Planktonic Foraminifera Research Papers - Academia.edu (original) (raw)

The lithological and biological sequence of events across the Cretaceous-Tertiary (K/T), as developed in thick and complete landbased sections and termed the standard K/T event sequence, is also found in many I)SDP cores from all over the... more

The lithological and biological sequence of events across the Cretaceous-Tertiary (K/T), as developed in thick and complete landbased sections and termed the standard K/T event sequence, is also found in many I)SDP cores from all over the globe.

Palaeoceanographic conditions in the eastern Indian Ocean for the last ¾30 kyr are documented by means of planktonic foraminiferal analyses of 10 gravity cores. Quantitative foraminiferal analysis (%), Q-mode factor analysis, the modern... more

Palaeoceanographic conditions in the eastern Indian Ocean for the last ¾30 kyr are documented by means of planktonic foraminiferal analyses of 10 gravity cores. Quantitative foraminiferal analysis (%), Q-mode factor analysis, the modern analog technique (MAT) and oxygen-isotope analyses are used. A conspicuous increase during the last glacial maximum (LGM) of foraminiferal fragmentation resulting from a more productive Java upwelling system and=or a more corrosive Antarctic Intermediate Water (AAIW) was found at intermediate water depths (¾1000 m). Contrasting Q-mode factors based on foraminifera between today and the LGM suggest changes in the thermocline depth, sea-surface temperature (SST), upwelling, and the strength of both the Australasian Mediterranean Water (AAMW) and the Indian Central Water (ICW). The decrease in the percentage abundance of shallow-dwelling and symbiont-bearing planktonic foraminifera, the increase in percentage of the upwelling-related species Globorotalia cultrata and Neogloboquadrina dutertrei, and factor 3 (dominated by Globorotalia tumida and Globigerinella siphonifera) suggest a stronger Java upwelling system during the LGM. A steeper, steric latitudinal gradient (in the presence of a weak Leeuwin Current), and a geostrophic flow similar to today's is postulated for the LGM, and this must have prevented upwelling offshore Western Australia. Today's AAMW-ICW sharp front was weaker during the LGM when the AAMW was saltier, cooler, and nutrient richer and more similar to the ICW. During the LGM, a more gentle SST latitudinal gradient over the ¾16 to ¾23ºS region contrasts with today's steeper conditions at the AAMW-ICW Front. Also, for the LGM, a nutrient-rich ICW may explain previously documented increases in mass accumulation rates of CaCO 3 , organic carbon and benthonic foraminifera in a region where the nutricline was deep and within the lower euphotic zone.

Late Quaternary paleoclimatic changes in the Levant are difficult to extract from carbonate oxygen isotope records partly because the factors controlling the terrestrial d 18 O signals are not fully understood in this region characterized... more

Late Quaternary paleoclimatic changes in the Levant are difficult to extract from carbonate oxygen isotope records partly because the factors controlling the terrestrial d 18 O signals are not fully understood in this region characterized by sharp climatic gradients. Here, we address this purpose by presenting the first 14 C-dated isotope record from the northern Levant. The record is based on oxygen isotopes from ostracod shells from lacustrine-palustrine deposits accumulated in a small karstic, hydrologically open basin (Yammoû neh), located on the eastern flank of Mount Lebanon. We have first constructed a composite isotopic record obtained from three different ostracod taxa. This yields an oxygen isotope record of ostracods (d ost) related to the most widespread species (Ilyocypris inermis), and converted to d 18 O values coeval with calcite precipitated in equilibrium (d C) with the lake water (d L). As with other records from the Mediterranean region, the Yammoû neh profile shows maximum and minimum d C values during the LGM and the early Holocene, respectively, and a slight late Holocene increase. In order to discuss the potential causes of the observed d 18 O values fluctuations (e.g., changes in the isotopic composition of the moisture source, temperature, precipitation minus evaporation (P-E) balance, or atmospheric circulation), we tentatively reconstruct the lake water isotope composition by correcting the d C values for lake water temperature using regional paleotemperature estimates. Inferred d L values were then corrected for the isotopic composition of the Eastern Mediterranean sea surface water (the moisture source) derived from planktonic foraminifera d 18 O values corrected for alkenone-based sea surface temperature. Our study suggests that Holocene d L fluctuations are primarily linked to changes in the sea surface water composition (source effect) amplified by enhanced inland rainfall during the early Holocene. During the LGM, low d L values at Yammoû neh are likely due to the ground-temperature effect on the rainfall isotope composition, possibly associated with a steeper altitudinal thermal gradient inland, and with changes in air mass trajectories over the Mediterranean Sea.

Ce chapitre présente la synthese des résultats acquis au cours des recherches développées par le Groupe de Travail Maastrichtien sur les foraminiferes planctoniques de Tercis. Comme pour tous les gro upes fossiles d' intéret... more

Ce chapitre présente la synthese des résultats acquis au cours des recherches développées par le Groupe de Travail Maastrichtien sur les foraminiferes planctoniques de Tercis. Comme pour tous les gro upes fossiles d' intéret stratigraphique, les recherches ont été effectuées indépendamment par plusieurs experts ou groupes d'experts. Ceci a permis de découvrir dans la succession une variété de taxons dont la présence n' était pas évidente au vu des études préliminaires dont certaines avaient laissé supposer que ce groupe fossile ne pouvait pas etre utilisé avec profit dans cette série. Les deux techniques par lavage et par lames minces ont été mises en oeuvre pour tenter de caractériser pres de 200 niveaux essentiellement concentrés de part et d'autre de la limite d'Étages.

