Structural changes of potassium-saturated smectite at high pressures and high temperatures: Application for subduction zones

Carniel, Larissa Colombo; Conceição, Rômmulo Vieira; Dani, Norberto; Stefani, Vicente Fiorini; Balzaretti, Naira Maria; Reis, Roberto dos

doi:10.1016/j.clay.2014.09.037

Cited by 13 publications

(3 citation statements)

References 17 publications

(19 reference statements)

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“…The thermal expansion responses measured under near-atmospheric pressure conditions, and any damage attributed to them, may be pushed to higher temperatures under the increased pressure conditions associated with burial, as dehydration is suppressed [74]. However, without a change in temperature, an increase in pressure alone does not result in smectite dehydration [76].…”

Section: Impact Of Temperature On the Thermal Expansivity Ofmentioning

confidence: 99%

Thermal Liability of Hyaloclastite in the Krafla Geothermal Reservoir, Iceland: The Impact of Phyllosilicates on Permeability and Rock Strength

et al. 2020

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Geothermal fields are prone to temperature fluctuations from natural hydrothermal activity, anthropogenic drilling practices, and magmatic intrusions. These fluctuations may elicit a response from the rocks in terms of their mineralogical, physical (i.e., porosity and permeability), and mechanical properties. Hyaloclastites are a highly variable volcaniclastic rock predominantly formed of glass clasts that are produced during nonexplosive quench-induced fragmentation, in both subaqueous and subglacial eruptive environments. They are common in high-latitude geothermal fields as both weak, highly permeable reservoir rocks and compacted impermeable cap rocks. Basaltic glass is altered through interactions with external water into a clay-dominated matrix, termed palagonite, which acts to cement the bulk rock. The abundant, hydrous phyllosilicate minerals within the palagonite can dehydrate at elevated temperatures, potentially resulting in thermal liability of the bulk rock. Using surficial samples collected from Krafla, northeast Iceland, and a range of petrographic, mineralogical, and mechanical analyses, we find that smectite dehydration occurs at temperatures commonly experienced within geothermal fields. Dehydration events at 130, 185, and 600°C result in progressive mass loss and contraction. This evolution results in a positive correlation between treatment temperature, porosity gain, and permeability increase. Gas permeability measured at 1 MPa confining pressure shows a 3-fold increase following thermal treatment at 600°C. Furthermore, strength measurements show that brittle failure is dependent on porosity and therefore the degree of thermal treatment. Following thermal treatment at 600°C, the indirect tensile strength, uniaxial compressive strength, and triaxial compressive strength (at 5 MPa confining pressure) decrease by up to 68% (1.1 MPa), 63% (7.3 MPa), and 25% (7.9 MPa), respectively. These results are compared with hyaloclastite taken from several depths within the Krafla reservoir, through which the palagonite transitions from smectite- to chlorite-dominated. We discuss how temperature-induced changes to the geomechanical properties of hyaloclastite may impact fluid flow in hydrothermal reservoirs and consider the potential implications for hyaloclastite-hosted intrusions. Ultimately, we show that phyllosilicate-bearing rocks are susceptible to temperature fluctuations in geothermal fields.

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Section: Impact Of Temperature On the Thermal Expansivity Ofmentioning

confidence: 99%

Thermal Liability of Hyaloclastite in the Krafla Geothermal Reservoir, Iceland: The Impact of Phyllosilicates on Permeability and Rock Strength

et al. 2020

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“…Experimental run times were 8 hours. Experiments performed in the described apparatus had pressure and temperature accuracies of ± 0.5 GPa and ± 25ºC, respectively (Carniel et al, 2014). Some experiments were performed twice to verify the reproducibility of this methodology.…”

Section: Methodsmentioning

confidence: 99%

“…Carniel et al (2014) demonstrated that pelagic K-rich smectites play a major role carrying potassium to deep Earth via subduction. This sediment input can represent an important source of potassium, not only to the mantle wedge, but also to the whole Earth's mantle.…”

Section: K 2 O Na 2 O and Cao Mantle Source Concentrationmentioning

confidence: 99%

Study of silica-undersaturated magmas through the Kalsilite- Nepheline-Diopside-Silica system at 4.0 GPa and dry conditions

Souza

Conceição

Cedeño

et al. 2018

Geol. USP. Sér. cient.

