REVUE DE MICROPALEONTOLOGIE最新文献

A detailed palynostratigraphic study of two Somincor/Lundin Mining exploration drill holes intercepting the Phyllite-Quartzite (PQ) Formation in the geological basement of the Neves-Corvo mine region (Portuguese sector of the Iberian Pyrite Belt – IPB) allowed to first recognise the oldest ages for this formation in this region, ranging from midGivetian/midFrasnian (base unknown) to late Famennian. The TA Miospore Biozone (Cristatisporites triangulatus-Ancyrospora ancyrea) of middle Givetian age (Middle Devonian) was identified in NK30B-1 drill hole (Lombador North mine sector), whereas the BM Miospore Biozone (Verrucosisporites bulliferus-Lophozonotriletes media) and IV Miospore Biozone (based in the first occurrence of Rugospora bricei and Diducites cf. poljessicus) of middle Frasnian (Late Devonian) age were both recognised in drill hole SJ32 (Corvo-Semblana mine sector). The common presence of Early-Middle Devonian reworked spores, as well as similar inherited zircon ages may suggest that the lower PQ Formation age is not yet known.

At Neves-Corvo mine, the Volcano-Sedimentary Complex is deposited directly above the PQ basement, spanning different ages, pointing out two major unconformities, a VSC/upper and/or lower PQ sequences and an upper PQ/lower PQ sequences.

A palynostratigraphic correlation of the lowermost Phyllite-Quartzite Formation across the IPB is established. Phyllite-Quartzite Formation palynoassemblage of Neves-Corvo region is compared with lowermost PQ assemblages recovered in the NW sector of IPB (S. Francisco da Serra and Lousal-Caveira mine structures, Portugal) and in E sectors of the IPB in Spain (Gerena-El Garrobo section). The similar palynological record (also including the same reworked taxa signature) and ages obtained, suggests identical sedimentary provenance, close paleogeographic domain and temporal affinity throughout the lowermost IPB Phyllite-Quartzite Formation.

Mediterranean mountain ecosystems have been attractive to human societies due to their valuable resources, but are also susceptible to environmental and climate changes. The Rhodope Mountain Range hosts one of the least disturbed natural forests of Europe and is a conservation priority area in the Southern Balkans. Located in the borderlands of the plain of Macedonia, the forest ecosystem development of Rhodope Mountains was shaped not only by Late Holocene climatic variability, but also by changes in human activities since Byzantine times. Palynological and microscopic charcoal analysis of the Livaditis ombrotrophic bog record offers unique insights into vegetation and landscape evolution under the influence of human land-use practices in the south Rhodope area during the last c.a. 1100 years. The findings show a forested landscape, with well-developed Pinus and Abies forests of in the montane zone and mixed deciduous oak forests below that flourished in the area until 900 AD. The expansion of human activity in mountainous areas during the period of Byzantine economic growth (ca. 1000 AD) is evidenced by forest clearance through fire, affecting mainly the Abies populations. The Livaditis record bears evidence about both, arboriculture and cereal cultivation as well as animal husbandry during the first period of human activities in the uplands, while a shift towards pastoralism is most likely associated with the establishment of the Vlach population in the region (ca. 1200 AD). Subsequently, a short-lived expansion of the Pinus percentages could be attributed to the afforestation of abandoned pasture land during the Little Ice Age. Finally, a further intensification of pastoralism is most likely concurrent with the population expansion documented during the Ottoman period (after 1500 AD). The Livaditis pollen record shows significant vegetation shifts in the upland area of southern Rhodope Mountains that could be associated with changes in climate, population mobility and density, as well as evolving land-use practices.

