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Maria Petrizzo

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Daniel P Le Heron

University of Vienna

Armando Marques-Guedes

UNL - New University of Lisbon

Columbia University

Dinçer Başdemir

Ege University

Dr. K. B. Padmakumar

Cochin University of Science and Technology

Universiti Malaysia Terengganu

Universität Bremen

Blanca Figuerola

CSIC (Consejo Superior de Investigaciones Científicas-Spanish National Research Council)

Fernando Ángel Fernández-Álvarez

CSIC (Consejo Superior de Investigaciones Científicas-Spanish National Research Council)

Adam Mickiewicz University in Poznań

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Papers by Maria Petrizzo

Stratigraphy of the Albian−Cenomanian boundary interval in the Agadir Basin, Morocco: ammonites, microcrinoids, planktonic foraminifera

Acta Geologica Polonica, Jul 26, 2023

The uppermost Albian and lowermost Cenomanian succession at Abouda Plage, north of Agadir, in the... more The uppermost Albian and lowermost Cenomanian succession at Abouda Plage, north of Agadir, in the Agadir Basin, western Morocco, is described in detail, and ammonites, microcrinoids and planktonic foraminifera are recorded and illustrated. The lower part of the Aït Lamine Formation yields ammonites indicative of the Pervinquieria (Subschloenbachia) rostrata and P. (S.) perinflata ammonite zones, and the Thalmanninella appenninica planktonic foraminiferan Zone. The base of the Cenomanian is identified at 42.2 m above the base of the Aït Lamine Formation, based on the lowest occurrence of the planktonic foraminiferan Thalmanninella globotruncanoides Sigal, 1948. Lower Cenomanian ammonites of the Graysonites adkinsi Zone enter 3 m higher in the succession. Microcrinoid zones AlR11 and AlR12 are identified in the Upper Albian, and the base of the CeR1 Zone coincides with the lowest occurrence of Cenomanian ammonites. The ammonite and microcrinoid occurrences and detailed distributions are very similar to those found in north central Texas, which, in the Cenomanian, was 5,300 km to the west. The new records suggest that the G. adkinsi Zone is equivalent to the uppermost (Lower Cenomanian) part of the Pleurohoplites briacensis Zone of the Global Stratotype Section for the base of the Cenomanian stage. An hiatus, of global extent, immediately underlies the base of the G. adkinsi Zone and is represented in the Agadir Basin by an erosion surface containing bored and encrusted hiatus concretions.

Calcareous Plankton Biostratigraphy of the Santonian-Campanian Boundary Interval in the Bottaccione Section (Umbria-Marche Basin, Central Italy)

Rivista Italiana Di Paleontologia E Stratigrafia, Oct 6, 2020

The Bottaccione section (Umbria-Marche Basin, central italy) was analyzed for calcareous nannofos... more The Bottaccione section (Umbria-Marche Basin, central italy) was analyzed for calcareous nannofossil and planktonic foraminiferal biostratigraphy across the Santonian-Campanian boundary interval to achieve a high-resolution and updated zonation directly calibrated with magnetostratigraphy. Several calcareous plankton events were detected, including zonal markers and additional potential biohorizons. The base of magnetochron C33r, proposed for placement of the base of the Campanian, lies between the first occurrence of Aspidolithus parcus parcus and the last occurrence of Dicarinella asymetrica in the Bottaccione section. The literature survey indicates that these events were found in the Santonian-Campanian boundary interval at supraregional scale and, may be used to confidently approximate the base of the Campanian.

Evidence for changes in sea-surface circulation patterns and ~20° equatorward expansion of the Boreal bioprovince during a cold snap of Oceanic Anoxic Event 2 (Late Cretaceous)

Global and Planetary Change, 2022

Abstract The Plenus Cold Event (PCE) temporarily interrupted the supergreenhouse conditions exace... more Abstract The Plenus Cold Event (PCE) temporarily interrupted the supergreenhouse conditions exacerbated during much of the Cenomanian–Turonian Oceanic Anoxic Event 2 (OAE 2). The PCE is coeval to the occurrence of Boreal benthic macroinvertebrates and of the nektonic belemnite Praeactinocamax plenus (after which the event is named) in Europe, and to the re-oxygenation of bottom waters in the Northern Hemisphere. However, its effects on the sea-surface circulation are unknown and evidence for changes in the biogeography of planktonic organisms are limited to the equatorward migration of the dinoflagellate cysts grouped in the Cyclonephelium compactum–membraniphorum morphological plexus. This study presents new planktonic foraminiferal quantitative data from two complete OAE 2 records of the Anglo-Paris (Eastbourne, SE England) and Vocontian (Clot Chevalier, SE France) basins that registered the equatorward pulse of Boreal macroinvertebrates during the PCE and have been extensively studied for bio- and chemostratigraphy. At the onset of OAE 2 (before the PCE), planktonic foraminifera are mainly represented by oligo-mesotrophic Tethyan taxa (rotaliporids and whiteinellids) in both localities, but this assemblage is sharply replaced by cold and meso-to-eutrophic species (praeglobotruncanids, dicarinellids and muricohedbergellids) during the PCE. The cold-water assemblage shows strong affinities with the coeval fauna of the Norwegian Sea and yields the Boreal endemic species Muricohedbergella kyphoma and Praeglobotruncana plenusiensis. This observation combined with previously published data collected in other localities of the Northern Hemisphere and on other fossil groups suggest a ~20° equatorward expansion of the Boreal marine bioprovince during the PCE. Moreover, contrarily to the nektonic belemnitellids that were able to move independently of ocean circulation, planktonic organisms are passively transported by currents and changes in the planktonic foraminiferal assemblages documented in the Anglo-Paris and Vocontian basins have been interpreted to reflect the transition from a dominant influence of warm, saline, and thermally stratified waters carried by the proto-Gulf Stream before the PCE to cold and low-saline Boreal waters originated in the Norwegian Sea during the PCE. We suggest that such changes were forced by the equatorward shift of the proto-Arctic Front (i.e., the boundary between warm saline Tethyan-Atlantic and cold low-saline Boreal waters) from offshore Norway to Southern England. In this southerly position, the proto-Arctic Front represented an oceanographic barrier that limited the influence of the proto-Gulf Stream in the Anglo-Paris Basin, and favored the inflow of Boreal waters in the European epicontinental basins. The sea-surface cooling and equatorward expansion of Boreal planktonic assemblages during the PCE are of the same order of magnitude of those reconstructed between some glacial and interglacial intervals of the Plio-Pleistocene. Despite obvious differences between Cretaceous and Plio-Pleistocene paleogeography and climate dynamics, this study reviews the extent of environmental changes occurred during the PCE, provides evidence for a profound re-organization of the sea-surface circulation patterns and a more comprehensive overview of the equatorward migration of Boreal marine communities in the Northern Hemisphere.

