Petrographical differentiation between Palaeozoic oolitic ironstones from France, Belgium and Germany and application to the provenance study of archaeological artefacts – preliminary results

Conference (2013, February 07)

Samples of Palaeozoic oolitic ironstone beds susceptible of having being used as raw materials for Neolithic red ochres, have been petrographically investigated. The preliminary results of this first ... [more ▼]

Samples of Palaeozoic oolitic ironstone beds susceptible of having being used as raw materials for Neolithic red ochres, have been petrographically investigated. The preliminary results of this first comparative analysis are quite encouraging: microfacies differences have been observed between Ordovician oolitic ironstones from Normandy (France), late Upper Devonian oolitic ironstones from Belgium and uppermost Lower Devonian to lowermost Middle-Devonian (Emsian-Eifelian) oolitic ironstones from the Eifel area (Germany). Petrographical differentiation is based upon contrasting grain size, mineralogy (hematite/chlorite ratio) and typology of the ferruginous ooids, besides differences in mineralogy, diagenetic history and lithologic nature of the host sediments. Most conspicuous are differences in ferruginous ooid typology, including “true” concentric ooids, superficial ooids, algal oncoids and pseudo-ooids (ferruginized cortoids and rounded bioclasts). “Flax seed” or Clinton-type iron ores (rich in flattened ooids) and “fossil iron ores” (essentially composed of ferruginized bioclasts) can be identified as well as transitional or mixed types. Homogenous and well-sorted, often flattened and fine-grained ferruginous “true” ooids (flax seed ore) with alternating hematite and chlorite cortices in a sideritic- chloritic or fine siliciclastic matrix, are characteristic for the Ordovician (Llanvirn) oolitic ironstones of Normandy (basal part of the Urville Shales). Locally, weathered levels exist, enclosing limonitic (goethitic) crusts. Medium-sorted, fine-to coarse- grained ferruginous hematitic pseudo-ooids (ferruginized bioclasts) in a bioclastic limestone matrix (fossil ore) characterize the Lower-Middle Devonian boundary oolitic ironstone beds (Heisdorf and Lauch Formations, Eifel Synclines). Finally, well- to medium-sorted heterogenous, fine- to medium-grained, pure or mixed flax seed- and fossil ore-type hematitic oolitic ironstones in siliclastic and/ore carbonate matrices, characterize the Belgian Latest Upper Devonian (Famennian) ironstone deposits (Hodimont Formation, Famenne Shales Group). Several stratigraphic levels do exist within the Lower Famennian and basal part of the Upper Famennian in the Namur, Dinant and Vesdre Synclinoria, but the lowermost Famennian one is the only level that has been mined. Within some of the younger Famennian oolitic ironstone levels, proximal and distal facies can be distinguished on the basis of microfacies differences and mineralogy of the ferruginous pseudo-ooids. Only the proximal hematitic facies of the lowest stratigraphical oolitic ironstone level (level I) is supposed to have been used in prehistoric times for the manufacturing of ochre. Diagenetic sideritization and dolomitization, particle deformation as well as sulphide mineralizations, affect most of the studied oolitic ironstones. However, the intensity of these mineralizations varies strongly (even within the same deposit) and depends on local tectonics. A distinction can be made between the Emsian-Eifelian and Famennian fossil iron ores, based on the nature of the bioclasts and other ferruginzed components). Eifelian oolitic ironstones contain ferruginized crinoids, bryozoans, trilobites, brachiopods, goniatites besides ferruginized siliciclastic intraclasts, whereas the Famennian ones are dominated by ferruginous ooids and algal oncoids, mixed with ferruginized bioclasts including crinoids, bryozoans, brachiopods, ostracods, algae and incertae sedis, and locally intraclasts (ferruginized stromatolitic crusts). Distal facies contain slightly Fe-impregnated bioclasts only such as crinoid ossicles and display a higher chlorite/hematite ratio. Thin sections have been made in archeological objects (red ochre), allowing a first comparative petrographical analysis indicating their probable geological and geographical provenance. References Ph. Joseph, 1982. Le minerai de fer oolithique Ordovicien du Massif Armoricain: sédimentologie et paléogéographie. Thèse présentée à l’Ecole Nationale Supérieure des Mines de Paris. 325 p. R. Dreesen, 1989. Oolitic ironstones as event-stratigraphical marker beds within the Upper Devonian of the Ardenno-Rhenish Massif, in: Young, T.P. & Taylor, W.E.G. (eds), Phanerozoic Ironstones. Geological Society Special Publications, n°46, pp. 65-78 Rath, S., 2003. Die Erforschungsgeschichtede Eifel-Geologie. Ph.D. Dissertation, Rheinisch- Westfälische Technische Hochschule Aachen, 239 p. [less ▲]

Geological record and sedimentology of the Palaeozoic oolitic ironstone deposits in Western Europe. Spatial relationships with the Linienbandkeramik settlements (LBK) in Belgium.