A 3 m thick carbonate sequence from northern Chios Island is assigned here to the latest Capitanian/earliest Wuchiapingian transitional interval. It is characterized by abundant gymnocodiacean algae, associated with some miliolate, nankinellin and nodosariate foraminifers. These strata display bioaccumulated perireefal microfacies with richthofeniid brachiopods and inozoa calcisponges. They are biostratigraphically characterized by a foraminifera assemblage composed of Reichelina cf. simplex, Dunbarula? sp., Altineria alpinotaurica together with the genera Labioglobivalvulina, Frondina and Robuloides. Other perireefal microfacies show abundant fragments of a new tubiphytid species, Tubiphytella guevenci Vachard nov. gen. nov. sp. Based on this study, the paleogeographical distribution of Altineria alpinotaurica now includes Chios, in addition to the Taurus and the NW and central Iran, whereas primitive forms of the genus are also known in Tunisia and Armenia. This paleobiogeographic distribution would suggest that all these regions still belonged to the Perigondwana margin in the early Wuchiapingian times. Consequently, it is likely that the opening of the Neotethys ocean did not begin prior to the late Wuchiapingian-early Changshingian transitional interval.

We describe paper models which represent the cortical shell structures of radiolarian genus Pantanellium using the unit origami method: the construction of a polyhedral frame using origami units. Each unit corresponds to the edge of a polyhedron. The models are constructed based on planar graphs representing the cortical shell structures of real specimens. The resulting models reproduce the cortical shell structures appropriately. This means that the origami model is useful for both naked-eye practical observation of shell structures and group educational/art activities.

Introduction of new, more specialized, non-destructive techniques into palaeoenvironmental and palaeoclimatic research, has proven to be of a great asset, over the last decades. Geoarchives like sediment cores can thus be studied with much higher resolution, faster and with less effort, providing significantly more information about sediment composition, grain size and structure. In this study, we applied X-ray fluorescence (XRF) and computed tomography (CT) analysis on two different sediment cores, retrieved from a typical lagoonal environment and a marsh field in western Peloponnese, Greece. XRF scanning was used with a step of 0.5 cm in order to obtain a detailed elemental profile of the core, whereas CT scan was performed with a resolution of 0.3 mm. Concerning elemental compound and X-ray absorption, distinct correlation between HU and terrigenous elements was observed. Furthermore, through 3D reconstruction of the cores sections, we explored possible methods for fauna/sediment ratio, as well as microstructural characteristics. The combined appliance of those two techniques on the two sediment cores that were studied seems to provide robust results concerning sedimentological facies, biofacies and sediment structure.

A new orbitolinid is described as Orbitolinopsis cenomaniensis n. sp. from the middle-?late Cenomanian of the Sarvak Formation, Zagros Zone, SW Iran. It is characterized by a high-conical test, a simple embryo consisting of proloculus and deuteroconch in subapical position, a rather narrow marginal zone and a prominent central zone with cupules that can present a jagged outline. The regular occurrence of one short rafter is considered a species characteristic of the species, one case that is also encountered in other dictyoconid taxa (e.g., Montseciella, Paracoskinolina, Simplorbitolina, Valserina). Single sporadic rafters have been reported from the early Albian Orbitolinopsis ajoensis Schlagintweit et al. demonstrating a distinct trend towards an increasing in morphological complexity. The Iranian find represents the first record of Orbitolinopsis from the Cenomanian. Like several other taxa of larger benthic foraminifera (agglutinating and porcelaneous), O. cenomaniensis is here considered an endemic taxon for the Arabian Plate.

This study discusses three species of Stylotrochus recently observed in small numbers in six cores from the southern Indian Ocean and seven in the Bellingshausen Basin. It describes their geographical and chronological distributions and relates them to the reports of previous researchers. It also seeks to erect two new species of Stylotrochus, one of which is designed to replace Spongodiscus biconcavus, nomen dubium.

A new radiolarian assemblage was recovered from upper Ladinian–lower Carnian strata of the southeastern part of Omolon Massif. The assemblage has several taxa in common with the upper Ladinian of the western part of the Omolon Massif and the lower Carnian of Kotel’nyi Island (New Siberian Islands, Arctic) and displays clear boreal features: low taxonomic and morphological diversity, abundance of taxa known from high-latitude regions and rare presence of taxa known from low-latitude areas. Two new species are described: Praenanina? hirsuta nov. sp. and Hindeosphaera venusta nov. sp.