The global warming and major perturbation of the global carbon cycle that occurred during the Paleocene-Eocene Thermal Maximum (PETM) have been investigated in the lower bathyal-upper abyssal Alamedilla section (Spain). Geochemical... more

The global warming and major perturbation of the global carbon cycle that occurred during the Paleocene-Eocene Thermal Maximum (PETM) have been investigated in the lower bathyal-upper abyssal Alamedilla section (Spain). Geochemical anomalies and dramatic faunal changes (including the globally recognized extinction event of deep-sea benthic foraminifera and the rapid evolutionary turnover of planktic foraminifera and calcareous nannofossils) are associated with the PETM at Alamedilla.

Since the end of the 19th century the interval comprising the uppermost Upper Albian, the Cenomamian, the Turonian and the basal Coniacian has been subdivided, first into ammonite zones, then, beginning in the middle of the 20th century,... more

Since the end of the 19th century the interval comprising the uppermost Upper Albian, the Cenomamian, the Turonian and the basal Coniacian has been subdivided, first into ammonite zones, then, beginning in the middle of the 20th century, into zones of planktonic foraminifera. These two groups, one macrofossil, the other microfossil, are particularly effective for bio-chronostratigraphy thanks to their rapid rates of evolution. But differences in the faunal makeup between the Boreal domain (northwestern Europe) and the Tethyan domain (Mediterranean) have for a long time hindered precise correlation of the two domains. Today, in a time interval covering about 16 million years, there are 29 ammonite zones in the Tethyan domain versus 24 in the Boreal one, of which 16 are common to both domains. For the planktonic foraminifera the Tethyan domain has 11 zones, the Boreal domain 10, with 7 in common.

La limite Crétacé-Tertiaire est marquée par une disparition quasi-complète des producteurs carbonatés pélagiques (nannofossiles calcaires et foraminifères planctoniques). Cependant, des nannofossiles calcaires connus dans les niveaux... more

La limite Crétacé-Tertiaire est marquée par une disparition quasi-complète des producteurs carbonatés pélagiques (nannofossiles calcaires et foraminifères planctoniques). Cependant, des nannofossiles calcaires connus dans les niveaux maastrichtiens se retrouvent dans les sédiments du Danien basal. La nature de ces taxons (remaniées vs. survivantes) est toujours source de débat. Un protocole de séparation des différents constituants carbonatés des sédiments du Danien basal a permis de contraindre la signature isotopique des nannofossiles calcaires de part et d'autre de la limite Crétacé-Paléocène. Les nannofossiles calcaires « daniens » d'aspect maastrichtien ont des rapports isotopiques (carbone et oxygène) très proches de celles des nannofossiles crétacés. Ces données prouvent qu'à Bidart, les nannofossiles d'aspect maastrichtien sont en majorité remaniés. © 2004 Elsevier SAS. Tous droits réservés.

A planktonic foraminiferal zonal scheme is presented for subdivision of the Upper Cretaceous pelagic carbonate sequence from southern mid-high latitudes. Definition of the zones is based on first and last occurrences of planktonic... more

A planktonic foraminiferal zonal scheme is presented for subdivision of the Upper Cretaceous pelagic carbonate sequence from southern mid-high latitudes. Definition of the zones is based on first and last occurrences of planktonic foraminifera from Ocean Drilling Program Holes 762C and 763B (Leg 122; Exmouth Plateau, south Indian Ocean). During the Late Cretaceous the studied holes were located close to 50 S and for the first time a complete sedimentary record for the mid-high latitudes was obtained. A detailed biostratigraphic analysis has allowed recognition of two new zones (Falsotruncana maslakovae Zone and Marginotruncana marianosi Zone) for the interval extending from the last occurrence of Helvetoglobotruncana helvetica to the first occurrence of Dicarinella asymetrica (upper Turonian-lower Santonian). From this study it is apparent that some low latitude (Globotruncana ventricosa, Hedbergella flandrini, Marginotruncana marianosi) and high latitude (Globigerinelloides impensus and Hedbergella sliteri) marker taxa display a vertical distribution at mid-high latitudes which is different from that known from low latitudes; moreover, one species (Heterohelix papula), overlooked at low latitudes, exhibits a restricted range that seems to be useful for chrono-biostratigraphic correlations: its appearance is suggested to coincide with the Coniacian/Santonian boundary. The proposed biozonation, which is integrated with calcareous nannofossil and magnetostratigraphic data available for the sections studied, is compared with both the low-latitude standard zonation and the planktonic foraminiferal zonal scheme for the circum-Antarctic region, in order to define a bio-chronostratigraphic scale that is useful for mid-high latitudes of the southern oceans.

The Second International Symposium on Cretaceous stage boundaries held in Brussels from September 8 -14 1995 reached a preliminary agreement on the definition of the base of the Cenomanian stage as the first occurrence of the planktonic... more

The Second International Symposium on Cretaceous stage boundaries held in Brussels from September 8 -14 1995 reached a preliminary agreement on the definition of the base of the Cenomanian stage as the first occurrence of the planktonic foraminiferan Rotalipora globotruncanoides Sigal , with a section at Mont Risou near Rosans , Dro ˆ me , SE France as the global reference section , where the first occurrence of R . globotruncanoides lies 36 m below the top of the Marnes Bleues as defined by a zero datum limestone at the base of the succeeding unit . The succession yields ammonites , inoceramid bivalves , nannofossils and planktonic foraminifera that provide a series of marker levels across the boundary , while an ornate ␦ 13 C curve provides a geochemical marker that can also be recognized in NE England and Italy . Proxies for R . globotruncanoides are : the first appearance of Mantelliceras mantelli and other ammonites of the mantelli Zone at Ϫ 30 m , the first occurrence of the nannofossil Calculites anfractus , the first occurrence of the planktonic foraminiferan Rotalipora gandolfii and the last occurrence of the planktonic foraminiferan Rotalipora ticinensis at Ϫ 40 m , and the last occurrence of the nannofossil Staurolithites glabra at Ϫ 12 m .

