Romanus  Obasi, Henry  Madukwe, Olajumoke  Adewumi, 
    Geochemistry, Classification and Geotectonic Studies of Pan-African Rocks Around Akure,
Southwestern Nigeria,
    Research Journal of Applied Sciences,
    Volume 16,Issue 2,
    2021,
    Pages 85-101,
    ISSN 1815-932x,
    rjasci.2021.85.101,
    (https://makhillpublications.co/view-article.php?doi=rjasci.2021.85.101)
    Abstract: The study of geochemistry, classification and
geotectonics of granitic rocks of Akure, Southwestern
Nigeria are undertaken. Geochemical analysis classified
the rocks suites as quartz-rich, silica-saturated,
alumina-saturated, dorminant peraluminous, S-type,
slightly metaluminuos, I-type and A-type granites. A plot
of total alkalies-silica of alkaline and sub-alkaline rock
suites indicated granite, syenite, quartz-diorite, gabbro,
monzogranite and monzodiorite as rock types. The
sub-alkaline rocks exhibited evidence of crystal
fractionation from a magmatic melt generated by partial
melting of basaltic materials. The Y/Nb ratio (1.39-7.03
1.2) affirmed that magmas that produced the rocks were
either derived from crustal or mixed sources. Significant
variations in the correlation of Sr, Zr, Ba and Rb with
SiO<sub>2</sub> suggested the involvement of more than one sources
in the genesis of the rocks. The depletion of Ba
(0.48-8.76), the presence of distinct negative Eu in the
REE pattern, with a strong negative correlation of Al<sub>2</sub>O<sub>3</sub>
and CaO with increasing SiO<sub>2</sub> are characteristics
suggestive of an extensive fractionation of plagioclase.
These rocks were involved in the active magmatic and
tectonic activities with post collision uplift and late
orogeny that were in conformity with the tectonic scenario
of Pan-African granite. These geodynamic activities
resulted in the emplacement of granitic rocks suites into
the host rock.
    Keywords: Classification;fractionation;geochemistry;geotectonics;mixed sources