Earth Sciences Pakistan (ESP)

RARE EARTH GEOCHEMISTRY AND PETROGENESIS OF CHARNOCKITIC AND ASSOCIATED ROCKS AROUND IKARE, SOUTHWESTERN NIGERIA

June 13, 2024 Posted by Natasha In Earth Sciences Pakistan (ESP)

ABSTRACT

RARE EARTH GEOCHEMISTRY AND PETROGENESIS OF CHARNOCKITIC AND ASSOCIATED ROCKS AROUND IKARE, SOUTHWESTERN NIGERIA

Journal: Earth Sciences Pakistan (ESP)
Author: Oyeshomo, A.V, Ogunribido, T.H.T, Okpoli, C.C, Altenberger, U., Bolarinwa, A.TThis is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Doi: 10.26480/esp.02.2024.72.80

Charnockitic and associated rocks outcropping around Ikare were investigated for their rare earth element concentration and distribution patterns. REE data on these rocks are scanty due to lack of geochemical data. Hence, this study was designed to determine the rare earth element distribution patterns and infer the nature of their protoliths. A total of 40 rock samples were subjected to geochemical analyses using inductively coupled plasma-mass spectrometry. Results showed that igneous charnockites are more enrinched in average total REE of 278.75, while the granite had the least of 151.52. All the rock samples showed a strong compositional similarity with pronounced enrichment in light rare earth elements in relative to heavy rare earth elements. La/YbN ratios for all rock types are above 5 with the metapelites having average ratio of 40.6. The Gd/YbN ratios are below 2.0 for the charnockitic rocks. The rocks generally showed significant europium anomalies due to previous segregation of Ca-rich phases such as Ca-rich plagioclase for a magmatic origin or Ca-poor protolith in case of metasedimentary. Eu/Eu*anomalies are below 1.0 for charnockitic and gneissic rocks except for the granites. It is evident that the precursors of these rocks evolved through magmatic differentiation processes and signaled partial melting of the lower crust which was later got contaminated at the upper crustal level.

Pages 72-80
Year 2024
Issue 2
Volume 8

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