摘要
The Pan-African/Brasiliano orogenic belts are a part of numerous Neoproterozoic orogenic belts that belong to the long-lived orgenic cycle that distancing phase started at the Tonian around 1.0 Ga. The Tonian magmatism fairly documented in the Neoproterozoic belts of Borborema Province (NE-Brazil), seemed so far inexistent in the Central African Orogenic Belt (CAOB) although these two belts <span style="font-family:Verdana;">were</span><span style="font-family:Verdana;"> geologically correlated. Through the Lu-Hf geochronological analysis on zircon of tonalite, the present work, coupled with the previous data, suggests the existence of a Tonian age magmatism in the Central Cameroon Domain of the CAOB although the latter is much reworked. The Nguesseck tonalite outcrops in the northern part of the Mbé</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">Sassa-Mbersi region, in the northern edge of Central Cameroon Domain of the CAOB and in the Tcholliré</span><span style="font-family:Verdana;">-</span><span style="font-family:;" "=""><span style="font-family:Verdana;">Banyo shear zone (TBSZ). The Lu-Hf data obtain on the zircon grains of this tonalite reveal juvenile Hf</span><sub><span style="font-family:Verdana;">TDM</span></sub><span style="font-family:Verdana;"> age of ca. 1.0 Ga. This age, combined to the previous geochemical data suggest</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> that the protholites of this tonalite would have extracted from the source during the distancing phase (rifting and oceanization) of the Pan-african/Brasiliano orogeny at the early Neoproterozoic.</span>
The Pan-African/Brasiliano orogenic belts are a part of numerous Neoproterozoic orogenic belts that belong to the long-lived orgenic cycle that distancing phase started at the Tonian around 1.0 Ga. The Tonian magmatism fairly documented in the Neoproterozoic belts of Borborema Province (NE-Brazil), seemed so far inexistent in the Central African Orogenic Belt (CAOB) although these two belts <span style="font-family:Verdana;">were</span><span style="font-family:Verdana;"> geologically correlated. Through the Lu-Hf geochronological analysis on zircon of tonalite, the present work, coupled with the previous data, suggests the existence of a Tonian age magmatism in the Central Cameroon Domain of the CAOB although the latter is much reworked. The Nguesseck tonalite outcrops in the northern part of the Mbé</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">Sassa-Mbersi region, in the northern edge of Central Cameroon Domain of the CAOB and in the Tcholliré</span><span style="font-family:Verdana;">-</span><span style="font-family:;" "=""><span style="font-family:Verdana;">Banyo shear zone (TBSZ). The Lu-Hf data obtain on the zircon grains of this tonalite reveal juvenile Hf</span><sub><span style="font-family:Verdana;">TDM</span></sub><span style="font-family:Verdana;"> age of ca. 1.0 Ga. This age, combined to the previous geochemical data suggest</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> that the protholites of this tonalite would have extracted from the source during the distancing phase (rifting and oceanization) of the Pan-african/Brasiliano orogeny at the early Neoproterozoic.</span>
作者
Alliance Nicaise Saha-Fouotsa
Rigobert Tchameni
Olivier Vanderhaeghe
Armin Zeh
Periclex Martial Fosso Tchunte
Aurélien Eglinger
Emmanuel Negue Nomo
Pierre Barbey
Alliance Nicaise Saha-Fouotsa;Rigobert Tchameni;Olivier Vanderhaeghe;Armin Zeh;Periclex Martial Fosso Tchunte;Aurélien Eglinger;Emmanuel Negue Nomo;Pierre Barbey(Department of Earth Sciences, Faculty of Science, University of Maroua, Maroua, Cameroon;Department of Earth Sciences, Faculty of Science, University of Ngaoundéré, Ngaoundéré, Cameroon;GET, Université de Toulouse, UPS, CNRS, IRD, CNES, Toulouse, France;KIT-Karlsruher Institut für Technologie, Campus Süd, Institut für Angewandte Geowissenschaften, Abteilung Mineralogie und Petrologie, Karlsruhe, Germany;Université de Lorraine, CNRS, GeoRessources, Nancy, France;Department of Earth Sciences, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon;Université de Lorraine, CNRS, CRPG, Nancy, France)