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| Registros recuperados: 66 | |
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| Scarpa,Romina; Malumián,Norberto. |
| Se describen dos agrupamientos de foraminíferos calcáreos del Oligoceno Temprano de las capas de la Estancia María Cristina, críticos en la cronología de los acontecimientos tectónicos y paleoecológicos de los Andes Fueguinos. Estos agrupamientos indican el inicio de la más profunda antefosa del Cretácico Superior-Cenozoico fueguino y acotan la edad de la fosilización del frente plegado. Las capas se han depositado mayormente por debajo de la línea de compensación de la calcita y contienen principalmente foraminíferos aglutinados que atestiguan el ingreso de aguas corrosivas antárticas. De muy restringidos niveles que han escapado a la disolución en el interior de la Isla, y próximo a la Estancia, se ha recuperado uno de los agrupamientos, de ambiente... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Foraminifera; Oligoceno Temprano; Antefosa; Andes Fueguinos. |
| Ano: 2008 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0002-70142008000200010 |
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| Malumián,Norberto; Scarpa,Romina. |
| En la Formación Irigoyen (Mioceno superior-Plioceno, cuenca transtensiva del río Irigoyen, costa atlántica de Tierra del Fuego) se reconocen dos agrupamientos de foraminíferos bentónicos de aguas someras de fuerte carácter austral. El agrupamiento inferior, dominado por Angulogerina angulosa fueguina (Malumián), es en general similar a los foraminíferos de la Formación Carmen Silva, contiene " Trochoelphidiella " sp., previamente descrita para el Oligo-Mioceno de la Antártida. El agrupamiento superior está dominado por Nonion hancocki Cushman y McCulloch, una especie previamente conocida sólo en las actuales costas peruanas, y contiene frecuente Cribrorotalia meridionalis (Cushman y Kellett), especie que en la actualidad se distribuye abundantemente desde... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Foraminifera; Neogeno; Tierra del Fuego; Paleobiogeografía. |
| Ano: 2005 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0002-70142005000200008 |
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| Ferrero,Laura. |
| Sobre la base del estudio de foraminíferos y ostrácodos, se describe la evolución de ambientes marino- costeros al sudeste de la provincia de Buenos Aires afectados por las variaciones del nivel del mar durante el Pleistoceno tardío. Fueron estudiadas dos perforaciones realizadas al sur de la laguna Mar Chiquita. En las secciones inferiores de las perforaciones (A y B) se registran ambientes marinos marginales que pueden ser asignados a la Formación Canal 5 correlacionable con el último máximo interglacial (subestadio isotópico 5e). En los niveles fértiles inferiores de la perforadión A y en toda la sección B las asociaciones de foraminíferos, dominadas por Ammonia beccarii (Linné), permiten inferir ambientes marinos litorales a lagunas costeras. Las... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Foraminifera; Ostracoda; Pleistoceno tardío; Transgresión marina; Paleoambientes. |
| Ano: 2009 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0002-70142009000400005 |
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| PIOVESAN,ENELISE K.; MELO,ROBBYSON M.; LOPES,FERNANDO M.; FAUTH,GERSON; COSTA,DENIZE S.. |
| ABSTRACT Paleocene ostracods and planktonic foraminifera from the Maria Farinha Formation, Paraíba Basin, are herein presented. Eleven ostracod species were identified in the genera Cytherella Jones, Cytherelloidea Alexander, Eocytheropteron Alexander, Semicytherura Wagner, Paracosta Siddiqui, Buntonia Howe, Soudanella Apostolescu, Leguminocythereis Howe and, probably, Pataviella Liebau. The planktonic foraminifera are represented by the genera Guembelitria Cushman, Parvularugoglobigerina Hofker, Woodringina Loeblich and Tappan, Heterohelix Ehrenberg, Zeauvigerina Finlay, Muricohedbergella Huber and Leckie, and Praemurica Olsson, Hemleben, Berggren and Liu. The ostracods and foraminifera analyzed indicate an inner shelf paleoenvironment for the studied... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brazil; Ostracods; Paleocene; Paraíba Basin; Foraminifera. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652017000401443 |
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| Malaize, B.; Joly, C.; Venec-peyre, M. -t.; Bassinot, F.; Caillon, N.; Charlier, K.. |