CUADERNOS INTERDISCIPLINARES es una publicación periódica del Seminario Interdisciplinar de la Universidad de Zaragoza. Tiene como objeto promover los estudios interdisciplinares de temas científicos, así como los relativos a la... more

CUADERNOS INTERDISCIPLINARES es una publicación periódica del Seminario Interdisciplinar de la Universidad de Zaragoza. Tiene como objeto promover los estudios interdisciplinares de temas científicos, así como los relativos a la Filosofía, Sociología e Historia de la Ciencia. Cada número de esta publicación tiene un caracter monográfico, difundiendo los resultados de los trabajos de investigación y de docencia realizados en el seno del Seminario Interdisciplinar y en los que colaboran los miembros del SIUZ con expertos diversos y profesores de otras universidades.

Chamber elongation is a recurring morphological character in Cretaceous and Cenozoic planktonic foraminiferal evolution suggesting that the clavate body-plan takes advantage through particular environmental conditions. Cretaceous... more

Chamber elongation is a recurring morphological character in Cretaceous and Cenozoic planktonic foraminiferal evolution suggesting that the clavate body-plan takes advantage through particular environmental conditions. Cretaceous planktonic foraminifera bearing radially elongated chambers become repeatedly a consistent component of assemblages in correspondence with the deposition of remarkable organic layers that record the effects of oceanic anoxic events (OAEs). Due to this apparent correspondence, chamber elongation has been recently interpreted as an adaptation to low oxygen levels in the upper water column. The paleoceanographic significance of planktonic foraminifera with radially elongated chambers remains however unclear.

makalah tentang rotifera dan protozoa

En el presente trabajo se desarrolló la correlación geológica y estructural a partir de los perfiles litológicos del sector oriental del rompeolas principal del puerto de Manta, ubicada al Norte de la península del mismo nombre, S-O de la... more

En el presente trabajo se desarrolló la correlación geológica y estructural a partir de los perfiles litológicos del sector oriental del rompeolas principal del puerto de Manta, ubicada al Norte de la península del mismo nombre, S-O de la provincia de Manabí; zona costera central del Ecuador. Los perfiles se construyeron en número de diez paralelos al eje longitudinal del rompeolas de dirección NE-SO, a partir de la descripción de las muestras obtenidas de las sesenta y seis perforaciones de estudios de suelos realizadas por el equipo técnico de Sinecuanon. Se hace una revisión de los antecedentes geológicos del lugar analizando el comportamiento tectónico de la costa ecuatoriana y su influencia directa en el sector de Manta. Los resultados de las perforaciones se presentan en columnas litológicas las que se utilizan para formar perfiles, que describen claramente la geología del sector. En términos generales se interpreta la historia de la depositación de los sedimentos y se determina la edad relativa de los estratos perforados a través de la presencia de foraminíferos bentónicos del Mioceno-Holoceno y foraminíferos planctónicos del Plioceno-Holoceno. La estructura del sector tiene una dirección general OSO-ENE, relacionada a la falla principal "Aromo-Montecristi". Palabra Clave: Geología del puerto de Manta, estudios de suelos, Provincia de Manabí, falla, perfil litológico.

The vertical distribution of Albian ammonites of the North Pacific Province is described on the basis of several sections located in Northern California. Nine Albian ammonite assemblages are identified, compared to the 4 previously... more

The vertical distribution of Albian ammonites of the North Pacific Province is described on the basis of several sections located in Northern California. Nine Albian ammonite assemblages are identified, compared to the 4 previously described by Murphy in 1956. Owing to several gaps of observation possibly more assemblages could exist. In the North California Albian history, the first results show

This is the final scientific work of Dick Cifelli. I expect it will be of considerable interest because it spans over 150 years of foraminiferal research. It is not just an historical account, but delves into the philosophy... more

This is the final scientific work of Dick Cifelli. I expect it will be of considerable interest because it spans over 150 years of foraminiferal research. It is not just an historical account, but delves into the philosophy ofclassifications and reveals a good deal about the people who made them. Over the 20 years that we were curators together of the U.S. National Museum's foraminiferal collection, we discussed the philosophy of clas sification and the resulting schemes many times. His mind had an ability to grasp the "big picture," an asset which is truly rare.

Deposition of the Upper Cretaceous of central-east Sinai was controlled by a long-term transgressive phase and several higher order sea-level¯uctuations. The paper gives a ®rst sequence stratigraphic interpretation for this interval in... more

Deposition of the Upper Cretaceous of central-east Sinai was controlled by a long-term transgressive phase and several higher order sea-level¯uctuations. The paper gives a ®rst sequence stratigraphic interpretation for this interval in the region, based on detailed sedimentological, biostratigraphical and palaeoecological investigations of 13 Turonian-Maastrichtian sections and a review of all published data. Six main facies zones have been differentiated: coastal mud¯ats with tidal channels, gypsiferous sabkha plains, peritidal siliciclastics, peritidal carbonates, high-and low-energy carbonate inner shelf facies, and microfossil-rich outer shelf pelites. The biostratigraphy is based mainly on planktonic foraminifera, calcareous nannofossils, ostracods and ammonites. The study is restricted to an area that had been tectonically rather quiet during the Late Cretaceous-early Tertiary, lying south of the Syrian Arc intraplate foldbelt which experienced major uplifting during this period. Within the Turonian to Maastrichtian interval, six major sequence boundaries have been recognized. Cycle duration varied between 4 and 9 Ma, which indicates a cycle order intermediate between 3rd and 2nd. Correlation with other sea-level reconstructions for the region (Egypt, Israel, Jordan, Tunisia) points to a more or less synchronous regional sea-level development. Comparison of the regional sequences with thè eustatic' model of involves uncertainties; nevertheless, some of the sea-level¯uctuations recorded in Sinai may be related to worldwide eustatic sea-level changes.

