Measuring plume-related exhumation of the British Isles in Early Cenozoic times

Mantle plumes have been proposed to exert a first-order control on the morphology of Earth's surface. However, there is little consensus on the lifespan of the convectively supported topography. Here, we focus on the Cenozoic uplift and exhumation history of the British Isles. While uplift in the absence of major regional tectonic activity has long been documented, the causative mechanism is highly controversial, and direct exhumation estimates are hindered by the near-complete absence of onshore post-Cretaceous sediments (outside Northern Ireland) and the truncated stratigraphic record of many offshore basins. Two main hypotheses have been developed by previous studies: epeirogenic exhumation driven by the proto-Iceland plume, or multiple phases of Cenozoic compression driven by far-field stresses. Here, we present a new thermochronological dataset comprising 43 apatite fission track (AFT) and 102 (U–Th–Sm)/He (AHe) dates from the onshore British Isles. Inverse modelling of vertical sample profiles allows us to define well-constrained regional cooling histories. Crucially, during the Paleocene, the thermal history models show that a rapid exhumation pulse (1–2.5 km) occurred, focused on the Irish Sea. Exhumation is greatest in the north of the Irish Sea region, and decreases in intensity to the south and west. The spatial pattern of Paleocene exhumation is in agreement with the extent of magmatic underplating inferred from geophysical studies, and the timing of uplift and exhumation is synchronous with emplacement of the plume-related British and Irish Paleogene Igneous Province (BIPIP). Prior to the Paleocene exhumation pulse, the Mesozoic onshore exhumation pulse is mainly linked to the uplift and erosion of the hinterland during the complex and long-lived rifting history of the neighbouring offshore basins. The extent of Neogene exhumation is difficult to constrain due to the poor sensitivity of the AHe and AFT systems at low temperatures. We conclude that the Cenozoic topographic evolution of the British Isles is the result of plume-driven uplift and exhumation, with inversion under compressive stress playing a secondary role

Transgenesis and humanization of murine antibodies.

International audienceThe properties of monoclonal antibodies explain why they are such a successful class of therapeutic molecules. However, pionneered initial antibodies were of murine origin and triggered an immune response which limited the therapeutic potential of the antibody and generated deleterious effects. Consequently, tremendous efforts have been developped to engineer these murine Ig by introducing human sequences in vitro, or in vivo by humanization of murine antibodies, leading to chimeric immunoglobulins, and more recently generation of fully human antibodies in transgenic mice with a more or less diversified V repertoire. These approaches have led to the development of an increasing number of these chimeric or humanized monoclonal antibodies entering pharmaceutical pipelines. double dagger

A new paleogeographic configuration of the Eurasian landmass resolves a paleomagnetic paradox of the Tarim Basin (China)

International audienceNew paleomagnetic data from Permian red beds and Middle Jurassic limestones from the Tarim Basin pose a paradox. Their declinations are similar to Upper Carboniferous to Neogene rocks collected from the same sections, and their inclinations parallel present values. When assuming that lower than expected inclinations in continental sedimentary rocks arise from inclination shallowing effects, then the paleolatitudes of all Upper Carboniferous to Present rocks from Tarim are indistinguishable. Local vertical axis block rotations occurring in the last 20 million years explain why declinations vary at different localities in the basin. Our Middle Jurassic data positions Tarim 23.6 ± 8.4° farther south than that predicted from the coeval reference pole for Eurasia; however, no geologic argument exists to support the closure of a large ocean basin between Tarim and Siberia since the Middle Jurassic. Thus the paradox: are the rocks from Tarim totally overprinted, or is the middle Mesozoic part of the reference Eurasian apparent polar wander path erroneous? Several lines of evidence suggest the Tarim rocks are not remagnetized. We conclude that Tarim has experienced little or no apparent polar wander since the Carboniferous. Moreover, our Middle Mesozoic reconstruction of Eurasia using the new Middle Jurassic pole from Tarim results in a more geologically compatible solution for the eastern Asian blocks over previous reconstructions

