12:00 〜 12:15
[PPS09-12] Experimental reproduction of hematitic spherules formation
キーワード：spherulitic hematite, laboratory experiments, coal waste, sulfuric acid speleologenesis, Earth, Mars
Morphologically comparable spherules composed of hematite (alfa-Fe2O3), often associated with sulfates and chlorides, have been identified in various environments on both Earth and Mars. These occur as individual spheroids and botryoidal clusters at the burning coal-waste dumps in the Upper Silesian Coal Basin in Poland (Radlin, Chwalowice, Czerwionka, and Welnowiec dumps). They were also recorded in the Gruta con Lago cave within the Mulapampa travertine deposits in the vicinity of the active Ampato-Sabancaya Volcanic Complex in Peru (the Western Cordillera, the Peruvian Andes) and formed due to sulfuric acid speleologenesis (Tyc et al., 2024).
A series of simple experiments aimed at replicating the conditions leading to their formation has been conducted, providing a further terrestrial analogue for the Martian spherules, commonly known as blueberries, one of many intriguing features found on the surface of Mars. The starting material was goethite alfa-FeOOH, as it is ubiquitous in Martian soil, dispersed in the gangue rocks at dumps and travertine cover.
The first set of seven experiments with forty-two combinations were conducted under laboratory conditions in a Binder heating chamber ED23 and a laboratory tubular furnace in open and semi-closed systems. Temperatures at 150, 200, 450-500, 600-650, 700, and 900oC were used, and assigned times were 90 min, 5 h, 78 h, 90 h, 7, and 16 days. Experiments in solution were conducted at pH from neutral to 0 and involved substrates as goethite α-FeOOH, salammoniac NH4Cl, elemental sulphur S8, phthalimide C8H5NO2, FeSO4 7H2O, naphthalene C10H8, water steam, NaCl, AlCl3, FeSO4, MnSO4, HCl, and powdered coal waste from the Radlin dump. Of these, pH stands out as crucial (Ciesielczuk et al., 2024).
The second set of experiments is continued in a Binder heating chamber ED23 and limited to strongly acidic conditions with 1m HCl (2 mL and 0.2 mL) and H2SO4, a closed system (three steel autoclaves with PTFE inserts), low temperatures (150-200oC), short time (2-4 weeks) and reactants: laboratory-produced goethite, AlCl3, NiSO4 7H2O, MnSO4 5H2O, Cr2(SO4)3 18H2O, and CaCO3.
The initial results highlight the uniqueness of the spherulitic shape of hematite. However, in over-acidic conditions, hematite spherules were not formed, whereas in semi-dry conditions, some spherulitic shapes began to be formed. The experiments are in progress...
This study was partly funded by the National Science Centre (Poland), grant No 2020/39/B/ST10/00042, and the Institute of Earth Sciences, University of Silesia, Poland.
References
Ciesielczuk, J., Fabianska, M.J., Gaidzik, K., Nadudvari, A., Misz-Kennan, M., Abramowicz, A., 2024. Botryoidal and spherulitic hematite as experimental evidence of highly acidic conditions in burning coal-waste dumps and potentially on Mars. Science of the Total Environment, 932, 172759.
Tyc, A., Gaidzik, K., Ciesielczuk, J., Wator, K., 2024. Manifestations of sulfuric acid speleogenesis in the Mulapampa travertine, Central Andes of Peru: evidence from the Gruta con Lago. International Journal of Speleology, 53(2), 235-251. https://doi.org/10.5038/1827-806X.53.2.2503
A series of simple experiments aimed at replicating the conditions leading to their formation has been conducted, providing a further terrestrial analogue for the Martian spherules, commonly known as blueberries, one of many intriguing features found on the surface of Mars. The starting material was goethite alfa-FeOOH, as it is ubiquitous in Martian soil, dispersed in the gangue rocks at dumps and travertine cover.
The first set of seven experiments with forty-two combinations were conducted under laboratory conditions in a Binder heating chamber ED23 and a laboratory tubular furnace in open and semi-closed systems. Temperatures at 150, 200, 450-500, 600-650, 700, and 900oC were used, and assigned times were 90 min, 5 h, 78 h, 90 h, 7, and 16 days. Experiments in solution were conducted at pH from neutral to 0 and involved substrates as goethite α-FeOOH, salammoniac NH4Cl, elemental sulphur S8, phthalimide C8H5NO2, FeSO4 7H2O, naphthalene C10H8, water steam, NaCl, AlCl3, FeSO4, MnSO4, HCl, and powdered coal waste from the Radlin dump. Of these, pH stands out as crucial (Ciesielczuk et al., 2024).
The second set of experiments is continued in a Binder heating chamber ED23 and limited to strongly acidic conditions with 1m HCl (2 mL and 0.2 mL) and H2SO4, a closed system (three steel autoclaves with PTFE inserts), low temperatures (150-200oC), short time (2-4 weeks) and reactants: laboratory-produced goethite, AlCl3, NiSO4 7H2O, MnSO4 5H2O, Cr2(SO4)3 18H2O, and CaCO3.
The initial results highlight the uniqueness of the spherulitic shape of hematite. However, in over-acidic conditions, hematite spherules were not formed, whereas in semi-dry conditions, some spherulitic shapes began to be formed. The experiments are in progress...
This study was partly funded by the National Science Centre (Poland), grant No 2020/39/B/ST10/00042, and the Institute of Earth Sciences, University of Silesia, Poland.
References
Ciesielczuk, J., Fabianska, M.J., Gaidzik, K., Nadudvari, A., Misz-Kennan, M., Abramowicz, A., 2024. Botryoidal and spherulitic hematite as experimental evidence of highly acidic conditions in burning coal-waste dumps and potentially on Mars. Science of the Total Environment, 932, 172759.
Tyc, A., Gaidzik, K., Ciesielczuk, J., Wator, K., 2024. Manifestations of sulfuric acid speleogenesis in the Mulapampa travertine, Central Andes of Peru: evidence from the Gruta con Lago. International Journal of Speleology, 53(2), 235-251. https://doi.org/10.5038/1827-806X.53.2.2503