{"title":"Geochemical evolution of Pan-African magmatic rocks from the basement complex between Okene and Lokoja, Southwestern Nigeria","authors":"M.I. Odigi , M.C. Ezepue , A.C. Onyeagocha","doi":"10.1016/0899-5362(93)90010-N","DOIUrl":null,"url":null,"abstract":"<div><p>The Pan-African rocks found in the area between Okene and Lokoja are situated in a complex, tectonised and polymetamorphic terrain.</p><p>The geochemical variation observed in 2-pyroxene diorites can be explained by pyroxene, hornblende, plagioclase, Fe-Ti oxide and apatite fractionation. Granitic rocks show variation typical of granites with minimum melt composition. The trace element data indicate that the granites were formed by fractional crystallization of dioritic magma. Geochemically, the late-formed rocks are characterized by variable trace elements such as Zn, Rb, Sr, Li, La, Ce, Y.</p><p>The dioritic and granitic rocks have calc-alkaline affinity. The origin of the diorites could be through hybridization of basic magma with anatectic crustal material to produce magma of intermediate composition and the granites are compared with S-types granites.</p></div>","PeriodicalId":100750,"journal":{"name":"Journal of African Earth Sciences (and the Middle East)","volume":"17 4","pages":"Pages 541-553"},"PeriodicalIF":0.0000,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0899-5362(93)90010-N","citationCount":"6","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of African Earth Sciences (and the Middle East)","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/089953629390010N","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 6
Abstract
The Pan-African rocks found in the area between Okene and Lokoja are situated in a complex, tectonised and polymetamorphic terrain.
The geochemical variation observed in 2-pyroxene diorites can be explained by pyroxene, hornblende, plagioclase, Fe-Ti oxide and apatite fractionation. Granitic rocks show variation typical of granites with minimum melt composition. The trace element data indicate that the granites were formed by fractional crystallization of dioritic magma. Geochemically, the late-formed rocks are characterized by variable trace elements such as Zn, Rb, Sr, Li, La, Ce, Y.
The dioritic and granitic rocks have calc-alkaline affinity. The origin of the diorites could be through hybridization of basic magma with anatectic crustal material to produce magma of intermediate composition and the granites are compared with S-types granites.