The tectonically controlled emplacement of a vertically sheeted gabbro-pyroxenite intrusion: Feeder-zone of an ocean-island volcano (Fuerteventura, Canary Islands)

The Miocene PX1 gabbro-pyroxenite pluton, Fuerteventura, Canary Islands, is a 3.5 x 5.5 km shallow-level intrusion (0.15-0.2 GPa and 1100-1120 degrees C), interpreted as the feeder-zone to an ocean-island volcano. It displays a vertical magmatic banding expressed in five 50 to 100 metre-wide NNE-SSW trending alkaline gabbro sequences alternating with pyroxenites. This emplacement geometry was controlled by brittle to ductile shear zones, generated by a regional E-W extensional tectonic setting that affected Fuerteventura during the Miocene. At a smaller scale, the PX1 gabbro and pyroxenite bands consist of metre-thick differentiation units, which suggest emplacement by periodic injection of magma pulses as vertical dykes that amalgamated, similarly to a sub-volcanic sheeted dyke complex. Individual dykes underwent internal differentiation following a solidification front parallel to the dyke edges. This solidification front may have been favoured by a significant lateral/horizontal thermal gradient, expressed by the vertical banding in the gabbros, the fractionation asymmetry within individual dykes and the migmatisation of the wall rocks. Pyroxenitic layers result from the fractionation and accumulation of clinopyroxene +/- olivine +/- plagioclase crystals from a mildly alkaline basaltic liquid. They are interpreted as truncated differentiation sequences, from which residual melts were extracted at various stages of their chemical evolution by subsequent dyke intrusions, either next to or within the crystallising unit. Compaction and squeezing of the crystal mush is ascribed to the incoming and inflating magma pulses. The expelled interstitial liquid was likely collected and erupted along with the magma flowing through the newly injected dykes. Clinopyroxene mineral orientation - as evidenced by EBSD and micro X-ray tomography investigations - displays a marked pure-shear component, supporting the interpretation of the role of compaction in the generation of the pyroxenites. Conversely, gabbro sequences underwent minor melt extraction and are believed to represent crystallised coalesced magma batches emplaced at lower rates at the end of eruptive cycles. Clinopyroxene orientations in gabbros record a simple shear component suggesting syn-magmatic deformation parallel to observed NNE-SSW trending shear zones induced by the regional tensional stress field. This emplacement model implies a crystallisation time of 1 to 5 years for individual dykes, consistent with PX1 emplacement over less than 0.5 My. A minimum amount of approximately 150 km(3) of magma is needed to generate the pluton, part of it having been erupted through the Central Volcanic Centre of Fuerteventura. If the regional extensional tectonic regime controls the PX1 feeder-zone initiation and overall geometry, rates and volumes of magma depend on other, source-related factors. High injection rates are likely to induce intrusion growth rates larger than could be accommodated by the regional extension. In this case, dyke intrusion by propagation of a weak tip, combined with the inability of magma to circulate through previously emplaced and crystallised dykes could result in an increase of non-lithostatic pressure on previously emplaced mushy dyke walls; thus generating strong pure-shear compaction within the pluton feeder-zone and interstitial melt expulsion. These compaction-dominated processes are recorded by the cumulitic pyroxenite bands. (C) 2010 Elsevier B.V. All rights reserved.

The newly defined "Greenstone Unit'' of the Aiguilles Rouges massif (western Alps): remnant of an Early Palaeozoic oceanic island-arc ?

In the southwestern part of the Aiguilles Rouges massif (pre-Alpine basement of the Helvetic realm, western Alps), a metavolcanic sequence, newly defined as the ``Greenstone Unit'',is exposed in two NS trending belts of several 100 metres in thickness. It consists of epidote amphibolites, partly epidote and/or calcic amphibole-bearing greenschists, and small amounts of alkali feldspar-bearing greenschists, which underwent low- to medium-grade metamorphism during Visean oblique collision. Metamorphic calcic amphiboles and epidotes show strong chemical zoning, whereas metamorphic plagioclase is exclusively albitic in composition (An 1-3). The SiO2 content of the subalkaline tholeiitic to calc-alkaline suite ranges continuously from 44 wt% to 73 wt%,but andesitic rocks predominate. The majority of samples have chemical compositions close to recent subduction-related lavas; some are even restricted to recent oceanic arcs (extremely low Ta and Nb contents, high La/Nb and Th/Ta ratios). But several basaltic to basalto-andesitic samples resemble continental tholeiites (low Th/Ta, La/Nb ratio). As it is very probable that both lava types are to some extent contemporaneous, it is proposed that the Greenstone Unit represents a former oceanic volcanic are which temporarily underwent extension during which emplacement of continental tholeiite-like rocks occurred. The cause of the extension remains ambiguous. Considering palaeotectonic significance and age of other metavolcanic units in the Aiguilles Rouges massif, the Greenstone Unit most likely formed in the Early Palaeozoic.

25/3/20, hockey [sur gazon], Ecole alsacienne contre Ile de France : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58655

25/3/20, équipe [de hockey sur gazon de l'] Ile de France : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58656

25/3/20, équipe [de hockey sur gazon de l'] Ile de France : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58657

Los Angeles [le bâtiment du tribunal, County Court House] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 60150

[Magnificentiores selectioresque Urbis Venetiarum prospectus quos olim Michael Marieschi, Venetus pictor et architectus in plerisque tabulis depinxit, nunc vero ab ipsomet acurate delineante, incidente, tyspisque mandante, iterum in sexdecim aereis tabulis in lucem aeduntur]. [21], Templum cum Platea Sanctae Mariae Formosae, ex archetiipo Jacobi Sansovini desumptum. : [estampe] / Mich.l Marieschi del.t et inci.t

Référence bibliographique : Toledano, Marieschi, 30

Arrêt du Grand Conseil qui maintient les communautés régulières dans le droit de nommer aux bénéfices, le siège abbatial vaquant. (Maintient Ignace de Vaucanu en la possession de la cure de Notre-Dame d'Ommoy dont il a été pourvu par les religieux de Silly, contre Mich. Picot.)

[Acte. 1730-05-19. Paris]

Formulaire de chancellerie, formé d'actes du règne de LOUIS XI, parmi lesquels sont à signaler les suivants, qui tous, sauf indication contraire, émanent de ce prince.

Contient : 1° D'une table des pièces, qui commence au feuillet 134, se continue aux feuillets 135 et 136, et s'achève aux feuillets 131 v° et 132 r° ; 2° D'une ballade, dont le refrain est : « Faulte d'argent la douleur non pareille » (fol. 137 r°) ; 3° D'un petit glossaire latin (fol. 138 r°) ; 4° D'une ballade, dont le refrain est : « Tost est deffait qui autrui veult deffaire » (fol. 138 v°) ; 5° D'un petit glossaire latin-latin et latin-français (fol. 139 r°) ; 6° De deux lettres ; l'une de BONIFACE VIII à Philippe-le-Bel, l'autre de PHILIPPE-LE-BEL à Boniface VIII (fol. 139 v°)

Cartes de l'Ile-de-France, de la Picardie, du Soissonnais, de la Champagne, etc., dressées en 1599, par « Jacques FOUGEU, mareschal des logis du Roy etde ses armées ».

Original. — Ces cartes ont servi à « M. d'Escure », auquel sont adressées plusieurs demandes d'exemption de terres placées à la fin du volume.