Planktonic foraminiferal biostratigraphy and assemblage composition across the Cenomanian–Turonian boundary interval at Clot Chevalier (Vocontian Basin, SE France)

Cretaceous Research, Apr 1, 2016

The CenomanianeTuronian boundary interval is generally considered a critical time for planktonic ... more The CenomanianeTuronian boundary interval is generally considered a critical time for planktonic foraminifera due to the environmental perturbations associated with Oceanic Anoxic Event 2. However, only the rotaliporids became extinct at the onset of the event, whilst several lineages evolved and/or diversified. This remarkable morphologic plasticity is often overlooked in the literature, partly because a number of stratigraphic sections have only been studied in thin-section due to the degree of lithification of the samples. Improved documentation of the morphological variability of planktonic foraminifera and better defined species concepts are required in order to improve biostratigraphy, particularly as Helvetoglobotruncana helvetica is an unreliable marker for the base of the Turonian. At the same time, detailed study of the planktonic foraminiferal response to OAE 2 demands a more profound knowledge of the assemblage composition. We present new biostratigraphic, taxonomic, and quantitative data for planktonic foraminiferal species from the Clot Chevalier section (Vocontian Basin, SE France), with the aim of (1) providing a detailed biostratigraphic analysis of the section, (2) documenting the morphological plasticity of specimens in this time interval and stabilizing species concepts, and (3) identifying promising markers to improve the resolution of the present biozonation and allow regional correlation. Samples were processed with acetic acid to extract isolated planktonic foraminifera. Assemblages were assigned to the upper Cenomanian Rotalipora cushmani Zone and to the uppermost Cenomanianelowermost Turonian Whiteinella archaeocretacea Zone. Planktonic foraminiferal bioevents and assemblage composition identified at Clot Chevalier are compared with the well-studied Pont d'Issole section located ca. 15 km to the NE, highlighting similarities and differences in the species occurrences that may complicate the stratigraphic correlation between the two sections. The results of our study support the validity and common occurrence of species that have been misidentified and/or overlooked in the literature (i.e., Dicarinella roddai, Praeglobotruncana oraviensis, Marginotruncana caronae) and indicate that primitive marginotruncanids evolved before the onset of OAE 2, although species diversification occurred only after the event. Moreover, we believe that the first appearance of P. oraviensis might represent a promising bioevent for approximating the Cenomanian/ Turonian boundary, after calibration with bio- and chemostratigraphically well-constrained sections. Finally, we describe three new trochospiral species, named \u201cPseudoclavihedbergella\u201d chevaliensis, Praeglobotruncana pseudoalgeriana and Praeglobotruncana clotensis

Pforams@microtax: A new online taxonomic database for planktonic foraminifera

Micropaleontology, 2017

A new relational taxonomic database for planktonic foraminifera (Pforams@microtax) has been const... more A new relational taxonomic database for planktonic foraminifera (Pforams@microtax) has been constructed and is now freely available online at http://www.mikrotax.org. It represents amajor advance from its predecessor, the CHRONOS online taxonomic database, which has served the research community since 2005. The benefits of the new database to the research and industrial biostratigraphic communities are many, as it will serve as an immediately accessible taxonomic guide and reference for specialists and non-specialists alike by providing access to a wealth of information and images from original authors and from expertswho have inserted recent authoritative updates to planktonic foraminiferal taxonomy, phylogeny and biostratigraphy. The database will be continually updated and used as a guide for training current and future generations of students and professionals who will be able to self-educate on planktonic foraminiferal taxonomy and biostratigraphy. Further investigation of species traditionally included in the Cretaceous genera Heterohelix, Globigerinelloides, Marginotruncana, and Globotruncana is required to exclude the use of polyphyletic morphotaxa. The taxonomy for Paleogene planktonic foraminifera is quite stable following publication of the Paleocene, Eocene, and Oligocene taxonomic atlases, but revisions to the taxonomy and phylogeny of Neogene taxa are needed to incorporate results from genetic sequencing studies and recent biostratigraphic observations.

Taxonomy and phylogeny of Albian-Maastrichtian planispiral planktonic foraminifera traditionally assigned to Globigerinelloides

Micropaleontology, 2022

We propose a considerably revised taxonomy and phylogeny for Albian-Maastrichtian planispiral pla... more We propose a considerably revised taxonomy and phylogeny for Albian-Maastrichtian planispiral planktonic foraminiferal species that have traditionally been included in Globigerinelloides. The revised taxonomy is necessary because of a ~6 m.y. gap between the extinction of planispiral species during the late Aptian and the next younger occurrence of planispiral species in the middle Albian. Our stratophenetic taxonomic groupings utilize ontogenetic morphometric data, shell wall ultrastructure, and general morphologic features observed from Scanning Electron Microscope and X-radiograph images of primary type specimens and globally distributed hypotype specimens. The planispiral lineage Laeviella n. gen., whose type species is La. bentonensis (Morrow), first appeared in the middle Albian and is postulated to have evolved from the evolutionary series Ticinella primula Luterbacher-Laviella primuloides n. sp. Laeviella is characterized as having a smooth to finely pustulose wall texture and a moderate chamber size increase rate. Two additional species, La. tururensis (Bronnimann) and La. bollii (Pessagno), are included in Laeviella with the youngest species of the genus, La. bollii, becoming extinct during the late Campanian. Planohedbergella, with Plh. aspera (Ehrenberg) as its type species, is revised to include 10 species that show a wide variation in chamber arrangement, wall microstructure and test morphology, but all have a moderately to coarsely pustulose wall texture on some or most final whorl chambers. Its stratigraphic range is from the late Albian-Cretaceous/Paleogene boundary. The oldest species is Plh. ultramicra (Subbotina), which evolved from Planomalina pulchella Todd and Low during the late Albian. Planohedbergella circularis n. sp. is described as a new late Campanian-Maastrichtian species representing forms with evolute coiling, a large number of final whorl chambers, and a slow chamber size increase rate. Polycamerella n. gen. is described as a monospecific genus, with Po. tardata n. sp. as the type species. It is a small, biapertural form with a very slow chamber expansion rate and a stratigraphic range from the late Campanian-Maastrichtian. The ancestor of Po. tardata, is tentatively identified as Plh. ultramicra.

Patterns of planktonic foraminiferal extinctions and eclipses during Oceanic Anoxic Event 2 at Eastbourne (SE England) and other mid-low latitude locations

Cretaceous Research, Dec 1, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Phylogenetic relationships and evolutionary history of the Early Paleogene genus Igorina (planktonic foraminifera) through parsimony analysis

Background: The evolutionary history of biodiversity in South America has been poorly studied in ... more Background: The evolutionary history of biodiversity in South America has been poorly studied in the seasonal dry tropical forest (SDTF). Species diversification in this ecosystem may have a twofold explanation. First, intermittent connections in the middle and late Pleistocene promoted species dispersal and/or genetic connectivity between lineages isolated in disjunct patches of forest. Second, allopatric speciation proceeded immediately after the formation and colonization of the SDTF in the Neogene. Here we studied the diversification of Psammolestes, a genus endemic of the SDTF and naturally infected with Trypanosoma cruzi (agent of Chagas disease), using a combination of phylogenetic, population genetics and niche model methods, and evaluated the reliability of the three morphospecies currently recognized. Results: Our multilocus analyses recovered P. coreodes and P. tertius in a monophyletic clade sister to P. arthuri. Species delimitation tests recovered these lineages as different species despite the shared genetic variation observed between P. coreodes and P. tertius in five genes. Also, genetic variation of the genus clustered in three groups that were consistent with the three morphospecies. Our demographic model predicted a scenario of divergence in absence of gene flow, suggesting that mixed haplotypes may be the result of shared ancestral variation since the divergence of the subtropical-temperate species P. coreodes and P. tertius. In contrast, the tropical species P. arthuri was highly differentiated from the other two in all tests of genetic structure, and consistently, the Monmonier's algorithm identified a clear geographical barrier that separates this species from P. coreodes and P. tertius. Conclusions: We found three genetically structured lineages within Psammolestes that diverged in absence of gene flow in the late Miocene. This result supports a scenario of species formation driven by geographical isolation rather than by divergence in the face of gene flow associated with climatic oscillations in the Pleistocene. Also, we identified the Amazon basin as a climatic barrier that separates tropical from subtropical-temperate species, thus promoting

