Davide Olivero - Academia.edu (original) (raw)

Papers by Davide Olivero

HAL (Le Centre pour la Communication Scientifique Directe), Sep 1, 2022

Si William Smith (1769-1839), géologue britannique, est considéré comme le fondateur de la strati... more Si William Smith (1769-1839), géologue britannique, est considéré comme le fondateur de la stratigraphie, c'est par l'étude des bassins sédimentaires d'Europe continentale, en particulier de France, que cette discipline fondamentale de la géologie allait se développer et permettre aux stratigraphes et paléontologues d'établir l'essentiel du calendrier géologique. C'est Alcide d'Orbigny (1802-1857) qui suggéra de diviser les systèmes géologiques (Crétacé, Jurassique…) en étages, qui devinrent les unités chronostratigraphiques de base. A. d'Orbigny et les stratigraphes qui suivirent, définirent ainsi de nombreux étages, dans des régions ou sur des coupes précises, les stratotypes et, le plus souvent, dans des séries de plate-forme peu profonde avec des limites d'étages souvent lacunaires. Il en résulta une charte chronostratigraphique qui était plutôt une échelle de temps discontinue. C'est dans la deuxième moitié du XX e siècle qu'une réflexion émergea dans le cadre des travaux de la Commission Internationale de Stratigraphie, une des commissions de l'Union Internationale des Sciences Géologiques (UISG), sur la nécessité de définir un calendrier géologique, une charte chronostratigraphique internationale, basée sur des limites d'étages présentant une sédimentation continue. Ces limites devaient pour chaque étage être clairement définies en un lieu précis, et basées sur un critère utilisable à l'échelle globale. C'est ainsi que furent établis à partir des années 70 les premiers Points Stratotypiques Mondiaux (PSM), équivalent du terme anglais Global Boundary Stratotype Section and Points (GSSP), qui marquent la base des étages. Symboliquement lorsqu'un PSM est ratifié par l'UISG, un Clou d'or (en acier généralement) est planté sur le site considéré. Actuellement 78 PSM ont été ratifiés sur les 102 étages composant l'éonothème Phanérozoïque ; 8 de ces PSM sont situés en France (voir figure). Le plus récemment ratifié d'entre eux, en 2019, est l'Hauterivien (Crétacé inférieur), tout près du village de La Charce (Drôme). L'inauguration du Clou d'or Hauterivien, retardé pour cause de Covid-19, est programmée pour 2022, voire 2023, ce qui nous donne l'occasion de présenter dans ce dossier les huit PSM de France. Au même titre que les stratotypes historiques de France, pour la plupart maintenant protégés au titre du patrimoine géologique national, les huit PSM devraient en toute logique profiter d'un classement en site patrimonial protégé et valorisé. La situation est toutefois contrastée : certains PSM sont effectivement intégrés dans des réserves naturelles sous divers statuts, d'autres sont un peu perdus dans la nature, voire sur un terrain privé, sans valorisation.

