You can check out the following works

1.Geochemical characteristics of basaltic volcanism within back-arc basins

Andrew D. Saunders

2.Geochemistry and tectonic significance of peridotites from the South Sandwich arc–basin system, South Atlantic

2. Geochemistry of late Paleozoic mafic igneous rocks from the Kuerti area, Xinjiang, northwest China: implications for backarc mantle evolution

I assume you are talking about igneous rocks? Back-arc magmas vary in composition between MORB-like and arc-like, the latter often with quite high K2O contents. Fore-arc rocks are typically low-K.

You may try these papers on the Egyptian Shield:

1-https://www.researchgate.net/publication/308789276_Neoproterozoic_serpentinites_from_the_Eastern_Desert_of_Egypt_Insights_into_Neoproterozoic_mantle_geodynamics_and_processes_beneath_the_Arabian-Nubian_Shield

2-https://www.researchgate.net/publication/262416756_Cryogenian_ophiolite_tectonics_and_metallogeny_of_the_Central_Eastern_Desert_of_Egypt

3-https://www.researchgate.net/publication/234065739_Geochemistry_and_tectonic_evolution_of_the_Neoproterozoic_incipient_arc-forearc_crust_in_the_Fawakhir_area_Central_Eastern_Desert_of_Egypt

Article Neoproterozoic serpentinites from the Eastern Desert of Egyp...

Article Cryogenian ophiolite tectonics and metallogeny of the Centra...

Article Geochemistry and tectonic evolution of the Neoproterozoic in...