Journal articles: 'Diatomées fossiles'

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Lortie, Guy. "Les diatomées fossiles de deux tourbières ombrotrophes du Bas-Saint-Laurent, Québec." Géographie physique et Quaternaire 37, no. 2 (November 29, 2007): 159–77. http://dx.doi.org/10.7202/032512ar.

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RÉSUMÉ Les diatomées fossiles de deux tourbières ombrotrophes du Bas-Saint-Laurent, Québec, comprennent 34 genres et 143 taxons dont seulement 49 sont communs aux deux tourbières. La distribution stratigraphiques des taxons spécifiques et les associations de diatomées permettent d'observer l'évolution des tourbières étudiées. La tourbière à sphaignes de Rivière-du-Loup possède une flore fossile hydroterrestre et acidobionte (association à Eunotia paludosa et var. pumila et E. tenella) assez stable. Dans les 30 cm supérieurs, l'association mono-spécifique à E. paludosa var. pumila suggère un changement notable dans la végétation de sphaignes et un environnement écologique plus rigoureux. Les sédiments de la pessière à sphaignes de la tourbière du Fleuve contiennent une flore qui a probablement évolué depuis un milieu stagnant, franchement minérotrophe et légèrement acide (association à Cymbella aspera et Pinnularia cf. sfreptoraphe) à des conditions oligotrophes. acides et sub-aériennes (association à E. paludosa, Pinnularia aff. hilseana et P. subcapitata). Ces flores distinctes sont attribuées principalement à des trophismes et acidités différents. E. paludosa var. pumila, Navicula subtillissima et Asterionella ralfsii var. americana sont typiques de la tourbière de Rivière-du-Loup et reflètent des conditions ombrotrophes strictes. E. paludosa, P. aff. hilseana et P. subcapitata caractérisent la tourbière du Fleuve et suggèrent des eaux légèrement minérotrophes et moins acides. Les fluctuations négatives et positives des teneurs absolues en valves pourraient impliquer des conditions plus sèches ou plus humides strictement locales ou, peut-être, liées à des phases climatiques.

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Tremblay, R., S. Légaré, R. Pienitz, W. F. Vincent, and R. I. Hall. "Étude paléolimnologique de l'histoire trophique du lac Saint-Charles, réservoir d'eau potable de la Communauté Urbaine de Québec." Revue des sciences de l'eau 14, no. 4 (April 12, 2005): 489–510. http://dx.doi.org/10.7202/705429ar.

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Cette étude utilise une approche paléolimnologique pour reconstituer l'histoire trophique du réservoir d'eau potable de la Communauté Urbaine de Québec (CUQ), le lac Saint-Charles. Ce lac manifeste présentement un manque d'oxygène près du fond à la fin de la stratification estivale et hivernale. L'étude révèle des changements dans la communauté diatomifère fossile depuis environ les 150 dernières années. L'événement ayant entraîné le plus de changements biologiques et physico-chimiques dans le bassin est la transformation hydrologique engendrée par la construction d'un barrage en 1934 qui éleva le niveau du lac d'environ 1,5 à 2 mètres. Par conséquent, il y eut des changements dans la structure des communautés de diatomées avec des effets sur le ratio espèces planctoniques / benthiques, sur la paléoproductivité et les caractéristiques physico-chimiques des sédiments suivant cette période. Les assemblages diatomifères indiquent que les conditions mésotrophes se sont maintenues pendant toute la période étudiée. L'analyse du phosphore total dans les sédiments et la reconstitution à partir des diatomées fossiles du phosphore total dans l'eau montrent une légère diminution de la concentration en phosphore avec le temps. Ces observations démontrent qu'il n'y a pas eu d'accélération du processus d'eutrophisation engendrée par les activités humaines. Par contre, l'analyse géochimique des sédiments révèle un apport plus important de métaux depuis la fin du 19e siècle, qui atteint un plateau vers la fin des années 70.

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Saulnier-Talbot, Émilie, and Reinard Pienitz. "Isolation au postglaciaire d'un bassin côtier près de Kuujjuaraapik-Whapmagoostui, en Hudsonie (Québec) : une analyse biostratigraphique diatomifère." Géographie physique et Quaternaire 55, no. 1 (October 2, 2002): 63–74. http://dx.doi.org/10.7202/005662ar.

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Résumé En vue de retracer les phases d'isolation postglaciaire d'un lac côtier situé près de Kuujjuaraapik-Whapmagoostui (baie d'Hudson), le contenu diatomifère d'une carotte de sédiments a été analysé. La séquence sédimentaire recueillie dans le lac Kachishayoot démontre trois unités de changements paléoenvironnementaux provoqués par le relèvement isostatique postglaciaire. Ces unités se distinguent entre elles par une sédimentologie et des assemblages fossiles de diatomées contrastants. Le passage de l'argile marine à la gyttja et l'évolution des assemblages diatomifères successivement dominés par des espèces poly-mésohalobes, oligohalobes, puis halophobes, démontrent bien les effets de la salinité décroissante sur le milieu aquatique. De plus, les valeurs décroissantes d'alcalinité calculées par l'intermédiaire d'une fonction de transfert (basée sur les assemblages de diatomées) reflètent le passage d'un environnement riche à un environnement pauvre en nutriments lors de l'isolation du bassin lacustre des eaux de la Mer postglaciaire de Tyrrell. Le recyclage graduel de ses eaux a ainsi éliminé les nutriments et les ions majeurs (carbone inorganique dissous, Ca, Mg) issus du délavement du till et des argiles marines. La datation, par spectrométrie de masse à l'aide d'un accélérateur de particules (SMA) de matériel provenant de la carotte a permis d'évaluer le taux de sédimentation et d'estimer la durée des trois différentes étapes de la succession lacustre dans le bassin du lac Kachishayoot (conditions marines de 5400-4500 ans cal. BP, phase d'isolation entre 4500-1600 ans cal. BP et la phase lacustre depuis 1600 ans cal. BP). Cette étude biostratigraphique fournit aussi des indices quant à l'évolution du paysage dans le sud de l'Hudsonie par suite du retrait de la Mer postglaciaire de Tyrrell, il y a environ 5000 ans.

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Krueger, Andrea M., and Francine M. G. McCarthy. "Great Canadian Lagerstätten 5. Crawford Lake – A Canadian Holocene Lacustrine Konservat-Lagerstätte with Two-Century-Old Viable Dinoflagellate Cysts." Geoscience Canada 43, no. 2 (May 18, 2016): 123. http://dx.doi.org/10.12789/geocanj.2016.43.086.