Remarks on Globotruncana insignis types: how the reconstruction of the phyletic lineare can solve taxonomic debates

On the phylogeny of Paleogene planktonic foraminifera: wall texture structure and a new genus name for the broedermanni lineage

The broedermanni lineage has been traditionally placed in the genus Igorina (see Berggren and oth... more The broedermanni lineage has been traditionally placed in the genus Igorina (see Berggren and others, 2006) being characterized by possessing a biconvex globorotaliid morphology, subglobular to subquadrate chambers, and by having a nonspinose wall texture with thin muricae on the test surface. Our analysis of specimens from the Pacific Ocean (ODP Leg 198, Shatsky Rise and ODP Leg 143, Alllison Guyot) suggest that the broedermanni group is phylogenetically related to Acarinina as the calcite structures of the wall are similar to the muricae rather than to the short pustules of the Paleocene igorinids (i. e., I. pusilla, I. albeari). In particular, the oldest species lodoensis shows a typical coarse muricate test similar to Acarinina while in its descendants, broedermanni and anapetes, the muricae are finer on the spiral side, and heavier muricae are developed only around the umbilicus. Moreover, in the broedermanni group the shell is not encrusted as in Igorina because the pustules remained isolated and increased in size to become thick muricae. The analysis of the pore structure in cross section seems to confirm the similarities and affinities between the wall texture of the broedermanni group and Acarinina. Both show an hourglass shape of the pores that become narrow in the outer calcite layer whereas in Igorina species the pores are tight in the inner calcite layer. In addition, the results from parsimony analysis (Soldan and other, 2011) confirm that the broedermanni group evolved in the late Paleocene/early Eocene from the group of round acarininids (A. mckannai and A. soldadoensis). The new genus Pearsonites (named in honor of Professor Paul N. Pearson) with Pearsonites broedermanni as type species, is here proposed to accommodate the early-middle Eocene globorotaliid taxa of the broedermanni lineage with a wall texture bearing muricae. Three species previously considered morphologically and evolutionary related to the Paleocene genus Igorina are here included in Pearsonites nov. gen., P. lodoensis, P. broedermanni, and P. anapetes. Species assigned to Pearsonites nov. gen. are relatively common in the stratigraphic interval from the upper Paleocene (Zone P5) to the middle Eocene (Zone E9). References Berggren W.A., Pearson P.N., Huber B.T., Wade B.S., 2006. Chapter 19: Taxonomy, biostratigraphy and phylogenetic affinities of Eocene Acarinina, in Pearson P. N., Olsson R.K, Huber B.T., Hemleben C., Berggren W.A (eds), Atlas of Eocene Planktonic Foraminifera: Cushman Foundation Special Pubblication, v. 41, p. 257-326. Soldan D.M., Petrizzo M.R., Premoli Silva I., Cau A., 2011. Phylogenetic relationships and evolutionary history of the Paleogene genus Igorina through parsimony analysis: Journal of Foraminiferal Research, v. 41, p. 260-284

Planktonic foraminiferal bioevents and evolutionary trends across the late Paleocene Globanomalina pseudomenardii Zone in the tropical-subtropical Pacific record (ODP Leg 143 and 198)

Phylogenetic relationships and evolutionary history of the Early Paleogene genus Igorina through parsimony analysis

The planktonic foraminiferal Contusotruncana plummerae Zone and additional bioevents improving the Santonian-Campanian biozonation

The new mid Campanian Contusotruncana plummerae Zone, recently defined as the stratigraphic inter... more The new mid Campanian Contusotruncana plummerae Zone, recently defined as the stratigraphic interval between the lowest occurrence of the nominate species and the lowest occurrence of Radotruncana calcarata (Petrizzo et al., 2011) is here discussed. This zone replaces the Globotruncana ventricosa Zone, which cannot be reliably applied, because of the uncertain identification and diachronous appearance across latitudes of its nominate marker species. This study is based on the detailed biostratigraphic analyses of the Santonian\u2013Campanian time interval recovered at the following deep-sea drilling sites (a) Shatsky Rise (ODP Leg 198, Hole 1210B), (b) Exmouth Plateau (ODP Leg 122, Hole 762C), (c) Caribbean Sea (DSDP Leg 15, Site 146), and of four boreholes drilled by the Tanzania Drilling Project (TDP) in southeastern Tanzania (TDP23, TDP28, TDP32 and TDP35). Results have been compared to the sequence of planktonic foraminiferal bioevents falling in the coeval stratigraphic interval at the Bottaccione section, that represents the standard for the Tethyan Realm. A high-resolution biostratigraphy of this section was provided by Premoli Silva and Sliter (1995), but their study was based on thin section analysis only. In this study, planktonic foraminiferal bioevents have been revised thanks to the recent availability of washed residues that allow more reliable species identification. Validity of identified bioevents have been integrated with calcareous nannofossil and magnetostratigraphic data when available in literature and their reliability for correlations at regional and global scale has been tested through depth vs. depth plots. Age-depth curves have been tentatively created for the Bottaccione section and for the Exmouth Plateau to obtain a reliable estimate of the relative timing of species first and last occurrence data. This study also provides evidence that the lowest occurrence of Globotruncanita atlantica and other secondary planktonic foraminiferal bioevents are very promising to further improve the Santonian\u2013Campanian biostratigraphic resolution across mid and low latitudes

A morphometric methodology to assess planktonic foraminiferal response to environmental perturbations: the case study of Oceanic Anoxic Event 2, Late Cretaceous

