Polen y esporas de la Formación La Irene (Maastrichtiano), sudoeste de la provincia de Santa Cruz, Argentina: primeros resultados

Palynological assemblages are reported for the first time for the La Irene Formation, southwestern Santa Cruz Province, Argentina. This unit represents the sedimentation during a regressive period from transitional or delta-plain to fluvial environments. Palynological assemblages are scarce and moderately well preserved. They mainly consist of continental elements (wood remains, cuticles, spores and pollen grains) with scarse marine palynomorphs (dinoflagellate cysts). The spore-pollen assemblages are dominated by fern spores, followed by angiosperm and gymnosperm pollen grains. Bryophyte spores and fungal remains are also present. Among ferns, Cyatheaceae and spores of Laevigatosporites, of uncertain affinity, are dominant. Of the angiosperm pollen, those of Chloranthaceae (Clavatipollenites sp.) and Arecaceae (Arecipites spp., Longapertites sp., Spinizonocolpites hialinus Archangelsky and Zamaloa) are the most abundant. Pollen of Liliaceae (Liliacidites spp.), Proteaceae (Proteacidites sp., Peninsulapollis gillii (Cookson) Dettmann and Jarzen, Retidiporites camachoii Archangelsky) and Ericaceae (Ericipites scabratus Harris) are also present. Gymnosperm pollen is represented by Podocarpaceae (Podocarpidites spp.) and Ephedraceae (Equisetosporites sp.). These palynological suites would represent a fern-angiosperm dominated coastal vegetation, developed under warm and at least locally humid climatic conditions. La Irene Formation is considered Maastrichtian in age based on stratigraphic evidence, which is, in turn consistent with the ages suggested by the species ranges and the similarities observed with others previously described assemblages. This is the southernmost record of Spinizonocolpites, similar to the extant mangrove palm Nypa.     

Late Carboniferous palynostratigraphy of the Itararé Subgroup, northeastern Paraná Basin, Brazil

A new biozonation is proposed for the Late Carboniferous strata of the northeastern Paraná Basin (São Paulo and Paraná States), based on well-preserved palynological assemblages recovered from outcrops and core samples retrieved from the Itararé Subgroup. Assemblages include forty-nine species of trilete spores and twenty-five pollen species. The oldest biozone, the Ahrensisporites cristatus Interval Zone (AcZ), in the basal portion of the Itararé Subgroup, includes eleven exclusive spore species, and is assigned a Pennsylvanian (late Bashkirian to Kasimovian) age. The overlying proposed biozone, the Crucisaccites monoletus Interval Zone (CmZ), dated late Pennsylvanian (Kasimovian to Gzhelian), ranges approximately from the top of the lower portion to the middle portion of the Itararé Subgroup, bears only one exclusive species of pollen. Both zones are characterized by the dominance of trilete spores and monosaccate pollen grains, including also few taeniate pollen grains. Furthermore, the basal Protohaploxypinus goraiensis Subzone of the Vittatina costabilis Interval Zone (VcZ) is broadly recognized for the first time in the upper portion of the Itararé Subgroup in the northeastern Paraná Basin. This subzone is attributed to the Early Permian (Early Cisuralian), and is characterized by the dominance of monosaccate pollen grains, a significant increase of taeniate grains (mainly Protohaploxypinus spp.), apart from the appearance of polyplicate pollen (Vittatina spp.). Reference sections and the main characteristics of the two new zones (AcZ and CmZ) are presented, along with a preliminary palynological correlation and discussion on their ages.     

Succession des peuplements d’échinides du Crétacé inférieur dans le Haut Atlas atlantique (Maroc) ; révision systématique et intérêt stratigraphique

The rich echinoid fauna from the Lower Cretaceous of the Agadir, Haha and Essaouira basins has been revised taxonomically, based on new and abundant collections. Forty-seven species have been identified, of which 20 are reported for the first time from this region and a further three represent new species left in open nomenclature. Their stratigraphic ranges have been determined accurately by reference to the regional ammonite zonation. However, it is also possible to use a local biostratigraphical scheme based on the echinoid succession, where ammonites are rare. The Toxasteridae, which are very abundant and underwent rapid evolution, are the most useful biostratigraphically. The genus Toxaster appears in the Lower Berriasian and continues until the Gargasian passing through the following succession: T. africanus, T. granosus, T. kiliani, T. lorioli, T. obtusus, T. exilis, T. retusus, T. maurus, T. peroni, T. collegnoi. The presence of Eoholaster, Macraster, Douvillaster, Palhemiaster, Heteraster and Pygopyrina is signaled for the first time in the Atlantic High Atlas region.     