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In addition to commonly preserved microfossils like pollen and diatoms, the varved sediments of Crawford Lake, Ontario, contain the fossilized remains of otherwise rare microfossils. Bottom water anoxia resulted from the physiography of this small, deep lake and enhanced biochemical oxygen demand (BOD) during two distinct phases of human settlement: prehistoric Iroquoian (approximately 1268–1486 CE) and historic Euro-Canadians (since 1822 CE). The exceptional preservation of delicate organic-walled microfossils like rotifer loricae and cellulosic dinoflagellate thecae provides unparalleled insights into a Holocene freshwater lake ecosystem and allows the biological and taphonomic components of the fossil assemblage to be isolated. Bottom water anoxia may also have increased the longevity of cell contents: resting cysts of Parvodinium [Peridinium] inconspicuum (Lemmermann) Carty and Peridinium volzii Lemmermann. These were germinated from varves deposited nearly two centuries ago, extending the known span of viability of dinoflagellates.RÉSUMÉEn plus des microfossiles couramment conservés comme le pollen et les diatomées, les sédiments varvés du lac Crawford en Ontario, contiennent les restes fossilisés de microfossiles très rares. Le caractère anoxique des eaux de fond s’explique par la physiographie de ce petit lac profond et par une augmentation de la demande biochimique en oxygène (DBO) durant deux phases distinctes de peuplement humain : phase préhistorique iroquoienne (environ 1268 à 1486 CE) et une phase historique euro-canadienne (depuis 1822 CE). La préservation exceptionnelle de délicats microfossiles à membranes organiques comme rotifère lorica et les thèques cellulosiques de dinoflagellés, ouvre une fenêtre inédite sur l’écosystème d’un lac d’eau douce Holocène et permet aux composants biologiques et taphonomiques de l'assemblage de fossiles d'être préservés isolément. L’anoxie des eaux de fond peut également avoir augmenté la longévité du contenu des cellules: kystes dormants de Parvodinium [Peridinium] inconspicuum (Lemmermann) Carty et de Peridinium volzii Lemmermann. Ces derniers ont été activés à partir de varves déposés il y a près de deux siècles, ce qui allonge la durée connue de la viabilité des dinoflagellés.

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WILLIAMS, DAVID M. "Notes on the diatom collection of the Natural History Museum, London (BM) I: The first place of publication for Cymatopleura brunii P. Petit, a review of its type specimens with a note on the name Surirella undata." Phytotaxa 460, no. 2 (September 23, 2020): 160–66. http://dx.doi.org/10.11646/phytotaxa.460.2.6.

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The species Cymatopleura brunii was named by Paul Petit (Paul Charles Mirbel Petit, 1834–1913, TL-2: 199) but assumed to be first published by Jacques-Joseph Brun (1826–1908) in his article ‘Diatomées lacustres, marines ou fossiles, espèces nouvelles ou insuffisamment connues’ published in Le Diatomiste (Brun 1895: pl. XIV, fig. 24, reproduced here as Figure 5). Brun’s article is composed of only a series of plates accompanied with brief descriptions of most of the specimens illustrated. Although the four plates (XIV–XVII) were issued in sequence as part of the short-lived journal Le Diatomiste, they came with separate covers (the front cover is reproduced here as Figure 12; the end cover is plain). Brun (1895) is often cited as consisting of Pls XIV–XVII and plates XIX–XX. There are, however, just four plates: Pls XIV–XVII. Plate XVIII was never issued (see Le Diatomiste 2: 252) and plates XIX–XXIV are those illustrating Brun (1896), a different article. (A publication history of Le Diatomiste is in preparation). This series of plates included the figure of Cymatopleura brunii with the comment that “Peut etre consideree comme une variété arrondie et tres ridée de la Cym. hybernica W. Sm.” (Brun 1895: pl. XIV, fig. 24). Although without any proper written description, it can still be considered a validly published name (see Guiry in Guiry & Guiry 2020). Yet there is an earlier account, which appears to have never been cited since its publication, where Petit provided both a full description and a figure of Cymatopleura brunii (Petit in Lortet 1883: 191, pl. 23, fig. 61, description reproduced here as Figure 11, Petit’s figure is reproduced here as Figure 1). This figure appears to differ from that in Brun (1895: pl. XIV, fig. 24, reproduced here as Figure 5).

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MOHAN, JOSEPH, JEFFERY R. STONE, and CHRISTOPHER J. CAMPISANO. "Three novel species of Bacillariophyta (Diatoms) belonging to Aulacoseira and Lindavia from the Pliocene Hadar Formation, Afar Depression of Ethiopia." Phytotaxa 272, no. 4 (September 2, 2016): 235. http://dx.doi.org/10.11646/phytotaxa.272.4.1.

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Paleolake Hadar was an expansive lake in the lower Awash Valley of Ethiopia’s Afar Depression that existed periodically through the Late Pliocene. The sedimentary deposits from this ancient lake (Hadar Formation) have broad importance because a significant number of hominin fossils have been recovered from the formation. Samples of the Hadar Formation lacustrine sequence were collected from sediment cores extracted as part of the Hominin Sites and Paleolakes Drilling Project (HSPDP). A paleoecological study of the HSPDP Northern Awash (Hadar Formation) material has unearthed three novel species of Bacillariophyta (diatoms) from diatomites that appear periodically in the cores. The Hadar Formation assemblage represents a newly revealed excerpt from the evolutionary history of freshwater diatoms in East Africa during the Piacenᴢian age (2.59–3.60 Ma). The HSPDP Northern Awash diatom species are compared to previously reported diatoms from Pliocene outcrops, modern and fossil core material from Lake Malawi, and extant species. Here we describe two new species of Aulacoseira and one of Lindavia. Taxonomic treatment of two diatom varieties reported by previous researchers as Melosira are transferred into Aulacoseira herein.

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7

Lipps, Jere H. "Microfossils." Paleontological Society Papers 2 (October 1996): 217–26. http://dx.doi.org/10.1017/s1089332600003284.

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Microfossils are the tiny remains of bacteria, protists, fungi, animals, and plants. Microfossils are a heterogeneous bunch of fossil remains studied as a single discipline because rock samples must be processed in certain ways to remove them and microscopes must be used to study them. Thus, microfossils, unlike other kinds of fossils, are not grouped according to their relationships to one another, but only because of their generally small size and methods of study. For example, fossils of bacteria, foraminifera, diatoms, very small invertebrate shells or skeletons, pollen, and tiny bones and teeth of large vertebrates, among others, can be called microfossils. But it is an unnatural grouping. Nevertheless, this utilitarian subdivision of paleontology, first recognized in 1883, is very significant in geology, paleontology, and biology.

