Des Pillaouer de Ploeuc-sur-Lié aux chiffonniers de Gournay-en-Bray (1881-1977)

L'émigration bretonne prit différentes formes aux XIXe et XXe siècle. Le métier de chiffonnier offrait des possibilités d'amasser un petit pécule ou bien même de s'enrichir. Les chiffonniers du canton de Gournay-en-Bray illustrent assez bien ce propos et cet article et montre l'organisation d'une petite colonie chiffonnière dans un pays d'élevage.Migration from Brittany took many forms during the XIXth and XXth centuries. Working as a rag picker offered an opportunity to save a small sum or even to become rich. Rag pickers of the canton of Gournay-en-Bray are a good case in point: a small rag pickers’ colony organizes around an unhealthy profession in a cattle-raising district

Culture de thyrocytes humains en monocouches et en follicules : aspects fondamentaux et appliques

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Palynostratigraphie du paléozoïque du super-groupe du Karoo et intérêt des palynofacies pour les interprétations paléoenvironnementales, bassin du Karoo-Kalahari, Botswana

Les strates du carbonifère supérieur et Permien de la séquence du Karoo inférieur, dans le bassin du Karoo Kalahari au Botswana, se sont révélées riches en palynomorphes et favorables pour une étude palynostratigraphique. Neuf sondages ont été échantillonnés et l analyse systématique à permis d identifier cent soixante-cinq espèces de spores et pollens, onze espèces d acritarches, sept espèces de prasinophycées et une espèce de chlorophycée. Sur la base de la distribution des espèces dans les sondages, STRAT 1 et CKP6, 3 zones d intervalles (2 zones d intervalles de concurrence et 1 zone d intervalle de taxon) et 3 zones d assemblages ont été définies. La section STRAT 1, riche en palynomorphes bien conservés, a été choisie comme section standard de référence. Par comparaison avec d autres zonations régionales ou définies à l échelle du Gondwana, les palynozones du sondage STRAT 1 indiquent des âges allant du Carbonifère supérieur (Kasimovien Gzhelien) â la base du Permien supérieur (Roadien), pour les séries du Karoo inférieur dans le bassin du Karoo Kalahari. De grandes variations paléoclimatiques sont déduites de l analyse qualitative, depuis des conditions froides â humides durant le dépôt des faciès glaciaires de la Formation Dwyka, à des conditions chaudes et sèches durant le dépôt correspondant à la partie inférieure de la Formation Ecca. Les conditions paléoclimatiques deviennent humides par la suite, dans la partie moyenne de la Formation Ecca, et sont responsables de la formation de charbons. Les interprétations paléoenvironnementales basées sur les palynofaciès, indiquent un mode de dépôt essentiellement proximal pour l ensemble des séries du Karoo.Late Carboniferous to Permian strata of the Lower Karoo sequence in the Kalahari Karoo Basin, Botswana, contains suitably preserved palynomorphs for biostratigraphic classifications. Nine boreholes have been sampled for the study, and one hundred and sixty-five miospore species, eleven acritarchs species, seven prasinophytes species, and 1 chlorophyte species are described. On the basis of species ranges, in boreholes STRAT 1 and CKP8, three Range Zones (2 concurrent range zones and 1 taxon range zone) and three Assemblage Zones, for each section have been distinguished. STRAT 1, choose as reference section, has also been subdivided on the basis of palynofacies data generating stratigraphic marker horizons. Lithological comparisons with the palynozones reveal a younging of the Dwyka glacial fades to the southwest, from CKP6 to STRAT 1, representing the palaeo-trend in glacial migration. Age determination deduced from a comparison of the palynozones of STRAT I section, with other regional and Gondwana-wide zonation schemes indicate Late Carboniferous (Kasimovian Gzhelian) to earliest Late Permian (Roadian) ages for the Lower Karoo sequence in the Kalahari Karoo Basin. Broad palaeoclimatic inferences from the qualitative analysis support a transition from cold and humid conditions, during deposition of the Dwyka glacial facies, to warm and drier conditions during deposition of the lower Ecca sequences. Palaeoclimatic conditions ultimately turned wet during middle Ecca times generating coal-forming settings. Palaeoenvironmental interpretations based on palynofacies data indicate a predominantly proximal palaeo-depositional setting for the entire Lower KarooBREST-BU Droit-Sciences-Sports (290192103) / SudocSudocFranceF

Palynology and geochemistry of the Frasnian global transgression in the Parnaiba Basin, Brazil

An integrated palynological and geochemical approach has been initiated to date and to precise the geochemical events of the Pimenteiras Formation, in the Late Devonian from the Parnaiba Basin, Brazil. Based on good biostratigraphic markers and presence of index species among miospores, acritarchs and chitinozoa, the investigated sequences are referred to the Middle to early Late Frasnian. Among Miospores, Chelinospora concinna and Verrucosisporites Witt-eras are likely to be from the BPi Interval Zone defined in the Amazon Basin. Chitinozoans of the Early to early Late Frasnian Angochitina (Lagenochitina) avelinoi zone of the Parnaiba Basin are present, and acritarch assemblages arc also consistent with a Middle to early Late Frasnian age, by comparison to assemblages previously described in other Brazilian basins. Some important accompanying species of palynomorphs are illustrated. In the studied outcrops, black shale intervals are referred to top of the Radioactive Sale B and Radioactive Shale C according to Rodrigues (1995) definitions. Top of Radioactive Shale B shows good concentration of terrestrial organic matter, but low potential source of gas. By comparison Radioactive Shale C of the upper part of the Pimenteiras Formation, with important concentration of marine organic matter have low to high potential as source of gas and condensate. This study shows that a progressive flooding took place during the Devonian period in the Parnaiba Basin with maximum marine transgression in the Frasnian. These global events of interest for hydrocarbon exploration, are regarded as markers for Gondwanan regional chronostratigraphic correlations. (C) 2020 Published by Elsevier B.V

Le Paléozoïque de la Presqu'île de Crozon, Massif Armoricain (France)

Geological outcrops are of good quality along the foreshore and cliffs in Crozon Peninsula allowing the study of Paleozoic series of the Armorican Massif. The sedimentary and faunal evolution of this area is part of the history of the Gondwana margin and records the opening of the Rhéic Ocean, eustatic variations and paleogeographic migration from high latitudes in the Ordovician to a sub-equatorial position in the Carboniferous. Geological outline of the Armorican Massif is briefly exposed and integrated in a climatic, eustatic and tectonic global framework. Afterwards, the second part deals with formations of the Crozon Peninsula since the Ordovician to Upper Devonian with their faunal and sedimentological characteristics. In the third part, the main outcrops visited during the fieldtrip of the Paleozoic French Group (GFP) during the Congress « Strati 2010 » are described; these outcrops illustrate some aspects of the armorican geological history