Late Carboniferous miospores from the Tarma Formation,Pongo de Mainique,Peru

For the first time, a palynologic assemblage is described from the upper section of the Tarma Formation, Peru. It is dominated by monosaccate pollen grains with subordinate striate grains and very few spores. The abundance of Illinites unicus has allowed a revision of the systematic position of the form-genus Illinites. The assemblage is correlated with the Illinites unicus palynozone from the Amazonas Basin, and is considered to be of Westphalian C/Late Atokan age.     

Pennsylvanian miospore assemblages from the Bèdero Section,Varese, Italian Southern Alps

Thin continental Carboniferous sequences crop out sparsely in the western Southern Alps (Alpe Logone, Mesenzana, Grantola, Bosco Valtravaglia-Fabiasco, Val Tresa, etc.) and are currently the subject of a detailed litho- and biostratigraphic revision, to reconsider their chronological position with respect to previously published age constraints. The age of these Upper Palaeozoic sedimentary successions, scattered over a wide area and strongly tectonized along major structural lineaments, has long been debated between Westphalian and Stephanian. The present work focuses mainly on the palynology of the Brezzo di Bèdero section (Luino, Lake Maggiore). The recovered palynoflora is assigned to 42 spore genera and 76 species of which one genus and 10 species are newly proposed. Fifty-seven spore species and 19 pollen species are described and illustrated. Qualitatively, the Bèdero palynoflora shows strong affinities to those of Western Europe. The most abundant palynomorphs are trilete spores known to be characteristics of the late Westphalian and early Stephanian assemblages. These are characterized by the remarkable presence of Florinites and subordinately Wilsonites species, low numbers of Potonieisporites, rare Limitisporites and Vesicaspora, and very rare Latensina-Cordaitina pollen. The occurrence of diverse monolete spores Laevigatosporites, Punctatosporites, Spinosporites, Thymospora and Torispora, with common Lundbladispora gigantea, L. simonii, Stenozonotriletes rubius n. sp. together with the absence of plicate and taeniate pollen grains suggests a strong resemblance to the late Westphalian–early Stephanian interval assigned to the OT Zone of Western Europe. Variations in the quantitative composition can be likely attributed to variations in the environmental setting with regards to non-forming peat deposits. The palynological suite is indicative of the existence of a well-established lowland Cordaiteans vegetation and well settled pterophytic, pteridosperm and subordinately sphenophytic and lycophytic, hygrophytic plant communities.     

Plant remains from Early Cretaceous deposits on the Goban Spur,Bay of Biscay,North Atlantic Ocean,and their palaeoenvironmental significance

Site 549 of the Deep Sea Drilling Project was drilled on the Goban Spur in the Bay of Biscay in 1981. The core recovered from this North Atlantic location included 290 m of Barremian and possibly partly Hauterivian “syn-rift” deposits overlain unconformably by rocks of early Albian age. The number and variety of spores and pollen grains in the palynomorph assemblages and associated palynofacies through these units together with the presence of some pieces of wood, fragments of foliage, and a few megaspores in the lowest part of the Cretaceous succession suggest that the source area vegetation was, at least initially, relatively close to the site of deposition. Ginkgoalean, bennettitalean, and other gymnosperm groups are represented in the plant mesofossil assemblage but most of the fragments of foliage show cheirolepidiaceous characteristics. Five species belonging to this family have been identified and described. Two of these, Frenelopsis atlantica Zhou and Batten and Frenelopsis? alvinii Zhou and Batten, are new and one is unnamed. The composition of the three informally identified suites of spore and pollen assemblages recovered from 49 samples through the Early Cretaceous succession is consistent with age determinations of parts of it determined previously on the basis of dinoflagellate cysts, foraminifera, nannoplankton, and other fossils.     