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Khodaei, Lucas. "Digest: Fossils, evolutionary models, and diatoms*." Evolution 74, no. 1 (December 3, 2019): 210–11. http://dx.doi.org/10.1111/evo.13869.

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9

Balazuc, Jean. "Quelques insectes fossiles des diatomites de Saint-Bauzile (Ardèche)." Bulletin mensuel de la Société linnéenne de Lyon 58, no. 8 (1989): 240–45. http://dx.doi.org/10.3406/linly.1989.10892.

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10

Bradbury, J. P., and W. N. Krebs. "Fossil Continental Diatoms: Paleolimnology, Evolution, and Biochronology." Short Courses in Paleontology 8 (1995): 119–38. http://dx.doi.org/10.1017/s2475263000001458.

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Diatoms are golden brown algae (class Bacillariophyceae) whose cellular contents are enclosed between two valves or shells of silica. They are classified into groups with radial symmetry (centric diatoms) and axial symmetry (pennate diatoms). The latter are subdivided as raphid and araphid diatoms according to the presence or absence of raphes (slit-like structures) that allow diatoms to move along firm surfaces. Many centric and some araphid diatoms are planktonic, maintained by turbulence in the limnetic region of a lake, whereas raphid diatoms live on the lake bottom or are attached to objects in the illuminated zone.

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Sow, El, Pierre Hadji Compère, and Raphaël Sarr. "Fossil diatoms of lake Retba (Senegal West Africa) Palaeoenvironmental assessment." Algological Studies/Archiv für Hydrobiologie, Supplement Volumes 120 (July 1, 2006): 63–80. http://dx.doi.org/10.1127/1864-1318/2006/0120-0063.

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Burchell, M. J., K. H. McDermott, M. C. Price, and L. J. Yolland. "Survival of fossils under extreme shocks induced by hypervelocity impacts." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2023 (August 28, 2014): 20130190. http://dx.doi.org/10.1098/rsta.2013.0190.

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Experimental data are shown for survival of fossilized diatoms undergoing shocks in the GPa range. The results were obtained from hypervelocity impact experiments which fired fossilized diatoms frozen in ice into water targets. After the shots, the material recovered from the target water was inspected for diatom fossils. Nine shots were carried out, at speeds from 0.388 to 5.34 km s −1 , corresponding to mean peak pressures of 0.2–19 GPa. In all cases, fragmented fossilized diatoms were recovered, but both the mean and the maximum fragment size decreased with increasing impact speed and hence peak pressure. Examples of intact diatoms were found after the impacts, even in some of the higher speed shots, but their frequency and size decreased significantly at the higher speeds. This is the first demonstration that fossils can survive and be transferred from projectile to target in hypervelocity impacts, implying that it is possible that, as suggested by other authors, terrestrial rocks ejected from the Earth by giant impacts from space, and which then strike the Moon, may successfully transfer terrestrial fossils to the Moon.

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Girard, Vincent, Simona Saint Martin, Eric Buffetaut, Jean-Paul Saint Martin, Didier Néraudeau, Daniel Peyrot, Guido Roghi, Eugenio Ragazzi, and Varavudh Suteethorn. "Thai amber: insights into early diatom history?" BSGF - Earth Sciences Bulletin 191 (2020): 23. http://dx.doi.org/10.1051/bsgf/2020028.

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The origin of the diatoms still remains enigmatic. Their fossil record is scarce until the Late Cretaceous and great divergences exist between molecular data and the earliest fossil evidence. While molecular data indicate an origin during the Triassic or Early Jurassic, early fossil evidence is only from the Late Jurassic-Early Cretaceous. The discovery of diatoms in French mid-Cretaceous amber by the end of the 2000s already suggested a potential bias in the diatom fossil record as it made older many diatom lineages, the record of which hitherto began at the end of the Cretaceous. The Jurassic/Early Cretaceous fossil record of diatoms is extremely sparse and any new occurrence is important for retracing the evolutionary, palaeogeographical and palaeoenvironmental history of diatoms. Thai amber has yielded a new diatom specimen that has been attributed to the genus Hemiaulus. Fossil assemblages and sedimentological data indicate that Thai amber and its Hemiaulus specimen are Late Jurassic in age. This discovery represents the oldest hitherto known specimen of Hemiaulus and so extends the fossil record of the bipolar diatoms and of the genus Hemiaulus by several dozens of millions of years and brings closer the fossil evidence and molecular data (that estimated an origin of the bipolar diatoms about 150 Ma ago). It reinforces the hypothesis of a pre-Cretaceous fossil diatom records and also supports an origin of the diatoms in shallow coastal environments.

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Platt Bradbury, J. "Fossil diatoms and neogene paleolimnology." Palaeogeography, Palaeoclimatology, Palaeoecology 62, no. 1-4 (January 1988): 299–316. http://dx.doi.org/10.1016/0031-0182(88)90059-4.

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Milburn, Darolyn, Melonie Moses, and Ernest Hammond. "Scanning electron microscopy and x-ray analysis of fossilized materials from calvert cliffs, md." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1098–99. http://dx.doi.org/10.1017/s0424820100130122.

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Diatoms are classified in the plant kingdom as Bacillariophyta. They are unicellular plants with cell walls of silica and are found in all types of fresh and salt waters. Some species have been found in different types of soils, as well. The oldest diatoms were marine and were from the Cretacious period. “No fresh water diatoms are known prior to the Miocene era.”Several students went to the Calvert Cliffs located on the Western Shore of the Chesapeake Bay, near the confluent of the Patuxent River in southern Maryland. Fossils were collected and the scrapings were examined under the scanning electron microscope. Also, an x ray analysis was made and the objects were photographed for digital imaging processing. The x ray analysis revealed that the fossils contained large quantities of silicon, calcium, magnesium, iron and oddly enough, plutonium.From the photographs and x ray analysis, the identification of the diatoms is narrowed down and eventually identified.

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Siemińska, Jadwiga. "On the age of fossil diatoms." Acta Palaeobotanica 55, no. 1 (June 1, 2015): 116–18. http://dx.doi.org/10.1515/acpa-2015-0007.

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Abstract The finding of fossil freshwater diatoms in late Cretaceous chert in Mexico suggests - together with all the discoveries of fossil freshwater diatoms known from positions older than the Cretaceous - that the extinct marine Cretaceous diatom taxa cannot be considered to be the oldest.