Upper Cenomanian pelagic sediments from the northern Alpine Helvetic fold-and-thrust belt (northern Tethyan margin) coeval with Oceanic Anoxic Event (OAE) 2 are characterized by the temporal persistence of micrite sedimentation and lack... more

Upper Cenomanian pelagic sediments from the northern Alpine Helvetic fold-and-thrust belt (northern Tethyan margin) coeval with Oceanic Anoxic Event (OAE) 2 are characterized by the temporal persistence of micrite sedimentation and lack of organic carbon-rich layers. We studied an expanded section in the Chrummflueschlucht (east of Euthal, Switzerland), which encompasses the OAE 2 time interval. In order to identify the paleoceanographic and paleoenvironmental conditions during OAE 2 in this part of the northern Tethyan margin, and more specifically to trace eventual changes in nutrient levels and oxic conditions, we investigated the biostratigraphy (planktonic foraminifera), the bulk-rock mineralogy, and measured stable carbon-and oxygen-isotopes, total phosphorus (P) and redox-sensitive trace-element (RSTE) contents.

The plains of northwest South Asia receive rainfall during both the Indian summer (June–September) and winter (December–March) monsoon. Researchers have long attempted to deconstruct the influence of these precipitation regimes in... more

The plains of northwest South Asia receive rainfall during both the Indian summer (June–September) and winter (December–March) monsoon. Researchers have long attempted to deconstruct the influence of these precipitation regimes in paleoclimate records, in order to better understand regional climatic drivers and their potential impact on human populations. The mid–late Holocene transition between 5.3 and 3.3 ka is of particular interest in this region because it spans the period of the Indus Civilization from its early development, through its urbanization, and onto eventual transformation into a rural society. An oxygen isotope record of the surface-dwelling planktonic foraminifer Globigerinoides ruber from the northeast Arabian Sea provided evidence for an abrupt decrease in rainfall and reduction in Indus River discharge at 4.2 ka, which the authors linked to the decline in the urban phase of the Indus Civilization (Staubwasser et al., 2003). Given the importance of this study, we used the same core (63KA) to measure the oxygen isotope profiles of two other foraminifer species at decadal resolution over the interval from 5.4 to 3.0 ka and to replicate a larger size fraction of G. ruber than measured previously. By selecting both thermocline-dwelling (Neogloboquadrina dutertrei) and shallow-dwelling (Globigerinoides sacculifer) species, we provide enhanced detail of the climatic changes that occurred over this crucial time interval. We found evidence for a period of increased surface water mixing, which we suggest was related to a strengthened winter monsoon with a peak intensity over 200 years from 4.5 to 4.3 ka. The time of greatest change occurred at 4.1 ka when both the summer and winter monsoon weakened, resulting in a reduction in rainfall in the Indus region. The earliest phase of the urban Mature Harappan period coincided with the period of inferred stronger winter monsoon between 4.5 and 4.3 ka, whereas the end of the urbanized phase occurred some time after the decrease in both the summer and winter monsoon strength by 4.1 ka. Our findings provide evidence that the initial growth of large Indus urban centers coincided with increased winter rainfall, whereas the contraction of urbanism and change in subsistence strategies followed a reduction in rainfall of both seasons.

One of the most enigmatic features of long-term Cenozoic climatic evolution, with some analog potential for present/future global climate change, is the last sustained warm and high-atmospheric CO 2 interval in Earth's history, which... more

One of the most enigmatic features of long-term Cenozoic climatic evolution, with some analog potential for present/future global climate change, is the last sustained warm and high-atmospheric CO 2 interval in Earth's history, which started after the end of the Messinian Salinity Crisis (5.971–5.332 Ma) in the Mediterranean Sea. We present high-resolution, astronomically-tuned climate (Mg/Ca, δ 18 O) and productivity (Ba/Ca, δ 13 C) proxy records from the planktonic foraminifera Globigerinoides obliquus in the Kalamaki section (Zakynthos Island, Greece), which sheds new light on the early Pliocene Mediterranean hydrographic dynamics, and the associated climatic transition from 5.33 to 5.11 Ma. We recognized four distinct climatic phases with variable amplitude changes: (1) very warm climate interval prior to 5.28 Ma characterized by minimum ice volume, large salinity fluctuations, enhanced productivity, and intense river runoff, (2) stable paleoceanographic conditions from 5.28 to 5.23 Ma, which reflect a relatively warm and mesotrophic to eutrophic open-marine environment with improved ventilation, (3) a brief interval (20 ky) characterized by the most pronounced ice growth and intense cooling (∼5 °C) coupled with the abrupt decrease of ventilation and primary productivity, and (4) reinstate-ment of relatively stable conditions (warm and well-ventilated mesotrophic upper water column) in conjunction with relatively stable sea-level after 5.21 Ma. Overall, the succession of these phases provides an explanation for the more variable Mediterranean climate and stronger hydrographic variability with respect to other regions during the early Pliocene.

We review the four main extinction events in the Paleogene, from the Cretaceous/Paleogene boundary to the Eocene/Oligocene boundary, integrating the results obtained from a study of foraminiferal assemblages with other paleontological and... more

We review the four main extinction events in the Paleogene, from the Cretaceous/Paleogene boundary to the Eocene/Oligocene boundary, integrating the results obtained from a study of foraminiferal assemblages with other paleontological and geological data. Different survival strategies followed by the species are described and the duration of the phases of extinction, survival, and recovery is estimated. The models and patterns of extinction of the foraminifera are highlighted. We present a range of evidence and paleo-environmental factors and analyze the possible causes of extinction. A new terminology for mass extinction events is proposed: sudden mass extinction would have happened virtually instantaneously and the process would have taken a few years or decades (Cretaceous/Paleogene boundary). Rapid mass extinction is defined as that which occurred in relatively short events, around 100 kyr (Paleocene/Eocene and Eocene/Oligocene boundaries). Slow mass extinctions are suggested to have lasted around 1 Myr (Bartonian/Priabonian transition) and may even have lasted for several million years.