Travaux et Documents des Laboratoires de Géologie de Lyon, 1994

The trace fossil Zoophycos Massalongo 1 855 is developed from the Cambrian to the Holocene ; obje... more The trace fossil Zoophycos Massalongo 1 855 is developed from the Cambrian to the Holocene ; object, since last century, of numerous studies, it is characterized by morphological complexity and by its occurrence, during geologic times, in various paleoenvironmental settings. Zoophycos from the Middle Jurassic Formation of the «Calcaires à Cancellophycus» (Cancellophycus being a synonymous of Zoophycos) have been studied. This Formation is developed in the whole French south-eastern Basin. Numerous sections, often unpublished, have been selected in the French Southern Subalpine Range, in the Ardèche region and in the surroundings of Lyon. They are located on the basin margin, a paleogeographic setting looking as propitious to Zoophycos development. The results of this work, most a field work, are very interesting concerning morphology and paleoenvironmental implications. According to our numerous observations we suggest a new fabricational model : Zoophycos is a feeding trace, a spirally coiled spreite constructed by an organism constantly moving upwards. This hypothesis is in contrast with most of the accepted interpretations, which describe Zoophycos as a spreite constructed downwards. The complex structure of Zoophycos can be maintained only in a sufficiently coherent substrate, between softground and firmground. This condition can be achieved, in these settings, only with a very low rate, or even lack of sedimentation. The typical sediment consists of a filaments-rich biopelmicrite. In the studied series, the horizontal and vertical evolution of Zoophycos marks a precise setting : the trace reaches its maximum development on the slope areas, where the nutrient supply, from proximal areas, is yet important. It is a low energy area and this seems essential for Zoophycos. The study of the trace evolution could be used as a supplementary parameter in sequence stratigraphy. In fact Zoophycos is widely developed in vertical stacking (top lowstands and top highstands). On the contrary the trace completely disappears at the beginning of the transgressive system tracts. A crisis, more or less intense, characterizes the beginning of the lowstand system tracts. Zoophycos proves to be a good biosedimentologic tool ; its use could be generalized in paleoenvironmental reconstructions.L'ichnofossile Zoophycos Massalongo 1855 si sviluppa dal Cambriano fino all'Olocene ; oggetto, fin dal secolo scorso, di numerosi studi, colpisce per la sua complessa morfologia e per la sua presenza, nel corso dei tempi geologici, in facies apparentemente assai diverse tra loro. Lo studio è staio compiuto su Zoophycos caratterizzanti la Formazione dei «Calcaires à Cancellophycus» (dove Cancellophycus è sinonimo di Zoophycos), la quale affiora in tutto il Bacino del Sud-Est della Francia. Si è scelto un periodo particolare : il Giurassico medio. Un certo numero di sezioni, in gran parte inedite, è stato selezionato nelle Catene Subalpine Meridionali francesi, in Ardèche e nella regione lionese. Tutte si situano sul margine del bacino, posizione paleogeografica che pare favorevole allo sviluppo di Zoophycos. I risultati di questo lavoro, svoltosi per lo più sul terreno, sono assai interessanti sia per quanto riguarda la morfologia stessa della traccia, sia per le sue implicazioni paleoambientali. Le numerose osservazioni effettuate hanno condotto a proporre una nuova interpretazione sull'organizzazione di Zoophycos. La quasi totalità dei modelli interpretativi accettati fino ad ora descrive la traccia come una tana costruita scendendo in profondità nel sedimento. Al contrario qui si vuol proporre il modello di una lama costruita da un limivoro, a partire da una certa profondità e salendo verso la superficie secondo una spirale elicoidale. La complessa architettura della traccia, per mantenersi intatta, necessita di un substrato già coerente, ma non ancora del tutto litificato ; intermedio dunque tra il tipo «softground» ed il tipo «firmground». Negli ambienti studiati, queste condizioni si raggiungono durante fasi di rallentamento od anche interruzione della sedimentazione. Il sedimento tipico è una biopelmicrite a filamenti. Nelle serie studiate, l'evoluzione orizzontale e verticale degli Zoophycos indica un ambiente preciso : la traccia si sviluppa soprattutto in facies di scarpata, dove gli apporti di origine prossimale, ricchi in materiale nutritivo, possono essere ancora importanti, ma dove le condizioni di sedimentazione sono anche assai tranquille. Zoophycos si sviluppa durante i periodi di crisi nella sedimentazione.La trace fossile Zoophycos Massalongo 1855 est connue depuis le Cambrien jusqu'à l'Holocène ; objet de nombreuses études, déjà à partir du siècle dernier, elle frappe par la complexité de sa morphologie et par sa présence, au cours des temps géologiques, dans des milieux apparemment différents. Une étude a été menée sur les Zoophycos caractérisant les «Calcaires à Cancellophycus» (Cancellophycus est synonyme de…

Elsevier eBooks, 2007

ABSTRACT Zoophycos is a very complex trace fossil and there is still no real agreement concerning... more ABSTRACT Zoophycos is a very complex trace fossil and there is still no real agreement concerning the taxonomy and the significance of the ichnofossil. What exactly are the varied structures collected under the name Zoophycos? The type specimen, the first trace fossil named Zoophycos, must be found and studied in order to approach this problem from a taxonomic point of view. The name Zoophycos was proposed in 1855 by Abramo Massalongo; but the specimens he used to describe the ichnogenus were macroalgae, not trace fossils. By chance, among the material described by Massalongo, a new type ichnospecies can be designated. As it is a true trace fossil, the name Zoophycos may be preserved.

Palaeogeography, Palaeoclimatology, Palaeoecology, Sep 1, 2004

... turbiditic deposits by the benthic fauna has been approached by several authors ( Seilacher, ... more ... turbiditic deposits by the benthic fauna has been approached by several authors ( Seilacher, 1962 , Gaillard, 1988 , Miller, 1986 , Miller, 1993 , Frey ... Seven of these specimens indicate a late Barremian age (determination by F. Cecca), instead of early Barremian as indicated in ...

