Geochemistry and Genesis of Beryl Crystals in the LCT Pegmatite Type, Ebrahim-Attar Mountain, Western Iran

Ebrahim-Attar granitic pegmatite, which is distributed in southwest Ghorveh, western Iran, strongly peraluminous and contains minor beryl crystals. Pale-green to white grains are crystallized the rim central parts of granite body. The characterized by low contents alkali oxides (Na2O = 0.24–0.41 wt.%, K2O 0.05–0.17 Li2O 0.03–0.04 Cs2O 0.01–0.03 wt.%) high Be2O oxide (10.0 11.9 wt.%). elements (oxides), Na/Li (apfu) ratios (2.94 5.75), variations iron (FeO= 0.28–1.18 reveal a poorly evolved magmatic source grains. Low abundances rare earth (ΣREE 0.8–4.9 ppm) with 87Sr/86Sr(i) 0.739 ±0.036 for 0.7081 host granites infer that primary magma was directly produced partial melting upper continental crust (UCC). crystallization temperature pegmatite changes from 586 755 °C (average 629 °C), as calculated based on zircon saturation index. Furthermore, quartz geobarometer calculation shows occurred at pressures approximately 233–246 MPa. This pressure range promising condition Be magma. During crystallization, melt gradually saturated Be, then assemblage main minerals such feldspar. Likewise, Nb/Ta (4.79–16.3) Zr/Hf (12.2–19.1), signatures compatible Be-bearing LCT (Li-Ce Ta) pegmatites.