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This study experimentally investigates the Kalsilite-Nepheline-Diopside-Silica system at high pressure and temperature, with emphasis on silica-undersaturated volume (leucite-nepheline-diopside -Lct-Nph-Di; and kalsilite-nepheline-diopside -Kls + Nph + Di -planes), at 4.0 GPa (~120 km deep), temperatures up to 1,400ºC and dry conditions, to better understand the influence of K 2 O, Na 2 O, and CaO in alkali-rich silica-undersaturated magma genesis. In the Lct-Nph-Di plane, we determined the stability fields for kalsilite (Kls ss ), nepheline (Nph ss ) and clinopyroxene (Cpx ss ) solid solutions, wollastonite (Wo) and sanidine (Sa); and three piercing points: (i) pseudo-eutectic Kls + Nph + Di + liquid (Lct 62 Nph 29 Di 9 ) at 1,000ºC; (ii) Kls + Sa + (Di + Wo) + liquid (Lct 75 Nph 22 Di 2 ) at 1,200ºC; and (iii) pseudo-eutectic Kls + Di + Wo + liquid (Lct 74 Nph 17 Di 9 ) at 1,000ºC. Kalsilite stability field represents a thermal barrier between ultrapotassic/potassic vs. sodic compositions. In the plane Kls-Nph-Di, we determined the stability fields for Kls ss , Nph ss and Cpx ss and two aluminous phases in smaller proportions: spinel (Spl) and corundum (Crn). This plane has a piercing point in Kls + Nph + Di(± Spl) + liquid (Kls 47 Nph 43 Di 10 ) at 1,100ºC. Our data showed that pressure extends K dissolution in Nph (up to 39 mol%) and Na in Kls (up to 27 mol%), and that these solid solutions, if present, determinate how much enriched in K and Na an alkaline magma will be in an alkaline-enriched metasomatic mantle. Additionally, we noted positive correlation between K 2 O and SiO 2 concentration in experimental melts, negative correlation between CaO and SiO 2 , and no evident correlation between Na 2 O and SiO 2 .Keywords: Experimental petrology; Alkaline rocks; Potassium; Mantle. ResumoEste trabalho trata do estudo experimental do sistema kalsilita-nefelina-diopsídio-sílica em condições mantélicas, com ên-fase em sua parte subsaturada em sílica (planos leucita-nefelina-diopsídio -Lct-Nph-Di; e kalsilita-nefelina-diopsídio -Kls + Nph + Di), a 4 GPa (profundidade de aproximadamente 120 km), até 1.400ºC em condições anidras. O objetivo é melhor compreender como K 2 O, Na 2 O e CaO influenciam a gênese de magmas ricos em álcalis e subsaturados em sílica. Para o plano Lct-Nph-Di, foram determinados campos de estabilidade para as soluções sólidas kalsilita (Kls ss ), nefelina (Nph ss ) e clinopiroxênios (Cpx ss ), além de wollastonita (Wo) e sanidina (Sa). Foram também definidos os pontos invariantes: (i) pseudoeutético Kls+Nph+Di+líquido (Lct 62 Ne 29 Di 9 ) a 1.000ºC; (ii) Kls + Sa + (Di + Wo) + líquido (Lct 75 Nph 22 Di 2 ) a 1.200ºC; (iii) pseudoeutético Kls + Di + Wo + líquido (Lct 74 Nph 17 Di 9 ) a 1.000ºC. O campo da kalsilita, nesse diagrama, representa um alto termal entre os extremos composicionais potássico/ultrapotássico vs. sódico. No plano Kls-Nph-Di, encontramos campos de estabilidade para Kls ss , Nph ss e Cpx ss , além de pequenas quantidades de espinélio (Spl) e coríndon (Crn) e um ponto...

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Calcined Palygorskites as Supplementary Cementitious Materials

Poussardin

Roux

Wilson

et al. 2022

Clays and clay miner.

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Reducing the environmental footprint of cement is an absolute necessity to meet the commitments of COP26 and to limit global warming to + 1.5°C compared to the pre-industrial level. In this context, particular interest has developed in recent years in the use of calcined clays as supplementary cementitious materials (SCMs). Due to their high reactivity, large reserves and homogeneous distribution on the earth's surface, calcined clays represent a viable alternative to conventional SCMs. Clay minerals are highly variable and numerous, each with their own characteristics. As a result, not all of them have potential for use as SCMs. The present paper investigated the use of palygorskite (a clay that has been relatively poorly studied) as an SCM. Two commercial palygorskites of different grades were selected and their calcination was studied by X-ray diffraction and pozzolanic activity tests. Blended cements incorporating 20% of each calcined palygorskite were prepared and the mechanical performance and resistivity of the mortars measured. The results show that the optimum calcination temperature is 800°C (allowing complete amorphization of the clay fraction and the highest pozzolanic reactivity) for both clays. Mortars made with 80% ordinary Portland cement (OPC) blended with 20% of 800°C calcined palygorskite allowed a significant increase in compressive strength and electrical resistivity compared to the reference (100% OPC). The clay sample with palygorskite as the dominant mineral exhibited the greatest pozzolanic reactivity and mechanical performance in cementitious systems, confirming that palygorskite is a clay mineral with a significant potential for a use as a SCM. The second sample with smaller palygorskite content also allowed a significant increase in mechanical performance. This demonstrated that it is not necessary to use high-purity samples and enhances the value of this type of material.

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Structural changes of potassium-saturated smectite at high pressures and high temperatures: Application for subduction zones

Cited by 13 publications

References 17 publications

Thermal Liability of Hyaloclastite in the Krafla Geothermal Reservoir, Iceland: The Impact of Phyllosilicates on Permeability and Rock Strength

Thermal Liability of Hyaloclastite in the Krafla Geothermal Reservoir, Iceland: The Impact of Phyllosilicates on Permeability and Rock Strength

Study of silica-undersaturated magmas through the Kalsilite- Nepheline-Diopside-Silica system at 4.0 GPa and dry conditions

Calcined Palygorskites as Supplementary Cementitious Materials

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