Speleothems of the granite Gobholo Cave in Eswatini

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F20%3A00532062" target="_blank" >RIV/67985831:_____/20:00532062 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216208:11310/20:10424442

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S1464343X20302375" target="_blank" >https://www.sciencedirect.com/science/article/pii/S1464343X20302375</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jafrearsci.2020.103986" target="_blank" >10.1016/j.jafrearsci.2020.103986</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Speleothems of the granite Gobholo Cave in Eswatini

Popis výsledku v původním jazyce

The Gobholo Cave is one of the ten worldʼs largest granite caves (and the longest on the African continent),nabound with relatively rich speleothem deposits. For the first time, a set of instrumental techniques (XRD, SEM/nEDS, Raman micro-spectroscopy) was used to characterize the speleothems and also waters (ICP-OES) fromnwhich these speleothems have been deposited. Several types of speleothems (and sedimentary fill) werendistinguished and studied: “muddy” flowstone, coralloids, black coatings. The results show that the mass of allnstudied speleothems is amorphous with a variable chemical composition. Therefore, the speleothems are rathernnatural substances than mineral species. Four main groups of substances were distinguished, based on theirngeneral chemistry: i) Al-rich substances close to gibbsite composition, ii) Al + Si-rich substances close to allophanencomposition, iii) Si-rich substances close to opal-A composition, and iv) Mn-rich substances (unspecifiednMn oxyhydroxides). Although the samples are nearly amorphous, poorly crystalline gibbsite and birnessite werenfound to be possibly present. Based on Raman spectroscopy, strongly altered kerogen was detected in some Al +nSi-rich samples. Raman data indicate that the growth of Gobholo speleothems is most probably tightly related tonthe activity of microorganisms. Based on collected instrumental data, the problematic issue of “mineral” pigotiten(a substance commonly referred to from granite caves but only vaguely defined) is critically discussed in thenpaper.

Název v anglickém jazyce

Speleothems of the granite Gobholo Cave in Eswatini

Popis výsledku anglicky

The Gobholo Cave is one of the ten worldʼs largest granite caves (and the longest on the African continent),nabound with relatively rich speleothem deposits. For the first time, a set of instrumental techniques (XRD, SEM/nEDS, Raman micro-spectroscopy) was used to characterize the speleothems and also waters (ICP-OES) fromnwhich these speleothems have been deposited. Several types of speleothems (and sedimentary fill) werendistinguished and studied: “muddy” flowstone, coralloids, black coatings. The results show that the mass of allnstudied speleothems is amorphous with a variable chemical composition. Therefore, the speleothems are rathernnatural substances than mineral species. Four main groups of substances were distinguished, based on theirngeneral chemistry: i) Al-rich substances close to gibbsite composition, ii) Al + Si-rich substances close to allophanencomposition, iii) Si-rich substances close to opal-A composition, and iv) Mn-rich substances (unspecifiednMn oxyhydroxides). Although the samples are nearly amorphous, poorly crystalline gibbsite and birnessite werenfound to be possibly present. Based on Raman spectroscopy, strongly altered kerogen was detected in some Al +nSi-rich samples. Raman data indicate that the growth of Gobholo speleothems is most probably tightly related tonthe activity of microorganisms. Based on collected instrumental data, the problematic issue of “mineral” pigotiten(a substance commonly referred to from granite caves but only vaguely defined) is critically discussed in thenpaper.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of African Earth Sciences

ISSN

1464-343X

e-ISSN

—

Svazek periodika

172

Číslo periodika v rámci svazku

December

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

16

Strana od-do

103986

Kód UT WoS článku

000590387100030

EID výsledku v databázi Scopus

2-s2.0-85090358848