Les grands mammifères du Villafranchien supérieur des travertins du Bassin de Denizli (Sud-Ouest Anatolie,Turquie)

The large mammals from travertine deposits in the Denizli basin include the following species: Archidiskodon meridionalis meridionalis, Equus cf. altidens s. l., E. cf. apolloniensis, Stephanorhinus cf. etruscus, Metacervoceros rhenanus, Cervalces (Libralces) ex gr. minor-gallicus, Palaeotragus sp., Bovinae gen. and sp. indet. This association resembles those from the late Villafranchian of Southern and Eastern Europe, and, to some extent, fromWestern Asia, and could be older than 1.2 Ma.     

L’ambre campanien du Mas d’Azil (Ariège,France) : gisement,micro-inclusions,taphonomie

The amber of Le Mas d’Azil (Ariège, France), fashioned by the Magdalenian people of Le Mas d’Azil cave, was collected in clay levels rich in Cupressinoxylon Göppert, of the Campanian Labarre Sandstone Formation, which is a large deltaic set, infilling the sub-Pyreneean trough. The amber pieces are small and resemble modern resin exudates on coniferous trunks. We describe following micro-inclusions. Actinomycetes: Cardonia stellata, nov. gen., nov. sp., located close to the surface of amber pieces, is abundant and displays chains of conidia and isolated aleuriospore. Nocardiopsis ? sp. D is rare. Actinomycete “de type Salignac” is abundant. Its filaments often display a tendril shape, which seems to prelude to a mycelium fragmentation. Other bacteria: Leptotrichites resinatus Schmidt ( Schmidt and Schäfer, 2005), poorly represented, is more variable than the already known material; cf. Sphaerotilus sp., very abundant, also displays differences with the Cenomanian “Sphaerotilus sp.”. Eukaryotes: one fungal filament, and a group of spores, pollens or cysts. Inorganic inclusions: gas bubbles, pseudo-protists of B and C? types, and tiny, transparent, cubic crystals. It seems that most of the quoted prokaryotes were resinicolous organisms, able to settle on the surface of the exudate, and grow in the resin, after inoculation either by a contact with the substrate, or by an anemophilic dispersion of spores. This “taphonomic way” seems here to be more general than trapping.     

A Late carboniferous palynoflora from the Itararé Subgroup (Paraná Basin) in Campinas, São Paulo State, Brazil

Upper Paleozoic sedimentary sequences from several localities of the northeastern Paraná Basin were sampled for paleobotanical and palynological studies. Well-preserved terrestrial assemblages from samples of Campinas, São Paulo State, from an outcrop at the 97 km mark on the Bandeirantes Highway, located at the Municipality of Campinas, São Paulo State were recorded where fertile bryophytes and megaspores were previously also found. The Campinas palynoflora is composed of 23 species of bryophytic and pteridophytic spores, 16 species of pollen grains, and one algae (Botryococcus braunii Kützing). Among the sporomorphs, Reticulatisporites asperidictyus Playford and Helby is described for the first time from the Paraná Basin. Assemblages bear diagnostic species of the Ahrensisporites cristatus Interval Zone, such as Anapiculatisporites argentinensis Azcuy, Cristatisporites inordinatus (Menéndez and Azcuy) Playford, and Psomospora detecta Playford and Helby, of Late Carboniferous age (Pennsylvanian). Palynological content suggests a glacio-deltaic/lacustrine environment of deposition. This is supported by lithological data and by the absence of marine palynomorphs.     

Albian Palynostratigraphy of ODP Leg 207 (Holes 1257A, 1258C and 1260B), Demerara Rise,Equatorial Atlantic

Palynological analyses were carried out in 96 core samples with the objective of determining the relative age of calcareous clays, in holes 1257A, 1258C and 1260B of ODP Leg 207, drilled on the Demerara Rise, northern coast of Suriname, Equatorial Atlantic. The palynological assemblages recovered consisted of spores, pollen grains, dinoflagellate cysts, palynoforaminifers and prasinophytes and appeared reasonably well preserved. The miospores showed little diversification, where the most significant genera were Crybelosporites and Elaterosporites. The dinocysts showed greater diversity and abundance, predominating over the miospores in the three holes. In the three holes analyzed, eight genera and three species of spores, eight genera and eleven species of pollen grains, and 24 genera and 44 species of dinoflagellates were identified. The middle to late Albian age was determined on the basis of bioevents of recognized species with chronostratigraphic value. The species diagnosed mostly included the miospores Elaterosporites protensus, Elaterosporites verrucatus, Inaperturopollenites simplex and the dinocysts Cribroperidinium muderongense, Dinopterygium cladoides, Litosphaeridium arundum, Litosphaeridium conispinum, Oligosphaeridium complex and Stiphrosphaeridium anthophorum.     

