TITLE:
Lu-Hf Isotopic Data of the Mbé-Sassa-Mbersi Tonalite (Central Cameroon Domain): Indicator of ca. 1.0 Ga Juvenile Tonian Magmatism in the Region
AUTHORS:
Alliance Nicaise Saha-Fouotsa, Rigobert Tchameni, Olivier Vanderhaeghe, Armin Zeh, Periclex Martial Fosso Tchunte, Aurélien Eglinger, Emmanuel Negue Nomo, Pierre Barbey
KEYWORDS:
Mbé-Sassa-Mbersi, Central Cameroon Domain, Central African Orogenic Belt, Tonian magmatism, Lu-Hf Isotopic Data
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.9 No.9,
September
6,
2021
ABSTRACT: 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 were 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-Sassa-Mbersi region, in the northern edge of Central
Cameroon Domain of the CAOB and in the Tcholliré-Banyo shear zone (TBSZ). The Lu-Hf data obtain on
the zircon grains of this tonalite reveal juvenile HfTDM age of ca.
1.0 Ga. This age, combined to the previous geochemical data suggests 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.