Selknamella: a new agglutinated foraminiferal genus from the early Eocene southern high latitudes

A new, unusual agglutinated foraminifera, Selknamella basketi n. gen., n. sp. is described from the Fuegian lower Eocene, Magallanes Basin, southernmost South America. It has a morphology and paleohabitat similar to those of the subfamily Remaneicinae Loeblich and Tappan, 1964, particularly to the Holocene genera Bruneica Brönnimann, Keij and Zaninetti, 1983, and Remaneica Rhumbler, 1938: It has a low trochospirally coiled to patelliform small test; the first two or three embryonic chambers are globular and undivided; following chambers are semilunate-shaped from spiral view and mushroom-shaped from umbilical view, and subdivided by radial secondary septula. Selknamella n. gen. differs from all the organically-cemented Remaneicinae by the perforate rigid wall, completely calcareous in the initial chambers to very finely agglutinated in the last whorls. The new genus is the only case of calcareous cemented agglutinated foraminifera in the Cretaceous and Cenozoic of the Magallanes Basin, and is restricted to the early Eocene, coincident with the warmest time in the high southern latitudes.Fil: Malumian, Norberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; ArgentinaFil: Nañez, Carolina Adela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; ArgentinaFil: Jannou, Gabriel Eugenio. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; ArgentinaFil: Arenillas, I.. Universidad de Zaragoza; Españ

Blooms of aberrant planktic foraminifera across the K/Pg boundary in the Western Tethys: causes and evolutionary implications

We report a detailed study of the different categories and types of abnormal morphologies in planktic foraminifera recognizable in the lowermost Danian, mainly from the El Kef and Ain Settara sections, Tunisia. Various types of abnormalities in the test morphology were identified, including protuberances near the proloculus, abnormal chambers, double or twinned ultimate chambers, multiple ultimate chambers, abnormal apertures, distortion in test coiling, morphologically abnormal tests, attached twins or double tests, and general monstrosities. Detailed biostratigraphic and quantitative studies of the Tunisian sections documented a major proliferation of aberrant planktic foraminifera (between approximately 5% and 18% in relative abundance) during the first 200 Kyr of the Danian, starting immediately after the Cretaceous/Paleogene (K/Pg) boundary mass extinction (spanning from the Guembelitria cretacea Zone to the lower part of the P. pseudobulloides Zone). This contrasts with the proportionately low frequency of aberrant tests (generally 18%). These main pulses of aberrants coincide approximately with relevant quantitative and evolutionary turnovers in the planktic foraminiferal assemblages. In this paper, we explore the relation of these high values of the foraminiferal abnormality index with the environmental changes induced by the meteorite impact of Chicxulub in Yucatan, Mexico, and the massive eruptions of the Deccan Traps, India

An updated suprageneric classification of planktic foraminifera after growing evidence of multiple benthic-planktic transitions

Planktic foraminifera have traditionally been classified within a single order: Globigerinida. However, recent phylogenetic studies, both molecular and stratophenetic, are evidencing the polyphyletic origin of planktic foraminifera from several benthic ancestors. At least four independent events of benthic-planktic transition have been identified. One of them occurred after the Cretaceous–Paleogene boundary mass extinction, originating the first Cenozoic globigerinids. Another three occurred in the Mesozoic, originating three groups of planktic foraminifera (globotruncanids, heterohelicids and guembelitriids) not related phylogenetically to each other or to current globigerinids. These findings make it necessary to carry out an exhaustive review of their suprageneric systematics, mainly at the order level. Here we propose a new, more natural classification, grouping them into four orders: Globigerinida, Heterohelicida, Globotruncanida n. ord., and Guembelitriida n. ord. To better reflect the diversity and phylogeny of planktic foraminifera, we have also defined two new superfamilies: Abathomphaloidea n. superfam. and Parvularugoglobigerinoidea n. superfam., and one new family: Parvularuglobigerinidae n. fam

Biostratigraphic study with planktic foraminifera of the Santonian-Campanian in the Deba-Zumaia section (Gipuzkoa): New biozonation with heterohelicids

A biostratigraphic study with Santonian and Campanian planktic foraminifera was carried out in the turbiditic facies of the coastline between Deba and Zumaia (Gipuzkoa), which comprises the Itziar and Aguinaga formations. Due to the low abundance of planktic foraminifera, particularly in globotruncanids, the biostratigraphic study was based on species belonging to the group of heterohelicids. We have identified 7 biozones, one of which (Sigalia rugocostata Zone) has been defined in this work. The position of the Santonian/Campanian boundary has been recognized for the first time in the Basque Coast Geopark through the use of this new biozonation with heterohelicidsSe ha realizado un estudio bioestratigráfico con foraminíferos planctónicos del Santoniense y Campaniense en las facies turbidíticas del tramo litoral entre Deba y Zumaia (Guipúzcoa), el cual comprende las formaciones Itziar y Aguinaga. Debido a la escasez de foraminíferos planctónicos del grupo de globotruncánidos, el estudio bioestratigráfico se ha basado en especies pertenecientes al grupo de los heterohelícidos. Se han identificado 7 biozonas, una de las cuales (Zona de Sigalia rugocostata) ha sido definida en este trabajo. Esta nueva biozonación ha permitido reconocer por primera vez la posición del límite Santoniense/Campaniense en el Geoparque de la Costa Vasc