| High-resolution faunal and isotopic analyses of foraminifera were performed on core MD96-2073 (10 degrees 94'N, 52 degrees 62'E, 3142 m depth), located close to Socotra Island in the upwelling area of the Somali Basin ( NW Indian Ocean). This work focuses on Marine Isotopic Stage 6.5 in order to reconstruct paleo-upwelling changes and their links with the Arabian Sea summer monsoon and the migration of the Intertropical Convergence Zone (ITCZ). Correspondence and cluster analyses of planktonic foraminiferal abundances, partly controlled by temperature and water mass productivity, together with an upwelling intensification index, show the occurrence of a strong upwelling between 176 and 165 ka. This upwelling intensification responds to a northward... |
| Tipo: Text |
Palavras-chave: Paleoclimatology; Foraminifera; Isotopes; Indian monsoon; ITCZ; Sapropels; Upwelling. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00234/34487/33433.pdf |
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| Le Calvez, Yolande. |
| Foraminifera were abundant in samples obtained from the Mauritanian coast. Their ecology and geographical location was studied. The genera and species are initially grouped according to the nature of the seabed and its depth. Those found in (1) deep mud at 500-1200 m, (2) muddy sand at 20-340 m, (3) shelly sand at 30-52 m are considered in turn. Group (I) varied according to the station of collection, and were affected by factors in addition to depth, such as the presence of corals. Muddy sand was poor in large individuals and in empty shells, but contained many displaced littoral forms. The very few living forms found in the shelly sand area was surprising; it may reflect the constant agitation of the sand or the small size of individuals, which could... |
| Tipo: Text |
Palavras-chave: Foraminifera; Atlantic Sahara coast; Indexing in process. |
| Ano: 1972 |
URL: http://archimer.ifremer.fr/doc/1972/publication-2045.pdf |
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| Carson, Brooke E.; Francis, Jason M.; Leckie, R. Mark; Droxler, Andre W.; Dickens, Gerald R.; Jorry, Stephan J.; Bentley, Sam J.; Peterson, Larry C.; Opdyke, Bradley N.. |
| Ashmore Trough in the western Gulf of Papua (GoP) represents an outstanding modern example of a tropical mixed siliciclastic-carbonate depositional system where significant masses of both river-borne silicates and bank-derived neritic carbonates accumulate. In this study, we examine how benthic foraminiferal populations within Ashmore Trough vary in response to sea level-driven paleoenvironmental changes, particularly organic matter and sediment supply. Two 11.3-m-long piston cores and a trigger core were collected from the slope of Ashmore Trough and dated using radiocarbon and oxygen isotope measurements of planktic foraminifera. Relative abundances, principal component analyses, and cluster analyses of benthic foraminiferal assemblages in sediment... |
| Tipo: Text |
Palavras-chave: Papua New Guinea; Margins; Foraminifera. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00087/19837/17482.pdf |
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| Leutert, Thomas J.; Sexton, Philip F.; Tripati, Aradhna; Piasecki, Alison; Ling Ho, Sze; Nele Meckler, A.. |
| Applying the clumped isotope (Δ47) thermometer to foraminifer microfossils offers the potential to significantly improve paleoclimate reconstructions, owing to its insensitivity to the isotopic composition of seawater (unlike traditional oxygen isotope (δ18O) analyses). However, the extent to which primary Δ47 signatures of foraminiferal calcites can be overprinted during diagenesis is not well known. Here, we present Δ47 data as well as high-resolution (∼10 kyr) δ18O and δ13C middle Eocene time series, measured on benthic and planktic foraminifera from ODP/IODP Sites 1408, 1409, 1410, 1050, 1260 and 1263 in the Atlantic Ocean. The sites examined span various oceanographic regimes, including the western tropical to mid-latitude North Atlantic, and the... |
| Tipo: Text |
Palavras-chave: Clumped isotopes; Foraminifera; Diagenesis; Eocene; Stable-isotope geochemistry; Preservation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00495/60683/64757.pdf |
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| Peral, Marion; Daeron, Mathieu; Blamart, Dominique; Bassinot, Franck; Dewilde, Fabien; Smialkowski, Nicolas; Isguder, Gulay; Bonnin, Jerome; Jorissen, Frans; Kissel, Catherine; Michel, Elisabeth; Vazquez Riveiros, Natalia; Waelbroeck, Claire. |
| Accurate reconstruction of past ocean temperatures is of critical importance to paleoclimatology. Carbonate clumped isotope thermometry (“Δ47”) is a relatively recent technique based on the strong relationship between calcification temperature and the statistical excess of 13C-18O bonds in carbonates. Its application to foraminifera holds great scientific potential, particularly because Δ47 paleotemperature reconstructions do not require assumptions regarding the 18O composition of seawater. However there are still relatively few published observations investigating the potential influence of parameters such as salinity or foraminiferal size and species. We present a new calibration data set based on 234 replicate analyses of 9 planktonic and 2 benthic... |