Le patriciat milanais et ses propriétés urbaines au XVIIIe siècle

L’historiographie présente traditionnellement le patriciat milanais comme l’élite politique, sociale et économique de la Lombardie, tendant à gommer la diversité des familles qui le composent. L’étude des propriétés urbaines du groupe social, au milieu du XVIIIe siècle, est l’occasion de mettre en évidence sa nature composite en expliquant la grande variété des profils patrimoniaux (nombre et valeur des biens, place de la résidence). Les familles patriciennes se caractérisent en effet par de grands écarts de fortune ou de pouvoir et par des origines sociales variées (monde marchand, juridique ou féodal). Ces décalages dans les niveaux de richesse, d’implication institutionnelle ou de provenance sociale apparaissent déterminants pour comprendre leurs choix d’investissements immobiliers.Traditionally, the historiography presents the Milanese patriciate like the political, social and economic elite of Lombardy, tending to smooth out the family diversity they are made of. The study of urban properties of this social group in the middle of the eighteenth century gives rise to highlight on his composite nature, explaining the large variety of properties profiles (quantity and value of estates, place of residence). The patricians’ families are indeed qualified by large differences of fortune or power and by various social origins (trade, juridical or feudal society). These discrepancies on wealth standards, institutional involvement or social origins are clearly decisive to understand the choices about housing investments.La storiografia presenta tradizionalmente il patriziato milanese come la élite politica, sociale ed economica della Lombardia, mirante a cancellare la diversità delle famiglie che la compongono. Lo studio delle proprietà urbane del gruppo sociale, nella metà del Settecento, offre l’occasione di evidenziare la sua natura composita palesando la grande varietà dei profili patrimoniali (numero e valore dei beni, collocazione della residenza). Le famiglie patrizie si caratterizzano in effetti con grandi divari di fortune o di potere e da origini sociali varie (mondo mercantile, giuridico o feodale). Tali sfasature nei livelli di ricchezza, di coinvolgimento istituzionale o di provenienza sociale appaiono decisivi per capire le loro scelte negli investimenti immobiliari

Entre Paris et la province : construction à plusieurs voix d'un média par correspondance au XVIIIe siècle

Ce mémoire propose une étude sur le texte Correspondance de quelques gens du monde sur les affaires du tems publié à Paris en 1790, c’est-à-dire au début de la Révolution française. L’approche choisie permet de s’intéresser à la présence de personnages fictifs, mais vraisemblables, dans le cadre de la transmission d’un discours journalistique entre Paris et la province. Il s’agit, en outre, de mieux comprendre les formes textuelles utilisées pour la mise en récit des nouvelles et la mise en scène de débats d’opinions. Cette recherche tente aussi de saisir comment l’auteur conçoit l’opinion publique et comment il l’emploie pour influencer ses lecteurs et ses lectrices. Enfin, l’utilisation de personnages permet de donner un sens à la transmission qui s’opère entre l’écrivain et son lectorat

Apparent synfolding magnetization as a result of overlap of pre‐ and post‐folding magnetizations

International audienceIn most rocks, Natural Remanent Magnetization (NRM) can involve two or more superimposed components. Demagnetizations hopefully result in the separation of these components, which may then be resolved using least‐squares regression methods. In a study of Cretaceous redbed sites from Qaidam (China), thermal demagnetization of most specimens revealed 3 rectilinear segments in orthogonal plots, giving the appearance of a 3‐component magnetization. In order to help deciding if the intermediate straight segments could have resulted from overlap between post‐folding low temperature (LTC) and pre‐folding high temperature components (HTC), we modeled the overlap using a priori information on the directions and relative intensities of LTC and HTC derived from the actual observations. We constructed typical synthetic Zijderveld (1967) diagrams for each site, which could be compared with those obtained from the real samples. We conclude for the Qaidam samples that the intermediate temperature component (ITC) is most likely an artifact resulting from overlap between the LTC and HTC

Influence Of Building Zoning On Annual Energy Demand

Simulation tools are widely used to assess the energy consumption of a building. In the modeling process, some choices should be made by the simulation tool user such as the division of the building into thermal zones. The zoning process is user dependent, which results in some difference in energy consumption results and model set-up and computational times. The aim of this work is to assess the influence of building zoning on the results of the dynamic thermal simulation including airflow and thermal transfers between zones For this purpose, several different building zonings are applied to the same office building, and then the results of the dynamic thermal simulations are compared in terms of energy consumption (heating, cooling, and auxiliaries) and computational and set-up times. To assess the impact of thermal zoning, five cases are studied (from the most to the least complex): - 1) *49-zone model* : each zone gathers the premises with the same air handling system, the same occupancy profile, at each floor and building orientation. - 2) *44-zone model* : the premises containing the same air handling system are gathered at every floor, even though their occupancy profile is different. - 3) *26-zone model*: all floors are merged, except for the first and the top floors (under-roof). - 4) *21-zone model* : the first and the under-roof floors are merged with the others if the premises have the same occupancy profile and handling system. - 5) *11-zone model* : the premises with a different orientation but with the same occupancy profile and handling system are gathered. The importance of airflow coupling is evaluated by using the most detailed model (49 zones) and comparing the cases with or without considering air transfer from offices to corridors and toilets (from which air is extracted). Then, to study the impact of thermally connecting juxtaposed zones, the “21-zone model” with and without thermal transfer are compared. Finally, the impact of merging the floors is analyzed by considering different roof and floor insulations and the impact of merging the orientations is studied by using different glazed surface ratio

