|
|
|
|
|
| Authemayou, Christine; Le Gall, Bernard; Caroff, Martial; Bussien Grosjean, Denise. |
| During the Carboniferous collision stage, the West European Variscan orogen was affected by oblique convergence, wrenching, plate-scale oroclinal bending, and widespread exhumation of the deep crust. One of these exhumed units forms the Leon dome located on the northern flank of the Ibero-Armorican Arc in the western part of the Armorican massif. Structural field data from the Ouessant Island reveal kinematic changes between 330 and 300 Ma that affected the northwestern margin of the Leon dome. This margin underwent two ductile deformation phases with opposite strike-slip shear senses. Dextral strike-slip wrenching combined with orogen-normal shortening, orogen-parallel stretching, and local top-to-the-NE shearing occurred during the Leon dome formation... |
| Tipo: Text |
Palavras-chave: Variscan; Armorican massif; Gneiss dome formation; Wrenching; Orogenic syntax; Ouessant Island. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74906/75947.pdf |
| |
|
|
| Clement, Jean-philippe; Caroff, Martial; Dudoignon, Patrick; Launeau, Patrick; Bohn, Marcel; Cotten, Joseph; Blais, Sylvain; Guille, Gérard. |
| This paper reports new field observations and new petrological, textural and geochemical data on two gabbroic intrusions and one pegmatoid dyke from the French Polynesian islands Maupiti and Bora Bora, respectively. Olivine crystals from the Faataufi and Barque de Hiro gabbros (Maupiti) include High Temperature Iddingsite (HTI), exhibiting three distinct morphological facies. Chemical and crystallographical data performed by electron microprobe, scanning microscope, X-ray diffractometry and Near InfraRed spectroscopy show that HTI results from modifications of olivine structure through intense hydroxylation and Fe-oxidation. The HTI-free 120 m-wide Cloche de Hiro dyke (Bora Bora) exhibits a textural zonation from heterogranular/intergranular gabbro... |
| Tipo: Text |
Palavras-chave: Society Islands; French Polynesia; Pegmatoid; Vapor differentiation; Olivine; Gabbros. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2999.pdf |
| |
|
|
| Caroff, Martial; Le Gall, Bernard; Authemayou, Christine; Grosjean, Denise Bussien; Labry, Cyrill; Guillong, Marcel. |
| The metasedimentary and magmatic terranes in the southern part of the Ouessant Island (Western Brittany, France) are the offshore prolongation of the Leon Variscan metamorphic domain. They mainly consist of micaschists and subordinate amphibolitic lenses (meta-pillow lavas and volcaniclastic successions) cut by a swarm of trondhjemite sills, together with a large porphyritic monzogranite body, newly dated at 336 Ma, and later syeno-leucogranitic intrusions. A large spectrum of fluidal peperites, including spectacular "fiamme"-bearing breccias, is observable at the contact between metasediments and most of the intrusives. The coexistence of amphibolitized basalts, adakitic trondhjemites, and peraluminous granites in the inferred South Ouessant basin is... |
| Tipo: Text |
|
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00639/75091/75557.pdf |
| |
|
|
|
