Raman spectroscopy of anhydrous and hydrated aluminum sulfates: Experience from burning coal heaps

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F22%3A10452739" target="_blank" >RIV/00216208:11310/22:10452739 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=dPRUQHyDHi" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=dPRUQHyDHi</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/jrs.6420" target="_blank" >10.1002/jrs.6420</a>

Result language

angličtina

Original language name

Raman spectroscopy of anhydrous and hydrated aluminum sulfates: Experience from burning coal heaps

Original language description

Hydrated aluminum-rich sulfates belong to less widespread secondary minerals on Mars, which are probably connected with hydrothermal alterations. On Earth, such sulfates result from acidic weathering of aluminosilicates, and their formation is controlled by factors such as pH, temperature, or water activity. Physical-chemical conditions can be reconstructed if specific sulfate phases are detected, and therefore, the investigation of sulfate assemblages in high-temperature settings is important for planetology and exobiology research. Raman spectroscopy is a powerful analytical tool for the discrimination of sulfates, and the degree of hydration, which is a sensitive marker of temperature conditions, can be tracked using this method. However, spectral similarities of sulfates and metastability and rapid transformations may hinder their correct identification. We take advantage of in situ and laboratory Raman spectroscopy to characterize uncommon anhydrous and hydrated Al-NH4 sulfate mineralogy which forms under elevated temperature at the Anna burning coal waste dump, Alsdorf, Germany, and can be considered as analogous to fumarolic environments. We detected a suite of hydrated Al sulfates (e.g. alunogen, khademite, and tschermigite) in the medium-temperature zones (similar to 50 degrees C). To minimize possible rehydration processes, we deployed two miniaturized Raman spectrometers (532 and 1064 nm) for field investigations in the high-temperature zone (similar to 130 degrees C to 150 degrees C). Mixtures of anhydrous (godovikovite and millosevichite) and hydrated phases along with intermediate phases were detected in the field as well as in the laboratory. Such observations are consistent with the premise that the degree hydration of sulfates increase with decreasing temperature. These results confirm that Raman spectroscopy is, despite several analytical challenges, capable of distinguishing Al sulfates, and their hydration states, within complex aggregates and crusts, and future applications in planetary research are promising.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10505 - Geology

Project

—

Continuities

S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

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

Name of the periodical

Journal of Raman Spectroscopy

ISSN

0377-0486

e-ISSN

1097-4555

Volume of the periodical

53

Issue of the periodical within the volume

11

Country of publishing house

GB - UNITED KINGDOM

Number of pages

15

Pages from-to

1959-1973

UT code for WoS article

000822623500001

EID of the result in the Scopus database

2-s2.0-85133681599