La transgression thanétienne (Paléocène supérieur) dans l’Aurès occidental (Algérie), d’après les associations de Foraminifères de la coupe d’El Kantara

In the W-Aures (Algeria), the El Kantara pass displays about 50 m of Red Marls overlying the Maastrichtian limestones with Laffitteina. The Red Marls are, in their turn, overlain by the Thanetian marly limestones of the river El Haï. The micropaleontological inventory of these Red Marls establishes the co-occurrence of subaerian (Microcodium = Paronipora), fresh-water (Charophyta) and marine microfossils (Foraminifers). The stratigraphical significance of these microfossils is discussed. The upper part of the Red Marls, yielding abundant Valvulina and scarce Glomalveolina, is of Thanetian age. The age of the lower part is less established, but the occurrence of Microcodium suggests a Thanetian age too. Located at the margin of the northern opening of the trans-Saharan epeiric sea, the El Kantara section establishes a Thanetian age for the beginning of the Paleocene transgression. Danian deposits are missing, in spite of the absence of an obvious hiatus on the field. After general emersion during the early Paleocene, the Thanetian transgression starts with the set up of lakes at the depositional area of the Red Marls. Marine influences, limited at first, become gradually prevailing, and end with the deposition of neritic marly limestones of river El Haï.     

Fern spore and pollen airspora profile of Singapore

Monitoring atmospheric fern spore and pollen loads in Singapore was initiated in June 1990. Aside from the more numerous fungal spores, fern spores and pollen grains made up 6.2–8.6% and 4.4–5.4% of the total airspora sampled, respectively. The most frequently encountered fern spores, in descending order, were those of Nephrolepis auriculata, Dicranopteris linearis, Stenochlaena palustris, Asplenium nidus, Pteridium aquilinum, and Dicranopteris curranii. For pollen grains, the most frequently encountered, in descending order, were Elaeis guineensis, Casuarina equisetifolia, Acacia auriculiformis, Kyllingia polyphylla, Podocarpus, and Poaceae pollen grains. Seasonal patterns for individual fern spore or pollen types were discernible despite the relatively uniform tropical climate in Singapore. The fern spore and pollen calendar for the period 1991–1995 was compared to that of 2005–2006 as a follow-up study to keep abreast with the rapidly changing landscape of Singapore. Diurnal patterns showing a late morning to afternoon peak period were seen in fern spores, while the peak period was in the morning for pollen types studied with the exception to oil palm pollen. Additionally, association between fern spore and pollen counts and local meteorological conditions were also analyzed and found to be highly correlated. This study has thus identified the fern spores and pollen airspora components, and determined the calendars, as well as diurnal profiles of the Singapore airspora and provides invaluable information for allergy studies by highlighting the trigger sources present in the environment.     

Étude biostratigraphique et paléoenvironnementale des diatomées pyritisées de l'intervalle Paléocène supérieur-Éocène inférieur du sondage de Saint-Josse (France)

