Geochemical Characterisation of Anatexite within High Grade Migmatite Complex Terrain from Ogbomoso, Southwest of the Nigerian Precambrian Basement Complex
AbstractMigmatite rocks are complex rocks largely due to the degree of partial melting and nature of parent rocks of this rock type. Partial melting or anatexis yield metatexite and diatexite components with variable mineralogical and chemical compositions. The nature of fractionation of elements during anatexis is not clearly understood. The migmatite quartzite gneiss complex of southwestern Nigeria exposed at Ogbomoso was studied in order to constrain the geochemical character of its metatexite and diatexite components. Field mapping revealed migmatite with stromatic, surreitic and dictyonitic structures represented the metatexite while parts of the migmatite with schollen structure and granitic component represent the diatexite. Several sections of representative samples were cut and examined for mineralogical compositions. Thin section analysis revealed occurrence of hornblende and garnet with plagioclase, microcline, biotite and muscovite implying greenschist to amphibolite facies for the migmatite quartzite gneiss complex. Twelve representative samples were selected and analysed for their elemental concentrations using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Major oxide geochemical data revealed a silica enriched migmatite with schollen structure having moderate alkali concentration while the granitic component and porphyroblastic gneiss with lesser silica concentrations showed relative Na2O and K2O enrichments respectively. Classification plots demonstrated that the migmatite of the study are ortho gneisses and have a Tonalite Trondjhemite Granodiorite (TTG) parentage. Trace element ratios revealed that the diatexite had lower than average upper continental crustal values for Nb/Ta ratio while the metatexite revealed average values slightly above 12. Normalised REE plot discriminated the migmatite with schollen structure as parts having HREEs closest to chondrite values.
Rahaman, M. A., 1976. Review of the basement geology of southwestern Nigeria. In: C. A. Kogbe (ed), Geology of Nigeria. Elizabethan Publ. Co. Lagos, Nigeria. pp 41–58.
Nedelec, A. and Bouchez, J., 2015. Granite: Petrology, Structure, Geological setting and Metallogeny. Oxford University Press. 335p.
Patino Douce, A. E., 1999. What do experiments tell us about the relative contributions of crust and mantle to the origin of granitic magmas? In: Castro, A., Fernandez, C. and Vignerisse, J. L. (eds) Understanding Granites: Integrating New and Classical Techniques. Geological Society, London, Special Publications, pp. 168, 55-75.
Turtle, O. F. and Bowen, N. L., 1958. Origin of granite in the light of experimental studies in the NaAlSi3O8- KAlSi3O8- SiO2-H2O, Geological Society of America Memoirs, No. 74, 153p.
Milord, I., Sawyer, E. W. and Brown, M., 2001. Formation of diatexite migmatite and granite magma during anatexis of semi-pelitic metasedimentary rocks: an example from St. Malo, France. Journal of Petrology. Vol. 42 (3), pp. 487–505.
Zeng, L. Saleeby, J. B. and Ducea, M., 2005. Geochemical characteristics of crustal anatexis during the formation of migmatite at the Southern Sierra Nevada, California. Contib. Mineral Petrol. Springer-Verlag. 150 (4), pp. 386–402.
Sawyer, E. W., 1998. Formation and evolution of granitic magmas during crustal reworking: the significance of diatexite. Journal of Petrology 39, pp. 1147-1167.
Mehnert, K. R., 1968. Migmatites and the origin of Granitic rocks. Elsevier. Amsterdam.
Oyawoye, M. O. 1964. The Geology of the Nigerian Basement Complex. Journ. Nigerian Min. Geol. And Metall. Soc. Vol. 1., pp 87–102.
Rahaman, M. A., 1976. Review of the Basement Geology of the South-Western Nigeria. In: C. A. Kogbe (ed), Geology of Nigeria. Elizabeth Publ. Co. Lagos, Nigeria. pp 41–58.
Afolabi, O. A., Kolawole, L. L., Abimbola, A. F., Olatunji, A. S. and Ajibade, O. M., 2013. Preliminary study of the geology and structural trends of the lower Proterozoic Basment rocks in Ogbomoso, SW Nigeria. Jour. of Environment and Earth Science, Vol 3, No. 8, pp. 82–95.
