首页|Origin and geochemical characteristics of beryllium mineralization in the Zabara-Wadi El Gemal region,South Eastern Desert,Egypt

Origin and geochemical characteristics of beryllium mineralization in the Zabara-Wadi El Gemal region,South Eastern Desert,Egypt

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Origin and geochemical characteristics of beryllium mineralization in the Zabara-Wadi El Gemal region,South Eastern Desert,Egypt
Beryl is the commercial source of beryllium and several varieties of it are valued as a gemstone.To contribute to understanding the mechanism of beryl forma-tion,we carried out detailed geological,petrographical,and geochemical investigations on beryl mineralization occur-rences in the Zabara-Wadi El Gemal(Z-WG)region.This region is an NW-SE trending tract that includes six beryl-hosting areas.The green gem variety of beryl(emerald)is restricted to phlogopite schist,pegmatite,and quartz veins.Prismatic hexagonal emerald crystals are well-developed in phlogopite schist and pegmatite.The gem variety emerald examined is sodic and Cr-dominant.It contains high con-centrations of chromophore transition elements ordering Cr(up to 1511 ppm)＞V(up to 242 ppm)＞Sc(up to 245 ppm),giving rise to its vivid green color,reflecting mafic-ultra-mafic source contribution.Among the investigated emeralds,the Sikait area contains the highest BeO(av.10.76wt.％)concentration.The compositional variability of emeralds is most likely attributed to the contribution from the host rocks.This is revealed by the examined emerald mineralization,for instance;the Abu Rusheid area(one of the best areas expos-ing rare metal-bearing granitoids)possesses the highest average of trace and REEs concentrations.In contrast,Um Kabu emerald has the highest contents of Co(av.20 ppm),Ni(av.299 ppm),MgO(av.8.2wt.％),Fe2O3(av.3.12wt.％),and CaO(avg.3.4wt.％)relative to other areas,which may be linked to contribution of ultramafic rocks exposed there.The proposed mechanism we suggest for emerald genesis is metasomatic interaction between felsic(intrusions,that are enriched with K,Na,Be,Li,and B,with mafic-ultramafic rocks that are enriched in Cr,V,Mg,Fe,and Ca.This inter-action is marked by the formation of phlogopite schist,the growth of emerald crystals,and desilicated pegmatite.

Beryl chemistryEmerald genesisPhlogopite schistPegmatiteEastern Desert

Gehad M.Saleh、Farrage M.Khaleal、Mohammed Z.El-Bialy、Mohamed S.Kamar、Mokhles K.Azer、Mohamed M.Omar、Mohamed N.El Dawy、Ahmed Abdelaal、El Saeed R.Lasheen

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Nuclear Materials Authority,El-Maadi,P.O.Box 530,Cairo,Egypt

Geology Department,Faculty of Science,Port Said University,Port Said 42522,Egypt

Geological Sciences Department,National Research Centre,Cairo,Egypt

Environmental Sciences Department,Faculty of Science,Port Said University,Port Said 42522,Egypt

Geology Department,Faculty of Science,Al-Azhar University,P.O.Box 11884,Cairo,Egypt

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Beryl chemistry Emerald genesis Phlogopite schist Pegmatite Eastern Desert

2024

10.1007/s11631-024-00698-y

地球化学学报(英文版)
中国科学院地球化学研究所

地球化学学报(英文版)

EI
影响因子：0.33
ISSN：2096-0956
年,卷(期)：2024.43(6)