New Mesozoic and Cenozoic data help constrain the age of motion on the Altyn Tagh fault and rotation of the Qaidam basin.

In order to better understand the tectonic evolution of central Asia under the influence of the India-Asia collision, we carried out a paleomagnetic study of 1500 cores from 106 sites along the Altyn Tagh fault, in the Qaidam and Tarim basins, and on the Tibetan plateau. Samples were mainly collected from Jurassic to Neogene siltstones and sandstones. In most cases stepwise thermal demagnetization unblocks low and high temperature components carried by magnetite and hematite. Low temperature components are north and down directed and lie close to the recent geomagnetic field. High temperature components from 10 of 13 age/locality groups pass fold and/or reversal tests and likely represent primary remanent magnetizations. The ten overall mean directions display a complex pattern of vertical-axis block rotations that are compatible with a tectonic model of clockwise rotation of the Qaidam Basin and concomitant left-lateral slip on the Altyn Tagh fault. Two of the ten localities are rotated significantly counterclockwise; they lie adjacent to the Altyn Tagh fault zone, consistent with the idea that left-lateral strike-slip motion occurred along it. The age of counterclockwise rotation near the eastern extremity of the fault was dated as younger than 19 Ma. Three widely spread areas within the Qaidam Basin exhibit similar and significant clockwise rotations, on the order of 20°, with respect to the North China Block, Tarim and Eurasia. The mean of the three values is thought to represent the total rotation of Qaidam. Because the youngest rocks displaying clockwise rotations are Oligocene, the main phase of Qaidam Basin rotation, and hence shear on the Altyn Tagh fault, took place after or near the end of the Oligocene (∼24 Ma). Upper Neogene strata located on the Qaidam Basin are not significantly rotated, thus tectonic deformation acting since the Upper Neogene (∼5 Ma) is not resolvable by paleomagnetic methods. Given a 20° ± 5° clockwise rotation of the Qaidam Basin with respect to the Tarim Basin, the maximum left-lateral displacement on the Altyn Tagh fault since 24 Ma is 500 ± 130 km

Phase Transformations of Liquid Drops Containing Mineral Dust and Organic Compound (Citric Acid)

International audienc

Palaeomagnetic evidence and tectonic origin of clockwise rotations in the Yangtze fold belt, South China Block

International audienceFold axis strikes in the Yangtze fold belt of the South China Block (SCB) undergo significant changes over distances of >1000 km. This large-scale variation provides an ideal opportunity to test the oroclinal-bending hypothesis using palaeomagnetic methods, which we have attempted by drilling the Lower Triassic Daye Formation limestones in western Hubei Province. Thermal demagnetization isolated two components in most samples. A low unblocking temperature component (400 °C , unblocks univectorially towards the origin. The HTC passes the McFadden-fold test with an overall mean tilt-corrected direction of Dec = 255°, Inc =-24° (N= 7, α95= 9°) . Scanning electron microscopy (SEM) observations suggest an early diagenetic, possible (bio)chemical origin for the magnetic extracts dominated by Ti-poor magnetite. Rock magnetic data show no evidence that the HTC has been affected by tectonic or compaction strain. Our data together with previously published results suggest a general clockwise rotation pattern in the Middle Yangtze fold belt, which is probably related to the collision between the North and SCBs. Comparison of palaeomagnetic rotations with fold axis trends in the fold belt suggests that about 30° clockwise rotation occurred in the Middle reaches of the Yangtze River, while a 15° difference in fold axis trends would be due to initial variation within the fold belt. However, since little is known about the timing of the clockwise rotation, whether the Middle Yangtze fold belt is an orocline awaits further studies