Mineral replacement reactions: from macroscopic observations to microscopic mechanisms

Putnis, Andrew

doi:10.1180/0026461026650056

Cited by 997 publications

(597 citation statements)

References 80 publications

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“…In this case, metasomatism is easily achieved because the reaction solution can penetrate the pores to reach the surface of the replaced mineral. On the contrary, metasomatism hardly proceeds when V2/V1 is greater than 1 because the reaction solution cannot penetrate the pores easily (Schouten, 1934;Ridge, 1949;Nakata et al, 1994;Putnis, 2002). Although the V2/V1 value was 1.12 for the present study, the metasomatism of huebnerite to scheelite occurred.…”

Section: Discussioncontrasting

confidence: 40%

Experimental study on metasomatism in huebnerite — CaCl2 solution system

Tamura

Shikazono

Nakata

2009

Journal of Mineralogical and Petrological Sciences

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Experiments on metasomatism in a system comprising huebnerite and aqueous CaCl 2 solution were performed at 130, 150, and 170 °C. SEM observations revealed the formation of euhedral crystals of scheelite replacing huebnerite in all experiments. The replacement texture of huebnerite by scheelite was classified as rim replacement texture. Although the molar volume ratio of replacing mineral to replaced mineral was 1.12 for the present study, huebnerite was replaced by scheelite. This suggests that the influence of molar volume ratio is small on the metasomatism of huebnerite to scheelite, which has not been expected in previous studies. Our results also suggest that the metasomatism of huebnerite to scheelite can be achieved if the CaCl 2 concentration in the solution and the reaction temperature are sufficiently high. The apparent rate constant k for huebnerite dissolution in the metasomatism is approximately 10 −9 -10 −6 mol l −1 s −1 ; the activation energies are 9.6, 20.7, and 31.2 kJ/mol for CaCl 2 concentrations of 0.01, 0.10, and 1.00 mol/l, respectively. The precipitation of scheelite can be the rate -determining process of the metasomatism during the initial stage when the W concentration in the solution is high.

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Section: Discussioncontrasting

confidence: 40%

Experimental study on metasomatism in huebnerite — CaCl2 solution system

Tamura

Shikazono

Nakata

2009

Journal of Mineralogical and Petrological Sciences

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“…This process is dynamic and occurs along inwardmoving interfaces (e.g. Putnis 2002). Micrometer-sized pores, which may be a criterion for such a reaction (Tomaschek et al 2003), result from differences in the molar volume between the parent zircon and the reprecipitated zircon.…”

Section: Discussionmentioning

confidence: 99%

Zircon texture and chemical composition as a guide to magmatic processes and mixing in a granitic environment and coeval volcanic system

Gagnevin

Daly

Kronz

2009

Contrib Mineral Petrol

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This study documents the chemical and textural responses of zircon in the Elba igneous complex, with particular reference to the 7-to 7.8-Ma-old Monte Capanne pluton in relation to its coeval volcanic counterpart (Capraia), using BSE imaging and quantitative electron microprobe analyses. The Monte Capanne pluton displays multiple field and geochemical evidence for magma mixing. The samples we have investigated (including monzogranitic, mafic enclave and dyke samples) display similar zircon textures and are associated with an extremely large range of trace and minor element (Hf, Y, HREE, Th, U) compositions, which contrast with relatively simple textures and zoning patterns in zircons from a Capraia dacite. We have used a relatively simple textural classification (patchy zoning, homogenous cores, oscillatory zoning and unzoned zircon) as the basis for discussing the chemical composition and chemical variation within zircons from the Monte Capanne pluton. Based on these data and other works in Lithos 78:101-118, 2004 , it is inferred that mixing between metaluminous and peraluminous melts occurred early in the evolution of the Monte Capanne magma chamber. In particular, mixing was responsible for the development of the patchy-zoning texture in the zircon cores, which was associated with reactions between other accessory phases (including monazite, apatite, allanite), which we infer to have significantly affected the Th distribution in zircon. Zircons from the MC pluton displaying ''homogeneous cores'' have chemical affinities with zircons in the coeval Capraia volcanic system, consistent with the participation of a Capraia-like mantle end-member during mixing. Further zircon growth in the MC pluton produced the oscillatory zoning texture, which records both long-term (crystal fractionation) and transient (recharge with both silicic and mafic magmas) events in a hybrid magma chamber. It is inferred that Hf and the Th/U ratio cannot be used alone to infer magmatic processes due to their dependency on temperature, nor are they a diagnostic feature of xenocrystic grains. This study shows that zircon chemistry coupled with detailed textural analysis can provide a powerful tool to elucidate the complex evolution of a magma system.