Ichnos, May 1, 1996

The study of Jurassic Zoophycos from south‐eastern France has led us to some original results con... more The study of Jurassic Zoophycos from south‐eastern France has led us to some original results concerning its morphological organization and paleoenvironmental significance. Zoophycos represents a spreite constituted by a coiling lamina, constructed upwards in sediments, with only one opening at the sediment‐water interface. Zoophycos, produced by a deep sediment feeder, is emplaced late in an almost coherent substrate, intermediate between

Palaeoworld, Jun 1, 2013

Enigmatic biogenic structures are reported from the Palaeogene of southeastern France in the Cast... more Enigmatic biogenic structures are reported from the Palaeogene of southeastern France in the Castellane-Blieux area (Alpes de Haute-Provence French department). They occur at the Eocene/Oligocene transition at the top of the Marnes Bleues Formation, which corresponds to a clearly defined regressive sequence, where thick marls are overlain by lacustrine limestones or sandstones. The marls have abundant shallow marine fauna and the upper part of the Formation corresponds to a rapid transition to non-marine deposits. The studied structures exhibit three main morphologies: vertical shafts, furrows, and tunnels. They can also form dense clusters and crosscut marginal marine crustacean burrows such as Psilonichnus. By comparison with modern and fossil examples, these trace fossils are interpreted as probably aestivation burrows. The possible trace-makers could be lungfish (in particular for the common vertical burrows) or amphibians (for the furrows and tunnels). The occurrence of these different aestivation burrows defines the border of a basin and probably indicates increasing droughts on the coastal plain. This could reflect the well-known development of arid conditions in southeastern France at the beginning of the Oligocene.

Palaeogeography, Palaeoclimatology, Palaeoecology, Mar 1, 2003

The complex and enigmatic trace fossil Zoophycos is recorded worldwide, from Cambrian to Holocene... more The complex and enigmatic trace fossil Zoophycos is recorded worldwide, from Cambrian to Holocene. The possible evolution of the ichnofossil has already been proposed by some authors, but their works concerned the very large group of trace fossils related to Zoophycos (structures that could be assigned potentially to several ichnogenera) recorded in several depositional basins. This paper focuses on the Subalpine Basin of southeastern France, where excellent outcrops facilitate the study of changes in Zoophycos that occurred between the Early Jurassic and Late Cretaceous. Thousands of specimens have been studied in detail. It appears that several trace fossils, classically related to Zoophycos, are so different that they could actually represent separate ichnogenera. But a group of them can be considered as belonging to a single ichnogenus, as they share the same morphological characters: a thin layer of bioturbated sediment (lamina), constituted by a network of primary and secondary lamellae and bordered by a marginal tube. The outline may be simple or lobate. The general architecture is a flattened cone, spirally coiled around a virtual central axis, without a vertical tunnel, and constructed upward, or, rarely, downward, in the sediment. One or several subsequent whorls are observed. The producers could have been specialized deposit feeders (sipunculans?), following a K-selected strategy. All these trace fossils are found in fine-to medium-grained limestones and marls. Inside this group, subtle differences make it possible to distinguish four morphotypes; they differ in size and how lobate they are, and they could be assigned to true ichnospecies. They succeed in time with slow and gradual changes and two trends are documented. These Zoophycos underwent evolutionary and environmental changes during the Jurassic^Cretaceous interval, becoming more lobate and larger, as they migrate to deeper and deeper environments. The four morphotypes share the same basic morphology, result from the same general activity, and are restricted to the same depositional basin. Therefore a unique clade of Mesozoic Zoophycos producers could be proposed. These animals have constructed structurally elaborate burrow systems that record complex and varied behavior. These trace fossils can also be regarded as extended phenotypes, that is adaptive projections of the organisms' body and activity. The changes of the ichnofossils documented in the basin can thus reflect real changes in the organisms themselves and in their ethology: their phylogenetic history is mirrored to a certain extent in the succession of morphotypes. So, complex trace fossils, such as Zoophycos, are not only biosedimentary structures, but true mirrors of the evolutionary trends of their producers. This opens a new biological perspective for ichnological studies.

