부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jafrearsci.2009.02.006 Byline: E. Errami (a), B. Bonin (b), D. Laduron (c), L. Lasri (d) Keywords: Post-collisional magmatism; Pan-African; Charnockite; Saghro; Anti-Atlas Abstract: The Saghro Group consists of a thick volcanic-sedimentary sequence with intercalated basaltic lavas, the first magmatic event in eastern Saghro area. Nd isotopes of basaltic pillow lavas show T.sub.DM model ages ranging from 640 to 580Ma, which represent a maximum age for basalt eruption. Granitoids within the Saghro Group consist of a charnockitic suite, tonalites, granodiorites and monzogranites. They are high-K calc-alkaline (HKCA) with a post-collisional character, and were emplaced at high-levels in the crust. Their ages of emplacement are within the 580-560Ma bracket, implying that the entire Saghro Group is slightly older than or partly coeval to granitoid emplacement and implying a common geodynamical setting. Sr-Nd isotopic compositions and Nd T.sub.DM model ages point to a mixed origin, combining a juvenile mantle source and an Eburnean crustal component, which could be the West African Craton (WAC). The juvenile component in the Saghro granitoids could be the depleted upper mantle that has sourced the earlier basalts. Field observations, geochemical and geochronological data together support that, during the Pan-African orogeny, the Anti-Atlas was subjected to a regional transpressional to transtensional event. This event would have been responsible for the dissection of the northern margin of the WAC into several blocks, the development of deep sedimentary basins and the emplacement of HKCA magmas. Author Affiliation: (a) Universite ChouaiA[umlaut]b Doukkali, Geodynamic Laboratory, B.P 20, 24000 El Jadida, Morocco (b) Universite de Paris-Sud, UMR8148 'IDES', BAcentstiment 504, 91405 ORSAY CEDEX, France (c) Laboratoire de geologie, Universite Catholique de Louvain, 1348, Louvain La Neuve, Belgium (d) Office National des Hydrocarbures et des Mines, 5 Avenue My Hassan, B.P. 99, 10050 Rabat, Morocco Article History: Received 30 April 2008; Accepted 28 February 2009