Experimental crystallization of trioctahedral smectites under hydrothermal conditions. Implication for alkaline hydrothermal vents
Present day hydrothermal vents are considered as analogues of sites where live could have emerged on primitive earth. Strýtan (Iceland) is a shallow hydrothermal system composed of vertical Si-Mg structures, whose mineral association corresponds to a low crystallinity silica, trioctahedral smectites...
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ftunivmalaga:oai:riuma.uma.es:10630/24867 2023-07-16T03:59:14+02:00 Experimental crystallization of trioctahedral smectites under hydrothermal conditions. Implication for alkaline hydrothermal vents Bentabol-Manzanares, María José Huertas Puerta, Francisco Javier Van Driessche, Alexander 2022 https://hdl.handle.net/10630/24867 eng eng AIPEA 17th International Clay Conference Estambul (Turquía) julio de 2022 https://hdl.handle.net/10630/24867 info:eu-repo/semantics/openAccess Hydrothermal vents Trioctahedral smectite Hydrothermal synthesis info:eu-repo/semantics/conferenceObject 2022 ftunivmalaga 2023-06-27T23:16:05Z Present day hydrothermal vents are considered as analogues of sites where live could have emerged on primitive earth. Strýtan (Iceland) is a shallow hydrothermal system composed of vertical Si-Mg structures, whose mineral association corresponds to a low crystallinity silica, trioctahedral smectites (Sm) and smaller amounts of carbonates. To better understand mineral formation in such vent systems we have synthesized trioctahedral Sm in the kerolite (Krl)-stevensite (Stv)-saponite (Sap) series using hydrothermal conditions in slightly alkaline solutions from amorphous hydrous Mg-Al silicates. The starting material consisted of coprecipitated gels with different Si/Mg/Al/Na atomic ratios. Gels were aged with water for 60 days at 150, 175, 200 and 225 °C in Teflon lined reactors. The solid samples were characterized by XRD, DTA-TG, FTIR and TEM. XRD revealed the formation of low crystallinity phyllosilicates. The 001 reflection evolved with increasing T and Al from 9.7, to 12 and 14.5 Å. The patterns contained peaks corresponding to Krl and Stv/Sap. In oriented mounts, solvation with ethylene glycol shifted the 001 peak to 17.4 Å in gels 2 and 3, whereas in Gel 1 it remained at 9.7 Å with a shoulder at 17.2 Å. FTIR bands were also associated to talc-Krl and Stv-Sap. TEM images of Gel 1 at 225°C showed unresolved aggregates of tiny crystals of 10 nm, with turbostratic structures. Gel 3 produced layered crystals containing numerous defects and with spacings of 10-11 Å, typical of trioctahedral Sm. Thus, aging treatment transformed gels into Krl-Sm interstratified minerals and trioctahedral Sm. T increased the conversion rate from 40 to 75% at 150°C to 225°, respectively. Gel 1 produced a 20-80% Stv-Krl interstratified mineral, composed of tiny crystals. Increasing Al content improved the crystallinity and the % of the Sm. Gel 2 consisted of a Sm-Krl interstratified mineral richer in Sm, while Gel 3 is fully transformed into Sap with tetrahedral Al. Conference Object Iceland RIUMA - Repositorio Institucional de la Universidad de Málaga |
institution |
Open Polar |
collection |
RIUMA - Repositorio Institucional de la Universidad de Málaga |
op_collection_id |
ftunivmalaga |
language |
English |
topic |
Hydrothermal vents Trioctahedral smectite Hydrothermal synthesis |
spellingShingle |
Hydrothermal vents Trioctahedral smectite Hydrothermal synthesis Bentabol-Manzanares, María José Huertas Puerta, Francisco Javier Van Driessche, Alexander Experimental crystallization of trioctahedral smectites under hydrothermal conditions. Implication for alkaline hydrothermal vents |
topic_facet |
Hydrothermal vents Trioctahedral smectite Hydrothermal synthesis |
description |
Present day hydrothermal vents are considered as analogues of sites where live could have emerged on primitive earth. Strýtan (Iceland) is a shallow hydrothermal system composed of vertical Si-Mg structures, whose mineral association corresponds to a low crystallinity silica, trioctahedral smectites (Sm) and smaller amounts of carbonates. To better understand mineral formation in such vent systems we have synthesized trioctahedral Sm in the kerolite (Krl)-stevensite (Stv)-saponite (Sap) series using hydrothermal conditions in slightly alkaline solutions from amorphous hydrous Mg-Al silicates. The starting material consisted of coprecipitated gels with different Si/Mg/Al/Na atomic ratios. Gels were aged with water for 60 days at 150, 175, 200 and 225 °C in Teflon lined reactors. The solid samples were characterized by XRD, DTA-TG, FTIR and TEM. XRD revealed the formation of low crystallinity phyllosilicates. The 001 reflection evolved with increasing T and Al from 9.7, to 12 and 14.5 Å. The patterns contained peaks corresponding to Krl and Stv/Sap. In oriented mounts, solvation with ethylene glycol shifted the 001 peak to 17.4 Å in gels 2 and 3, whereas in Gel 1 it remained at 9.7 Å with a shoulder at 17.2 Å. FTIR bands were also associated to talc-Krl and Stv-Sap. TEM images of Gel 1 at 225°C showed unresolved aggregates of tiny crystals of 10 nm, with turbostratic structures. Gel 3 produced layered crystals containing numerous defects and with spacings of 10-11 Å, typical of trioctahedral Sm. Thus, aging treatment transformed gels into Krl-Sm interstratified minerals and trioctahedral Sm. T increased the conversion rate from 40 to 75% at 150°C to 225°, respectively. Gel 1 produced a 20-80% Stv-Krl interstratified mineral, composed of tiny crystals. Increasing Al content improved the crystallinity and the % of the Sm. Gel 2 consisted of a Sm-Krl interstratified mineral richer in Sm, while Gel 3 is fully transformed into Sap with tetrahedral Al. |
format |
Conference Object |
author |
Bentabol-Manzanares, María José Huertas Puerta, Francisco Javier Van Driessche, Alexander |
author_facet |
Bentabol-Manzanares, María José Huertas Puerta, Francisco Javier Van Driessche, Alexander |
author_sort |
Bentabol-Manzanares, María José |
title |
Experimental crystallization of trioctahedral smectites under hydrothermal conditions. Implication for alkaline hydrothermal vents |
title_short |
Experimental crystallization of trioctahedral smectites under hydrothermal conditions. Implication for alkaline hydrothermal vents |
title_full |
Experimental crystallization of trioctahedral smectites under hydrothermal conditions. Implication for alkaline hydrothermal vents |
title_fullStr |
Experimental crystallization of trioctahedral smectites under hydrothermal conditions. Implication for alkaline hydrothermal vents |
title_full_unstemmed |
Experimental crystallization of trioctahedral smectites under hydrothermal conditions. Implication for alkaline hydrothermal vents |
title_sort |
experimental crystallization of trioctahedral smectites under hydrothermal conditions. implication for alkaline hydrothermal vents |
publisher |
AIPEA |
publishDate |
2022 |
url |
https://hdl.handle.net/10630/24867 |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
17th International Clay Conference Estambul (Turquía) julio de 2022 https://hdl.handle.net/10630/24867 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1771546797747994624 |