Okezie, L. N., 1974. Geological Map of Nigeria, Scale 1:2,000,000.- Geological Survey; Lagos.
Key, R. M., 1992. An introduction to the crystalline basement of Africa.- In: Hydrogeology of crystalline basement aquifers in Africa, E. P. Wright & W.G. Burgess (eds.), Geol. Soc. Spec. Publ. London 66, pp. 29-57.
Oluyide, P. O., Nwajide, C, S. and Oni, A. O., 1998. The Geology of Ilorin area. Ministry of Solid Minerals Development, Geol. Surv. of Nig. Bulletin No. 42, 84P.
Jones, H. A. and Hockey, R. D., 1964. The Geology of Part of South-western Nigeria. Geological Survey of Nigeria, Bull. No 31. 101p.
Sawyer, E. W., 2008b. Working with Migmatite. In E. W. Sawyer and M. Brown (eds). Working with Migmatite. Mineralogical Association of Canada, Short Course Series Vol. 38, Quebec City, Quebec, pp 1–28.
Nabelek, P.I. (1997) Quartz-sillimanite leucosomes in high-grade schists, Black Hills, South Dakota: A perspective on the mobility of Al in high-grade metamorphic rocks. Geology, 25, 995–998.
Garrels, R. M. and MacKenzie, F. T., 1971. Evolution of Sedimentary rocks. Norton & Co. New York. 394P.
Cox, K. G., Bell, J. D. & Pankhurst, R. J., 1979. The Interpretation of Igneous Rocks. George Allen & Unwin.
Middlemost, E. A. K., 1985). Naming materials in the magma-igneous rock system. Earth-Sciences Reviews 37, pp. 215–224.
O'Connor, J. T., 1965. A classification for quartz-rich igneous rocks based on feldspar ratios. In: US Geological Survey Professional Paper B525. USGS, pp. 79–84.
Shand, S. J., 1943. Eruptive Rocks. Their Genesis, Composition, Classification, and Their Relation to Ore-Deposits with a Chapter on Meteorite. , 2nd edn New York: John Wiley & Sons. 444 P.
Taylor, S. R. and McLennan, S. M., 1985. The Continental crust: Its Composition and Evolution. Oxford: Blackwell, 312p.
Boynton, W. V. 1984. Cosmochemistry of the rare earth elements: meteorite studies. In: Henderson P (eds) Rare Earth Element Geochemistry. Elsevier, Amsterdam, pp 63-114.
White, R. W., 2008b. Insights gained from the petrological modeling of Migmatites: particular reference to mineral assemblages and Common replacement textures. In E. W. Sawyer and M. Brown (eds). Working with Migmatite. Mineralogical Association of Canada, Short Course Series Vol. 38, Quebec City, Quebec, pp. 77-96.
Copyright (c) 2019 American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS)
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Authors who submit papers with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
- By submitting the processing fee, it is understood that the author has agreed to our terms and conditions which may change from time to time without any notice.
- It should be clear for authors that the Editor In Chief is responsible for the final decision about the submitted papers; have the right to accept\reject any paper. The Editor In Chief will choose any option from the following to review the submitted papers:A. send the paper to two reviewers, if the results were negative by one reviewer and positive by the other one; then the editor may send the paper for third reviewer or he take immediately the final decision by accepting\rejecting the paper. The Editor In Chief will ask the selected reviewers to present the results within 7 working days, if they were unable to complete the review within the agreed period then the editor have the right to resend the papers for new reviewers using the same procedure. If the Editor In Chief was not able to find suitable reviewers for certain papers then he have the right to accept\reject the paper.B. sends the paper to a selected editorial board member(s). C. the Editor In Chief himself evaluates the paper.
- Author will take the responsibility what so ever if any copyright infringement or any other violation of any law is done by publishing the research work by the author
- Before publishing, author must check whether this journal is accepted by his employer, or any authority he intends to submit his research work. we will not be responsible in this matter.
- If at any time, due to any legal reason, if the journal stops accepting manuscripts or could not publish already accepted manuscripts, we will have the right to cancel all or any one of the manuscripts without any compensation or returning back any kind of processing cost.
- The cost covered in the publication fees is only for online publication of a single manuscript.