A six-component chlorite solid solution model and the conditions of chlorite formation in hydrothermal and geothermal systems

Walshe, John L.

doi:10.2113/gsecongeo.81.3.681

Cited by 227 publications

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“…Several solid solution models have been put forward for the clay minerals, from the simple ideal mixing on homologicai sites (Tardy and Fritz, 1981;Aagaard and Helgeson, 1983;Helgeson and Aagaard, 1985;Walshe, 1986) to more "non ideal" models (Stoessel, 1979(Stoessel, , 1981(Stoessel, , 1984. The actual solid solution behavior of illites and chlorites is far from known in any detail, and by realizing the uncertainties in the thermodynamic data of several of the end member components, as well, we feel that any advanced solution model is not warranted at our present stage of knowledge.…”

Section: End Member Activities and Reaction Quotientmentioning

confidence: 98%

“…By applying appropriate solid solution models for the minerals in question, the aqueous phase composition can be calculated. Chlorite is, therefore, a key phase for estimating the activity of ferrous/ferric iron as well as magnesium ions (Stoessel, 1984;Walshe, 1986;Jahren and Aagaard, 1989). Walshe (1986) has specifically demonstrated how the oxygen fugacity can be calculated from the chemical composition of hydrothermal chlorites.…”

Section: Introductionmentioning

confidence: 99%

“…Chlorite is, therefore, a key phase for estimating the activity of ferrous/ferric iron as well as magnesium ions (Stoessel, 1984;Walshe, 1986;Jahren and Aagaard, 1989). Walshe (1986) has specifically demonstrated how the oxygen fugacity can be calculated from the chemical composition of hydrothermal chlorites. The approach employed in this paper is quite different, as an evaluation of internal equilibrium in chlorite-illite pairs requires no information about the pore water chemistry, and offers an independent test of equilibrium formation.…”

Section: Introductionmentioning

confidence: 99%

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Diagenetic Illite-Chlorite Assemblages in Arenites. II. Thermodynamic Relations

Aagaard

Jahren

1992

Clays and clay miner.

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Abstract--The internal equilibrium status among chlorite-itlite pairs has been evaluated through coupled substitution reactions. Compositional data of chlorites and illites from arenites at present burial temperatures between 90 ~ and 180~ have been used to calculate end member activities and reaction quotients of the combined Tschermak reaction:Muscovite + Clinochlore = MgAl-celadonite + Amesite.The reaction quotient data in the 90 ~ to 180~ temperature range have then been compared with the equilibrium curve for the same reaction, and found to be in reasonable agreement. This indicates that chlorites and illites in these arenites grow at near equilibrium conditions.The data set has also been compared with chlorite-illite pairs from hydrothermally altered arenites of the Salton Sea area. For chlorite-iUite containing assemblages, these data agree well with the diagenetic ones. The introduction of biotite at higher temperatures alters with the iron-magnesium distribution and breaks down the substitution relationship between chlorite and illite.The model predicts an increasing stability of muscovite and clinochlore components with increasing temperature, while celadonite and amesite would be stabilized with increasing pressure. This is consistent with high pressure occurrences of phengite. However, at the low pressure region of diagenesis and hydrothermal alteration, the temperature effect is dominant.

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Section: End Member Activities and Reaction Quotientmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diagenetic Illite-Chlorite Assemblages in Arenites. II. Thermodynamic Relations

Aagaard

Jahren

1992

Clays and clay miner.

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“…(Naglik 2016) Chlorite is one of the most common silicates in variety of geological environments occurring as a product of metamorphism as well as hydrothermal or diagenetic rocks alteration (Jiang et al 1994). The relationship between chlorite chemical composition and physico-chemical conditions of its formation was observed by many authors (Cathelineau & Nieva 1985, Walshe 1986, Kranidiotis & McLean 1987, Cathelineau 1988, Vidal et al 2001, Inoue 2009). A new model published by Bourdelle et al (2013) is applicable for the chlorites formed at the wide range of temperatures (50-350°C) and under pressure lower than 4 kbars.…”

Section: Products Of Hydrothermal Alterationmentioning

confidence: 99%

Mineral assemblages as a record of the evolutionary history of the Pepper Mts. Shale Formation (the Holy Cross Mts.).