Conference (2013, February 07)

Mined since prehistoric times, oolitic ironstones (OIS) were a very important world source of iron from 1850 to 1945: hereafter they have been progressively replaced by the Precambrian Banded Iron ... [more ▼]

Mined since prehistoric times, oolitic ironstones (OIS) were a very important world source of iron from 1850 to 1945: hereafter they have been progressively replaced by the Precambrian Banded Iron- Formations (BIF). OIS are iron-rich sedimentary rocks bearing ferruginous ooids. They consist of at least 15% iron. In Western Europe, their overall depositional environment is that of a shallow shelf, most often located close to the transition from non-marine to marine environments. Their main age range is concentrated within the Ordovician through Devonian and the Jurassic through Paleogene. Proterozoic occurrences are known but these occur outside Europe. The host rocks of the ironstones are predominantly clastic, whereas the host sediment of the ferruginous ooids can be either clastic or carbonate or both. The OIS occur at the top of coarsening and shoaling upward cycles. They represent condensed deposits and transgressive system tracts. Numerous oolitic ironstone deposits are interpreted as tempestites or as intertidal deposits. It is generally agreed that ferruginous ooids formed in shallow marine water conditions, near the water-sediment interface, with repeated reworking of the sediment. Such an environment implies oxidizing conditions, the sedimentary iron being in the ferric state. The exact source of the iron is still a matter of discussion and speculation, just as the primary or secondary origin of the ferruginous ooids. Besides hematite (or goethite), also siderite, Fe-dolomite and berthierine/chamosite are present in the OIS as iron-bearing minerals. Due to weathering processes the carbonate matrix is often removed, the iron is released and oxidized, whereas the ferrous silicates are converted into ferric oxides or ferric hydroxides. Many old mining activities are based on occurrences of this weathered ore. The latter material has also strong staining properties. 1. Germany OIS are outcropping in the Eifel area. The latter is part of the Ardenno-Rhenish Massif and lies in the eastern extension of the Neufchateau Synclinorium, south of the Ardenne Anticlinorium (enclosing the Cambro-Ordovician Stavelot-Venn inlier). The general structure of the Eifel corresponds to an intensively folded and faulted synclinorium In the center of this synclinorium, outcrops of OIS occur on both flanks of successive synclines that are individually named (from the north to the south): the Sötenicher Mulde, the Blankenheimer Mulde the Rohrer Mulde, the Dollendorfer Mulde, the Ahrdorfer Mulde and the Hillesheimer Mulde. Two important stratigraphic levels with IOS are known and they coincide more or less with the Lower-Middle Devonian boundary (Uppermost Emsian- Lowermost Eifelian). These OIS represent excellent marker beds for geological mapping. 2. The Netherlands There is no outcrop of OIS in this country. 3. Belgium Oolitic iron ores were formed during different periods in Belgium: the Lochkovian (Lower Devonian, Dinant Synclinorium, restricted to the Belgian-French border), the Givetian (Middle Devonian, Dinant Synclinorium), the Frasnian (Upper Devonian, Dinant Synclinorium), the Famennian (Upper Devonian, Namur S., Dinant S. & Vesdre S.) and the Toarcian-Aalenian (Jurassic, Lorraine area, Paris Basin – called “minette ore”). The most important OIS level is the Lower Famennian one. It has been intensively mined until the middle of the 20th century, essentially in the Namur Synclinorium, between the cities of Namur and Huy. In this area, its important thickness (until 1.85m) and the number of layers triggered the development of an important economic activity. Outcrops were restricted to the tributaries of the Meuse River. The Famennian oolitic ironstone facies change from north to south by a gradual decrease in the number of layers, in their thickness, grain size, ooid concentration, clast size and iron content. They represent also excellent lithostratigraphical marker beds. The clay-dolomitic matrix is being progressively replaced by a calcitic cement. The other Devonian OIS levels are not of great economic importance, they were only mined locally, to supply smith’s working places. Due to surface mining, outcrops are now very rare, and often indicated by a light depression in the topography only. 4. Grand-Duchy of Luxembourg OIS are restricted to the Jurassic (Aalenian-Lower Bajocian) in the NW part of the Paris Basin. This essentially goethitic ore (“minette”) was intensively mined in the three adjacent country borders area (FR-BE-LU). No OIS levels in the Lower Devonian are outcropping in the northern part of the Grand Duchy. 5. France Numerous OIS layers are known in France at several stratigraphical levels, but a lot of them cannot be considered as a real ore. Paleozoic OIS belonging to the Armorican Massif were mined in the Normandy area (Urville Fm, Llanvirn, Middle Ordovician) and in the Bretagne area (Arenig, Lower Ordovician). In Normandy, OIS do outcrop inside several synclines (e.g. May and Urville Sy.), as one thick composite layer.  The spatial relationships of the different oolitic ironstone levels with the Linienbandkeramik settlements (LBK) in the studied area, will be presented. [less ▲]