Dwarfism of planktonic foraminiferal specimens is recognised across several intervals subject to ... more Dwarfism of planktonic foraminiferal specimens is recognised across several intervals subject to globally extended environmental disturbances such as the Cretaceous/Palaeogene boundary and the latest Cenomanian-earliest Turonian Oceanic Anoxic Event 2 (OAE 2) in the Late Cretaceous. However, the occurrence of dwarfed specimens is generally based on the observation of a decrease in the size of specimens at the stereomicroscope without acquiring morphometric data. This approach prevents from assessing the inter-sample morphometric variation of species, reconstructing species-specific trends, and comparing data from different localities to extrapolate global from local signals. We present herein a first step toward the development of a morphometry-based methodology to assess planktonic foraminiferal response to past environmental perturbations. To perform this study, we selected OAE 2 as a target event and we focused on two species, Rotalipora cushmani (Morrow, 1934) and Whiteinella brittonensis (Loeblich & Tappan, 1961), commonly occurring in the assemblages and likely having different palaeoecological preferences. Specimens analysed are from Eastbourne (England), Clot Chevalier (SE France), and Tarfaya (core S57, Morocco). For both species, we measured selected shell parameters (i.e., the number of chambers in the last whorl, the maximum diameter and the height of the test). Our study suggests that the maximum diameter across the first chamber of the inner whorl visible in spiral view is the simplest and most objective methodology to estimate shell size variation in trochospiral planktonic foraminifera, and that this morphometric parameter is likely the most sensitive to the Cenomanian-Turonian environmental disturbances, and thus its variability through time appears worth investigating across other key-stratigraphic intervals. Moreover, this study indicates that the acquisition of morphometric data is required to accurately reconstruct planktonic foraminiferal response to environmental perturbations, because specimen dimensions show high inter-sample variability and based on the data collected in this study they do not experience the predicted size reduction. RIASSUNTO-[Un metodo morfometrico per stabilire la risposta dei foraminiferi planctonici alle perturbazioni ambientali: il caso di studio dell'Evento Anossico Oceanico 2, Cretacico Superiore]-Il nanismo nei foraminiferi planctonici è stato riconosciuto in molti intervalli stratigrafici caratterizzati da importanti perturbazioni ambientali a scala globale come l'estinzione di massa al limite Cretacico/Paleogene e l'Evento Anossico Oceanico 2 (OAE 2) nel Cenomaniano superiore-Turoniano inferiore (Cretacico Superiore). Negli studi precedenti, tuttavia, la presenza di esemplari nani è stata identificata solo sulla base di osservazioni allo stereomicroscopio senza ricorrere all'acquisizione di dati morfometrici. Questo approccio impedisce di quantificare le variazioni morfometriche delle singole specie in campioni diversi in una successione stratigrafica ed il confronto delle variazioni morfometriche acquisite in località diverse per estrapolare eventuali variazioni sincrone a scala regionale e/o globale. In questo studio viene presentata una metodologia basata sull'analisi morfometrica per valutare la risposta dei foraminiferi planctonici alle perturbazioni ambientali nel passato geologico. A questo scopo è stato selezionato come caso di studio l'OAE 2, poiché non sono mai state acquisite analisi morfometriche sui foraminiferi planctonici in questo intervallo. Le analisi sono state svolte su due specie, Rotalipora cushmani (Morrow, 1934) e Whiteinella brittonensis (Loeblich & Tappan, 1961), selezionate poiché sono relativamente comuni nelle associazioni ed erano probabilmente adattate ad habitat diversi. I campioni studiati provengono da tre località chiave con un record stratigrafico continuo a cavallo dell'evento anossico: Eastbourne (Inghilterra), Clot Chevalier (SE della Francia) e Tarfaya (carota S57, Marocco). Per entrambe le specie sono state contate e misurate alcune caratteristiche del guscio (ovvero il numero di camere nell'ultimo giro, il diametro massimo del guscio e l'altezza della trocospira), che in base alle informazioni derivanti dalla biologia dei foraminiferi planctonici viventi potrebbero essere state soggette a variazioni in condizioni ambientali di stress. I risultati di questo studio suggeriscono che: 1) la misura del diametro massimo che attraversa la prima camera in vista spirale è il metodo più semplice ed oggettivo per stimare le variazioni di dimensione dei foraminiferi planctonici con avvolgimento trocospirale, 2) le sue variazioni sono probabilmente legate alla variazione dei parametri ambientali, 3) la ricostruzione della sua variabilità a cavallo di altri intervalli stratigrafici chiave potrebbe essere molto utile per ricostruire la risposta dei foraminiferi planctonici alle perturbazioni ambientali. Inoltre, sulla base dei dati raccolti in questo studio, non si riscontra alcuna riduzione nella dimensione delle specie di foraminiferi planctonici associabile alle perturbazioni legate all'OAE 2.

Remarks on the identification of the Albian/Cenomanian boundary and taxonomic clarification of the planktonic foraminifera index species<i>globotruncanoides, brotzeni</i>and<i>tehamaensis</i>

Geological Magazine, Oct 3, 2014

The planktonic foraminifera assemblage across the Global Boundary Stratotype Section and Point (G... more The planktonic foraminifera assemblage across the Global Boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage defined at Mont Risou (Haute-Alpes in France) is here restudied to clarify the identification and stratigraphic distribution of Thalmanninella globotruncanoides (= Rotalipora globotruncanoides Sigal, 1948) and Pseudothalmanninella tehamaensis (= Rotalipora tehamaensis Marianos & Zingula, 1966) whose appearance levels are primary and secondary criteria for placing the Albian/Cenomanian boundary. Since the ratification of the GSSP in 2002, the identification of the foraminifera index species across the Albian/Cenomanian boundary has been reported to be sometimes difficult either because of their rarity or uncertainty in the taxonomic identifications. We discuss the taxonomic status of Thalmanninella brotzeni Sigal 1948, a species regarded for a long time to be a junior synonym of Th. globotruncanoides, through images of Sigal's type materials deposited at the Musée National d'Histoire Naturelle (Paris), and elucidate the taxonomically important characters that enable unequivocal identification of Th. brotzeni, Th. globotruncanoides and Ps. tehamaensis. Planktonic foraminifera marker species from Mont Risou are compared with well-preserved specimens from Blake Nose Plateau (ODP 171B, North Western Atlantic Ocean) to verify the reliability and stratigraphic distribution of these marker taxa outside the Mediterranean Tethyan area.

Planktonic foraminifera document palaeoceanographic changes across the middle Cenomanian carbon-isotope excursion MCE 1: new evidence from the UK chalk

Geological Magazine

Planktonic foraminifera were studied at Lydden Spout, near Folkestone (southeast England, UK), th... more Planktonic foraminifera were studied at Lydden Spout, near Folkestone (southeast England, UK), the reference section of the middle Cenomanian Event 1 (MCE 1) characterized by a prominent double-peak δ13C excursion of 1 ‰ identified in different ocean basins and considered a global event. Biostratigraphic and quantitative analysis of planktonic foraminifera are correlated to the δ13C perturbation, to the positive δ18O shifts identified within MCE 1 and to the occurrence of Boreal macrofossils (the bivalves Chlamys arlesiensis and Oxytoma seminudum, and the belemnite Praectinocamax primus). Variations in abundance and species richness of planktonic foraminifera and the inferred palaeoecological preferences of taxa permit the identification of distinct palaeoenvironmental settings across MCE 1. The stratigraphic interval corresponding to MCE 1 is characterized by the absence of oligotrophic rotaliporids, and by the evolutionary appearance of meso-eutrophic dicarinellids and of Muricohe...

Biotic and Paleoceanographic Changes Across the Late Cretaceous Oceanic Anoxic Event 2 in the Southern High Latitudes (IODP Sites U1513 and U1516, SE Indian Ocean)

Paleoceanography and Paleoclimatology

Oceanic Anoxic Event 2, spanning the Cenomanian/Turonian boundary (93.9 Ma), was an episode of ma... more Oceanic Anoxic Event 2, spanning the Cenomanian/Turonian boundary (93.9 Ma), was an episode of major perturbations in the global carbon cycle. To investigate the response of biota and the paleoceanographic conditions across this event, we present data from International Ocean Discovery Program sites U1513 and U1516 in the Mentelle Basin (offshore SW Australia; paleolatitude 59°–60°S in the mid‐Cretaceous) that register the first complete records of OAE 2 at southern high latitudes. Calcareous nannofossils provide a reliable bio‐chronostratigraphic framework. The distribution and abundance patterns of planktonic and benthic foraminifera, radiolaria, and calcispheres permit interpretation of the dynamics of the water mass stratification and provide support for the paleobathymetric reconstruction of the two sites, with Site U1513 located northwest of the Mentelle Basin depocenter and at a deeper depth than Site U1516. The lower OAE 2 interval is characterized by reduced water mass stra...

Tectonic, paleoclimate, and paleoceanographic history of high-latitude southern margins of Australia during the Cretaceous

The tectonic and paleoceanographic setting of the Great Australian Bight (GAB) and the Mentelle B... more The tectonic and paleoceanographic setting of the Great Australian Bight (GAB) and the Mentelle Basin (MB; adjacent to Naturaliste Plateau) offered an outstanding opportunity to investigate Cretaceous and Cenozoic climate change and ocean dynamics during the last phase of breakup among remnant Gondwana continents. Sediment recovered from sites in both regions during International Ocean Discovery Program Expedition 369 will provide a new perspective on Earth’s temperature variation at sub-polar latitudes (60°–62°S) across the extremes of the mid-Cretaceous hot greenhouse climate and the cooling that followed.

