The Lanthanide Tetrad Effects and its Correlation with Na2o, K2o, Alklis, and Zr/Hf Involving Granitoid Rocks of Wadi Kharm El Belawi Area, Northern Eastern Desert, Egypt

Basta, Magdy S.

doi:10.21608/egjg.2018.366382

The Lanthanide Tetrad Effects and its Correlation with Na2o, K2o, Alklis, and Zr/Hf Involving Granitoid Rocks of Wadi Kharm El Belawi Area, Northern Eastern Desert, Egypt

Document Type : Original Article

Author

Magdy S. Basta

Faculty of Petroleum and Mining Engineering, Suez University, Egypt

10.21608/egjg.2018.366382

Abstract

The basement rocks in Wadi Kharm El Belawi area are represented by Dokhan volcanics, granodiorites
and younger granites. They were produced from calc alkali magma, under a compress regional regime. The
lanthanide tetrad effects are observed in the REE pattern of older granites and younger granites of Wadi
Kharm El Belaw. The values, of tl. t3. t4, TE1, 3 were calculated and plotted vs. Na2O. K2O, total alkalis and
Zr/Hf. The diagrams reveal that the tetrad effect developed conformable with the evolution of the alkali
feldspar granites, and significant tetrad effects are confined to highly differentiated samples. The strong
decrease in the Eu concentration in the highly evolved rocks is related to Eu fractionation between the
residual melt and a coexisting high temperature aqueous fluid. The results point to significant changes in
element fractionation behavior in highly evolved granitic melts indicating that ionic radii and charge
(which commonly control the element distribution between minerals and melt), are no longer the exclusive
control.

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