Prévalence des cas de lymphadénite granulomateuse sous‐maxillaire chez des porcs abattus en Belgique

Poster (2013, February 06)

In pigs the Mycobacterium avium complex (MAC) causes granulomatous lymphadenitis. Carcasses with such lesions must be detected, as parts of the affected carcasses and organs have to be condemned. These ... [more ▼]

In pigs the Mycobacterium avium complex (MAC) causes granulomatous lymphadenitis. Carcasses with such lesions must be detected, as parts of the affected carcasses and organs have to be condemned. These nontuberculous mycobacteria are opportunistic pathogens which have acquired an increasing importance in public health in recent decades due to their ability to cause lung diseases, lymphadenitis in children and systemic infections in immunocompromised patients ‐ even if the potential risk of infection of an immunocompromised person by MAC in the consumption of undercooked pork still has to be determined. The first objective of this study was to evaluate the prevalence of submandibular granulomatous lymphadenitis in pigs slaughtered in Belgium. Between August 2010 and September 2011, 16,211 carcasses were inspected by the same veterinarian in 2 slaughterhouses – one in Flanders, the other in Wallonia. Eighty‐six suspected cases of submandibular granulomatous lymphadenitis (0.53% of pigs; 95% Confidence Interval: 0.42‐0.65%) were identified, collected and submitted to histopathological (Ziehl‐Neelsen and haematoxylin‐eosin staining) and bacteriological (culture, PCR, molecular typing) tests. The second objective of the study was to characterize lesions and to identify the relative importance of MAC and Rhodococcus equi to explain the lesions. Mycobacterium avium subsp. hominissuis (MAH) was isolated from 6 lymph nodes (7.0%; 95% CI: 2.6‐14.6%) and Rhodococcus equi from 45 (52.3%; 95% CI: 41.3‐63.2%). The final objective of the study consisted in farm investigation to evaluate the possible source of contamination of pigs by MAH. Potential sources such as sawdust, water, wild birds and/or cattle were identified. [less ▲]

(Re)productive Tradition in Ancient Egyptian

Conference (2013, February 06)

Compte rendu de Boschetti (Anna) (dir.), L’espace culturel transnational.

in COnTEXTES : Revue de Sociologie de la Littérature (2013)

Rôle de TGF alpha dans la thérapie du mésothéliome

Doctoral thesis (2013)

Background. Malignant mesothelioma (MM) is a cancer of the pleura caused mainly by the inhalation of asbestos fibers. The impact of chemotherapy on the outcome of patients with MM is still unclear. We ... [more ▼]