Dissolution control on planktonic foraminiferal micro-scale distributions: two case studies from the NW Pacific Paleocene deposits

Anuário do Instituto de Geociências, 2006

Late Cretaceous stratigraphy and paleoceanographic evolution in the Great Australian Bight Basin based on results from IODP Site U1512

Gondwana Research, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Stratigraphy of the Albian−Cenomanian boundary interval in the Agadir Basin, Morocco: ammonites, microcrinoids, planktonic foraminifera

Acta Geologica Polonica, Jul 26, 2023

The uppermost Albian and lowermost Cenomanian succession at Abouda Plage, north of Agadir, in the... more The uppermost Albian and lowermost Cenomanian succession at Abouda Plage, north of Agadir, in the Agadir Basin, western Morocco, is described in detail, and ammonites, microcrinoids and planktonic foraminifera are recorded and illustrated. The lower part of the Aït Lamine Formation yields ammonites indicative of the Pervinquieria (Subschloenbachia) rostrata and P. (S.) perinflata ammonite zones, and the Thalmanninella appenninica planktonic foraminiferan Zone. The base of the Cenomanian is identified at 42.2 m above the base of the Aït Lamine Formation, based on the lowest occurrence of the planktonic foraminiferan Thalmanninella globotruncanoides Sigal, 1948. Lower Cenomanian ammonites of the Graysonites adkinsi Zone enter 3 m higher in the succession. Microcrinoid zones AlR11 and AlR12 are identified in the Upper Albian, and the base of the CeR1 Zone coincides with the lowest occurrence of Cenomanian ammonites. The ammonite and microcrinoid occurrences and detailed distributions are very similar to those found in north central Texas, which, in the Cenomanian, was 5,300 km to the west. The new records suggest that the G. adkinsi Zone is equivalent to the uppermost (Lower Cenomanian) part of the Pleurohoplites briacensis Zone of the Global Stratotype Section for the base of the Cenomanian stage. An hiatus, of global extent, immediately underlies the base of the G. adkinsi Zone and is represented in the Agadir Basin by an erosion surface containing bored and encrusted hiatus concretions.

Calcareous Plankton Biostratigraphy of the Santonian-Campanian Boundary Interval in the Bottaccione Section (Umbria-Marche Basin, Central Italy)

Rivista Italiana Di Paleontologia E Stratigrafia, Oct 6, 2020

The Bottaccione section (Umbria-Marche Basin, central italy) was analyzed for calcareous nannofos... more The Bottaccione section (Umbria-Marche Basin, central italy) was analyzed for calcareous nannofossil and planktonic foraminiferal biostratigraphy across the Santonian-Campanian boundary interval to achieve a high-resolution and updated zonation directly calibrated with magnetostratigraphy. Several calcareous plankton events were detected, including zonal markers and additional potential biohorizons. The base of magnetochron C33r, proposed for placement of the base of the Campanian, lies between the first occurrence of Aspidolithus parcus parcus and the last occurrence of Dicarinella asymetrica in the Bottaccione section. The literature survey indicates that these events were found in the Santonian-Campanian boundary interval at supraregional scale and, may be used to confidently approximate the base of the Campanian.

Evidence for changes in sea-surface circulation patterns and ~20° equatorward expansion of the Boreal bioprovince during a cold snap of Oceanic Anoxic Event 2 (Late Cretaceous)

Global and Planetary Change, 2022

Abstract The Plenus Cold Event (PCE) temporarily interrupted the supergreenhouse conditions exace... more Abstract The Plenus Cold Event (PCE) temporarily interrupted the supergreenhouse conditions exacerbated during much of the Cenomanian–Turonian Oceanic Anoxic Event 2 (OAE 2). The PCE is coeval to the occurrence of Boreal benthic macroinvertebrates and of the nektonic belemnite Praeactinocamax plenus (after which the event is named) in Europe, and to the re-oxygenation of bottom waters in the Northern Hemisphere. However, its effects on the sea-surface circulation are unknown and evidence for changes in the biogeography of planktonic organisms are limited to the equatorward migration of the dinoflagellate cysts grouped in the Cyclonephelium compactum–membraniphorum morphological plexus. This study presents new planktonic foraminiferal quantitative data from two complete OAE 2 records of the Anglo-Paris (Eastbourne, SE England) and Vocontian (Clot Chevalier, SE France) basins that registered the equatorward pulse of Boreal macroinvertebrates during the PCE and have been extensively studied for bio- and chemostratigraphy. At the onset of OAE 2 (before the PCE), planktonic foraminifera are mainly represented by oligo-mesotrophic Tethyan taxa (rotaliporids and whiteinellids) in both localities, but this assemblage is sharply replaced by cold and meso-to-eutrophic species (praeglobotruncanids, dicarinellids and muricohedbergellids) during the PCE. The cold-water assemblage shows strong affinities with the coeval fauna of the Norwegian Sea and yields the Boreal endemic species Muricohedbergella kyphoma and Praeglobotruncana plenusiensis. This observation combined with previously published data collected in other localities of the Northern Hemisphere and on other fossil groups suggest a ~20° equatorward expansion of the Boreal marine bioprovince during the PCE. Moreover, contrarily to the nektonic belemnitellids that were able to move independently of ocean circulation, planktonic organisms are passively transported by currents and changes in the planktonic foraminiferal assemblages documented in the Anglo-Paris and Vocontian basins have been interpreted to reflect the transition from a dominant influence of warm, saline, and thermally stratified waters carried by the proto-Gulf Stream before the PCE to cold and low-saline Boreal waters originated in the Norwegian Sea during the PCE. We suggest that such changes were forced by the equatorward shift of the proto-Arctic Front (i.e., the boundary between warm saline Tethyan-Atlantic and cold low-saline Boreal waters) from offshore Norway to Southern England. In this southerly position, the proto-Arctic Front represented an oceanographic barrier that limited the influence of the proto-Gulf Stream in the Anglo-Paris Basin, and favored the inflow of Boreal waters in the European epicontinental basins. The sea-surface cooling and equatorward expansion of Boreal planktonic assemblages during the PCE are of the same order of magnitude of those reconstructed between some glacial and interglacial intervals of the Plio-Pleistocene. Despite obvious differences between Cretaceous and Plio-Pleistocene paleogeography and climate dynamics, this study reviews the extent of environmental changes occurred during the PCE, provides evidence for a profound re-organization of the sea-surface circulation patterns and a more comprehensive overview of the equatorward migration of Boreal marine communities in the Northern Hemisphere.