Contribution of orbital forcing and Deccan volcanism to global climatic and biotic changes across the Cretaceous-Paleogene boundary at Zumaia, Spain

Untangling the timing of the environmental effects of Deccan volcanism with respect to the Chicxulub impact is instrumental to fully assessing the contributions of both to climate change over the Cretaceous-Paleogene boundary (KPB) interval. Despite recent improvements in radiometric age calibrations, the accuracy of age constraints and correlations is insufficient to resolve the exact mechanisms leading to environmental and climate change in the 1 m.y. across the KPB. We present new high-resolution planktic foraminiferal, geochemical, and geophysical data from the Zumaia section (Spain), calibrated to an updated orbitally tuned age model. We provide a revised chronology for the major carbon isotope excursions (CIEs) and planktic foraminiferal events and test temporal relationships with different models of the eruptive phases of the Deccan Traps. Our data show that the major CIEs near the KPB, i.e., the late Maastrichtian warming event (66.25–66.10 Ma) and the Dan-C2 event (65.8–65.7 Ma), are synchronous with the last and the first 405 k.y. eccentricity maximum of the Maastrichtian and the Danian, respectively, and that the minor Lower C29n event (65.48–65.41 Ma) is well constrained to a short eccentricity maximum. Conversely, we obtained evidence of abrupt environmental change likely related to Deccan volcanism at ca. 65.9 Ma, based on a bloom of opportunistic triserial guembelitriids (Chiloguembelitria). The orbital, isotopic, and paleobiological temporal relationships with Deccan volcanism established here provide new insights into the role of Deccan volcanism in climate and environmental change in the 1 m.y. across the KPB. © 2021. The Authors. Gold Open Access: This paper is published under the terms of the CC-BY license

Planktic foraminiferal response to the earliest Danian Paleoenvironmental and paleoclimatic events at Caravaca (Murcia)

The recovery of ecosystems after the Cretaceous/Paleogene (K/Pg) boundary mass extinction is still highly debated. In order to assess the environmental and climate changes over the first 260 ka of the Danian, we carried out a quantitative study of the planktic foraminiferal assemblages and biometric measurements in three selected planktic foraminiferal species. A rapid evolution of very simple planktic foraminiferal species occurred during the first 32 ka, reoccupying the empty niches after the K/Pg extinction. An increase in the size of the measured species is recorded across the study section, mainly during episodes of environmental stability (probably cooling). The increase in their size halted during the two Chiloguembelitria acmes identified, which mark ecological stress episodes. Our results suggest that the environmental perturbations in the most superficial layer of the water column were driven by Deccan volcanic forcing

Planktonic foraminiferal and calcareous nannofossil biostratigraphy and magnetostratigraphy of the uppermost Campanian and Maastrichtian at Zumaia, northern Spain

The well-exposed and continuous uppermost Cretaceous in the coastal section of Zumaia (northern Spain) crops out as cyclic, deep-water, hemipelagic carbonate-rich sediments of significant geological interest. We present a new, high-resolution calibration of planktonic foraminiferal and calcareous nannofossil biostratigraphic datums, alongside new magnetostratigraphy. Six planktonic foraminiferal zones (Rugoglobigerina rotundata to Pseudoguembelina hariaensis) and nine nannofossil (sub)zones (UC15eTP? to UC20dTP) have been identified, encompassing the uppermost Campanian through uppermost Maastrichtian. Magnetostratigraphic data were obtained from the lower half of the section, where chrons C31r and C31n have been identified; the lithological nature of the upper part of the section provided spurious palaeomagnetic results. According to these data, the Campanian/Maastrichtian (C/M) boundary lies in Chron C31r at Zumaia. Differences between the planktonic foraminiferal and nannofossil datums at Zumaia and those from the Tercis boundary stratotype section (France) suggest that the biostratigraphic criteria used to identify the C/M boundary are problematic. We propose, therefore, two alternative, key biostratigraphic datums with which to determine the stratigraphic position of this boundary: the stratigraphic base occurrence datum (BO) of the planktonic foraminifer Pseudoguembelina palpebra and the top occurrence datum (TO) of the nannofossil Broinsonia parca subsp. constricta. The C31r/C31n magnetic polarity reversal, and the BOs of the planktonic foraminifer Racemiguembelina fructicosa and the nannofossil Lithraphidites quadratus are events that may prove useful in formally defining the lower/upper Maastrichtian boundary

Neural encoding of voice pitch and formant structure at birth as revealed by frequency-following responses