This paper presents the results of a biostratigraphic analysis of pyritized diatom assemblages in the Saint-Josse core (CC82) located in the northern part of the Paris basin (coordinates: X =555?000, Y =307?324 and Z =56.9 m). During the Paleocene-Eocene this locality was situated in a small bight of the North Sea Basin. The results are obtained from sediments of the Thanet and Mont-Bernon group equivalents belonging to the Paleocene-Eocene interval. Thirteen samples were studied and eleven contain pyritized diatoms. By epigenesis, the siliceous frustule of the diatom is changed into a pyritized skeleton with all the ornamentation very well preserved such as the velum, the areolae, the labiate processes, etc. Dispersive X-Ray analyses show this complete replacement of silica by pyrite. Another form of pyritization is crystallization of pyrite (in cubes, pyritohedrons, octahedrons, framboids) in internal cavities of the diatoms to produce internal moulds, also called steinkerns, which preserve the external morphology of the diatoms and some details such as the girdle. Despite pyritization, diatoms can often be recognized at the species level; brackish and marine species were observed but no fresh water specimens were encountered. Pyrite is easily altered into iron oxides. In outcrops, pyritized diatoms can be obscured or destroyed by oxidation. We have chosen borehole samples for this study to avoid the affects of weathering. Deposits from the Sorrus Unit (of the Thanet Group) have low abundances of pyritized diatoms (3 to 25 specimens per sample). This unit contains allochtonous diatom assemblages comprising Actinoptychussenarius, Coscinodiscus morsianus var. morsianus, and Coscinodiscus morsianus var. moelleri. Sample 34.31-34.45 from this unit is particularly interesting. It contains three specimens of Paralia siberica var. laevis, which is typical of an estuarine or littoral paleoenvironment, and corresponds to the more continental deposit of the Sorrus Unit. Seven samples, taken in the Argile de Saint-Aubin Unit (from the Mont-Bernon Group), contain more than 200 pyritized diatoms and between 9 to 16 different species per sample. A brackish assemblage (Actinoptychus senarius, Coscinodiscus commutatus and Stellarima microtrias) and a marine assemblage (C. morsianus var. morsianus, Coscinodiscus var. moelleri, Fenestrella antiqua, Odontellaheibergii, Rhizosolenia sp. 1 and Trinacria regina) are observed. The brackish assemblage expands in the upper part of the Saint-Aubin Unit indicating more widespread brackish paleoenvironmental conditions. Pyritized diatoms are important fossil markers in the Paris basin mainly when siliceous fossils (silicoflagellates or radiolarians) and others microfossils (foraminifers and dinoflagellates) are very poor or absent. Two diatom assemblages have been identified in the Saint-Josse borehole. The first assemblage D1, comprising C. morsianus var. moelleri (high occurrence), C. morsianus (a few) and T. regina (rare), is recorded in the Sorrus, La Calotterie, Bois Gorguette, Le Goulet and lower Saint-Aubin Units. The second assemblage D2, characterized by great abundance of F. antiqua and decreasing numbers of C. morsianus species, is found in the upper part of the Saint-Aubin Unit. These diatom assemblages can be correlated with other biozonations established in the North Sea basin and based on nannoplankton and diatoms (King, 1983), diatoms (Mitlehner, 1996) and calcareous nannoplankton (Martini, 1971). F. antiqua and C. morsianus var. moelleri are the more important diatom species encountered. F. antiqua (previously named Coscinodiscus sp. 1, King, 1983) is the fossil marker used by King to define his NSP4 biozone. The base of NSP4 corresponds to the lowest occurrence of F. antiqua and the top is marked by the highest occurrence of this species. The Sorrus, La Calotterie, Bois Gorguette, Le Goulet and Saint-Aubin (“Sparnacian” stage) Units, the last one comprising F. antiqua (increasing to acme), correspond to the NSP4 zone of King (1983). The Mont-Hulin and Château de la Bruyère Units correspond probably to the NSP5 zone of King (1983). F. antiqua and C. morsianus var. moelleri were also used by Mitlehner (1996) to differentiate the NSP4a zone (low abundance of F. antiqua and abundance of C. morsianus var. moelleri) from the NSP4b zone (great abundance and acme of F. antiqua). The abundance of C. morsianus var. moelleri is recorded in the lower part of Saint-Aubin Unit and the abundance of F. antiqua (high peak at 46% in the sample 17.87) is found in the upper part of Saint-Aubin Unit. Therefore, Sorrus, La Calotterie, Bois Gorguette, Le Goulet and the lower part of Saint-Aubin Units are correlated with the NSP4a zone and the upper part of Saint-Aubin Unit with the NSP4b zone. By correlating the calcareous nannoplankton biozonation (NP) of Martini (1971) with the biozonation of King (1983), adapted by Mitlehner (1996), the boundary between the NP9 and NP10 zones could be located in the 18.75-17.87 interval and the NP10-NP11 boundary at the top of Saint-Aubin Unit. Lithostratigraphic correlations between the units of the Saint-Josse borehole (Paris basin) and the formations of the North Sea basin can be established. The great abundance of C. morsianus var. moelleri and the great abundance (including acme) of F. antiqua are respectively recorded in the Sele and Balder Formations. Therefore, the interval Sorrus/lower Saint-Aubin Units is correlated with the Sele Formation and upper part of Saint-Aubin Unit with the Balder Formation.     