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“…The par tic u lar mech a nisms of monazite al ter ation are related to a fluid-me di ated cou pled dis so lu tion-reprecipitation pro cess, which is also rec og nized in var i ous other phases, such as feld spars, ap a tite, zir con and ore min er als (Putnis, 2002(Putnis, , 2009Putnis and Austrheim, 2012). The re-equil i bra tion induced by the in fil tra tion of flu ids into the min eral struc ture can in crease the vol ume dif fu sion and lead to ionic ex change within the de vel oped intracrystalline pores.…”

Section: Introductionmentioning

confidence: 99%

Monazite stability and the maintenance of Th-U-total Pb ages during post-magmatic processes in granitoids and host metasedimentary rocks: A case study from the Sudetes (SW Poland)

Budzyń

Jastrzębski

2015

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1 Pol ish Acad emy of Sci ences, In sti tute of Geo log i cal Sci ences, Senacka 1, 31-002 Kraków, Po land 2 Pol ish Acad emy of Sci ences, In sti tute of Geo log i cal Sci ences, Podwale 75, 50-449 Wroc³aw, Po land Budzyñ, B., Jastrzêbski, M., 2016. Monazite sta bil ity and the main te nance of Th-U-to tal Pb ages dur ing post-mag matic processes in granitoids and host metasedimentary rocks: a case study from the Sudetes (SW Po land). Geo log i cal Quar terly, 60 (1): 106-123, doi: 10.7306/gq.1254The sta bil ity and main te nance of the age re cord of monazite dur ing post-mag matic pro cesses were stud ied in gra nitic and host metasedimentary rocks from the Sudetes (SW Po land). Un al tered monazite in the K³odzko-Z³oty Stok granitoid provided a Th-U-to tal Pb age of 329 ± 5 Ma, which con strains tim ing of the late stage of pluton em place ment. In con trast, monazite in the Jawornik granitoid re mained un al tered or was par tially re placed by sec ond ary phases, in clud ing (1) al la nite, epidote and, oc ca sion ally, ap a tite; (2) cheralite, al la nite and a mix ture of clays, Fe ox ides and pos si ble un known rare earth el e ment (REE) phases; and (3) K-feld spar and cheralite with sub se quent for ma tion of ti tan ite. Dif fer ent al ter ation prod ucts on the thin sec tion scale in di cate the lo cal char ac ter of the post-mag matic pro cesses af fect ing monazite in duced by alkali-rich flu ids. The al tered and un al tered monazite grains both yielded a Th-U-to tal Pb age of 343 ± 4 Ma. The Th-U-to tal Pb ages of the monazite in the ac com pa ny ing metasedimentary rocks ther mally af fected by in trud ing mag mas were also constrained. In the paragneiss in con tact with the Jawornik granitoid, the un al tered monazite and monazite par tially re placed by al la nite yielded an age of 344 ± 5 Ma. The monazite from the mica schist, far ther from the con tact with the granitoids, ex hibited an age of 336 ± 4.5 Ma. The 344-336 Ma ages dem on strated a re cord of monazite (re)growth dur ing pro longed Variscan meta mor phism. The pre dom i nant early Visean ages con strain the tim ing of the de vel op ment of the Z³oty Stok-Skrzynka Shear Zone and the em place ment of the Jawornik granitoid in tru sion. The age re sults, which are con sis tent with pre vi ous geo chron ol ogy, in di cate that the par tial al ter ation of the monazite did not af fect the in ter nal do mains or the main te nance of the monazite ages. Thus, this study re veals that monazite geo chron ol ogy can pro vide mean ing ful data in crys tal line rocks affected by fluid-in duced post-mag matic pro cesses.

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Mineral replacement reactions: from macroscopic observations to microscopic mechanisms

Cited by 997 publications

References 80 publications

Experimental study on metasomatism in huebnerite — CaCl2 solution system

Experimental study on metasomatism in huebnerite — CaCl2 solution system

Zircon texture and chemical composition as a guide to magmatic processes and mixing in a granitic environment and coeval volcanic system

Monazite stability and the maintenance of Th-U-total Pb ages during post-magmatic processes in granitoids and host metasedimentary rocks: A case study from the Sudetes (SW Poland)

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