Kogarkoite, Na-3(SO4)F, from the Shalo hot spring, Main
Ethiopian Rift: implications for F-enrichment of thermal
groundwater related to alkaline silicic volcanic rocks

J 2015

Kogarkoite, Na-3(SO4)F, from the Shalo hot spring, Main Ethiopian Rift: implications for F-enrichment of thermal groundwater related to alkaline silicic volcanic rocks

ŽÁČEK, Vladimír; Vladislav RAPPRICH; Jiří ŠÍMA; Radek ŠKODA; František LAUFEK et al.

Základní údaje

Originální název

Kogarkoite, Na-3(SO4)F, from the Shalo hot spring, Main Ethiopian Rift: implications for F-enrichment of thermal groundwater related to alkaline silicic volcanic rocks

Autoři

ŽÁČEK, Vladimír; Vladislav RAPPRICH; Jiří ŠÍMA; Radek ŠKODA; František LAUFEK a Firdawok LEGESA

Vydání

Journal of Geosciences, Praha, Česká geologická společnost, 2015, 1802-6222

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10500 1.5. Earth and related environmental sciences

Stát vydavatele

Česká republika

Utajení

není předmětem státního či obchodního tajemství

Impakt faktor

Impact factor: 1.326

Označené pro přenos do RIV

Ano

Kód RIV

RIV/00216224:14310/15:00087127

Organizační jednotka

Přírodovědecká fakulta

Klíčová slova anglicky

kogarkoite; hot spring; fluorine; silicic; Shashemene; Ethiopia

Štítky

AKR, rivok

Změněno: 6. 4. 2016 16:36, Ing. Andrea Mikešková

Anotace

V originále

Kogarkoite, anhydrous monoclinic sodium fluorosulphate, was identified as a white granular coagulate in the Shalo hot spring situated between the towns of Hawasa and Shashemene, in the central part of the Main Ethiopian Rift in southern Ethiopia. The mineral crystallizes together with trona, Na-3(HCO3)(CO3)center dot 2H(2)O, and opal as white stratified sinter covering the surface of rhyolite chips semi-immerged in Na-HCO3 type thermal water with temperatures of up to 96 degrees C. The determined chemical composition of kogarkoite is close to the ideal formula Na-3(SO4)F and the refined unit-cell parameters are a = 18.089(2) angstrom, b = 6.965(1) angstrom, c = 11.457(1) angstrom, beta = 107.72(1 degrees), V = 1374.4(4) angstrom(3). Increased concentrations of fluorine in groundwater were detected in the area of the rift floor of the central and northern parts of the Main Ethiopian Rift including the wider vicinity of the towns of Shashemene and Hawasa; however, this is the first described occurrence of fluorine-bearing mineral related to hot springs in Ethiopia. The presence of "free" fluorine both in cold groundwater (up to 17 mg/l) and in the Shalo hot spring (40 mg/l) is related to the prevalence of highly alkaline silicic volcanic rocks (namely pantelleritic obsidians) extremely poor in calcium and phosphorus. This prevents fixing of fluorine in apatite or in other stable minerals.

Citovat

ŽÁČEK, Vladimír; Vladislav RAPPRICH; Jiří ŠÍMA; Radek ŠKODA; František LAUFEK a Firdawok LEGESA. Kogarkoite, Na-3(SO4)F, from the Shalo hot spring, Main Ethiopian Rift: implications for F-enrichment of thermal groundwater related to alkaline silicic volcanic rocks. Journal of Geosciences. Praha: Česká geologická společnost, 2015, roč. 60, č. 3, s. 171-179. ISSN 1802-6222. Dostupné z: https://doi.org/10.3190/jgeosci.195.

@article{1340743,
   author = {Žáček, Vladimír and Rapprich, Vladislav and Šíma, Jiří and Škoda, Radek and Laufek, František and Legesa, Firdawok},
   article_location = {Praha},
   article_number = {3},
   doi = {https://doi.org/10.3190/jgeosci.195},
   keywords = {kogarkoite; hot spring; fluorine; silicic; Shashemene; Ethiopia},
   language = {eng},
   issn = {1802-6222},
   journal = {Journal of Geosciences},
   title = {Kogarkoite, Na-3(SO4)F, from the Shalo hot spring, Main Ethiopian Rift: implications for F-enrichment of thermal groundwater related to alkaline silicic volcanic rocks},
   volume = {60},
   year = {2015}
}

TY  - JOUR
ID  - 1340743
AU  - Žáček, Vladimír - Rapprich, Vladislav - Šíma, Jiří - Škoda, Radek - Laufek, František - Legesa, Firdawok
PY  - 2015
TI  - Kogarkoite, Na-3(SO4)F, from the Shalo hot spring, Main Ethiopian Rift: implications for F-enrichment of thermal groundwater related to alkaline silicic volcanic rocks
JF  - Journal of Geosciences
VL  - 60
IS  - 3
SP  - 171-179
EP  - 171-179
PB  - Česká geologická společnost
SN  - 18026222
KW  - kogarkoite
KW  - hot spring
KW  - fluorine
KW  - silicic
KW  - Shashemene
KW  - Ethiopia
N2  - Kogarkoite, anhydrous monoclinic sodium fluorosulphate, was identified as a white granular coagulate in the Shalo hot spring situated between the towns of Hawasa and Shashemene, in the central part of the Main Ethiopian Rift in southern Ethiopia. The mineral crystallizes together with trona, Na-3(HCO3)(CO3)center dot 2H(2)O, and opal as white stratified sinter covering the surface of rhyolite chips semi-immerged in Na-HCO3 type thermal water with temperatures of up to 96 degrees C. The determined chemical composition of kogarkoite is close to the ideal formula Na-3(SO4)F and the refined unit-cell parameters are a = 18.089(2) angstrom, b = 6.965(1) angstrom, c = 11.457(1) angstrom, beta = 107.72(1 degrees), V = 1374.4(4) angstrom(3). Increased concentrations of fluorine in groundwater were detected in the area of the rift floor of the central and northern parts of the Main Ethiopian Rift including the wider vicinity of the towns of Shashemene and Hawasa; however, this is the first described occurrence of fluorine-bearing mineral related to hot springs in Ethiopia. The presence of "free" fluorine both in cold groundwater (up to 17 mg/l) and in the Shalo hot spring (40 mg/l) is related to the prevalence of highly alkaline silicic volcanic rocks (namely pantelleritic obsidians) extremely poor in calcium and phosphorus. This prevents fixing of fluorine in apatite or in other stable minerals.
ER  -

ŽÁČEK, Vladimír; Vladislav RAPPRICH; Jiří ŠÍMA; Radek ŠKODA; František LAUFEK a Firdawok LEGESA. Kogarkoite, Na-3(SO4)F, from the Shalo hot spring, Main Ethiopian Rift: implications for F-enrichment of thermal groundwater related to alkaline silicic volcanic rocks. \textit{Journal of Geosciences}. Praha: Česká geologická společnost, 2015, roč.~60, č.~3, s.~171-179. ISSN~1802-6222. Dostupné z: https://doi.org/10.3190/jgeosci.195.

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