Données paléoenvironnementales sur le Vraconnien/Cénomanien de la région de Tébessa (Atlas Saharien,nord-est Algérie). Caractérisation de l’OAE2

The micropalaeontological content of five sections, located in Northeastern Algeria (Saharan Atlas) was investigated by means of washing/counting of microfossils in marly levels, and microfacies analyses of calcareous levels. In these levels of Upper Cretaceous age, hundred species of foraminifera were identified but only about 15 species of ostracoda and about ten of radiolaria. This work allows, first of all, to establish a rather precise stratigraphic frame, in particular by means of studying planktonic foraminifera. Two to five biozones were defined, between the Vraconnian (Th. Appenninica biozone) and the early Turonian (Whiteinella archaeocretacea biozone, then Helvetoglobotruncana Helvetica biozone for certain sections). Secondly, the quantitative analyses led on foraminifera allowed the definition of palaeoenvironment. The ratio P/P+B, generally very high, coupled with a little diversified benthonic microfauna, indicates a calm and deep environment, of external platform or slope type. Furthermore, at numerous levels, various indications give evidence of the existence of a strong surface productivity (presence of upwellings), responsible for the proliferation of radiolaria (late Vraconnian/early Cenomanian especially) or of globular planktonic foraminifera (hedbergellids/heterohelicids); being both associated with low-oxygen deep waters. Two anoxic events were also revealed, the first one at the end of Vraconnian (OAE1d) and the second at the end of Cenomanian (OAE2). This last event in particular was characterized on all the sections, in a more or less detailed way, thanks to the identification of certain indicator: Heterohelix “bloom”, “filament” event, disappearance of rotaliporids, presence of “blackshales” strongly enriched in organic matter (Bahloul levels).     

Stratigraphie, paléoécologie et foraminifères du paléogène des Alpes Maritimes et des Alpes de Haute-Provence (Sud-Est de la France)

Paleogene sedimentation in the Alpes Maritimes and Alpes de Haute Provence regions is composed of one complete sedimentary sequence. This sequence begins with the continental Formation from Microcodium and continues with the Cerithium layers, the Calcaires Nummulitiques and the Marnes Bleues, which are overlaid by the turbidites of the Grès d’Annot Formation. Sedimentation starts in the Nummulites perforatus zone close to the base of ‘the Truncorotaloides rohri zone (P 14) and ends in the Cassigerinella chipolensis-Pseudohastigerina micra zone (P 18) and the NP21 zone in the upper part of the Grès d’Annot. More biomarkers were used in order to define a more detailed local biozonation (biozones AMP 1 to AMP 7). Four local zones were also defined by the last occurrence of Nummulites millecaput and N. perforatus-N. ptukhiani and then by the first appearance of N. retiatus (AMGF 1-4). The evolution of benthic foraminiferal assemblages shows an increase in bathymetry from the internal platform in the Cerithium layers to the calcareous platform with large foraminifers, then to the external platform and the deep offshore environment of the Marnes Bleues and Grès d’Annot. Low faunal diversity in the Grès d’Annot together with the predominance of agglutinated species indicates a poorly oxygenated, organic rich and turbidite environment. Seven steps (SD 1 to SD 7) in the Eocene marine transgression are shown from East to West by detailed local biozonation and sequence analysis. Grès d’Annot sedimentation is also diachronous, beginning within the Truncorotaloides rohri zone (P 14, AMP 1) in the East and ending within the Pararotalia opima opima zone (P 20, middle Rupelian) in the West (Barrême). Small foraminifer Paleogene fauna from the Alpes Maritimes and Alpes de Haute Provence was studied from 400 samples. It is composed of 378 species. Two new taxa are proposed: Fissurina niceana n. sp. and Globocassidulina alpina n. sp. The species from the Escarène and Gorbio neighborhood described by M. von Hantken (1884) were re-examined.     