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Yang, Hong, Charles J. Smiley, and Shipu Yang. "Comparative taphonomy of Miocene fossil biotas with soft tissues in lake deposits: Clarkia (Idaho, U.S.A.) and Shanwang (Shandong, P.R. China)." Paleontological Society Special Publications 6 (1992): 319. http://dx.doi.org/10.1017/s2475262200008790.

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The recent discovery of Tertiary plant fossil DNA from the Clarkia Miocene lacustrine deposits, northern Idaho, has raised concerns of the taphonomic conditions of preservation of fossil biotas with soft tissues and the further prediction of such occurrence in ancient lake deposits. The exceptionally preserved Clarkia fossil biota is compared with the Shanwang biota in Shandong Provence, eastern P.R.China, another example of Miocene conservative fossil lagerstatten. The comparison shows following similarities between the two extraordinarily preserved Miocene fossil biotas: (1) both were deposited under similar age, geological background, and depositional environment; (2) humid, warm-temperate paleoclimate was inferred in both areas; (3) both deposits contain diverse fossil biotas with soft tissues but having limited benthic organisms; (4) higher similarity coefficient exists between fossil diatoms, higher plants and insects at genus or higher taxonomic levels; and (5) overall similar taphofacies exists between the two fossil biotas.However, following differences appear between the two areas: (1) diverse vertebrate fossils in Shanwang site are sharply contrasted with the Clarkia biota in which terrestrial vertebrates are absent; (2) comparison of taphonomic signatures shows slightly different patterns between the two; (3) the two Miocene lakes originated in different manners, thus differences appear in configuration, stratification, and other paleolimnologic parameters between the two ancient lakes.The comparison of the two extraordinary fossil biotas, coupled with geologic, sedimentologic, paleoecologic and paleobiochemical studies, demonstrates that the formation and preservation of such fossil biotas with soft tissues in ancient lake deposits were strongly controlled by various paleolimnologic, paleoclimatic, taphonomic and compositional parameters.

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Izumi, Kentaro, and Kazuko Yoshizawa. "Star-shaped trace fossil and Phymatoderma from Neogene deep-sea deposits in central Japan: probable echiuran feeding and fecal traces." Journal of Paleontology 90, no. 6 (October 11, 2016): 1169–80. http://dx.doi.org/10.1017/jpa.2016.95.

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AbstractA co-occurrence of the ichnogenus Phymatoderma and a star-shaped horizontal trace fossil was discovered from Neogene deep-marine deposits (Misaki Formation, central Japan), and is described herein for the first time. Phymatoderma consists of a straight to slightly curved tunnel that shows first- or second-order branches. The tunnels are 5.30–27.25 mm in diameter and are filled with ellipsoidal pellets. The relatively well-preserved star-shaped trace fossil is a large horizontal structure (~18 cm×19 cm) that consists of at least 10 spokes with diameters ranging from 11.49–20.96 mm. As compared to modern analogous surface-feeding traces produced by abyssal echiuran worms and their burrow morphology, it is highly likely that the star-shaped trace fossil and Phymatoderma found from the Misaki Formation are feeding and fecal traces of ancient deep-sea echiurans, respectively. Difference in preservation potential between surface and subsurface traces may result in rare occurrence of star-shaped trace fossils as compared to Phymatoderma. Microscopic observation of the pelletal infill of Phymatoderma also reveals that the trace-maker fed on organic debris and microorganisms such as diatoms and radiolaria.

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Harwood, David M., Vladimir A. Nikolaev, and Diane M. Winter. "Cretaceous Records of Diatom Evolution, Radiation, and Expansion." Paleontological Society Papers 13 (October 2007): 33–59. http://dx.doi.org/10.1017/s1089332600001455.

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New information and discussions regarding Mesozoic diatoms presented over the last decade advanced our knowledge of their origin and early history. The oldest confirmed centric diatom fossils are presented here from the earliest Cretaceous, and araphid and raphid pennate diatoms now date from the Late Cretaceous; all from terrestrial sediments. Molecular sequencing helped clarify relationships between diatom lineages, and verify the position of diatoms within the heterokontophytes. Molecular clock approaches estimate a diatom origin near ~135 Ma, but not before 240 Ma. Biomarkers in marine sediments are able to trace a diatom presence back to the mid-Cretaceous, even when siliceous fossils are absent. Seasonal growth and encystment cycles in Late Cretaceous planktonic marine diatoms are now well documented. A biostratigraphic framework for the Late Cretaceous Arctic will aid regional and global biostratigraphic correlations. The systematic position of many new taxonomic groups is now included within a more natural classification scheme that better reflects phylogenetic relationships evident in molecular data and affirmed by biostratigraphic micropaleontology. Discussions regarding the impact of diatoms on several global systems are maturing, as more information becomes available. Four stages in diatom evolution are proposed to explain the history of radiation, extinction, and expansion into new environments and habitats during the Mesozoic.

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Cermeño, Pedro. "The geological story of marine diatoms and the last generation of fossil fuels." Perspectives in Phycology 3, no. 2 (September 9, 2016): 53–60. http://dx.doi.org/10.1127/pip/2016/0050.

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Riou, B. "Les fossiles des diatomites du Miocène supérieur de la montagne d'Andance (Ardèche, France)." Géologie Méditerranéenne 22, no. 1 (1995): 1–15. http://dx.doi.org/10.3406/geolm.1995.1565.

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Bishop, Ian W., S. T. Tucker, R. M. Joeckel, and Sarah A. Spaulding. "Benthic fossil diatoms from the upper Ogallala Group (late Miocene) near Scotia, NE (USA)." Nova Hedwigia, Beihefte 147 (October 4, 2018): 261–94. http://dx.doi.org/10.1127/nova-suppl/2018/021.

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Park, Mirye, Sang Deuk Lee, Hoil Lee, Jin-Young Lee, Daeryul Kwon, and Jeong-Min Choi. "Identification of New Sub-Fossil Diatoms Flora in the Sediments of Suncheonman Bay, Korea." Journal of Marine Science and Engineering 9, no. 6 (May 29, 2021): 591. http://dx.doi.org/10.3390/jmse9060591.

