Obsidian balls (marekanite) from Cerro Tijerina, central
Nicaragua: petrographic investigations

J 2011

Obsidian balls (marekanite) from Cerro Tijerina, central Nicaragua: petrographic investigations

MRAZOVA, Stepanka a Petr GADAS

Základní údaje

Originální název

Obsidian balls (marekanite) from Cerro Tijerina, central Nicaragua: petrographic investigations

Autoři

MRAZOVA, Stepanka a Petr GADAS

Vydání

Arabian Journal of Geosciences, HEIDELBERG, GERMANY, SPRINGER HEIDELBERG, 2011, 1866-7511

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10505 Geology

Stát vydavatele

Česká republika

Utajení

není předmětem státního či obchodního tajemství

Odkazy

URL

Impakt faktor

Impact factor: 1.141

Označené pro přenos do RIV

Ano

Organizační jednotka

Přírodovědecká fakulta

Klíčová slova anglicky

obsidian; marekanite; volcanic glass; Cerro Tijerina; Nicaragua

Štítky

rivok

Příznaky

Mezinárodní význam, Recenzováno

Změněno: 10. 7. 2020 13:04, Mgr. Marie Novosadová Šípková, DiS.

Anotace

V originále

The paper describes a find of volcanic glass in central Nicaragua. We investigated obsidian samples in perlite from a large profile of volcanic rocks (Cerro Tijerina) in the vicinity of the town of Matagalpa. The obsidian occurs in the form of up to 3-cm dark-coloured balls (spheres) randomly distributed in brittle grey perlite, which also has spherulitic texture. These balls, previously called marekanite, are characterised by an abundance of microphenocrysts (feldspar, biotite, amphibole, apatite and magnetite). Microprobe analysis of the homogenous glass of obsidian balls and perlite has confirmed their subalkaline, and particularly high-K calc-alkaline character (SiO(2) >= 70 %, Na(2)O + K(2)O < Al(2)O(3)), which is typical of rhyolitic melts. A sharp contact was observed between the core and the surface layer (approx. 0.1-0.2 mm) of the obsidian balls, reflecting changes in the H(2)O content.

Citovat

MRAZOVA, Stepanka a Petr GADAS. Obsidian balls (marekanite) from Cerro Tijerina, central Nicaragua: petrographic investigations. Arabian Journal of Geosciences. HEIDELBERG, GERMANY: SPRINGER HEIDELBERG, 2011, roč. 56, č. 1, s. 43-49. ISSN 1866-7511. Dostupné z: https://doi.org/10.3190/jgeosci.086.

@article{1669716,
   author = {Mrazova, Stepanka and Gadas, Petr},
   article_location = {HEIDELBERG, GERMANY},
   article_number = {1},
   doi = {https://doi.org/10.3190/jgeosci.086},
   keywords = {obsidian; marekanite; volcanic glass; Cerro Tijerina; Nicaragua},
   language = {eng},
   issn = {1866-7511},
   journal = {Arabian Journal of Geosciences},
   title = {Obsidian balls (marekanite) from Cerro Tijerina, central Nicaragua: petrographic investigations},
   url = {http://dx.doi.org/10.3190/jgeosci.086},
   volume = {56},
   year = {2011}
}

TY  - JOUR
ID  - 1669716
AU  - Mrazova, Stepanka - Gadas, Petr
PY  - 2011
TI  - Obsidian balls (marekanite) from Cerro Tijerina, central Nicaragua: petrographic investigations
JF  - Arabian Journal of Geosciences
VL  - 56
IS  - 1
SP  - 43-49
EP  - 43-49
PB  - SPRINGER HEIDELBERG
SN  - 18667511
KW  - obsidian
KW  - marekanite
KW  - volcanic glass
KW  - Cerro Tijerina
KW  - Nicaragua
UR  - http://dx.doi.org/10.3190/jgeosci.086
L2  - http://dx.doi.org/10.3190/jgeosci.086
N2  - The paper describes a find of volcanic glass in central Nicaragua. We investigated obsidian samples in perlite from a large profile of volcanic rocks (Cerro Tijerina) in the vicinity of the town of Matagalpa. The obsidian occurs in the form of up to 3-cm dark-coloured balls (spheres) randomly distributed in brittle grey perlite, which also has spherulitic texture. These balls, previously called marekanite, are characterised by an abundance of microphenocrysts (feldspar, biotite, amphibole, apatite and magnetite). Microprobe analysis of the homogenous glass of obsidian balls and perlite has confirmed their subalkaline, and particularly high-K calc-alkaline character (SiO(2) >= 70 %, Na(2)O + K(2)O < Al(2)O(3)), which is typical of rhyolitic melts. A sharp contact was observed between the core and the surface layer (approx. 0.1-0.2 mm) of the obsidian balls, reflecting changes in the H(2)O content.
ER  -

MRAZOVA, Stepanka a Petr GADAS. Obsidian balls (marekanite) from Cerro Tijerina, central Nicaragua: petrographic investigations. \textit{Arabian Journal of Geosciences}. HEIDELBERG, GERMANY: SPRINGER HEIDELBERG, 2011, roč.~56, č.~1, s.~43-49. ISSN~1866-7511. Dostupné z: https://doi.org/10.3190/jgeosci.086.

Přehled o publikaci