Differentiation between Neotropical rainforest,dry forest,and savannah ecosystems by their modern pollen spectra and implications for the fossil pollen record

Accurate differentiation between tropical forest and savannah ecosystems in the fossil pollen record is hampered by the combination of: i) poor taxonomic resolution in pollen identification, and ii) the high species diversity of many lowland tropical families, i.e. with many different growth forms living in numerous environmental settings. These barriers to interpreting the fossil record hinder our understanding of the past distributions of different Neotropical ecosystems and consequently cloud our knowledge of past climatic, biodiversity and carbon storage patterns. Modern pollen studies facilitate an improved understanding of how ecosystems are represented by the pollen their plants produce and therefore aid interpretation of fossil pollen records. To understand how to differentiate ecosystems palynologically, it is essential that a consistent sampling method is used across ecosystems. However, to date, modern pollen studies from tropical South America have employed a variety of methodologies (e.g. pollen traps, moss polsters, soil samples). In this paper, we present the first modern pollen study from the Neotropics to examine the modern pollen rain from moist evergreen tropical forest (METF), semi-deciduous dry tropical forest (SDTF) and wooded savannah (cerradão) using a consistent sampling methodology (pollen traps). Pollen rain was sampled annually in September for the years 1999–2001 from within permanent vegetation study plots in, or near, the Noel Kempff Mercado National Park (NKMNP), Bolivia. Comparison of the modern pollen rain within these plots with detailed floristic inventories allowed estimates of the relative pollen productivity and dispersal for individual taxa to be made (% pollen/% vegetation or ‘p/v’). The applicability of these data to interpreting fossil records from lake sediments was then explored by comparison with pollen assemblages obtained from five lake surface samples.Pollen productivity is demonstrated to vary inter-annually and conforms to a consistent hierarchy for any given year: METF > SDTF > cerradão. This suggests an association between pollen productivity and basic structural characteristics of the ecosystem, i.e. closed canopy vs. open canopy vs. savannah. Comparison of modern pollen and vegetation revealed that some important floristic elements were completely absent from the pollen: Qualea and Erisma (METF), Bauhinia, Simira and Guazuma (SDTF), and Pouteria and Caryocar (cerradão). Anadenanthera was found to be abundant in both the pollen and flora of SDTF (p/v = 3.6), while Poaceae was relatively poorly represented in cerradão (0.2). Moraceae, Cecropia and Schefflera were found to be over-represented palynologically in all ecosystems. Overall, the data demonstrated that no one taxon could be used as a definitive indicator of any of the ecosystems. Instead, associations of taxa were found to be important: METF = Moraceae (> 40%), Cecropia, Hyeronima, Celtis; SDTF = Anadenanthera, Apuleia, Ferdinandusa and non-arboreal Asteraceae, Bromeliaceae, Piper and fern spores; cerradão = Poaceae, Myrtaceae, Borreria, Solanum plus Asteraceae and fern spores. Interpretation of Poaceae pollen was highlighted as problematic, with relatively low abundance in the cerradão (< 20%) in comparison to high abundance in lake environments (c. 30–50%). Re-examination of fossil pollen records from NKMNP revealed that modern vegetation associations were only established in the last few thousand years.     

Ostracodes limniques de la Formation d'Irbzer, Crétacé terminal du Moyen-Atlas, Maroc : taxonomie, biostratigraphie, paléoécologie, paléobiogéographie

An association of limnic ostracodes has been discovered in the upper part of the Irbzer Formation, of Maastrichtian age, in the Moroccan Middle-Atlas. A new species is described, Gomphocythere achloujensis nov. sp. Paracandona occitanica, which is very common in terminal Cretaceous non-marine deposits of southern Europe (France, Spain), is found for the first time on the south Tethyan margin.     

Palynological characterisation of the Lower Carnian of the KEA5 borehole (Koudiat El Halfa Dome; Central Atlas, Tunisia)

In Central Tunisia, the Triassic outcrops of the Koudiat El Halfa and Rheouis Domes are mainly composed of an evaporite-dominated succession. The scarce biostratigraphic data available to date assign a Ladinian-Carnian age for the outcropping strata. The present palynological study data demonstrate an Early Carnian (Julian) age for the Triassic sediments penetrated by the KEA5 borehole in the Koudiat El Halfa Dome, which were previously considered to represent Middle Triassic. The palynological record mainly consists of Enzonalasporites vigens, Patinasporites densus, Vallasporites ignacii, Brodispora striata, Samaropollenites speciosus, Ovalipollis pseudoalatus in association with Circumpolles species such as Praecirculina granifer, Camerosporites secatus and Duplicisporites granulatus. In addition, Lagenella martini and Aulisporites astigmosus occur in the upper part of the drilled succession and their first appearance could indicate a Julian-Early Tuvalian age. These new data allow a palynostratigraphic correlation with the Rheouis Formation cropping out along the structural “North-South Axis” of Central Tunisia, particularly in the Jebel Rheouis Dome. The drilled succession can be correlated with the Black Dolostones (Tr3) and the Middle Gypsum (Tr4) members of the Rheouis Formation.     

