Volume: 42 Host publication title: The 2014 CETeG Conference "Lądek" Host publication sub-title: The Orlica-Śnieżnik Dome and the Upper Nysa Kłodzka Graben, the Sudetes 23-26 April 2014, Lądek Zdrój, Poland : Proceedings and Excursion GuideNon peer reviewe

Chopin, Francis

Corsini, Michel

El Houicha, Mohamed

Ghienne, Jean-Francois

Schulmann, Karel

Wernert, Pauline

Štípská, Pavla

Helsingin yliopiston digitaalinen arkisto

Geologia Sudetica, 2014, 42: 99.Tectonometamorphic evo lu tion of the Rehamna dome (Marocco)Pau line Wernert1, Fran cis Cho pin2, Pavla Štípská1,3, Karel Schulmann1,3, Michel Corsini4, Mohamed ElHouicha5 & Jean-François Ghienne11 École et Observatoire des Sci ences de la Terre, Institut de Phy sique du Globe – CNRS, UMR7516, Université de Strasbourg, 1 rueBlessig, 67084, Strasbourg Cedex, France2 De part ment of Geosciences and Ge og ra phy, P.O. Box 68, 00014,Uni ver sity of Hel sinki, Fin land3 Czech Geo log i cal Sur vey, Klárov 3, 11000, Prague 1, Czech Re pub lic4 Geoazur – CNRS UMR6526, Université de Nice Sophia Antipolis, 250 rue Al bert Ein stein, 06560 Valbonne, France5 Département de Géologie, Faculté des Sci ences, Université Chouaib Doukkali, El Jadida, Mo roccoThe Mo rocco Variscan belt is con sid ered to be thesouth-west ern con tin u a tion of the Eu ro pean Car bon if er ousorogen on the NW Gond wana mar gin. The Rehamna Mas sif in the west (be long ing to the Coastal Block) is com posed ofCam brian to De vo nian sed i ments cov er ing Pro tero zoicbase ment and shows only weak de for ma tion. The cen traland east ern Rehamna parts be long to the Cen tral zone of thewest ern Meseta, formed by Devono-Car bon if er ous intra-con ti nen tal bas ins and by un der ly ing Pro tero zoic base ment.These bas ins are re worked by late Palaeozoic de for ma tionun der Barrovian geo ther mal gra di ent and are in truded byfel sic mag mas.Three main de for ma tion events (D1, D2 and D3) ofvari able in ten sity and ge om e try were iden ti fied. The firstforms a flat-ly ing meta mor phic fo li a tion S1, which is de -formed by WSW–ENE trending F2 folds with as so ci atedsub-ver ti cal S2 cleav age, then het er o ge neously re worked by NNE–SSW trending F3 folds with an S3 cleav age mod er -ately to steeply dip ping to ESE. Crys tal li za tion–de for ma -tion re la tion ships in the Barrovian se quence show that bi o -tite, gar net, chloritoid and staurolite grew in the S1 subho-rizontal fab ric, and that chloritoid and staurolite con tin uedtheir growth dur ing the early stages of the de vel op ment ofthe S3 fab ric. An da lu site porpyroblasts around granitoid in -tru sions show ei ther S3 pres sure shad ows, point ing to thesyntectonic na ture of the in tru sions or are post-tec tonic.Crys tal li za tion–de for ma tion re la tion ships, com bined withmin eral chem is try and min eral zon ing are com bined withpseudosection mod el ling into P-T-d paths. Based on theseP-T-d paths, three main tec tonic events have been rec og -nized: 1) South ward thrust ing of an Or do vi cian se quenceover the Pro tero zoic base ment, its Cam brian sed i men tarycover and the over ly ing Devono-Car bon if er ous ba sin. Thisevent caused subhorizontal shear ing and prograde Barro-vian meta mor phism of the bur ied rocks. 2) Con tin u ousshort en ing re sult ing first in con tin u a tion of burial, then inthe de vel op ment of a syn-con ver gent ex tru sion of meta mor -phosed units to form a dome elon gated E–W. This was re -spon si ble for syn-con ver gent de tach ment of the Or do vi cianup per crustal se quence. 3) The next ep i sode of con ver gencetook place in a ESE–WNW di rec tion or thogo nal to the pre -vi ous one and is char ac ter ized by the ac cre tion of the Re-hamna dome to the con ti nen tal base ment in the east. Ex ist -ing Ar/Ar dat ing shows that the first and the sec ond de for -ma tions oc curred dur ing the Late Car bon if er ous to EarlyPerm ian (315–290 Ma) and that the third de for ma tion tookplace dur ing the Early Perm ian (290–275 Ma).CETeG 2014 AB STRACTS 99

Tectonometamorphic evolution of the Rehamna dome (Morocco)

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