| Tipo: Text |
Palavras-chave: Carbonate clumped isotopes; Foraminifera; Paleothermometry. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00450/56134/57676.pdf |
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| Fontanier, Christophe; Koho, K. A.; Goni-urriza, M. S.; Deflandre, Bruno; Galaup, S.; Ivanovsky, A.; Gayet, Nicolas; Dennielou, Bernard; Gremare, Antoine; Bichon, S.; Gassie, C.; Anschutz, P.; Duran, R.; Reichart, G. J.. |
| We present ecological and isotopic (δ18O and δ13C) data on benthic foraminifera sampled from 4 deep-sea stations in a pockmark field from the deep-water Niger delta (Gulf of Guinea, Equatorial Atlantic Ocean). In addition, a series of sedimentological and (bio)geochemical data are shown to back up foraminiferal observations. All stations are located within 1.2 km of each other, so prevailing oceanographic conditions can be assumed to be similar at each site. Two of the sites (GMMC-01 and GMMC-02) are located in a pockmark (named “pockmark A”) where current methane seepages were recorded by ROV observations. A third station (GMMC-03) is located in the topographic depression interpreted as a collapsed pockmark (named “pockmark B”). The fourth site (GMMC-04)... |
| Tipo: Text |
Palavras-chave: Niger delta; Hydrate pockmark; Foraminifera; Stable isotopes; Bacteria. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00211/32194/30628.pdf |
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| Weiner, Agnes K. M.; Morard, Raphael; Weinkauf, Manuel F. G.; Darling, Kate F.; André, Aurore; Quillévéré, Frédéric; Ujiie, Yurika; Douady, Christophe J.; De Vargas, Colomban; Kucera, Michal. |
| Single-cell genetic analysis is an essential method to investigate the biodiversity and evolutionary ecology of marine protists. In protist groups that do not reproduce under laboratory conditions, this approach provides the only means to directly associate molecular sequences with cell morphology. The resulting unambiguous taxonomic identification of the DNA sequences is a prerequisite for barcoding and analyses of environmental metagenomic data. Extensive single-cell genetic studies have been carried out on planktonic foraminifera over the past 20 years to elucidate their phylogeny, cryptic diversity, biogeography, and the relationship between genetic and morphological variability. In the course of these investigations, it has become evident that genetic... |
| Tipo: Text |
Palavras-chave: Foraminifera; Protists; Single-cell genetics; Cryptic diversity; Comparability; Methods; Laboratory protocols; Standardization. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00383/49460/49938.pdf |
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| Rasmussen, Tl; Oppo, Dw; Thomsen, E; Lehman, Sj. |
| [1] Results from two deep sea cores from northeast of Newfoundland at 1251 and 2527 m water depth, respectively, indicate that during the time period from 160,000 to 10,000 years BP, ice rafting events in the Labrador Sea were accompanied by rapid variations in deep and surface water circulation. Twelve ice-rafting events occurred, each coinciding with high concentrations of detrital carbonate and oxygen isotopic depletion of both surface and bottom waters. Eleven of these can be correlated with the North Atlantic Heinrich events H1-H11. The remaining very conspicuous ice-rafting event took place early in MIS substage 5e, at a time when the planktic faunal assemblage suggests marked warming of the sea surface. In the shallower core, benthic delta(13)C... |
| Tipo: Text |
Palavras-chave: Paleoceanography; Labrador Sea; Ice rafting; Foraminifera; Last climate cycle. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00496/60768/65083.pdf |
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| Rustic, Gerald Thomas. |
| The El Niño Southern Oscillation (ENSO) has been implicated in large-scale climate shifts of the past millennia, but paleoclimate records from the dynamically vital eastern equatorial Pacific Ocean (EEP) spanning the past millennium are sparse. This has limited our understanding of tropical Pacific dynamics, leaving questions regarding the source of ENSO variability unanswered. Here I seek to address some of these questions regarding relationship between ENSO and tropical Pacific mean state, and the relationship between the tropical Pacific and large-scale climate. Mean EEP sea surface temperature (SST) for the past millennium was reconstructed using Mg/Ca ratios in Globigerinoides ruber from a sub-centennially resolved sediment core collected near the... |
