Un nouvel appareil pour la mesure des températures sous le microscope : l'installation de microthermométrie Chaixmeca

Poty, B.; Leroy, Jacques; Jachimowicz, Léon

doi:10.3406/bulmi.1976.7049

Cited by 121 publications

(35 citation statements)

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“…All temperature data were collected on a Chaixmeca heating-freezing stage (Poty et al, 1976) modified to add insulation similar to that described by Cunningham and Carollo (1980). Numerous calibrations of the stage using natural and synthetic standards indicate an accuracy of +_0.5øC in the range -56.6 ø to 0øC and better than +__4øC in the range 0 ø to 398øC.…”

Section: Appendixmentioning

confidence: 99%

Geologic setting, depths of emplacement, and regional distribution of fluid inclusions in intrusions of the central Wasatch Mountains, Utah

John¹

1989

Economic Geology

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Nine mid-Tertiary calc-alkaline stocks, a subvolcanic porphyry system, and coeval volcanic rocks are exposed in a 45-km-long east-trending belt across the central Wasatch Mountains, Utah. The intrusions vary systematically from west to east in texture, style of emplacement, extent of contact metamorphism, hydrothermal alteration, and mineralization. Pressure-depth estimates based on metamorphic mineral assemblages, stratigraphic reconstructions, and fluid inclusion data indicate a regular variation in palcodepths ranging from about 11 km on the west to less than 1 km on the east. These data indicate that the central Wasatch Mountains have been tilted down to the east about 20 ø during the late Cenozoic. Fluid inclusion populations in igneous quartz also vary systematically with palcodepth; high-salinity (halite-saturated) fluid inclusions are present in the eastern porphyry stocks and in the upper parts of the Alta and Clayton Peak stocks in the center of the belt but are absent in the deeper parts of the Alta and Clayton Peak stocks and in the Little Cottonwood stock on the west side of the belt. In the Alta and Clayton Peak stocks, nearly planar high-paleosalinity horizons, presently dipping 15 ø to 20 ø east, separate rocks containing high-salinity fluid inclusions (above the high-paleosalinity horizon) from those lacking such fluid inclusions. Comparison of fluidinclusion populations in igneous and vein quartz in the Alta and Clayton Peak stocks indicates that high-salinity fluids predated most of the vein-forming hydrothermal activity and provide the earliest record of fluids to circulate in these stocks. High-salinity fluids probably formed either by boiling of fluids released during the late stages of crystallization in the parts of the intrusions where pressure was less than about 1,300 bars or by exsolution ofimmiscible highsalinity brines from the crystallizing magmas. Most hydrothermal mineralization associated with the intrusions, including Ag-Pb-Zn ores in the Park City district, are associated spatially with parts of the intrusions where high-salinity fluids were present. The major exception is the porphyry molybdenum system in the eastern part of the Little Cottonwood stock, which probably was at too great a depth (approximately 7 km) to form high-salinity brines and is dominated by low-salinity CO•-rich fluids. Introduction IN THE central Wasatch Mountains, Utah, a mid-Tertiary series of nine eale-alkaline granitoid stocks, a subvolcanic porphyry system, and coeval volcanic rocks are exposed in an east-trending belt that is the westward extension of the Uinta arch (Figs. 1 and 2). Important Ag-Pb-Zn replacement and fissure ores in the Park City district are spatially and temporally related to porphyry stocks (Barnes and Simos, 1968; Bromfield et al., 1977), and scattered base and precious metal mineralization is associated with several other stocks (Calkins and Butler, 1943; James, 1978; Bromfield and Patten, 1981). Variations in texture, style of emplaeement, hydrothermal alteration, and minerali...

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Section: Appendixmentioning

confidence: 99%

Geologic setting, depths of emplacement, and regional distribution of fluid inclusions in intrusions of the central Wasatch Mountains, Utah

John¹

1989

Economic Geology

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“…Microthermometric studies of fluid inclusions were performed on wafers using a Chaixmeca heating-freezing stage (Poty et al 1976). The stage was calibrated with melting point standards at T > 258C and with natural and synthetic fluid inclusions at T < 08C.…”

Section: Methodsmentioning

confidence: 99%

“…Microthermometric studies of fluid inclusions were performed on wafers using a Chaixmeca heating–freezing stage (Poty et al . 1976).…”

Section: Fluid Inclusion Datamentioning

confidence: 99%

Retrograde P–T evolution and high temperature–low pressure fluid circulation in relation to late Hercynian intrusions: a mineralogical and fluid inclusion study of the Charroux‐Civray plutonic complex (north‐western Massif Central, France)

