Cathodoluminescence and micro-structural evidence for crystallisation and deformation processes of granites in the Eastern Lachlan Fold Belt (SE Australia)

Müller, Axel; Lennox, Paul; Trzebski, R.

doi:10.1007/s00410-002-0361-x

Cited by 77 publications

(26 citation statements)

References 40 publications

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“…A prominent peak at 415 nm is positively correlated with Ti concentration (Mu« ller et al, 2002(Mu« ller et al, , 2005Rusk et al, 2006Rusk et al, , 2008Spear & Wark, 2009), and this luminescence is expected to dominate parachromatic images at Ti contents 440^50 ppm (Mu« ller et al, 2000(Mu« ller et al, , 2002Larsen et al, 2009). The Ti content of quartz is proportional to the crystallization temperature (Wark & Watson, 2006;Thomas et al, 2010).…”

Section: A Na Ly T I C a L M E T H O D S Scanning Electron Microscopymentioning

confidence: 99%

“…Cathodoluminescence (CL) of quartz is associated with lattice defects and trace element concentration (Smith & Stenstrom, 1965;Ramsayer et al, 1988;Ramseyer & Mullis, 1990;Seyedolali et al, 1997;Mu« ller et al, 2000Mu« ller et al, , 2002Mu« ller et al, , 2003aMu« ller et al, , 2003bGo « tze et al, 2001;Landtwing & Pettke, 2005;Rusk et al, 2006), and comprises a number of peaks in the visible spectrum, mostly blue or red. A prominent peak at 415 nm is positively correlated with Ti concentration (Mu« ller et al, 2002(Mu« ller et al, , 2005Rusk et al, 2006Rusk et al, , 2008Spear & Wark, 2009), and this luminescence is expected to dominate parachromatic images at Ti contents 440^50 ppm (Mu« ller et al, 2000(Mu« ller et al, , 2002Larsen et al, 2009).…”

Section: A Na Ly T I C a L M E T H O D S Scanning Electron Microscopymentioning

confidence: 99%

“…However, it is easy to qualitatively assess the brightness of the quartz across images by comparing it with different minerals with a more uniform luminescence in the same image. To test the relationship between quartz luminescence and Ti content (see Mu« ller et al, 2000Mu« ller et al, , 2002Larsen et al, 2009), we compared trace element concentrations in quartz with the greyscale in the CL images within $5 mm of the sampled point. The results of this comparison in nine SEM-CL images from four samples are shown in Fig.…”

Section: Determination Of Peak Metamorphic Temperaturementioning

confidence: 99%

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Contact Metamorphism of Precambrian Gneiss by the Skaergaard Intrusion

Bufe

Holness

Humphreys

2014

Journal of Petrology

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Section: A Na Ly T I C a L M E T H O D S Scanning Electron Microscopymentioning

confidence: 99%

Section: A Na Ly T I C a L M E T H O D S Scanning Electron Microscopymentioning

confidence: 99%

Section: Determination Of Peak Metamorphic Temperaturementioning

confidence: 99%

See 1 more Smart Citation

Contact Metamorphism of Precambrian Gneiss by the Skaergaard Intrusion

Bufe

Holness

Humphreys

2014

Journal of Petrology

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“…The presence of subgrains in "quartz eyes" from Goldstar (sample TB PM3) invaded by later fluids may imply tectonic effects as well. "Splatter" and "cobweb" textures had been reported in hydrothermal quartz from porphyry copper and epithermal deposits ( Rusk et al 2005), as well as in quartz from subvolcanic units worldwide, where they occur as dense networks of healed cracks with secondary quartz (van den Kerkhof et al 2001;Müller et al 2002aMüller et al , 2005. The ChromaSEM-CL response also allowed deciphering fragmental textures that were not observed through optical microscopy.…”

Section: Chromasem-cl Responsesmentioning

confidence: 99%

The nature of “quartz eyes” hosted by dykes associated with Au-Bi-As-Cu, Mo-Cu, and Base-metal-Au-Ag mineral occurrences in the Mountain Freegold region (Dawson Range), Yukon, Canada