| Tipo: Text |
Palavras-chave: Eastern tropical pacific; ENSO; Foraminifera; Paleoceanography; Paleoclimate. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00495/60657/64154.pdf |
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| Ohkushi, K.; Kennett, J. P.; Zeleski, C. M.; Moffitt, S. E.; Hill, T. M.; Robert, Cyril; Beaufort, L.; Behl, R. J.. |
| The oxygen minimum zone (OMZ) of the late Quaternary California margin experienced abrupt and dramatic changes in strength and depth in response to changes in intermediate water ventilation, ocean productivity, and climate at orbital through millennial time scales. Expansion and contraction of the OMZ is exhibited at high temporal resolution (107-126 year) by quantitative benthic foraminiferal assemblage changes in two piston cores forming a vertical profile in Santa Barbara Basin (569 m, basin floor; 481 m, near sill depth) to 34 and 24 ka, respectively. Variation in the OMZ is quantified by new benthic foraminiferal groupings and new dissolved oxygen index based on documented relations between species and water-mass oxygen concentrations.... |
| Tipo: Text |
Palavras-chave: Oxygen minimum zone; Foraminifera; Ventilation; Oxygen index; Pacific; Hypoxia. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37489/35811.pdf |
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| Nouet, Julius; Bassinot, Franck. |
| Several authors suggested that the thinning, with increasing depth of deposition, of calcite X-ray diffractometry (XRD) peaks obtained on planktonic foraminifera tests resulted from the preferential removal of their poorly crystallized parts as dissolution increases. By deconvolving XRD peak (104) from Globorotalia tumida (surface sediments, Sierra Leone Rise depth transect), we show that the full width at midheight does not depend only upon crystallinity, but reflects also the chemical and structural heterogeneity of foraminifera tests, which results in closely spaced, individual (104) diffraction peaks corresponding to phases with slightly different Mg contents. G. tumida contains two calcite phases: a well crystallized, Mg-poor calcite and a poorly... |
| Tipo: Text |
Palavras-chave: Dissolution; Foraminifera; X-ray diffraction; Crystallinity; Deconvolution. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34626/32973.pdf |
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| Gehlen, M; Bassinot, F; Beck, L; Khodja, H. |
| Micro particle-induced X-ray emission (PIXE) is a nondestructive elemental analysis technique that can be used to map the distribution of elements with a spatial resolution of +/-4 mum(2) and a penetration depth of +/-2 mum in a calcite matrix. To test its potential to improve our understanding of trace element distribution in foraminifera shells, we mapped the Mg distribution across individual chambers of the planktonic species Globigerinoides ruber. G. ruber shells were picked from equatorial Atlantic surface sediments (Sierra Leone Rise). They ranged from well-preserved to heavily dissolved tests. The mapping of trace elements across test chambers made it possible to discriminate between variability inherent to the shell material and heterogeneity... |
| Tipo: Text |
Palavras-chave: Foraminifera; Mg/Ca; Dissolution; Trace elements; Instruments and techniques. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00228/33892/32319.pdf |
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| Firesinger, Devon Robert. |
| The development of an accurate and precise geochronology is imperative to understanding archives containing information about Earth’s past. Unable to date all intervals of an archive, researchers use methods of interpolation to approximate age between dates. Sections of the radiocarbon calibration curve can induce larger chronological uncertainty independent of instrumental precision, meaning even a precise date may carry inflated error in its calibration to a calendar age. Methods of interpolation range from step-wise linear regression to, most recently, Bayesian statistical models. These employ prior knowledge of accumulation rate to provide a more informed interpolation between neighboring dates. This study uses a Bayesian statistical accumulation model... |
| Tipo: Text |
Palavras-chave: Gas ion source; Accelerator mass spectrometry; Isotope dilution; Foraminifera; Pigmy Basin. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00494/60601/64087.pdf |
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| Registros recuperados: 66 | |
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