Planktonic foraminiferal biostratigraphy and assemblage composition across the Cenomanian–Turonian boundary interval at Clot Chevalier (Vocontian Basin, SE France)

Cretaceous Research, Apr 1, 2016

The CenomanianeTuronian boundary interval is generally considered a critical time for planktonic ... more The CenomanianeTuronian boundary interval is generally considered a critical time for planktonic foraminifera due to the environmental perturbations associated with Oceanic Anoxic Event 2. However, only the rotaliporids became extinct at the onset of the event, whilst several lineages evolved and/or diversified. This remarkable morphologic plasticity is often overlooked in the literature, partly because a number of stratigraphic sections have only been studied in thin-section due to the degree of lithification of the samples. Improved documentation of the morphological variability of planktonic foraminifera and better defined species concepts are required in order to improve biostratigraphy, particularly as Helvetoglobotruncana helvetica is an unreliable marker for the base of the Turonian. At the same time, detailed study of the planktonic foraminiferal response to OAE 2 demands a more profound knowledge of the assemblage composition. We present new biostratigraphic, taxonomic, and quantitative data for planktonic foraminiferal species from the Clot Chevalier section (Vocontian Basin, SE France), with the aim of (1) providing a detailed biostratigraphic analysis of the section, (2) documenting the morphological plasticity of specimens in this time interval and stabilizing species concepts, and (3) identifying promising markers to improve the resolution of the present biozonation and allow regional correlation. Samples were processed with acetic acid to extract isolated planktonic foraminifera. Assemblages were assigned to the upper Cenomanian Rotalipora cushmani Zone and to the uppermost Cenomanianelowermost Turonian Whiteinella archaeocretacea Zone. Planktonic foraminiferal bioevents and assemblage composition identified at Clot Chevalier are compared with the well-studied Pont d'Issole section located ca. 15 km to the NE, highlighting similarities and differences in the species occurrences that may complicate the stratigraphic correlation between the two sections. The results of our study support the validity and common occurrence of species that have been misidentified and/or overlooked in the literature (i.e., Dicarinella roddai, Praeglobotruncana oraviensis, Marginotruncana caronae) and indicate that primitive marginotruncanids evolved before the onset of OAE 2, although species diversification occurred only after the event. Moreover, we believe that the first appearance of P. oraviensis might represent a promising bioevent for approximating the Cenomanian/ Turonian boundary, after calibration with bio- and chemostratigraphically well-constrained sections. Finally, we describe three new trochospiral species, named \u201cPseudoclavihedbergella\u201d chevaliensis, Praeglobotruncana pseudoalgeriana and Praeglobotruncana clotensis

Pforams@microtax: A new online taxonomic database for planktonic foraminifera

Micropaleontology, 2017

A new relational taxonomic database for planktonic foraminifera (Pforams@microtax) has been const... more A new relational taxonomic database for planktonic foraminifera (Pforams@microtax) has been constructed and is now freely available online at http://www.mikrotax.org. It represents amajor advance from its predecessor, the CHRONOS online taxonomic database, which has served the research community since 2005. The benefits of the new database to the research and industrial biostratigraphic communities are many, as it will serve as an immediately accessible taxonomic guide and reference for specialists and non-specialists alike by providing access to a wealth of information and images from original authors and from expertswho have inserted recent authoritative updates to planktonic foraminiferal taxonomy, phylogeny and biostratigraphy. The database will be continually updated and used as a guide for training current and future generations of students and professionals who will be able to self-educate on planktonic foraminiferal taxonomy and biostratigraphy. Further investigation of species traditionally included in the Cretaceous genera Heterohelix, Globigerinelloides, Marginotruncana, and Globotruncana is required to exclude the use of polyphyletic morphotaxa. The taxonomy for Paleogene planktonic foraminifera is quite stable following publication of the Paleocene, Eocene, and Oligocene taxonomic atlases, but revisions to the taxonomy and phylogeny of Neogene taxa are needed to incorporate results from genetic sequencing studies and recent biostratigraphic observations.

Taxonomy and phylogeny of Albian-Maastrichtian planispiral planktonic foraminifera traditionally assigned to Globigerinelloides

Micropaleontology, 2022

We propose a considerably revised taxonomy and phylogeny for Albian-Maastrichtian planispiral pla... more We propose a considerably revised taxonomy and phylogeny for Albian-Maastrichtian planispiral planktonic foraminiferal species that have traditionally been included in Globigerinelloides. The revised taxonomy is necessary because of a ~6 m.y. gap between the extinction of planispiral species during the late Aptian and the next younger occurrence of planispiral species in the middle Albian. Our stratophenetic taxonomic groupings utilize ontogenetic morphometric data, shell wall ultrastructure, and general morphologic features observed from Scanning Electron Microscope and X-radiograph images of primary type specimens and globally distributed hypotype specimens. The planispiral lineage Laeviella n. gen., whose type species is La. bentonensis (Morrow), first appeared in the middle Albian and is postulated to have evolved from the evolutionary series Ticinella primula Luterbacher-Laviella primuloides n. sp. Laeviella is characterized as having a smooth to finely pustulose wall texture and a moderate chamber size increase rate. Two additional species, La. tururensis (Bronnimann) and La. bollii (Pessagno), are included in Laeviella with the youngest species of the genus, La. bollii, becoming extinct during the late Campanian. Planohedbergella, with Plh. aspera (Ehrenberg) as its type species, is revised to include 10 species that show a wide variation in chamber arrangement, wall microstructure and test morphology, but all have a moderately to coarsely pustulose wall texture on some or most final whorl chambers. Its stratigraphic range is from the late Albian-Cretaceous/Paleogene boundary. The oldest species is Plh. ultramicra (Subbotina), which evolved from Planomalina pulchella Todd and Low during the late Albian. Planohedbergella circularis n. sp. is described as a new late Campanian-Maastrichtian species representing forms with evolute coiling, a large number of final whorl chambers, and a slow chamber size increase rate. Polycamerella n. gen. is described as a monospecific genus, with Po. tardata n. sp. as the type species. It is a small, biapertural form with a very slow chamber expansion rate and a stratigraphic range from the late Campanian-Maastrichtian. The ancestor of Po. tardata, is tentatively identified as Plh. ultramicra.

Patterns of planktonic foraminiferal extinctions and eclipses during Oceanic Anoxic Event 2 at Eastbourne (SE England) and other mid-low latitude locations

Cretaceous Research, Dec 1, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Phylogenetic relationships and evolutionary history of the Early Paleogene genus Igorina (planktonic foraminifera) through parsimony analysis

Background: The evolutionary history of biodiversity in South America has been poorly studied in ... more Background: The evolutionary history of biodiversity in South America has been poorly studied in the seasonal dry tropical forest (SDTF). Species diversification in this ecosystem may have a twofold explanation. First, intermittent connections in the middle and late Pleistocene promoted species dispersal and/or genetic connectivity between lineages isolated in disjunct patches of forest. Second, allopatric speciation proceeded immediately after the formation and colonization of the SDTF in the Neogene. Here we studied the diversification of Psammolestes, a genus endemic of the SDTF and naturally infected with Trypanosoma cruzi (agent of Chagas disease), using a combination of phylogenetic, population genetics and niche model methods, and evaluated the reliability of the three morphospecies currently recognized. Results: Our multilocus analyses recovered P. coreodes and P. tertius in a monophyletic clade sister to P. arthuri. Species delimitation tests recovered these lineages as different species despite the shared genetic variation observed between P. coreodes and P. tertius in five genes. Also, genetic variation of the genus clustered in three groups that were consistent with the three morphospecies. Our demographic model predicted a scenario of divergence in absence of gene flow, suggesting that mixed haplotypes may be the result of shared ancestral variation since the divergence of the subtropical-temperate species P. coreodes and P. tertius. In contrast, the tropical species P. arthuri was highly differentiated from the other two in all tests of genetic structure, and consistently, the Monmonier's algorithm identified a clear geographical barrier that separates this species from P. coreodes and P. tertius. Conclusions: We found three genetically structured lineages within Psammolestes that diverged in absence of gene flow in the late Miocene. This result supports a scenario of species formation driven by geographical isolation rather than by divergence in the face of gene flow associated with climatic oscillations in the Pleistocene. Also, we identified the Amazon basin as a climatic barrier that separates tropical from subtropical-temperate species, thus promoting

Remarks on Globotruncana insignis types: how the reconstruction of the phyletic lineare can solve taxonomic debates

On the phylogeny of Paleogene planktonic foraminifera: wall texture structure and a new genus name for the broedermanni lineage