Bulletin De La Societe Geologique De France, Mar 1, 2000

Cretaceous Research, Jun 1, 2012

A n e w trace fossil m a rk e r level, th e Halimedides horizon, is p ro p o sed for th e Low er ... more A n e w trace fossil m a rk e r level, th e Halimedides horizon, is p ro p o sed for th e Low er C retaceous pelagic to hem ipelagic succession o f th e Puez area (S o u th e rn Alps, Italy). The h o rizo n occurs in th e m id d le p a rt o f th e late B arrem ian Gerhardtia sartousiana Zone (Gerhardtia sartousiana Subzone). It is ap p ro x im ately 20 cm th ick an d re stric te d to th e u p p e rm o st p a rt o f th e Puez L im estone M em b er (m arly lim esto n es; H au teriv ian-B arrem ian; Puez F orm ation). It is fixed to th e to p 20 cm o f b ed P1/204. The g rey-w h itish lim esto n e b ed o f th e G. sartousiana Zone is p e n e tra te d by A ptian red m a rls-siltsto n es o f th e Redbed M em ber. The ho rizo n is d o c u m e n te d for th e first tim e from th e S o u th ern Alps, including th e D olom ites, an d can be co rre la te d w ith o th e r M e d ite rran ean localities. The trace fossil assem b lag e o f th is m a rk e r bed w ith th e coo ccu rren ce o f Halimedides, Spongeliom orpha an d Zoophycos sheds light o n th e Lower C retaceous sedim entological h isto ry an d c u rre n t sy stem o f th e Puez area w ith in th e D olom ites. It also highlights th e p a la e o e n v iro n m e n ta l evo lu tio n o f basins an d p lateau s an d p rovides insigh ts into th e late B arrem ian interval.

PALAIOS, Apr 1, 2009

Numerous rhabdoglyphid trace fossils in Cretaceous pelagic limestones from the French and Swiss A... more Numerous rhabdoglyphid trace fossils in Cretaceous pelagic limestones from the French and Swiss Alps are ascribed to the ichnogenus Halimedides Lorenz von Liburnau, 1902. The heart-shaped chambers, interpreted as storage chambers, are joined to tunnels in a linear pattern. The burrow system is classified as an agrichnium. Morphological characteristics of the burrows indicate that small infaunal crustaceans were the likely trace makers. Halimedides are deep-sea traces that indicate relatively firm media (substrates)-stiffground to firmground-based on paleoenvironmental and morphological evidence. The usual association of Halimedides with Rhizocorallium and Spongeliomorpha clearly place them in the Glossifungites ichnofacies. Halimedides may be an indicator of subtle gaps in sedimentation. Densely chambered Halimedides are interpreted to indicate lower oxygenation, whereas sparsely chambered burrows indicate higher oxygenation of bottom waters. Consequently, Halimedides may be a useful tool for interpreting water depth, media consistency, sedimentation rate, and seafloor oxygenation.

Historical Biology, Oct 30, 2018

ABSTRACT Zoophycos is a characteristic trace fossil in the Mississippian in the Alborz Basin depo... more ABSTRACT Zoophycos is a characteristic trace fossil in the Mississippian in the Alborz Basin deposits of north Iran, and is described for the first time in the Mobarak Formation. The vertical distribution of the carbonate deposits bearing Zoophycos provided the basis for distinguishing three distinct types of sedimentary sequences including Zoophycos (type A, B, and C) in shallow marine sediments of Mobarak Formation. Type A is composed of rare to common density of small to medium lobed Zoophycos. Type B is characterized by common density of medium lobed Zoophycos. This ichnogenus in type A and B is associated with Palaeophycus. The low diversity and bioturbation of the trace fossils would be the result of a stressful environment characterized by optimal water circulation and high-energy conditions. Type C consists of abundant density of large lobed Zoophycos. Type C is associated with Chondrites and planolites. The high diversity and bioturbation of the trace fossils in type C than type A and B would be the result of a calm environment characterized low-energy conditions. Under low sedimentation rate, stable paleoenvironment, dysaerobic conditions, and high amount of benthic food, the size of Zoophycos is the biggest, whereas in the high sedimentation rate, unstable paleoenvironment, aerobic conditions, and shortage of benthic food, the size of Zoophycos is small.

Palaeogeography, Palaeoclimatology, Palaeoecology, Jul 1, 1996

The trace fossil Zoophycos is characteristic in certain Jurassic and Cretaceous basinal deposits ... more The trace fossil Zoophycos is characteristic in certain Jurassic and Cretaceous basinal deposits of southeastern France. These deposits are cyclic marl/limestone alternations, in which depositional sequences can easily be recognized. Two kinds of sequence have been studied: the marl/limestone couplet and the third-order sequence. Detailed observations show that Zoophycos has a particular position in the sequences. In the marl/limestone couplet,

Les trente dernières années du XX e siècle ont permis d'apporter une valeur patrimoniale à la géo... more Les trente dernières années du XX e siècle ont permis d'apporter une valeur patrimoniale à la géologie, et en 1991, la Déclaration internationale des droits de la mémoire de la Terre (Digne-France) constitue une première base conceptuelle internationale du « patrimoine géologique ». Durant cette période, de nombreux pays le prennent en compte et adoptent de nouveaux dispositifs législatifs pour protéger essentiellement des sites géologiques.