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Suncheonman Bay, Korea’s most representative estuary, is an invasive coastal wetland composed of 22.6 km2 of tidal flats surrounded by the Yeosu and Goheung Peninsulas. In January 2006, this region was registered in the Ramsar Convention list in Korea, representing the first registered wetland. Estuaries are generally known to have high species diversity. In particular, several studies have been conducted on planktonic and epipelic diatoms as primary producers. Suncheonman Bay has already been involved in many biological and geochemical studies, but fossil diatoms have not been evaluated. Therefore, we investigated fossil diatoms in Suncheonman Bay and introduced sub-fossil diatoms recorded in Korea. One sedimentary core has been extracted in 2018. We identified 87 diatom taxa from 52 genera in the SCW03 core sample. Of these, six species represent new records in Korea: Cymatonitzschia marina, Fallacia hodgeana, Navicula mannii, Metascolioneis tumida, Surirella recedens, and Thalassionema synedriforme. These six newly recorded diatom species were examined by light microscopy and scanning electron microscopy. The ecological habitats for all the investigated taxa are presented.

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Levitan, Orly, Jorge Dinamarca, Gal Hochman, and Paul G. Falkowski. "Diatoms: a fossil fuel of the future." Trends in Biotechnology 32, no. 3 (March 2014): 117–24. http://dx.doi.org/10.1016/j.tibtech.2014.01.004.

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Lortie, Guy, and Jean-Claude Dionne. "Analyse préliminaire des diatomées de la coupe de Montmagny, côte sud de l’estuaire du Saint-Laurent, Québec." Géographie physique et Quaternaire 44, no. 1 (December 18, 2007): 89–95. http://dx.doi.org/10.7202/032801ar.

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RÉSUMÉ À Montmagny, sur la rive sud du moyen estuaire du Saint-Laurent, une coupe d'une dizaine de mètres de puissance et comprenant cinq unités stratigraphiques a été étudiée du point de vue de sa micro-flore fossile. Une analyse sommaire des diatomées a permis d'évaluer les conditions environnementales de la mise en place des divers dépôts composant la terrasse de 8-10m à cet endroit. À la base, l'unité I (argile pléni-marine glodthwaitienne, datée à environ 10 000 BP) contient une flore marine très pauvre. L'unité Il (limon argileux avec débris organiques et bois datés à environ 7300 BP dans sa partie supérieure) se caractérise par une flore littorale saumâtre incluant des formes planctoniques marines parfois très abondantes (Thalassiosira ssp. surtout), l'unité III (tourbe datée à environ 6500 BP) contraste par une flore acidophile dulcicole à Eunotia ssp. La flore de l'unité IV (limon sableux) diffère par une teneur en valves plus élevée que dans l'unité III et par des éléments dulcicoles d'eau neutre ou légèrement alcaline fréquents, en particulier à la base. La cinquième unité (tourbe datée à environ 4500 BP) contient une flore acidophile d'eau douce. Les diatomées des unités Il et III indiquent un milieu intertidal saumâtre à faible salinité, ayant évolué progressivement lors d'épisodes de transgression. Toutefois, les conditions du milieu (profondeur d'eau et salinité) semblent avoir varié légèrement selon les époques, avec une diminution de la salinité pour l'unité IV. L'étude des diatomées corrobore l'existence de fluctuations du niveau marin relatif dans l'estuaire du Saint-Laurent au cours de l'Holocène.

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Lortie, Guy. "Les diatomées de la mer de Goldthwait dans la région de Rivière-du-Loup, Québec." Géographie physique et Quaternaire 37, no. 3 (November 29, 2007): 279–96. http://dx.doi.org/10.7202/032523ar.

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RÉSUMÉ Les sédiments de la mer de Goldthwait de la région de Rivière-du-Loup ont livré une flore de diatomées subarctique comprenant 41 genres et 131 taxons. Cette micro-flore fossile se distingue de la flore actuelle par la rareté des espèces dulcicoles planctoniques, par l'abondance des formes polyhalobes méioeuryhalines et par le nombre restreint (32) de taxons communs. Les basses teneurs en valves des dépôts étudiés (<1 x 106valves par gramme) résultent surtout d'une biomasse médiocre accentuée par une forte sédimentation détritique. Un premier assemblage à Stephanopyxis turris var. intermedia et Coscinodiscus sp. 1 est attribué aux eaux profondes et salées de la phase pléni-marine. Le deuxième assemblage, défini par Cocconeis scutellum var. stauroneiformis, C. costata, Nitzschia cylindrus et Chaetoceros sp. 1 (soie), indique un milieu littoral et suggère que des conditions régressives moins profondes et moins salées ont pu prévaloir vers 10 500 ans BP. Le dernier assemblage marin à C. costata, Cyclotella caspia et C. scutellum var. stauroneiformis correspond à un milieu saumâtre et peu profond qui a pu exister localement durant la phase régressive. Les quelques diatomées tourbicoles relevées dans des sédiments marins suggère enfin une installation de la flore continentale dès 10 500 ans BP.

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MANNION, A. M. "FOSSIL DIATOMS AND THEIR SIGNIFICANCE IN ARCHAEOLOGICAL RESEARCH." Oxford Journal of Archaeology 6, no. 2 (July 1987): 131–47. http://dx.doi.org/10.1111/j.1468-0092.1987.tb00149.x.

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Bustuoabad, Oscar D., Roberto P. Meiss, Alfredo R. Molinolo, and Alejandro M. S. Mayer. "Inhibition of experimental autoimmune orchitis by fossil diatoms." Chinese Journal of Oceanology and Limnology 3, no. 1 (June 1985): 23–29. http://dx.doi.org/10.1007/bf02852899.

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Vona, Danilo, Gabriella Leone, Roberta Ragni, Fabio Palumbo, Antonio Evidente, Maurizio Vurro, Gianluca M. Farinola, and Stefania R. Cicco. "Diatoms Biosilica as Efficient Drug-Delivery System." MRS Advances 1, no. 57 (December 23, 2015): 3825–30. http://dx.doi.org/10.1557/adv.2015.22.

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ABSTRACTDiatoms are the most abundant resource of biosilica on Earth. These microalgae are encased in a 3-D amorphous silica “shell” called frustule whose size and morphology is strictly dependent on the diatom species. Naturally nanostructured biosilica from diatoms exhibit unique adsorption and confinement properties useful for delivery of molecules of pharmacological interest.In this work fossil biosilica was used as a carrier for Ophiobolin A (a fungal macrolide with anticancer and antiparasitic properties), with the aim to develop a model system of Ophiobolin A loading / delivery. Ophiobolin A delivery properties of fossil diatoms were investigated by spectophotometric analyses.

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Kemp, Andrew C., Benjamin P. Horton, D. Reide Corbett, Stephen J. Culver, Robin J. Edwards, and Orson van de Plassche. "The relative utility of foraminifera and diatoms for reconstructing late Holocene sea-level change in North Carolina, USA." Quaternary Research 71, no. 1 (January 2009): 9–21. http://dx.doi.org/10.1016/j.yqres.2008.08.007.