Detailed neural encoding of voice pitch and formant structure plays a crucial role in speech perception, and is of key importance for an appropriate acquisition of the phonetic repertoire in infants since birth. However, the extent to what newborns are capable of extracting pitch and formant structure information from the temporal envelope and the temporal fine structure of speech sounds, respectively, remains unclear. Here, we recorded the frequency-following response (FFR) elicited by a novel two-vowel, rising-pitch-ending stimulus to simultaneously characterize voice pitch and formant structure encoding accuracy in a sample of neonates and adults. Data revealed that newborns tracked changes in voice pitch reliably and no differently than adults, but exhibited weaker signatures of formant structure encoding, particularly at higher formant frequency ranges. Thus, our results indicate a well-developed encoding of voice pitch at birth, while formant structure representation is maturing in a frequency-dependent manner. Furthermore, we demonstrate the feasibility to assess voice pitch and formant structure encoding within clinical evaluation times in a hospital setting, and suggest the possibility to use this novel stimulus as a tool for longitudinal developmental studies of the auditory system

The Cretaceous-Palaeogene (K/P) boundary in the Aïn Settara section (Kalaat Senan, Central Tunisia): lithological, micropalaeontological and geochemical evidence

The Cretaceous-Palaeogene (K/P) boundary, until recently known as the "Cretaceous-Tertiary" or K/T boundary, is well exposed at Aïn Settara in the Kalaat Senan area (Central Tunisia), 50 km south of the El Kef section. Micropalaeontological and geochemical studies led to the identification of six main features tentatively named "events", which characterise the K/P boundary interval, and of which at least two (B and C) have global significance. The lowermost event A located at about 14 cm below the base of the Dark Boundary Clay is marked by a sudden increase in tiny bioturbations, by small nodules and a few macrofossils, a 50% drop in calcareous nannofossil abundance and an increase in Scytinascias (organic linings of foraminifera). It is thought to witness a slowdown in sedimentation. Event B is characterised by a burrowed surface, separating the ca 60-cm thick Dark Boundary Clay from the underlying Aïn Settara marls. It indicates an episode of nondeposition, just before a major change in lithology from marls to clays, corresponding to a major flooding. No substantial palaeontological changes have been recorded in relation to this event. Event C is characterised by maximum concentrations of Ir and Ni-rich spinels, which have been observed in platy nodules, similar to the level at El Kef (K/P boundary sensu ODIN, 1992). It coincides with a major extinction in planktonic foraminiferal species (71%) and a 60% drop in nannofossil abundance. The change in lithology (occurrence of small ripples and channel-like structures) recorded at event D, a few cm up-section, might be related to a locally recorded storm activity. Events E and F, which are situated higher up in the Dark Boundary Clay, are mainly determined by palaeontological changes (palynomorphs and nannofossils), probably resulting from small sea-level variations. The coincidence of the cosmic markers with the major biotic changes at event C pleads for the asteroid impact hypothesis. Their disjunction from the base of the Dark Boundary Clay shows that the change of lithology usually used to determine the K-P boundary is distinct from the major extinction (in the planktonic realm), classically referred to this boundary and linked to the presence of cosmic markers. These results argue the need for the revaluation of the K-P boundary GSSP at El Kef. It is suggested to redefine the K-P boundary at the level of coincidence of the major biotic changes and the cosmic markers

Direct utilization of lignite coal in a Co–CeO2/YSZ/Ag solid oxide fuel cell

The feasibility of employing lignite coal as a fuel in a Direct Carbon Fuel Cell (DCFC) of the type: lignite|Co–CeO2/YSZ/Ag|air is investigated. The impact of several parameters, related to anodic electrode composition (20, 40 and 60 wt.% Co/CeO2), cell temperature (700–800 °C), carrier gas composition (CO2/He mixtures), and total feed flow rate (10–70 cm3/min), was systematically examined. The effect of molten carbonates on DCFC performance was also investigated by employing a eutectic mixture of lithium and potassium carbonates as carbon additives. In the absence of carbonates, the optimum performance (∼10 mW cm−2 at 800 °C), was achieved by employing 20 wt.% Co/CeO2 as anodic electrode and pure CO2 as purging gas. An inferior behavior was demonstrated by utilizing He instead of CO2 atmosphere in anode compartment and by increasing purging gas flow rate. Carbonates infusion into lignite feedstock resulted in a further increase of maximum power density up to 32%. The obtained findings are discussed based also on AC impedance spectroscopy measurements, which revealed the impact of DCFC operating parameters on both ohmic and electrode resistances.The authors would like to acknowledge financial support from the European project “Efficient Conversion of Coal to Electricity – Direct Coal Fuel Cells”, which is funded by the Research Fund for Carbon & Steel (RFCR-CT-2011-00004). In addition the authors are grateful to Prof. V. Stathopoulos and Mr. P. Pandis for conducting the Direct Current Four Point (DC4P) measurements.Peer reviewe