An integrated study of the ammonites, inoceramid bivalves, planktonic foraminifera, calcareous nannofossils, geochemistry, stable carbon isotopes, and cyclostratigraphy is provided for the upper Middle to upper Upper Albian sucession... more

An integrated study of the ammonites, inoceramid bivalves, planktonic foraminifera, calcareous nannofossils, geochemistry, stable carbon isotopes, and cyclostratigraphy is provided for the upper Middle to upper Upper Albian sucession exposed in the Col de Palluel section east of Rosans in Hautes-Alpes, France. The Albian-Cenomanian boundary interval described by Gale et al. at Mont Risou is re-examined, a total thickness of 370 m of the Marnes Bleues Formation. Zonal schemes based on ammonites, inoceramid bivalves, planktonic foraminifera, and calcareous nannofossils are integrated with the stable carbon isotope curve and key lithostratigraphic markers to provide a sequence of more than 70 events in the uppermost Middle Albian to basal Cenomanian interval. Time series analysis of the Al 2 O 3 content of the 500 m Albian sequence present in the Col de Palluel and Risou sections reveals the presence of the 20 kyr precession, 40 kyr tilt, 100 kyr short eccentricity, and 406 kyr long eccentricity cycles. Correlation using planktonic foraminiferan and nannofossil data provide a link between the Col de Palluel and Risou sections and the Italian sequence at Gubbio, and in the Piobbico core. This provides a basis for the extension of the orbital time scale of Grippo et al. to the sequence. It reveals a major break in the Col de Palluel succession at the top of the distinctive marker bed known as the Petite Vérole that may represent as much as 2 Ma. It also provides a basis for the estimation of the length of the Albian Stage at 4.12 Ma, 0.8 Ma for the early Albian, 2.84 Ma for the Middle Albian, and 3.68 Ma for the late Albian substages.

How did the Messinian Salinity Crisis end is a matter of intense debate between two opposite concepts i.e., the generalised dilution event, the so-called Lago-Mare, followed by the sudden restoration of the marine conditions at the base... more

How did the Messinian Salinity Crisis end is a matter of intense debate between two opposite concepts i.e., the generalised dilution event, the so-called Lago-Mare, followed by the sudden restoration of the marine conditions at the base of the Zanclean, or the early partial or complete marine refill that would have happened earlier during the upper Messinian. The Chelif Basin of Northwestern Algeria, one of the greatest Messinian marginal basins of the Mediterranean, provides an exceptional opportunity to study in detail how this major paleoenvironmental change occurred through continuous sedimentary records of the Miocene-Pliocene boundary. Five sections representative of both the central and marginal areas of the Chelif basin were analysed in detail for sedimentology, mineralogy, foraminifera and ostracod assemblages, and stable isotope composition of carbonates. The late Messinian deposits exhibit a great lithological variability with predominant clastic deposits (sandstones, siltstones, conglomerates, carbonates) with, in some marginal areas, large slided masses of lower Messinian (Tripoli Unit) that settled just before the base of the Zanclean. Most sediments are either azoic or contain microfossils typical of hyposaline conditions sometimes mixed with benthic foraminifera known to be adapted to stressed environments and even to lacustrine conditions. Fewer types of sediment contain assemblages of planktonic foraminifera, including typical Messinian species, which are thought to be reworked. In contrast, diversified communities of benthic and planktonic foraminifera returned suddenly at the base of the Zanclean; the Messinian-Pliocene transition was marked by an abrupt change of the δ 18 O values of carbonates from variable but predominantly negative values characteristic of low salinity conditions in the upper Messinian to higher and more stable values in the Zanclean typifying marine conditions. The southern margin continued, however, to be submitted to large inputs of continental waters. The beginning of the marine inundation was a transitional period with poorly diversified assemblages of planktonic foraminifera and benthic communities tolerant to oxygen deficient bottom conditions; more stable marine conditions with better bottom water ventilation were set up after a lag time which would roughly correspond to a precession cycle. Except for the more marginal areas where conglomerates and erosional features are observed, the restoration of marine conditions occurred, without any significant erosion in the more central areas where the contact is well marked by strong burrowing activity by benthic organisms. This indicates the rapid substitution in the basin of brackish waters by marine waters. Both mixing of these two kinds of waters and permanence of freshwater inputs in the initial stage of the Pliocene transgression may explain why the community of marine planktonic foraminifera, introduced by the inflowing Atlantic waters, hardly survived in J.M. Rouchy), acaruso@unipa.it (A. Caruso), Catherine.Pierre@locean-ipsl.upmc.fr (C. Pierre), valleron@mnhn.fr (M.-M. Blanc-Valleron), Maria.Angela.Bassetti@ifremer.fr (M.A. Bassetti).