Freiberger¹,

Boiron²,

Cathelineau³

et al. 2001

Geofluids

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The calc‐alkaline plutonic complex from Charroux‐Civray (north‐western part of the French Massif Central) displays multiphase hydrothermal alteration. Plutonic rocks, as well as early retrograde Ca–Al silicate assemblages, which have crystallized during cooling and uplifting of the plutonic series, are affected by multiphase chlorite–phengite–illite–carbonate alteration linked to intense pervasive fluid circulation through microfractures. The petrographic study of alteration sequences and their associated fluid inclusions in microfissures of the plutonic rocks, as well as in mineral fillings of the veins, yields a reconstruction of the P–T–X evolution of the Hercynian basement after the crystallization of the main calc‐alkaline plutonic bodies. This reconstruction covers the uplift of the basement to its exposure and the subsequent burial by Mesozoic sediments. Cooling of the calc‐alkaline plutonic series started at solidus temperatures (∼650°C), at a pressure of about 4 kbar (1 bar = 105 N m−2), as indicated by magmatic epidote stability, hornblende barometry and fluid inclusion data. Cooling continued under slightly decreasing pressure during uplift down to 2–3 kbar at 200–280°C (prehnite–pumpellyite paragenesis). Then, a hot geothermal circulation of CO2‐bearing fluids was induced within the calc‐alkaline rocks leading to the formation of greisen‐like mineralizations. During this stage, temperatures around 400–450°C were still high for the inferred depths (∼2 kbar). They imply abnormal heat flows and thermal gradients of 60–80°C km−1. The hypothesis of the existence of one large or a succession of smaller peraluminous plutons at depth, supported by geophysical data, suggests that localized heat flows were linked to concealed leucogranite intrusions. As uplift continued, greisen mineralization was subsequently affected by the chlorite–phengite–dolomite assemblage, correlated with aqueous and nitrogen‐bearing fluid circulations in the temperature range of 400–450°C. In a later stage, a continuous temperature decrease at constant pressure (∼0.5 kbar) led to the alteration of the dolomite–illite–chlorite type in the 130–250°C temperature range.

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“…Les fluides piégés dans de petites cavités des ciments siliceux gardent leurs signatures en pression -température ainsi qu'en composition associée à la cristallisation du minéral [Poty et al, 1976]. Leur caractérisation se fait à partir de la détermination des températures d'homogénéisation de phase ainsi que des températures de fusion de la glace [Bodnard,1993] [Surma, 1999].…”

Section: Inclusions Fluides Et Isotopes De L'oxygène Des Nourrissagesunclassified

Porosity microstructures of a sandstone affected by a normal fault

Surma

Géraud

Pourcelot

et al. 2003

Bulletin De La Société Géologique De France

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Dans un système de failles normales de la bordure du fossé rhénan, les interactions eaux-roches de part et d'autre de ces failles peuvent contrôler les conditions des circulations fluides. L'objectif de ce travail est de caractériser les structures du réseau poreux dans la zone endommagée autour d'une de ces failles. Il est intéressant d'étudier la relation entre porosité et perméabilité dans cette zone. Des études pétrographiques et pétrophysiques, des mesures microthermométriques sur des inclusions fluides et la composition isotopique de l'oxygène ont permis de caractériser les structures de porosité des roches et notamment des ciments primaires et secondaires.Le couplage de ces approches montre qu'une faille normale peut à la fois jouer le rôle de drain et de barrière à la circulation des fluides. En fonction de la direction de circulation, la faille joue le rôle de drain en laissant remonter les fluides parallèlement au plan de faille et le rôle de barrière, en focalisant les circulations dans le toit. L'anisotropie, notamment des propriétés de transfert héritées des conditions de dépôts fluviatiles, est profondément modifiée par les transferts subits dans le matériau. Ainsi les modifications des transferts dépendent des modifications du réseau poreux : l'hétérogénéité de la structure du réseau et l'anisotropie d'orientation ou de connectivité. Ce modèle de circulation est contrôlé par une interaction entre les modifications des structures du réseau poreux et les circulations fluides, entraînant des modifications de l'anisotropie de certaines propriétés du matériau autour de la faille.Abstract. -Introduction -Normal faults are part of the elements that control fluid flows in sedimentary basins. They can play the role of a barrier or a drain [Hippler, 1993]. These pathways are anisotropic. The aim of this study is to determine the fluid pathways and to characterise the pore network and its role in the transfer properties.Petrophysics, petrographics, geochemical and fluid inclusion studies allow us to characterise a Buntsandstein sandstone affected by a normal fault. This sandstone has a fluviatile origin, field evidenced by fluviatile channels, but also by some clay layers. The fault is located in the north east of France, in the Rhine Graben. The vertical displacement is about 3 meters, and the dip is 70 o east. The fractured zone is composed of three compartments (the hanging wall and the footwall separated by a gouge) divided by three main faults ( fig. 1). Oriented samples were taken from the three blocks and were studied following the procedure figure 2. Results -The petrographical and mineralogical composition of the three compartments were different. The gouge and the footwall were characterised by quartz overgrowths, authigenic kaolinite (30 to 40 % of the clay fraction) and diagenetic illite (40 to 60 % of the clay fraction). The hanging wall was characterised by 70 to 80 % diagenetic illite of the clay fraction ( fig. 3).The isotopic composition of the footwall quartz overgrowth ( fig. 4) was δ 18 O ...

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Un nouvel appareil pour la mesure des températures sous le microscope : l'installation de microthermométrie Chaixmeca

Abstract: Description of an apparatus for measuring the temperature of micro-samples under the microscope in the range -180°C to + 600°C. Precision and accuracy are discussed. Use of this apparatus is foreseen in physics, chemistry, mineralogy and biology.

Cited by 121 publications

References 0 publications

Geologic setting, depths of emplacement, and regional distribution of fluid inclusions in intrusions of the central Wasatch Mountains, Utah

Geologic setting, depths of emplacement, and regional distribution of fluid inclusions in intrusions of the central Wasatch Mountains, Utah

Retrograde P–T evolution and high temperature–low pressure fluid circulation in relation to late Hercynian intrusions: a mineralogical and fluid inclusion study of the Charroux‐Civray plutonic complex (north‐western Massif Central, France)

Porosity microstructures of a sandstone affected by a normal fault

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