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AbstractForaminifera and diatoms preserved in salt-marsh sediments have been used to produce high-resolution records of Holocene relative sea-level (RSL) change. To determine which of these microfossil groups is most appropriate for this purpose we investigated their relative utility from salt marshes in North Carolina, USA. Regional-scale transfer functions were developed using foraminifera, diatoms and a combination of both (multi-proxy) from three salt marshes (Oregon Inlet, Currituck Barrier Island and Pea Island). We evaluated each approach on the basis of transfer-function performance. Foraminifera, diatoms and multi-proxy-based transfer functions all demonstrated a strong relationship between observed and predicted elevations (r2jack > 0.74 and RMSEP < 0.05 m), suggesting that they have equal utility. Application of the transfer functions to a fossil core from Salvo to reconstruct former sea levels enabled us to consider relative utility in light of ‘paleo-performance’. Fossil foraminifera had strong modern analogues, whilst diatoms had poor modern analogues making them unreliable. This result reflects the high diversity and site-specific distribution of modern diatoms. Consequently, we used foraminifera to reconstruct RSL change for the period since ∼ AD 1800 using a 210Pb- and 14C-based chronology, and we were able to reconcile this with tide-gauge records.

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Prössl, Klaus F., and Joachim R. Grösser. "Pyritized microfossils in palynological slides from the Late Cretaceous of Colombia." Journal of Micropalaeontology 28, no. 1 (May 1, 2009): 45–52. http://dx.doi.org/10.1144/jm.28.1.45.

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Abstract. Palynological investigations of Late Cretaceous to Tertiary sediments of the Andes in Colombia yielded some distinct groups of palynoclasts recovered as pyritized remains of diatoms, radiolaria and foraminifera. The different processes of pyritization are illustrated and the palaeontological use of these fossils is discussed. Techniques for investigating such opaque microfossils are also suggested.

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Vinebrooke, Rolf D., Roland I. Hall, Peter R. Leavitt, and Brian F. Cumming. "Fossil pigments as indicators of phototrophic response to salinity and climatic change in lakes of western Canada." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 3 (March 1, 1998): 668–81. http://dx.doi.org/10.1139/f97-263.

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High performance liquid chromatography was used to quantify changes in fossil pigments among 111 saline lakes in British Columbia and to reconstruct past changes in phototrophic communities in three closed-basin prairie lakes. Redundancy analysis of survey data demonstrated that pigment concentrations were greatest in deep stratified lakes but were unaffected by ion concentrations, pH, or conductivity. Algal standing crop (as chlorophyll) was correlated (r = 0.21-0.33, P < 0.01) only with fossil measures of total algal abundance ( beta -carotene, pheophytin a). In contrast, redundancy analysis demonstrated that relative abundance (%) of fossil carotenoids varied with lake chemistry. Lutein-zeaxanthin (from green algae, cyanobacteria) and diatoxanthin (diatoms) replaced fucoxanthin (diatoms, chrysophytes, dinoflagellates) as salinity increased, while alloxanthin (cryptophytes) and myxoxanthophyll (colonial cyanobacteria) were most common in lakes with low Ca2+ and high dissolved organic carbon contents. Ordinations of surficial sediments suggested that post-deposition degradation did not alter the relation between pigment abundance and environmental characteristics. Fossil profiles of chlorophyll b and lutein-zeaxanthin also recorded climatic signals from Antelope and Kenosee lakes. These findings suggest that fossil pigments are well preserved in saline lakes and are capable of recording phototrophic community response to changes in salinity and climate.

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HABERYAN, KURT A. "Fossil diatoms and the paleolimnology of Lake Rukwa, Tanzania." Freshwater Biology 17, no. 3 (June 1987): 429–36. http://dx.doi.org/10.1111/j.1365-2427.1987.tb01064.x.

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Maidana, Nora Irene. "FOSSIL DIATOMS FROM SALINAS DEL BEBEDERO (SAN LUIS, ARGENTINA)." Diatom Research 9, no. 1 (May 1994): 99–119. http://dx.doi.org/10.1080/0269249x.1994.9705290.

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Koizumi, Itaru, and Hirofumi Yamamoto. "Paleohydrography of the Kuroshio-Kuroshio Extension based on fossil diatoms." JAMSTEC Report of Research and Development 1 (March 1, 2005): 57–68. http://dx.doi.org/10.5918/jamstecr.1.57.

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Saito-Kato, Megumi, and Tatsuya Hayashi. "Problems and perspectives in studying fossil diatoms from freshwater sediments." Quaternary Research (Daiyonki-Kenkyu) 49, no. 3 (2010): 161–71. http://dx.doi.org/10.4116/jaqua.49.161.

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Sgro, Gerald V., and Euan D. Reavie. "Fossil diatoms, geochemistry, and the Anthropocene paleolimnology of Lake Huron." Journal of Great Lakes Research 44, no. 4 (August 2018): 765–78. http://dx.doi.org/10.1016/j.jglr.2018.05.015.

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Cohen, Andrew S. "Putting our science to work in the 21st Century: new directions in applied paleobiology?" Paleontological Society Special Publications 6 (1992): 64. http://dx.doi.org/10.1017/s2475262200006249.

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The scientific community is in great need of input from paleontologists today in two key areas of societal concern: the historical basis of global change and losses of biodiversity. Paleontologists, with their unique perspective on rates of change in biotic communities and their training in filtering signal from noise in the fossil record, are the best placed scientists in biology to approach these problems from an historical viewpoint. In the classroom we give lip service to the central role of paleontology in understanding these problems. Yet with the exclusion of Quaternary (and particularly Recent) paleoecology from the mainstream of our field, we have abrogated this responsibility to other disciplines. Paleontologists are in danger of losing the opportunity to provide guidance on the very issues in paleontology where political interest and funding will lie in the not too distant future. As opportunities for employment of paleontologists in the petroleum industry fade, it is critical that academic paleontologists define new directions for graduate education in our field.The paleontological community needs to reincorporate Quaternary paleoecology into its mainstream, emphasizing the importance of a paleobiological perspective in environmental problem solving. As the developers of theory and methodology in the interpretation of the fossil record it is our responsibility to set the agenda as to how paleobiology should be utilized. Our professional societies should provide leadership as advocates for funding research and training in the new areas of applied paleobiology, lest paleobiology (as we define it) be marginalized and traditional paleontology programs be viewed by their home institutions as increasingly irrelevant. Employment opportunities in biostratigraphy are a thing of the past; applied paleontology must redefine itself for career opportunities at the top of the column, in such areas as recent climate change or the fossil record of human-induced ecological disturbances. The PIRLA Project (Paleoecological Investigation of Recent Lake Acidification) provides an excellent example of applying paleobiology to such problems, using the Recent diatoms, crustaceans, insects and pollen fossils to understand the chronology of the acid rain problem in eastern North America.Academic departments bear a responsibility to bring the important new applications of paleobiology into the classroom, demonstrating its societal relevance and training students to avail themselves of potential opportunities for paleobiologists in global change and biodiversity research. Recent developments in taphonomy or stratigraphic ordering of fossils could be extremely powerful tools if applied to environmental change problem solving. We need to make our students marketable by spending more time in the classroom teaching them about Recent diatom paleoecology and less on brachiopod biostratigraphy. Otherwise paleobiology may go the way of Egyptology.