Background. Malignant mesothelioma (MM) is a cancer of the pleura caused mainly by the inhalation of asbestos fibers. The impact of chemotherapy on the outcome of patients with MM is still unclear. We hypothesized that unresponsiveness to chemotherapy is due to inadequate gene expression in tumor cells. We have previously shown that inhibitors of histones deacetylases (such as valproate, VPA) significantly increases the efficacy of compounds used in chemotherapy. A recent clinical trial on relapsing MM patients has shown that VPA in combination with doxorubicin improves response rates and quality of life. Methods. Using Agilent microarrays, we compared the transcriptome of two types of cell lines (M14K and H28). Bioinformatic analyzes (Ingenuity) identified the most relevant candidate genes. Expression of transforming growth factor-alpha (TGFα) was validated by RT-qPCR and ELISA. TGFα expression level was modulated negatively by RNA interference and positively by transfection of a cDNA vector. TGFα signaling was reduced with EGFR tyrosine kinase inhibitors gefitinib and erlotinib. Apoptosis was evaluated by different techniques assessing DNA fragmentation, phosphatidylserine externalization and caspase activity. Combination chemotherapy was investigated in two mouse models (ZL34 in SCID and AB12 in Balb/c). Results. To study the mechanisms associated with the response to chemotherapy, we compared two types of cell lines (M14K and H28) characterized by a difference in sensitivity to doxorubicin+VPA. We observed that the basal expression level of TGFα was higher in "resistant" H28 compared to "sensitive" M14K cells. To evaluate the functional relevance of TGFα, we modulated its expression either by RNA interference or by transfection of a cDNA vector. A decrease of TGFα expression correlated with induction of apoptosis. Inversely, an inhibition of apoptosis occurred when TGFα was over-expressed. As TGFα is the ligand of EGFR, we tested the effect of gefitinib and erlotinib in combination with VPA+doxorubicin. Both EGFR inhibitors increased apoptosis induced by VPA+doxorubicin in H28 chemoresistant cells. Finally, the VPA+doxorubicin+erlotinib regimen prevented tumor growth in mice. Conclusions. Our data demonstrates that TGFα is involved in the chemoresistance to VPA+doxorubicin, a second-line regimen for MM. Although inefficient alone, tyrosine kinase inhibitors synergize to induce apoptosis in chemoresistant cells and prevent tumor growth in mouse models. [less ▲]

Quand les carottes sont soumises à la question

Scientific conference (2013, February 05)

Phosphorus availability : influence of soil characteristics and fertilization

Scientific conference (2013, February 04)

« Aigre, sucré, amer et épicé » Comment les travailleurs migrants racontent leurs expériences de vie et de labeur en Chine

Scientific conference (2013, February 03)

Les migrations de ruraux vers les villes chinoises concernent aujourd’hui de 150 à 200 millions de personnes. Comment ces travailleurs migrants racontent-ils leurs expériences de vie, de labeur «de sang ... [more ▼]

Les migrations de ruraux vers les villes chinoises concernent aujourd’hui de 150 à 200 millions de personnes. Comment ces travailleurs migrants racontent-ils leurs expériences de vie, de labeur «de sang et de sueur», leurs aspirations et leurs espoirs ? Comment réinventent-ils leur village natal entre un milieu urbain souvent idéalisé et une expérience quotidienne faite d’indignité, de marginalisation et de précarité ? Quelles formes prennent les processus de construction de leur identité collective et comment ces processus s’articulent-ils aux luttes menées au quotidien pour défendre leurs droits ? Nous tenterons de répondre à ces questions en allant au plus près des vies de ces travailleurs à travers un exposé vivant, parsemé d’extraits de films, de chansons et autres récits populaires. [less ▲]

Galactic archaeology: mapping and dating stellar populations with asteroseismology of red-giant stars

in Monthly Notices of the Royal Astronomical Society (2013), 429

Our understanding of how the Galaxy was formed and evolves is severely hampered by the lack of precise constraints on basic stellar properties such as distances, masses and ages. Here, we show that solar ... [more ▼]

Our understanding of how the Galaxy was formed and evolves is severely hampered by the lack of precise constraints on basic stellar properties such as distances, masses and ages. Here, we show that solar-like pulsating red giants represent a well-populated class of accurate distance indicators, spanning a large age range, which can be used to map and date the Galactic disc in the regions probed by observations made by the CoRoT and Kepler space telescopes. When combined with photometric constraints, the pulsation spectra of such evolved stars not only reveal their radii, and hence distances, but also provide well-constrained estimates of their masses, which are reliable proxies for the ages of the stars. As a first application, we consider red giants observed by CoRoT in two different parts of the Milky Way, and determine precise distances for ˜2000 stars spread across nearly 15 000 pc of the Galactic disc, exploring regions which are a long way from the solar neighbourhood. We find significant differences in the mass distributions of these two samples which, by comparison with predictions of synthetic models of the Milky Way, we interpret as mainly due to the vertical gradient in the distribution of stellar masses (hence ages) in the disc. In the future, the availability of spectroscopic constraints for this sample of stars will not only improve the age determination, but also provide crucial constraints on age-velocity and age-metallicity relations at different Galactocentric radii and heights from the plane. [less ▲]