PETROGENESIS OF MG-CARBONATITES FROM TAMA ZERT IN THE MOROCCAN HIGH ATLAS

Carbonatites from the Tamazert complex comprise extrusive and intrusiv e Mg-carbonatites. They are identified for the first time in the compl ex, associated with central diatremes in Issli and Tisslit areas. A pr eliminary approach suggests that these rocks are mantellic in origin b ut the processes involved in their petrogenesis are multiple. The extr usive Mg-carbonatites (lapilli) containing Cr-spinels may represent a direct partial melt from the mantle whereas most of the intrusive term s are thought to be genetically related to Ca-carbonatites by a dolomi tization process.