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Podrobnosti záznamu
| Název | | |  | Behavior of trace elements in quartz from plutons of different geochemical signature: A case study from the Bohemian Massif, Czech Republic
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| | Autor | | | Jazyk | | | | anglicky
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| | Typ dokumentu | | | | článek v odborném periodiku
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| | Zdrojový dokument - seriál | | | Svazek/č. | | | | 175/176, 15 August
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| | Strany | | | | s. 54-67
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| | Rok | | | | 2013
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| | Poznámky | | | | Projekt: GAP210/10/1105, GA ČR 3cav_un_auth*0263315
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| | | Rozsah: 14 s. : E
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| | Předmětová kategorie | | | Klíčové slovo | | | Abstrakt (anglicky) | | | | The trace-element content in igneous quartz from granitoids of different geochemical types was investigated using the laser ablation ICP-MS technique. The Variscan granitoids in the Bohemian Massif provide an excellent opportunity to study the chemical composition of magmatic quartz from the following granite types: (1) geochemically primitive I-type tonalites and granodiorites, (2) peraluminous S-type two-mica granites, (3) moderately fractionated A-type volcano-plutonic complexes of the Teplice caldera, and (4) highly fractionated S- and A-type rare-metal granites. This diversity of granitoids permitted the study of the chemical composition of magmatic quartz as result of (i) different magma protoliths and (ii) variable degrees of differentiation.
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| | There were only small differences in the quartz trace-element contents, ranging from weakly to moderately differentiated plutons of all geochemical types: Al (mostly 20-250 ppm), Ti (mostly 20-110 ppm), B (<13 ppm), Be (<0.7 ppm), Ge (<1 ppm), Li (<30 ppm), and Rb (<2 ppm). Only the S-type granites from western Erzgebirge contain Al-enriched quartz (200-400 ppm Al) since the beginning of its evolution. However, quartz from the highly fractionated granites (group 4) differs significantly: it is poor in Ti (<20 ppm Ti) and enriched in Al (up to 600 ppm in A-type, and up to 1000 ppm in S-type granites), Be (up to 3.2 ppm), Ge (up to 5.7 ppm), Li (up to 132 ppm, particularly in the S-type granites), and Rb (up to 15 ppm). The input of Ti into quartz is controlled mainly by the temperature and pressure, the entry of Al into quartz increases as a function of the water and fluorine content of the residual melt. Ge and Li increase significantly with the fractionation of parental melt.
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| | Their concentrations are controlled by the order of crystallization of minerals: comb quartz crystallizing before Li-mica is strongly Li-enriched, whereas groundmass and snowball quartz crystallizing after mica is enriched in Ge.
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| | Přispěvatel | | | | AV ČR Brno, Geologický ústav
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| | Kód přispěvatele | | | | AV ČR, GLÚ
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| | Zdrojový formát | | | | U
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| | Datum importu | | | | 23. 10. 2014 |
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