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Abstracto

Petrology of Ibillo-Mangongo area of Igarra, Edo State, Nigeria

Oloto I. N. and Anyanwu D. E.

The study area lies within latitudes 7o24’5’’N-7030’N and longitudes 6o00’E-6010’5’’E in Igarra North-West of Edo State, Nigeria. It is underlain in the North by Precambrian Basement Complex and in the South by Cretaceous and Tertiary sediments. The field mapping and petrographic analysis of study area were carried out. Rock samples were collected from Ibillo, Lankpeshi and Magongo areas of the Northern fringe of Igarra. Field and petrographic studies of the area shows that the area is composed of mostly Gneiss-Migmatite complex and Metasediments. The metasediments, gneisses and migmatites are products of multiple periods of regional metamorphism that affected the ancient sedimentary series that covered study area. This metamorphism produced schists, quartzites and calcsilicates. Further metamorphism produced migmatites, gneisses and granites. Gneisses and Migmatites are polymetamorphic rock complexes. The gneisses can be classified into biotite gneiss and banded gneiss. The biotite gneisses show strong foliation and are widespread. The banded gneisses show alternation of light and dark bands