Upper Albian, Anglo-Paris basin, stratotype, Aube, ammonites, foraminifera

Eolian supply has significantly contributed to terrigenous sedimentation in the Mediterranean. Its reconstruction has further allowed the characterization of the atmospheric response to climate oscillations. Here we present a... more

Eolian supply has significantly contributed to terrigenous sedimentation in the Mediterranean. Its reconstruction has further allowed the characterization of the atmospheric response to climate oscillations. Here we present a high-resolution record of eolian input oscillations in the westernmost Mediterranean (Alboran Sea basin) for the last 20.000 yr. The Alboran Sea basin is a key zone for paleoclimate reconstruction because high

A high-resolution stable O and C isotope study is undertaken on all planktic foraminiferal species that are reasonably continuous through an Eemian sapropel S5 from the western side of the eastern Mediterranean. The data are considered... more

A high-resolution stable O and C isotope study is undertaken on all planktic foraminiferal species that are reasonably continuous through an Eemian sapropel S5 from the western side of the eastern Mediterranean. The data are considered within a context of high-resolution isotope records for two further S5 sapropels from the central and easternmost sectors of the basin, alkenone-based sea surface temperature records for all three sapropels, and planktic foraminiferal abundance records for the same sample sets through all three sapropels. Results are compared with similar data for Holocene sapropel S1. The adopted approach allows distinction between species that are most suitable to assess overall changes in the climatic/hydrographic state of the basin, including depth-related differentiations and the main seasonal developments, and species that are most affected by variable biological controls or local/regional and transient physico^chemical forcings. It is found that a-priori assumptions about certain species' palaeohabitats, based on modern habitat observations, may become biased when non-analogue conditions develop. In the case of Mediterranean sapropel S5, these consisted of enhanced freshwater dilution, elevated productivity, shoaling of the pycnocline between intermediate and surface waters, and stagnation of the subsurface circulation. Under these conditions, some species are found to 'shift' into habitat settings that differ considerably from those occupied today. The present multiple-species approach can identify such 'anomalous responses', and thus offers 0377-8398 / 03 / $^see front matter ß a sound background for further shell-chemistry investigations and quantitative interpretation of the isotopic profiles. We capitalise on the latter potential, and offer the first quantitative estimates of monsoon flooding into the Mediterranean during the deposition of Eemian sapropel S5. ß

Open marine sediments deposited during the CenomanianeTuronian transition are well exposed in the Spanish Ba~ nos de la Hedionda section (Betic Cordillera, South Iberian Palaeomargin). Analysis of fora-miniferal assemblages and... more

Open marine sediments deposited during the CenomanianeTuronian transition are well exposed in the Spanish Ba~ nos de la Hedionda section (Betic Cordillera, South Iberian Palaeomargin). Analysis of fora-miniferal assemblages and geochemical proxies allow inferences on the impact of the Oceanic Anoxic Event 2 (OAE2) in this area of the western Tethys. Three main intervals have been identified corresponding to different lithological units and biozones. (1) The top of the Capas Blancas Member (Rotali-pora cushmani Biozone) represents the pre-extinction phase with diverse foraminiferal assemblages and well developed water-column tiering, well-oxygenated, oligotrophic deep-waters and oxygenated to poorly oxygenated, mesotrophic surface-waters. Foraminiferal opportunist species point to a minor event with dysoxic conditions preceding the OAE2. (2) The black radiolaritic shales (Whiteinella archaeocretacea Biozone) consist of a foraminiferal-barren interval, except for the lowermost centimetres where planktic surface-dweller opportunists are common. Redox sensitive elements (Cr/Al, V/Al, U/Th, Mo EF , Mo aut , U EF and U aut) and increased TOC values reflect oxygen depleted conditions related to the OAE2. The increase in P/Ti values at the base of this stratigraphic interval indicates an abrupt increase in productivity. High concentrations of radiolarians are congruent with high surface productivity probably related to changes in oceanic circulation and enhanced upwelling currents, as well as subsequent shallowing of the oxygen-minimum zone. The increase in Mo EF and Mo aut towards the top of the black radiolaritic shales indicates temporal euxinic conditions. (3) A slow, bottom-up recovery of foraminiferal assemblages is inferred at the base of the Boquer on Member (Helvetoglobotruncana helvetica Biozone), with seafloor recolonization by benthic foraminifera being recorded previous to the water column colonization by planktic forms, mainly by intermediate-dwellers typical of mesotrophic waters. The subsequent proliferation of surface-dweller opportunists and deep-dweller opportunists adapted to mesotrophic to eutrophic conditions, and the decrease in planktic foraminiferal diversity, may indicate the persistence of poorly oxygenated conditions in the water column towards the lower-middle part of the H. helvetica Biozone.

Dinoflagellates are an important component of the extant eukaryotic plankton. Their organic-walled, hypnozygotic cysts (dinocysts) provide a rich, albeit incomplete, history of the group in ancient sediments. Building on pioneering... more

Dinoflagellates are an important component of the extant eukaryotic plankton. Their organic-walled, hypnozygotic cysts (dinocysts) provide a rich, albeit incomplete, history of the group in ancient sediments. Building on pioneering studies of the late 1970s and 1980s, recent drilling in the Southern Ocean has provided a wealth of new dinocyst data spanning the entire Paleogene. Such multidisciplinary studies have been instrumental in refining existing and furnishing new concepts of Paleogene paleoenvironmental and paleoclimatic reconstructions by means of dinocysts.

Despite many advances in sea-level research, the nature of cyclic eustatic sea-level fluctuations during warm periods without, or with much reduced, polar ice remains enigmatic. Recently published δ18O records from extremely... more