The broedermanni lineage has been traditionally placed in the genus Igorina (see Berggren and oth... more The broedermanni lineage has been traditionally placed in the genus Igorina (see Berggren and others, 2006) being characterized by possessing a biconvex globorotaliid morphology, subglobular to subquadrate chambers, and by having a nonspinose wall texture with thin muricae on the test surface. Our analysis of specimens from the Pacific Ocean (ODP Leg 198, Shatsky Rise and ODP Leg 143, Alllison Guyot) suggest that the broedermanni group is phylogenetically related to Acarinina as the calcite structures of the wall are similar to the muricae rather than to the short pustules of the Paleocene igorinids (i. e., I. pusilla, I. albeari). In particular, the oldest species lodoensis shows a typical coarse muricate test similar to Acarinina while in its descendants, broedermanni and anapetes, the muricae are finer on the spiral side, and heavier muricae are developed only around the umbilicus. Moreover, in the broedermanni group the shell is not encrusted as in Igorina because the pustules remained isolated and increased in size to become thick muricae. The analysis of the pore structure in cross section seems to confirm the similarities and affinities between the wall texture of the broedermanni group and Acarinina. Both show an hourglass shape of the pores that become narrow in the outer calcite layer whereas in Igorina species the pores are tight in the inner calcite layer. In addition, the results from parsimony analysis (Soldan and other, 2011) confirm that the broedermanni group evolved in the late Paleocene/early Eocene from the group of round acarininids (A. mckannai and A. soldadoensis). The new genus Pearsonites (named in honor of Professor Paul N. Pearson) with Pearsonites broedermanni as type species, is here proposed to accommodate the early-middle Eocene globorotaliid taxa of the broedermanni lineage with a wall texture bearing muricae. Three species previously considered morphologically and evolutionary related to the Paleocene genus Igorina are here included in Pearsonites nov. gen., P. lodoensis, P. broedermanni, and P. anapetes. Species assigned to Pearsonites nov. gen. are relatively common in the stratigraphic interval from the upper Paleocene (Zone P5) to the middle Eocene (Zone E9). References Berggren W.A., Pearson P.N., Huber B.T., Wade B.S., 2006. Chapter 19: Taxonomy, biostratigraphy and phylogenetic affinities of Eocene Acarinina, in Pearson P. N., Olsson R.K, Huber B.T., Hemleben C., Berggren W.A (eds), Atlas of Eocene Planktonic Foraminifera: Cushman Foundation Special Pubblication, v. 41, p. 257-326. Soldan D.M., Petrizzo M.R., Premoli Silva I., Cau A., 2011. Phylogenetic relationships and evolutionary history of the Paleogene genus Igorina through parsimony analysis: Journal of Foraminiferal Research, v. 41, p. 260-284

Planktonic foraminiferal bioevents and evolutionary trends across the late Paleocene Globanomalina pseudomenardii Zone in the tropical-subtropical Pacific record (ODP Leg 143 and 198)

Phylogenetic relationships and evolutionary history of the Early Paleogene genus Igorina through parsimony analysis

The planktonic foraminiferal Contusotruncana plummerae Zone and additional bioevents improving the Santonian-Campanian biozonation

The new mid Campanian Contusotruncana plummerae Zone, recently defined as the stratigraphic inter... more The new mid Campanian Contusotruncana plummerae Zone, recently defined as the stratigraphic interval between the lowest occurrence of the nominate species and the lowest occurrence of Radotruncana calcarata (Petrizzo et al., 2011) is here discussed. This zone replaces the Globotruncana ventricosa Zone, which cannot be reliably applied, because of the uncertain identification and diachronous appearance across latitudes of its nominate marker species. This study is based on the detailed biostratigraphic analyses of the Santonian\u2013Campanian time interval recovered at the following deep-sea drilling sites (a) Shatsky Rise (ODP Leg 198, Hole 1210B), (b) Exmouth Plateau (ODP Leg 122, Hole 762C), (c) Caribbean Sea (DSDP Leg 15, Site 146), and of four boreholes drilled by the Tanzania Drilling Project (TDP) in southeastern Tanzania (TDP23, TDP28, TDP32 and TDP35). Results have been compared to the sequence of planktonic foraminiferal bioevents falling in the coeval stratigraphic interval at the Bottaccione section, that represents the standard for the Tethyan Realm. A high-resolution biostratigraphy of this section was provided by Premoli Silva and Sliter (1995), but their study was based on thin section analysis only. In this study, planktonic foraminiferal bioevents have been revised thanks to the recent availability of washed residues that allow more reliable species identification. Validity of identified bioevents have been integrated with calcareous nannofossil and magnetostratigraphic data when available in literature and their reliability for correlations at regional and global scale has been tested through depth vs. depth plots. Age-depth curves have been tentatively created for the Bottaccione section and for the Exmouth Plateau to obtain a reliable estimate of the relative timing of species first and last occurrence data. This study also provides evidence that the lowest occurrence of Globotruncanita atlantica and other secondary planktonic foraminiferal bioevents are very promising to further improve the Santonian\u2013Campanian biostratigraphic resolution across mid and low latitudes

A morphometric methodology to assess planktonic foraminiferal response to environmental perturbations: the case study of Oceanic Anoxic Event 2, Late Cretaceous

Dwarfism of planktonic foraminiferal specimens is recognised across several intervals subject to ... more Dwarfism of planktonic foraminiferal specimens is recognised across several intervals subject to globally extended environmental disturbances such as the Cretaceous/Palaeogene boundary and the latest Cenomanian-earliest Turonian Oceanic Anoxic Event 2 (OAE 2) in the Late Cretaceous. However, the occurrence of dwarfed specimens is generally based on the observation of a decrease in the size of specimens at the stereomicroscope without acquiring morphometric data. This approach prevents from assessing the inter-sample morphometric variation of species, reconstructing species-specific trends, and comparing data from different localities to extrapolate global from local signals. We present herein a first step toward the development of a morphometry-based methodology to assess planktonic foraminiferal response to past environmental perturbations. To perform this study, we selected OAE 2 as a target event and we focused on two species, Rotalipora cushmani (Morrow, 1934) and Whiteinella brittonensis (Loeblich & Tappan, 1961), commonly occurring in the assemblages and likely having different palaeoecological preferences. Specimens analysed are from Eastbourne (England), Clot Chevalier (SE France), and Tarfaya (core S57, Morocco). For both species, we measured selected shell parameters (i.e., the number of chambers in the last whorl, the maximum diameter and the height of the test). Our study suggests that the maximum diameter across the first chamber of the inner whorl visible in spiral view is the simplest and most objective methodology to estimate shell size variation in trochospiral planktonic foraminifera, and that this morphometric parameter is likely the most sensitive to the Cenomanian-Turonian environmental disturbances, and thus its variability through time appears worth investigating across other key-stratigraphic intervals. Moreover, this study indicates that the acquisition of morphometric data is required to accurately reconstruct planktonic foraminiferal response to environmental perturbations, because specimen dimensions show high inter-sample variability and based on the data collected in this study they do not experience the predicted size reduction. RIASSUNTO-[Un metodo morfometrico per stabilire la risposta dei foraminiferi planctonici alle perturbazioni ambientali: il caso di studio dell'Evento Anossico Oceanico 2, Cretacico Superiore]-Il nanismo nei foraminiferi planctonici è stato riconosciuto in molti intervalli stratigrafici caratterizzati da importanti perturbazioni ambientali a scala globale come l'estinzione di massa al limite Cretacico/Paleogene e l'Evento Anossico Oceanico 2 (OAE 2) nel Cenomaniano superiore-Turoniano inferiore (Cretacico Superiore). Negli studi precedenti, tuttavia, la presenza di esemplari nani è stata identificata solo sulla base di osservazioni allo stereomicroscopio senza ricorrere all'acquisizione di dati morfometrici. Questo approccio impedisce di quantificare le variazioni morfometriche delle singole specie in campioni diversi in una successione stratigrafica ed il confronto delle variazioni morfometriche acquisite in località diverse per estrapolare eventuali variazioni sincrone a scala regionale e/o globale. In questo studio viene presentata una metodologia basata sull'analisi morfometrica per valutare la risposta dei foraminiferi planctonici alle perturbazioni ambientali nel passato geologico. A questo scopo è stato selezionato come caso di studio l'OAE 2, poiché non sono mai state acquisite analisi morfometriche sui foraminiferi planctonici in questo intervallo. Le analisi sono state svolte su due specie, Rotalipora cushmani (Morrow, 1934) e Whiteinella brittonensis (Loeblich & Tappan, 1961), selezionate poiché sono relativamente comuni nelle associazioni ed erano probabilmente adattate ad habitat diversi. I campioni studiati provengono da tre località chiave con un record stratigrafico continuo a cavallo dell'evento anossico: Eastbourne (Inghilterra), Clot Chevalier (SE della Francia) e Tarfaya (carota S57, Marocco). Per entrambe le specie sono state contate e misurate alcune caratteristiche del guscio (ovvero il numero di camere nell'ultimo giro, il diametro massimo del guscio e l'altezza della trocospira), che in base alle informazioni derivanti dalla biologia dei foraminiferi planctonici viventi potrebbero essere state soggette a variazioni in condizioni ambientali di stress. I risultati di questo studio suggeriscono che: 1) la misura del diametro massimo che attraversa la prima camera in vista spirale è il metodo più semplice ed oggettivo per stimare le variazioni di dimensione dei foraminiferi planctonici con avvolgimento trocospirale, 2) le sue variazioni sono probabilmente legate alla variazione dei parametri ambientali, 3) la ricostruzione della sua variabilità a cavallo di altri intervalli stratigrafici chiave potrebbe essere molto utile per ricostruire la risposta dei foraminiferi planctonici alle perturbazioni ambientali. Inoltre, sulla base dei dati raccolti in questo studio, non si riscontra alcuna riduzione nella dimensione delle specie di foraminiferi planctonici associabile alle perturbazioni legate all'OAE 2.

