozoans in the platform carbonates studied are interpreted to result not necessarily from a deepening of the depositional environment but from the combination of lower seasurface temperatures and the deterioration of underwater light conditions on account of elevated turbidity in surface waters, resulting from enhanced primary productivity. As bryozoan beds occur in several Italian localities around the Eocene-Oligocene boundary, they are interpreted to represent the regional expression of neritic carbonate depositional systems to global environmental changes occurring at the dawn of an ice-house Earth.

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Section: Facies Evolutionmentioning

confidence: 99%

Section: Change In Nutrient Supplymentioning

confidence: 99%

Bryozoan beds in northern Italy as a shallow-water expression of environmental changes during the Oligocene isotope event 1

Jaramillo‐Vogel

Bover‐Arnal

Strasser

2016

Sedimentary Geology

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“…The resulting estimates above correspond to cosmopolitan benthic foraminiferal taxa present in association, which indicate bathyal environments [23]. In our record we identified common bathyal taxa (Cibicidoides robertsonianus, C. mundulus, Gyroidinoides spp., and some bolivinids), but few abyssal taxa such as Cibicidoides grimsdalei and Vulvulina spinosa [6,62,85,86]. The Cibicidoides component of assemblages can be considered excellent palaeobathymetric marker, providing the means to distinguish between bathyal and abyssal depths.…”

Section: Bathymetric Significance Of Foraminiferal Assemblagesmentioning

confidence: 99%

“…Nuttallides umbonifera 0,00 0,00 0, 85 O. umbonatus 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 16,55…”

Section: Speciesunclassified

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

Drinia

2009

Open Geosciences

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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.

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“…The paleoecology (preferred biogeographical distribution and life position in the water column) and the paleoclimatic signifi cance of the recognized species and groups are based on the abundant literature, largely following Douglas and Savin (1978), Boersma et al (1979Boersma et al ( , 1987, Keller (1983), Poore and Matthews (1984), Nocchi et al (1988b), Premoli Boersma (1988, 1989), , Huber (1991, 1993), Boersma and Premoli Silva (1991), Spezzaferri and Premoli Silva (1991), Pearson et al (1993, 1997, 2001), Spez zaferri (1995, Van Eijden and Ganssen (1995), Pearson and Palmer (1999), Coxall et al (2000), and Wade and Kroon (2002).…”

Section: Paleoenvironmental Remarksmentioning

confidence: 99%

Late Eocene impact-induced climate and hydrological changes: Evidence from the Massignano global stratotype section and point (central Italy)

Coccioni

Frontalini

Spezzaferri

2009

The Late Eocene Earth—Hothouse, Icehouse, and Impacts

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The Eocene-Oligocene transition marks the passage from "greenhouse" conditions to an "icehouse state" with progressive global cooling starting in the early middle Eocene. The late Eocene is also characterized by a high concentration of extraterrestrial impacts, the effects of which, on living organisms and climatic changes, are still not understood. We carried out a high-resolution investigation on planktonic foraminiferal assemblages in an 8-m-thick segment of the Massignano global stratotype section and point for the Eocene-Oligocene boundary with the aim of assessing the effects that the impacts may have had on the environment and this group of organisms. The studied interval is punctuated by three late Eocene iridium-rich layers, several cosmic signatures, and enhanced levels of 3 He. The two lower closely spaced iridium anomalies are possibly linked to the Popigai and Chesapeake Bay impact events, respectively, whereas no particular impact event can be assigned to the third anomaly, even if it might be correlated with some large craters. Interpretation of data suggests that all the impacts had no abrupt, dramatic effects on planktonic foraminifera. However, acting as forcing factors, they induced some environmental perturbations and may have contributed to remarkable climate changes superimposed on the general late Eocene cooling trend. The Popigai and Chesapeake Bay impact events triggered signifi cant changes in the water mass structure, in terms of stratifi cation and trophic resources, associated with some climatic excursions that took place within chron C16n.1n and chron C15r and at the transition between planktonic foraminiferal zones P15 and P16.The short-term warming pulse recognized after the Popigai impact might have been due to greenhouse effects produced by injection of CO 2 into the atmosphere and/or the release of methane hydrate after the impact itself. The dynamic between *cron@info-net.it.

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Eocene and early oligocene micropaleontology and paleoenvironments in SE Umbria, Italy

Cited by 37 publications

References 41 publications

Bryozoan beds in northern Italy as a shallow-water expression of environmental changes during the Oligocene isotope event 1

Bryozoan beds in northern Italy as a shallow-water expression of environmental changes during the Oligocene isotope event 1

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

Late Eocene impact-induced climate and hydrological changes: Evidence from the Massignano global stratotype section and point (central Italy)

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