Une etude a ete menee sur les zoophycos caracterisant les calcaires a cancellophycus jurassiques ... more Une etude a ete menee sur les zoophycos caracterisant les calcaires a cancellophycus jurassiques du sud-est de la france. Un certain nombre de coupes, souvent inedites, a ete selectionne en haute provence, ardeche et dans la region lyonnaise. Les resultats de ce travail sont originaux pour ce qui concerne la morphologie de la trace et, surtout, sa signification paleoenvironnementale. On propose une nouvelle interpretation morphologique: le terrier est construit en remontant dans le sediment. On suppose un substrat coherent pour permettre l'installation du terrier. Ce substrat se forme dans des conditions de ralentissement ou d'arret de la sedimentation. Le sediment typique est une pelmicrite a filaments. Zoophycos se developpe dans des milieux de talus ou les apports d'origine proximale (matiere organique) sont importants. Zoophycos peut etre utilise en analyse sequentielle: la trace se developpe surtout dans les niveaux tres calcaires correspondant a des fins de sequence. La trace disparait aux debuts des phases transgressives. Zoophycos se revele donc un bon outil paleogeographique, paleoecologique et sedimentologique

Travaux et Documents des Laboratoires de Géologie de Lyon, 2002

Cotillon Pierre, Gaillard Christian, Olivero Davide. Indices de courants sur la marge sud du bass... more Cotillon Pierre, Gaillard Christian, Olivero Davide. Indices de courants sur la marge sud du bassin vocontien à l’Aptien inférieur : signal climatique probable. In: Documents des Laboratoires de Géologie, Lyon, n°156, 2002. STRATI 2002. 3ème congrès français de stratigraphie. Lyon, 8-10 juillet 2002. pp. 85-86

Elsevier eBooks, 2007

ABSTRACT Zoophycos is a complex trace fossil. Hundreds of these fossils, very similar to the type... more ABSTRACT Zoophycos is a complex trace fossil. Hundreds of these fossils, very similar to the type ichnospecies, have been observed in Devonian to Cretaceous deposits. The detailed analysis of the characteristics of the traces has resulted in a detailed constructional model. The specimens of Zoophycos that we have studied were constructed upwards into the sediment. They are the result of a very efficient mining programme, corresponding to the sediment feeding activity of a supposedly sipunculid worm. The formation of lobes may be linked to the evolution of the trace-maker or to its ethology.

Le Centre pour la Communication Scientifique Directe - HAL - INSU, Sep 1, 2022

L'étude traite des associations d'ammonites bajociennes de la Formation de l'Oolithe ... more L'étude traite des associations d'ammonites bajociennes de la Formation de l'Oolithe ferrugineuse de Bayeux. La coupe de " Les Fours à Chaux ", entre Croisilles et Les Moutiers-en-Cinglais, illustre une section condensée avec remaniement taphonomique omniprésent. Tous les fossiles sont des éléments remaniés qui ont été transportés ou remobilisés avant l'enfouissement définitif. L'étude s'est portée sur les ammonites, qui peuvent être distinguées par les paramètres taphonomiques propres aux éléments resédimentés et aux éléments réélaborés ; les premiers sont définis sur l'équivalence et la continuité sédimentaire entre la matrice encaissante et les moules internes ; les fossiles réélaborés se rapportent aux altérations des moules internes suite aux épisodes de transport, remobilisation, abrasion, fracturation et encroûtement biogénique ou ferrugineux. Ces fossiles ont été regroupés dans des enregistrements taphonomiques (tapho-enregistrements ou ...

aestivation burrows from the Eocene/Oligocene transition in south-eastern France and their palaeo... more aestivation burrows from the Eocene/Oligocene transition in south-eastern France and their palaeoenvironmental implications

HAL (Le Centre pour la Communication Scientifique Directe), Sep 1, 2022

Travaux et Documents des Laboratoires de Géologie de Lyon, 1994

Elsevier eBooks, 2007

Palaeogeography, Palaeoclimatology, Palaeoecology, Sep 1, 2004

Ichnos, May 1, 1996

Palaeoworld, Jun 1, 2013

Palaeogeography, Palaeoclimatology, Palaeoecology, Mar 1, 2003

Bulletin De La Societe Geologique De France, Mar 1, 2000

Cretaceous Research, Jun 1, 2012

PALAIOS, Apr 1, 2009

Historical Biology, Oct 30, 2018

Palaeogeography, Palaeoclimatology, Palaeoecology, Jul 1, 1996

Travaux et Documents des Laboratoires de Géologie de Lyon, 2002

Elsevier eBooks, 2007

Le Centre pour la Communication Scientifique Directe - HAL - INSU, Sep 1, 2022