Remarks on the identification of the Albian/Cenomanian boundary and taxonomic clarification of the planktonic foraminifera index species<i>globotruncanoides, brotzeni</i>and<i>tehamaensis</i>

Geological Magazine, Oct 3, 2014

The planktonic foraminifera assemblage across the Global Boundary Stratotype Section and Point (G... more The planktonic foraminifera assemblage across the Global Boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage defined at Mont Risou (Haute-Alpes in France) is here restudied to clarify the identification and stratigraphic distribution of Thalmanninella globotruncanoides (= Rotalipora globotruncanoides Sigal, 1948) and Pseudothalmanninella tehamaensis (= Rotalipora tehamaensis Marianos & Zingula, 1966) whose appearance levels are primary and secondary criteria for placing the Albian/Cenomanian boundary. Since the ratification of the GSSP in 2002, the identification of the foraminifera index species across the Albian/Cenomanian boundary has been reported to be sometimes difficult either because of their rarity or uncertainty in the taxonomic identifications. We discuss the taxonomic status of Thalmanninella brotzeni Sigal 1948, a species regarded for a long time to be a junior synonym of Th. globotruncanoides, through images of Sigal's type materials deposited at the Musée National d'Histoire Naturelle (Paris), and elucidate the taxonomically important characters that enable unequivocal identification of Th. brotzeni, Th. globotruncanoides and Ps. tehamaensis. Planktonic foraminifera marker species from Mont Risou are compared with well-preserved specimens from Blake Nose Plateau (ODP 171B, North Western Atlantic Ocean) to verify the reliability and stratigraphic distribution of these marker taxa outside the Mediterranean Tethyan area.

Planktonic foraminifera document palaeoceanographic changes across the middle Cenomanian carbon-isotope excursion MCE 1: new evidence from the UK chalk

Geological Magazine

Planktonic foraminifera were studied at Lydden Spout, near Folkestone (southeast England, UK), th... more Planktonic foraminifera were studied at Lydden Spout, near Folkestone (southeast England, UK), the reference section of the middle Cenomanian Event 1 (MCE 1) characterized by a prominent double-peak δ13C excursion of 1 ‰ identified in different ocean basins and considered a global event. Biostratigraphic and quantitative analysis of planktonic foraminifera are correlated to the δ13C perturbation, to the positive δ18O shifts identified within MCE 1 and to the occurrence of Boreal macrofossils (the bivalves Chlamys arlesiensis and Oxytoma seminudum, and the belemnite Praectinocamax primus). Variations in abundance and species richness of planktonic foraminifera and the inferred palaeoecological preferences of taxa permit the identification of distinct palaeoenvironmental settings across MCE 1. The stratigraphic interval corresponding to MCE 1 is characterized by the absence of oligotrophic rotaliporids, and by the evolutionary appearance of meso-eutrophic dicarinellids and of Muricohe...

Biotic and Paleoceanographic Changes Across the Late Cretaceous Oceanic Anoxic Event 2 in the Southern High Latitudes (IODP Sites U1513 and U1516, SE Indian Ocean)

Paleoceanography and Paleoclimatology

Oceanic Anoxic Event 2, spanning the Cenomanian/Turonian boundary (93.9 Ma), was an episode of ma... more Oceanic Anoxic Event 2, spanning the Cenomanian/Turonian boundary (93.9 Ma), was an episode of major perturbations in the global carbon cycle. To investigate the response of biota and the paleoceanographic conditions across this event, we present data from International Ocean Discovery Program sites U1513 and U1516 in the Mentelle Basin (offshore SW Australia; paleolatitude 59°–60°S in the mid‐Cretaceous) that register the first complete records of OAE 2 at southern high latitudes. Calcareous nannofossils provide a reliable bio‐chronostratigraphic framework. The distribution and abundance patterns of planktonic and benthic foraminifera, radiolaria, and calcispheres permit interpretation of the dynamics of the water mass stratification and provide support for the paleobathymetric reconstruction of the two sites, with Site U1513 located northwest of the Mentelle Basin depocenter and at a deeper depth than Site U1516. The lower OAE 2 interval is characterized by reduced water mass stra...

Tectonic, paleoclimate, and paleoceanographic history of high-latitude southern margins of Australia during the Cretaceous

The tectonic and paleoceanographic setting of the Great Australian Bight (GAB) and the Mentelle B... more The tectonic and paleoceanographic setting of the Great Australian Bight (GAB) and the Mentelle Basin (MB; adjacent to Naturaliste Plateau) offered an outstanding opportunity to investigate Cretaceous and Cenozoic climate change and ocean dynamics during the last phase of breakup among remnant Gondwana continents. Sediment recovered from sites in both regions during International Ocean Discovery Program Expedition 369 will provide a new perspective on Earth’s temperature variation at sub-polar latitudes (60°–62°S) across the extremes of the mid-Cretaceous hot greenhouse climate and the cooling that followed.

Dissolution control on planktonic foraminiferal micro-scale distributions: two case studies from the NW Pacific Paleocene deposits

Anuário do Instituto de Geociências, 2006

Late Cretaceous stratigraphy and paleoceanographic evolution in the Great Australian Bight Basin based on results from IODP Site U1512

Gondwana Research, 2020

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