Despite many advances in sea-level research, the nature of cyclic eustatic sea-level fluctuations during warm periods without, or with much reduced, polar ice remains enigmatic. Recently published δ18O records from extremely well-preserved Turonian microfossils from Tanzania do not support the contentious idea of glacioeustatic control of global sea-level changes during the warmest period of the Cretaceous. For the same locality (site TDP 31) we reconstruct relative sea-level changes based on sequence stratigraphy and integration of sedimentology, microfacies, geochemistry, and micropaleontology. Four local sequence boundaries (SBs TuTz1–4) are recognized: at the base, middle, and top of the Helvetoglobotruncana helvetica Zone and in the Late Turonian.
The lowstands are characterized by increased grain size, enhanced organic carbon flux, faunal assemblage changes, and bulk δ13Corg and foraminiferal δ13Cf and δ18Of minima. Strong benthic and planktic foraminiferal turnovers above the top Middle Turonian SB TuTz3 probably reflect shallowing (from upper slope to outer shelf) and/or eutrophication.
The TDP 31 age model is refined through inter-regional comparison of planktic foraminiferal ranges and δ13C records from three other South-Tethyan localities (ODP Holes 762C and 763B, Exmouth Plateau, and the Guru section, Tibet). This age model enables correlation of the regressive events at a global scale and suggests that, within stratigraphic uncertainty, the TDP 31 depositional sequences are synchronous with the global Turonian third-order sequences and are likely driven by eustasy. These correlations, together with recent astrochronological and radiometric dating, indicate a considerably younger age (91.17 ± 0.52 Ma) for the top H. helvetica Zone than currently assumed, resulting in zonal duration of 2.35 ± 0.52 myr. Foraminiferal stableisotope data fromTDP 31 indicate slight surface- and bottom-waterwarming during the regressions and possibly a minor surface-water salinity decrease,which is inconsistentwith glacio-eustatic forcing of Turonian third-order sea-level cycles and is more in line with the model of aquifer-eustasy.

The Foraminifera.eu-Project wants to foster the interest in foraminifera. It builds a bridge between science and community. It is run by amateurs. Experienced foraminiferologist get a platform to share their knowledge with inexperienced... more

The Foraminifera.eu-Project wants to foster the interest in foraminifera. It builds a bridge between science and community. It is run by amateurs. Experienced foraminiferologist get a platform to share their knowledge with inexperienced ones. We offer practical help in sampleprocessing, imaging and classification. Foraminifera.eu has become a popular website with more than 2400 monthly unique visitors viewing about 22.000 pages and staying on average for 8 minutes. More than 100 people have contributed samples, images, drawings, ideas and/or are working on mutual projects such as publications, exhibitions, talks and collections. Reasons for the popularity of the foraminifera.eu-project and perspectives for its development are discussed.

Taxonomic consistency is the prerequisite for any foraminiferal study. In particular, interpretation of planktonic foraminiferal geochemical data requires consistent selection of monospecific tests due to varying habitats of different... more

Taxonomic consistency is the prerequisite for any foraminiferal study. In particular, interpretation of planktonic foraminiferal geochemical data requires consistent selection of monospecific tests due to varying habitats of different species. In order to exemplify the impact of slightly varying morphological characteristics on geochemical signatures, we investigated three basic shape dimensions, test weights, stable isotope values, and Mg/Ca ratios of Globorotalia menardii and Globorotalia cultrata, which are often grouped or referred to as synonyms. Along with visual distinction, encrusted G. menardii is distinguished from shiny G. cultrata by its on average doubled test weight, when referring to the same maximum diameter. More elongated and flattened G. cultrata calcifies within the deeper mixed layer, which applies also for the initial calcification of G. menardii. Final encrustration of G. menardii after vertical migration is suggested to take place close to the bottom of the seasonal thermocline. Combined Mg/Ca ratios versus calcification-temperature calibration provides a reliable tool for monospecific thermal reconstructions for the seasonal thermocline (G. menardii) and the deeper mixed layer (G. cultrata).

Planktic Foraminifera are an extremely abundant, important and successful group of marine protists. They are particularly useful in reconstructing past environments and for biostratigraphic dating. Despite their importance, the origin of... more

Planktic Foraminifera are an extremely abundant, important and successful group of marine protists. They are particularly useful in reconstructing past environments and for biostratigraphic dating. Despite their importance, the origin of the group is uncertain. Previous work has suggested that they evolved from a benthic ancestor during the Triassic or, perhaps, the Mid-Jurassic (?Bajocian), but a reason for their origination has remained unclear. Here, we present evidence from the Toarcian (early Jurassic) of NW Europe that the origin of the planktic Foraminifera may have been one of the results of the early Toarcian oceanic anoxic event. This event appears to have been associated with a massive dissociation of gas hydrates and other, perhaps related, water chemistry changes.

The ''An der Schanz quarry'' near Burgberg exhibits parts of the Helvetic Seewen Formation. Its base is dated as Cenomanian, its top as Late Santonian by planktonic foraminifera by previous authors. A re-sampling of the section for... more

The ''An der Schanz quarry'' near Burgberg exhibits parts of the Helvetic Seewen Formation. Its base is dated as Cenomanian, its top as Late Santonian by planktonic foraminifera by previous authors. A re-sampling of the section for inoceramid and d 13 C stratigraphy gave an Early Coniacian age for the uppermost parts of the Seewen Formation. A literature review suggests that the top of Seewen Formation of the Allgä u (Bavaria) and Vorarlberg (Austria) is never younger than the Middle or terminal Middle Coniacian. d 13 C data confirm the biostratigraphic dating by inoceramids. Furthermore, although only 28 m thick, the section exhibits all important d 13 C events for interbasinal correlation previously recognized in sections of England and northwestern Germany. The d 13 C calibration of the LO of H. helvetica is shown to be diachronous and not of value for isochronous zonations. The Caburn d 13 C event is suggested as a marker for the Middle-Upper Turonian boundary due to the concomitant FO of I. perplexus. The re-dating of the facies turnover from a calcareous biosedimentary system towards a marl dominated system (succeeding Amden Formation) is briefly compared with the situation observed in northwestern Germany, where comparable trends are mapable.