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Nel, André. "Deux Dicladispa fossiles des gisements de diatomites néogènesde Bes-Konak (Turquie) et de Murat (France) (Coleoptera, Chrysomelidae, Hispinae)." Geobios 21, no. 3 (January 1988): 369–74. http://dx.doi.org/10.1016/s0016-6995(88)80059-7.

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Gasiński, M. Adam, Alexandra Olshtynska, and Alfred Uchman. "Late Maastrichtian foraminiferids and diatoms from the Polish Carpathians (Ropianka Formation, Skole Nappe): a case study from the Chmielnik-Grabówka composite section." Acta Geologica Polonica 63, no. 4 (December 1, 2013): 515–25. http://dx.doi.org/10.2478/agp-2013-0022.

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ABSTRACT Gasiński, M.A., Olshtynska, A. and Uchman, A. 2013. Late Maastrichtian foraminiferids and diatoms from the Polish Carpathians (Ropianka Formation, Skole Nappe): a case study from the Chmielnik-Grabowka composite section. Acta Geologica Polonica, 63(4), 515-525. Warszawa. Well-preserved foraminiferids have been found in the Chmielnik-Grabowka section (Skole Nappe, Polish Carpathians). The Abathomphalus mayaroensis (late Maastrichtian) and Racemiguembelina fructicosa (earlylate Maastrichtian) standard planktonic foraminiferal biozones have been recognized, based on the occurrence of their respective index species. Sediments of the R. fructicosa Zone contain diatoms, which are a rare component of Cretaceous flysch microfossil assemblages in the Carpathians. The diatom frustules and some foraminiferid tests are pyritized, probably after burial in the sediment, below the redox boundary or in the oxygen- deficient microenvironment inside the frustules or tests of microfossils; the presence of trace fossils and bioturbational structures in the same bed indicate an oxygenated sea floor.

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Knoll, Andrew H., and Michael J. Follows. "A bottom-up perspective on ecosystem change in Mesozoic oceans." Proceedings of the Royal Society B: Biological Sciences 283, no. 1841 (October 26, 2016): 20161755. http://dx.doi.org/10.1098/rspb.2016.1755.

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Mesozoic and Early Cenozoic marine animals across multiple phyla record secular trends in morphology, environmental distribution, and inferred behaviour that are parsimoniously explained in terms of increased selection pressure from durophagous predators. Another systemic change in Mesozoic marine ecosystems, less widely appreciated than the first, may help to explain the observed animal record. Fossils, biomarker molecules, and molecular clocks indicate a major shift in phytoplankton composition, as mixotrophic dinoflagellates, coccolithophorids and, later, diatoms radiated across shelves. Models originally developed to probe the ecology and biogeography of modern phytoplankton enable us to evaluate the ecosystem consequences of these phytoplankton radiations. In particular, our models suggest that the radiation of mixotrophic dinoflagellates and the subsequent diversification of marine diatoms would have accelerated the transfer of primary production upward into larger size classes and higher trophic levels. Thus, phytoplankton evolution provides a mechanism capable of facilitating the observed evolutionary shift in Mesozoic marine animals.

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Benoiston, Anne-Sophie, Federico M. Ibarbalz, Lucie Bittner, Lionel Guidi, Oliver Jahn, Stephanie Dutkiewicz, and Chris Bowler. "The evolution of diatoms and their biogeochemical functions." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1728 (July 17, 2017): 20160397. http://dx.doi.org/10.1098/rstb.2016.0397.

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In contemporary oceans diatoms are an important group of eukaryotic phytoplankton that typically dominate in upwelling regions and at high latitudes. They also make significant contributions to sporadic blooms that often occur in springtime. Recent surveys have revealed global information about their abundance and diversity, as well as their contributions to biogeochemical cycles, both as primary producers of organic material and as conduits facilitating the export of carbon and silicon to the ocean interior. Sequencing of diatom genomes is revealing the evolutionary underpinnings of their ecological success by examination of their gene repertoires and the mechanisms they use to adapt to environmental changes. The rise of the diatoms over the last hundred million years is similarly being explored through analysis of microfossils and biomarkers that can be traced through geological time, as well as their contributions to seafloor sediments and fossil fuel reserves. The current review aims to synthesize current information about the evolution and biogeochemical functions of diatoms as they rose to prominence in the global ocean. This article is part of the themed issue ‘The peculiar carbon metabolism in diatoms'.

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Kotrc, Benjamin, and Andrew H. Knoll. "A morphospace of planktonic marine diatoms. I. Two views of disparity through time." Paleobiology 41, no. 1 (January 2015): 45–67. http://dx.doi.org/10.1017/pab.2014.4.

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AbstractBoth molecular clocks and the first appearances of major groups in the fossil record suggest that most of the range of diatom morphologies observed today had evolved by the end of the Cretaceous Period. Despite this, a canonical reading of the Cenozoic fossil record suggests a dramatic rise in taxonomic diversity that can be interpreted as an explosion of morphological variety. We investigated this apparent discrepancy by using a discrete-character-based, empirical diatom morphospace, resolved by molecular phylogeny and by fossil occurrences through time. The morphospace shows little correspondence to phylogeny and little Cenozoic change in disparity as measured by mean pairwise distance. There is, however, an increase in the total volume of morphospace occupied. Although the increase in occupied volume through time ostensibly supports a conclusion of increasing morphological variety, sampling biases and other data suggest an underlying stationary pattern more consistent with molecular clock data.

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Cruz, José Alberto, José Luis Prado, and Joaquín Arroyo-Cabrales. "The mutual ecogeographical range and paleoclimatic reconstruction during the Late Pleistocene-Holocene in the Pampas (Argentina) using meso and microvertebrate fossils." Holocene 31, no. 6 (February 15, 2021): 983–92. http://dx.doi.org/10.1177/0959683621994652.