Naglik

Natkaniec‐Nowak

Heflik

2016

geol

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Abstract:The Pepper Mts. Shale Formation, consisting of: clayey shales, mudstones and sandstones, as one of the oldest unit of the Holy Cross Mts., was subjected to mineralogical and petrographical studies. In order to reconstruct the geological history of the succession, mineral assemblages were characterized from the genetic point of view. Pyrite and goethite taking a form of bacterial-cell pseudomorphoses, crystallized during sedimentation and/or diagenesis, while quartz, kaolinite, goethite and chlorite prove subsequent alteration due to the hydrothermal fluid circulation. Secondary sulphates occurring on the pyrite-bearing rock outcrops mark the way of weathering processes. According to the presented results, Cambrian sediments were affected by hot fluids, which caused mineral recomposition and maturing of organic matter.

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“…Ac cord ing to them this is only pos si ble for ho mo ge neous phases formed in con di tions of ther mo dy namic equi lib rium. Nev er the less, the ap pli ca tion of chem i cal com po si tion of chlorite as a geothermometer has not been aban doned (Walshe, 1986;Merriman et al, 1995;Zang and Fyfe, 1995;Xie et al, 1997;Zang et al, 1997;Zimák, 1999;Krzemiñski, 2000;Vidal et al, 2001Vidal et al, , 2005Plissart and Féménias, 2009), though is approached with con sid er able cau tion. Also, Parra et al (2005) ex per i men tally showed that the Si-con tent of chlorite is sen sitive to tem per a ture for the var i ous divariant as sem blages.…”

Section: Introductionmentioning

confidence: 99%

Chlorite of hydrothermal origin formed in the Strzelin and Borów granites (Fore-Sudetic Block, Poland)

Ciesielczuk

2012

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Chlorite, a prod uct of very low-to low-grade meta mor phism, is fre quently used as a geothermometer be cause of the fact that its struc ture and chem i cal com po si tion can re flect the phys i cal and chem i cal con di tions of its for ma tion. In the hy dro ther mally al tered Strzelin and Borów gran ites (the Fore-Sudetic Block, Po land) chlorite is ubiq ui tous. It is found in two forms: spherulitic and post-bi o tite, and was formed in dif fer ent ways in dif fer ent parts of the Strzelin and Borów gran ites: as re sult of (1) re place ment of bi o tite or (2) crystallisation from fluid. The chlorite formed in the Borów gran ite shows a higher Fe con tent than that in the Strzelin gran ite, a fea ture re lated to the con tent of Mg and Fe in the host rock. Tem per a tures of chlorite for ma tion are the low est for un al tered gran ite and then grad u ally in crease for slightly, mod er ately and strongly al tered gran ite and are the high est in hy dro ther mal veins. This means that the tem per a ture of the hydro ther mal fluid was higher than that of the al tered gra nitic bod ies. More over, the spherulitic chlorite formed at a higher tem per a ture than did the post-bi o tite chlorite, and is usu ally smaller be cause bi o tite re place ment lasted lon ger than did the crystallisation of spherulitic chlorite di rectly from hy dro ther mal fluid. Such pat terns are likely to oc cur in other gra nitic bod ies.

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A six-component chlorite solid solution model and the conditions of chlorite formation in hydrothermal and geothermal systems

Cited by 227 publications

References 0 publications

Diagenetic Illite-Chlorite Assemblages in Arenites. II. Thermodynamic Relations

Diagenetic Illite-Chlorite Assemblages in Arenites. II. Thermodynamic Relations

Mineral assemblages as a record of the evolutionary history of the Pepper Mts. Shale Formation (the Holy Cross Mts.).

Chlorite of hydrothermal origin formed in the Strzelin and Borów granites (Fore-Sudetic Block, Poland)

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