High-resolution δ 13C and δ 18O curves, calibrated against planktonic foraminiferal and calcareous nannofossil biostratigraphy, are provided for the upper Aptian–lower Cenomanian pelagic succession of the Gargano Promontory (Coppa della... more

High-resolution δ 13C and δ 18O curves, calibrated against planktonic foraminiferal and calcareous nannofossil biostratigraphy, are provided for the upper Aptian–lower Cenomanian pelagic succession of the Gargano Promontory (Coppa della Nuvola section, southern Italy). The succession consists of two superimposed formations: the Marne a Fucoidi and the Scaglia (lower portion only). According to our integrated biostratigraphy, the entire succession spans

Los foraminíferos planctónicos de la parte inferior de la Formación leper (Ypresiense) en el sondeo Knokke (11 E/138) en Bélgica constituyen una asociación de alta latitudes y poca profundidad. Se han identificado los siguientes taxones:... more

Los foraminíferos planctónicos de la parte inferior de la Formación leper (Ypresiense) en el sondeo Knokke (11 E/138) en Bélgica constituyen una asociación de alta latitudes y poca profundidad. Se han identificado los siguientes taxones: Subbotina hornibrooki, Subbotina triangularis, Subbotina eocaenica, Subbotina finlayi, Acaririna cf. pentacamerata, Muricoglobigerina aquiensis, Muricoglobigerina chascanona, Muricoglobigerina esnehensis, Muricoglobigerina soldadoensis y Paragloborotalia quadrilocula. Esta asociación permite datar la parte inferior del Ypresiense como perteneciente a la Biozona P 7 de Blow (1979) , Biozonas de Morozovella edgarí o Morozovella subbotíne de Toumarkine y Luterbacher (1985) y Biozona P 6b de Berggren y Millar (1988). Además, existe un nivel con algunos foraminíferos planctónicos cerca de la base de la Formación lepar, que junto a los datos aportados por otros microfósiles, permiten afirmar que la base del Ypresiense podría pertenecer a la Biozona P 6a de Berggren y Millar (1988), coincidiendo con el evento anóxico utilizado para marcar el límite Paleoceno/Eoceno.

A high-resolution biostratigraphic analysis of planktic foraminifers confirms that the Bidart section at the eastern margin of the Atlantic Ocean exhibits a continuous and complete Cretaceous/Paleogene (K/Pg) transition interval. The... more

A high-resolution biostratigraphic analysis of planktic foraminifers confirms that the Bidart section at the eastern margin of the Atlantic Ocean exhibits a continuous and complete Cretaceous/Paleogene (K/Pg) transition interval. The biozones and subzones recorded in this section are less expanded than their equivalent in Tunisian sections: El Kef (Global Stratotype Section and Point: GSSP for the K/Pg boundary) and Ellès (auxiliary section), but they are sufficiently thick to allow a detailed analysis of the evolution of the planktic foraminiferal assemblages across the K/Pg transition. Throughout the uppermost 4 m Maastrichtian, the planktic foraminiferal assemblages are highly diversified, containing up to 72 species. These Maastrichtian assemblages are rich in cosmopolitan taxa (70%), dominated by small biserial morphotypes which belong mainly to the genus Heterohelix which coexist with less abundant but highly diverse tropical and subtropical species. The extinction pattern at the Bidart section suggests a sudden catastrophic mass extinction at the K/Pg boundary which affected at least 53 out of 72 species. The species becoming extinct include globotruncanids (e.g. Contusotruncana spp., Globotruncana spp., Globotruncanita spp.) and complex heterohelicids (e.g. Racemiguembelina spp., Pseudotextularia spp., Gublerina spp.). At the Bidart section, only Archaeoglobigerina cretacea disappears 2 m below the K/Pg boundary event. Specimens of 18 small and even tiny Maastrichtian species, are found at the lowermost Danian. Only a few of these species belonging to the genera of Guembelitria, Hedbergella and Heterohelix are considered to be real "Cretaceous survivor species", whereas the specimens belonging to the rest, are most probably reworked, because they differ in their preservation. Throughout lowermost Danian, the planktic foraminiferal assemblages are dominated by "opportunistic" species of the genus Guembelitria. These opportunists are associated to small and poorly diversified pioneer globigerinids (Palaeoglobigerina spp. and Parvularugoglobigerina spp.). These assemblages became progressively more diversified across the early Danian containing species with cancellate walls (Eoglobigerina spp., Parasubbotina spp., Subbotina triloculinoides and Praemurica spp.) and new taxa of biserial heterohelicids (Woodringina spp. and Chiloguembelina spp.) suggesting a paleoenvironmental recovery.

The boron isotope-pH proxy, applied to mixed-layer planktic foraminifera, has great potential for estimating past CO2 levels, which in turn is crucial to advance our understanding of how this greenhouse gas influences Earth's climate.... more

The boron isotope-pH proxy, applied to mixed-layer planktic foraminifera, has great potential for estimating past CO2 levels, which in turn is crucial to advance our understanding of how this greenhouse gas influences Earth's climate. Previous culture experiments have shown that, although the boron isotopic compositions of various planktic foraminifera are pH dependent, they do not agree with the aqueous geochemical basis of the proxy. Here we outline the results of culture experiments on Globigerinoides ruber (white) across a range of pH (∼7.5–8.2) and analysed via multicollector inductively-coupled plasma mass spectrometry (MC-ICPMS), and compare these data to core-top and sediment-trap samples to derive a robust new species-specific boron isotope-pH calibration. Consistent with earlier culture studies, we show a reduced pH dependency of the boron isotopic composition of symbiont-bearing planktonic foraminifera compared to borate ion in seawater. We also present evidence for a size fraction effect in the δ11B of G. ruber. Finally, we reconstruct atmospheric CO2 concentrations over the last deglacial using our new calibration at two equatorial sites, ODP Site 999A and Site GeoB1523-1. These data provide further grounding for the application of the boron isotope-pH proxy in reconstructions of past atmospheric CO2 levels.