Referenza:
▪ Vereshchagin, O., Britvin, S., Wunder, B., Frank-Kamenetskaya, O.V., Wilke, F.D.H., Vlasenko, N.S., Shilovskikh, V.V., Bocharov, V., Danilov, D. (2022): Ln3+ (Ln3+ = La, Nd, Eu, Yb) incorporation in synthetic tourmaline analogues: Towards tourmaline REE pattern explanation. Chemical Geology, (in press).
Abstract:
Tourmaline rare-earth element (lanthanides + Y) patterns could provide valuable geological information as tourmalines are the most abundant borosilicates on Earth and are stable at extreme PT conditions. The lanthanide-bearing tourmalines were synthesized for the first time in a series of high- (4 GPa) and low-pressure (0.2 GPa) hydrothermal experiments. We have found that Ln-content (Ln = La3+, Nd3+, Eu3+ and Yb3+) in synthetic tourmalines varies significantly (1.13–8.35 wt% Ln2O3) with Yb < La ≤ Nd < Eu independent of pressure conditions. Ln-content in synthetic tourmalines, obtained at low pressure is 2–3 times higher, than those from high-pressure experiments. The Nd- and Eu-rich synthetic tourmalines exhibit cathodo- photoluminescence properties (blue and violet luminescence colors for Nd and Eu, respectively), which confirms trivalent state of Ln in tourmaline structure. Single-crystal X-ray diffraction data for synthetic tourmalines (Nd-rich a 15.893(1), c 7.130(1) Å; Eu-rich a 15.903(5), c 7.168(3) Å) show that Eu3+ and Nd3+ occupy the 9-coordinated X-site in the tourmaline structure. The general formula of obtained synthetic tourmalines can be expressed as Ln3+1-x (Mg,Al)3 (Al,Mg)6 (Si6O18) (BO3)3 (OH,O)3(OH,O) (0.05 ≤ x ≤ 0.97). The crystal-chemical features and lanthanide speciation in synthesized tourmalines are herein discussed and compared to natural and synthetic compounds.
Ln3+ (Ln3+ = La, Nd, Eu, Yb) incorporation in synthetic tourmaline analogues: Towards tourmaline REE pattern explanation
- Marco E. Ciriotti
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Ln3+ (Ln3+ = La, Nd, Eu, Yb) incorporation in synthetic tourmaline analogues: Towards tourmaline REE pattern explanation
Marco E. Ciriotti
«Things are interesting only in so far as they relate themselves to other things»
«Things are interesting only in so far as they relate themselves to other things»
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