Caractérisation de la production particulaire par l’oursin Echinometra mathaei sur les récifs Indo-Pacifiques : influence des peuplements coralliens et implications sur la dynamique sédimentaire

The characteristics of the sedimentary grains produced by the sea urchin Echinometra mathaei were described from two reef sites: a fringing Acropora-dominated reef at La Reunion island (Indian Ocean) and a barrier Porites-dominated reef at Moorea island (French Polynesia). The composition of the sediment produced by Echinometra was determined from SEM observations. The size and shape of the particles were measured by using image analysis method. The grain diameters range between a few micrometres and 2 mm, with a large predominance (more than 80 %) of particles smaller than 400 μm. The grain size distribution is dependent on the nature of the grazed substratum. Echinometra individuals collected at La Reunion on branching Acropora colonies produce a higher proportion of particles smaller than 200 μm compared to those collected at Moorea on massive Porites colonies. At Moorea, more grains having a diameter comprised between 200 and 500 μm are produced. The microstructure of coral substrata affects the mean particle diameter, which is 192,17 μm for a Acropora substratum and 244,69 μm for a Porites substratum. Since the sediment derived from Acropora erosion is finer, the proportion of suspended material that is exported from the reef is greater at La Reunion than at Moorea. We estimate that, for similar erosion rates and hydrodynamic conditions, the production of sands by Echinometra mathaei is higher and the retention of this erosional sediment more effective on reefs dominated by massive Porites than on Acropora-dominated reefs. This result is in accordance with the proportions of suspension-moving grains that have been previously measured on Moorea and La Reunion reefs. This study highlighted the effect of coral communities on the production of particles related to the bioerosion and on the sedimentary budget.     

The Zanclean palaeofloras around the Mont-Dore strato-volcano: A window into upper Neogene vegetation and environments in the Massif Central (Puy de Dome,France)

New Pliocene macrofloras and microfloras perfectly preserved from the Mont-Dore (Puy-de-Dôme, Massif central, France) have been reinvestigated. Samples come from different stratigraphical levels collected from three localities, Lac Chambon, La Gratade and Pont de Chocol. The ⁴⁰Ar/³⁹Ar radiometric datings bracketing the Chambon Lake and La Gratade fossil-bearing horizons give 4.46 ± 0.05 Ma and 3.94 ± 0.04 Ma, respectively, representative of the Zanclean Stage (= Brunssumian B and C), a period of the early Pliocene (5.32 to 3.6 Ma), much older than previously thought (i.e., Piacenzian). Pont de Chocol is considered to be close biostratigraphically, or even identical in age to La Gratade. Detailed morphological evaluation of leaf morphotypes completed with pollen analysis contributed to the better taxonomic knowledge of these palaeofloras. The overview focuses on floristic and phytostratigraphical characteristics of the defined stratigraphical units and their dating and correlation with previously defined palaeofloristic units of the Massif central. The study provides detailed identifications of plants representing 11 gymnosperms among which Pinaceae (pollen and winged seeds), Cupressaceae including “Taxodioid” pollen grains and Sciadopitaceae families (only pollen). Besides, different angiosperm trees and shrubs have been determined from both micro- and macro-remains. Fagaceae is the most diversified with several foliage of beech and deciduous oaks, while diversified Juglandaceae contribute mainly as abundant leaf remains of Carya, Pterocarya and Juglans; Ulmaceae with numerous leave of two Zelkova species, and also Ulmus. Various other deciduous dicotyledonous such as Alnus, Betula, Carpinus, Populus, Acer laetum and A. interrigenum are well documented. Leguminosae are recorded by a small number of leaflet imprints. Evergreen shrubs of Buxaceae (Buxus pliocenica) are scarce. All these taxa contribute to a rich biodiversity of these Pliocene assemblages. All three sites point towards riverine forest habitats dominated by hygrophilic diversified woody plants while in the surrounding plains and slopes the thermophilic elements were scarce and mesophilic taxa abundant as temperate elements. This vegetation can be compared with mixed mesophytic forests depicting a climate cooling during the two considered periods (ca. 4.46 and 3.95 Ma).