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The Pampas of Argentina is a large grassland ecosystem located in the oriental region southern of South America. As a study case, we present the results of the paleoclimatic analysis of the Tixi Cave site. This is a paleontological and archeological locality that shows a long chronologic sequence, with radiocarbon dates ranging from the Late Pleistocene to historical times, and one of the best records of meso and microvertebrate fossils in South America. Paleoclimatic reconstruction was assayed using the Mutual Ecogeographic Range method. Ecological niche models were made for each of the living representatives of the fossil taxa reported at the site. Potential distribution areas were superimposed to perform the paleoclimatic inference and to infer the annual average temperature and the annual average precipitation. During the Pleistocene-Holocene transition (12,287 ± 212–11,609 ± 218 ca BP) and in the Middle-Holocene (5592 ± 79 ca BP), colder and drier climates appear in comparison to the present climate, the remaining of the Holocene (3496 ± 81–160 ± 120 ca BP) shows warmer and humid climates as compared to today’s climate conditions. Our results are in agreement with the paleoenvironmental inferences obtained by other proxies, such as deposition, paleosols, phytoliths, diatoms, ostracods, and pollen for Late Pleistocene -Holocene of the region, showing that the abundance of small mammals can accurately record the climatic fluctuations of the Late Pleistocene-Holocene in the Pampas of Argentina.

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Olshtynskaya, A. P. "Fossil Holocene diatoms of the Karkinitskyi Bay, the Black Sea, Ukraine." Algologia 23, no. 3 (September 24, 2013): 341–56. http://dx.doi.org/10.15407/alg23.03.341.

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Sims, Patricia A., David G. Mann, and Linda K. Medlin. "Evolution of the diatoms: insights from fossil, biological and molecular data." Phycologia 45, no. 4 (July 2006): 361–402. http://dx.doi.org/10.2216/05-22.1.

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Nguyen, Hang Thi Gia, and Thuyen Xuan Le. "Holocene environmental change in Tonle Sap, Cambodia based on fossil diatoms." Science and Technology Development Journal - Natural Sciences 1, T5 (November 28, 2018): 5–17. http://dx.doi.org/10.32508/stdjns.v1it5.530.

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Tonle Sap Lake (“Great Lake”, Cambodia) is a biggest inland freshwater body. The size of the lake is changed dynamically following monsoon via connected to the Mekong river, especially the flood pulse. The flood pulse on Tonle Sap has affected considerably the lake’s ecological property as well diatom assemblages. The present study aimed to assess the impact of the flood pulse to diatom assemblages by time. Two short sediment cores from Tonle Sap Lake with the depth of 1.54 m and 1.27 m respectively below the lake floor were collected in May 2013 and 2015 and one short sediment core with the depth of 1.68 m was collected from the confluence of the Mekong River and Tonle Sap River in May, 2013. The sedimentations were dated by using radiometric dating (210Pb and 137Cs). Succession of fossil diatom assemblages was calculated by Rarefaction index (ES) and species richness is by Hill's N2 index. A total of 70 diatom species was released, and the diversity of diatom assemblages was extremely fluctuated in function of time (p-value = 0.0045***). Especially, 6 diatom taxa: Aulacoseira distans, Aulacoseira granulata, Aulacoseira granulata var. angustissima, Gyrosigma acuminatum, Gyrosigma attenuatum and Paralia sulcata characterized by the highest relative abundance (>1 %). In term of ecology, these species are the epipelic diatoms living commonly in eutrophication and high suspendid solid conditions. In fact, it is clear that the onset of flood pulses affected considerably the studied diatom assemblages in particular, and made sense to bio-community in general; also the lacustrine environment of Tonle Sap lake was changed very strongly in response to this shift of hydrological regime.

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Olshtynskaya, A. P., and Yu A. Tymchenko. "Fossil Holocene Diatoms of the Karkinit Bay, the Black Sea, Ukraine." International Journal on Algae 16, no. 2 (2014): 193–206. http://dx.doi.org/10.1615/interjalgae.v16.i2.90.

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Strelnikova, Nina I., and Andrey Yu Gladenkov. "Diatoms and their application in stratigraphic and paleogeographic studies." Issues of modern algology (Вопросы современной альгологии), no. 2(20) (2019): 1–38. http://dx.doi.org/10.33624/2311-0147-2019-2(20)-1-38.

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Modern data on diatom algae – unicellular microorganisms with siliceous frustule composing Class Bacillariophyceae, are reviewed. Brief characteristic of biology, morphology, frustule structure and its elements, principles of diatom systematics, and also biogeography and ecology are given. A role of diatoms in sedimentation and peculiarities of preservation of their remains in bottom sediments are discussed. Special attention is paid to issues of effective application of data on fossil diatoms for detailed biostratigraphic subdivision, dating and correlation of sedimentary successions (first of all, marine deposits) as well as for paleoenvironmental reconstructions. General characteristic of diatom zonations proposed for marine Cretaceous and Cenozoic sediments is given. Main features of diatom evolution are discussed.

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Van Eetvelde, Y., C. Dupuis, and C. Cornet. "Pyritized diatoms: a good fossil marker in the Upper Paleocene-Lower Eocene sediments from the Belgian and Dieppe-Hampshire Basins." Netherlands Journal of Geosciences - Geologie en Mijnbouw 83, no. 3 (September 2004): 173–78. http://dx.doi.org/10.1017/s0016774600020230.

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AbstractAssemblages of brackish and marine diatoms have been examined from Upper Paleocene-Lower Eocene strata of the Belgian Basin (Knokke well) and the Dieppe-Hampshire Basin (Saint-Josse borehole and Ailly sections). The diatoms observed are invariably preserved in pyrite as internal moulds and their siliceous skeletons are completely replaced by pyrite by epigenesis. Three major diatom assemblages have been observed which can be used to approximate the position of the recently defined Paleocene-Eocene boundary (defined by the Carbon Isotope Excursion). This isotope excursion occurs just below the strong increase in the abundance of Fenestrella antiqua and in the vicinity of the abundance peak of Coscinodiscus morsianus var. moelleri. They also allow correlations of the lithostratigraphic units of the Belgian Basin with the formations of the Dieppe-Hampshire and central North Sea Basins. For instance, investigations of diatoms recorded in the Knokke Clay Member of the Knokke well indicate that this unit corresponds to the lower units of the ‘Sparnacian facies’ of the Dieppe-Hampshire Basin and to the Sele Formation of the North Sea Basin.

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Journal articles on the topic 'Diatomées fossiles'

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