They are dominated by granites and are emplaced in pan african basement rocks on swells bordering sedimentary basins.
Younger granite of nigeria.
The younger granites the mesozoic younger granite ring complexes of nigeria form part of a wider province of alkaline anorogenic magmatism extending from northern niger republic to south central nigeria.
Other occur rences approximate a north south belt towards the middle benue in the south where the ages are younger and towards niger republic in the north.
Journal of african earth sciences 1983 vol.
The younger granites are primarily alkali feldspar granites although the ring complexes also include rhyolite gabbro and syenite.
From this description of rocks units and also the younger granite intrusion.
Vii of the society s memoir no.
Sufficient information is now available to indicate that the province includes some of the finest examples of granitic ring complexes in the world.
Careful examination of the younger granite complexes of this province as seen on the 1.
Journal of african earth sciences 1983 vol.
1 and 2 k feldspars from fayalite hedenbergite granite and porphyry.
The younger granite complexes in nigeria are found mainly on the jos plateau forming a distinc tive group of intrusive and volcanic rocks that are bounded by ring dykes or ring faults.
More than 50 complexes occur in nigeria obaje 2009.
The younger granite ring complexes of west africa extend from air to cameroun and range in age from palaeozoic to tertiary.
Large sedimentary basins formed in southern nigeria divided by the okitipupa ridge.
2 1 form part of a wider province of alkaline anorogenic magmatism.
Rare earth patterns of k feldspar separated from granitic rock of younger granites of nigeria.
Bibliography on the younger granite ring complexes and tin mineralization in west africa with emphasis of nigeria.
2 000 000 geological map of nigeria or on pl.
The mesozoic younger granite ring complexes of nigeria fig.
This memoir presents a summary of recent studies on the nigerian younger granite complexes.
1 shows also that these four planes of weakness appear to have exercised a significant control in the emplacement of the younger granites.
They occur in a zone 200 km wide and 1 600 km long extending from northern niger to south central nigeria.
The cycle of igneous activity was initiated by a volcanic phase during which large volumes of rhyolitic lavas were extruded.
3 and 4 k feldspars from has tingsite biotite granite and porphyry.
5 and 6 k feldspars from barren biotite granite 7 8 and 9 k feldspars from stanniferrous biotite granite.
Sedimentary basins the cretaceous to recent basins in nigeria include.