Betsi¹,

Lentz

2012

J. Geosci.

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Various origins have been assigned to rounded to subrounded and elliptical quartz megacrysts ("quartz eyes") in dyke rocks associated with mineral deposits/occurrences worldwide. An exact interpretation of their nature is likely to tightly constrain the petrogenesis of the host rocks, and by association may be critical in evaluating genetic models for spatially associated ore minerals. ChromaSEM-CL imaging and electron probe microanalysis (EPMA) of "quartz eyes" within porphyry dykes associated with Au-Bi-Cu-As, Mo-Cu, and base-metal-Au-Ag mineral occurrences across the Northern Freegold Resources (NFR) property in the Dawson Range of Yukon Territory, Canada, reveals that the cathodoluminescence (CL) response of quartz is a function of its trace-element abundance(s). Bright blue luminescent growth zones are in most cases richer in Fe (up to 8839 ppm) and Ti (up to 229 ppm) relative to CL dark growth zones, with up to 41 times lower concentration of these elements. Assuming a TiO 2 = 1, the Ti-poor dull cores consistently recorded lower temperatures (mostly < 600 °C) compared to Ti-rich brighter blue rims (up to 860 °C). This suggests either overgrowth on xenocrystic cores or an increase in crystallization temperature. The temperature rise likely reflects magma mixing, and is therefore consistent with the phenocryst/phenoclasts having formed in a magma chamber rather than by secondary processes. Also, the great variability in composition and temperature of crystallization and/or reequilibration of brighter blue growth zones of two quartz crystals (660 °C and 855 °C) from a single sample suggests that multiple episodes of magma mixing and incremental growth of parental magma chambers occurred. Some "quartz eyes" are overprinted by variably oriented, bifurcating, and anastomosing fluid migration trails ("splatter and cobweb textures") of red to reddish-brown CL quartz that is in most cases of low-temperature origin, and trace-elements poor, thus implying interaction of deuteric fluids with quartz phenocrysts/phenoclasts. The presence of "quartz eye" crystals with broken and angular blue cores, overgrown by oscillatory-zoned rims in which the zoning pattern does not correspond with the crystal boundaries, further suggests that some quartz crystals had been explosively fragmented (phenocrysts) and are now hosted in a recrystallized tuffisitic groundmass. The volatile exsolution that likely accompanied both magma mixing and decompression (as suggested by dendritic quartz, fine-grained recrystallized tuffisitic groundmass, and corroded quartz grains) was probably an important process that could have favoured the ore formation.

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“…The SEM-CL technique has enabled a range of geological problems to be resolved, such as sedimentary provenance (Seyedolali et al, 1997), the nature of diagenetic and pressure solution processes (Schieber et al, 2000), sandstone fracturing (Milliken and Laubach, 2000) and the character of crystallisation and deformation processes in granite (Müller et al, 2002;Sekine, 2003). SEM-CL has proven to be useful in hydrothermal alteration studies, with the potential to reveal a range of diagnostic depositional processes, including the relationship between electrum precipitation and specific fluid composition/quartz-precipitation events (Wilkinson et al, 1999), the role of temperature-pressure change in (quartz) vein formation (Rusk and Reed, 2002;Batkhishig et al, submitted for publication), quartz vein chronology (Penniston-Dorland, 2001), and occurrence of CL-distinctive hydrothermal quartz overprinting igneous quartz (Sekine, 2003).…”

Section: Introductionmentioning

confidence: 99%

Fluid-rock interaction processes in the Te Kopia geothermal field (New Zealand) revealed by SEM-CL imaging

BIGNALL

2004

Geothermics

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Scanning electron microscopy-cathodoluminescence (SEM-CL) imaging of hydrothermal quartz exposed by weathering in the Te Kopia geothermal field (New Zealand) has revealed a history of crystal growth, dissolution, overprinting and fracturing that cannot be detected using other observational techniques (e.g. transmitted or reflected light microscopy, back-scattered electron imaging or secondary electron imaging). The crystals initially grew as CL-dark quartz, at least 350 m below their present location on the Paeroa Fault scarp, in a neutral pH, 215 ± 10 • C liquid reservoir (inferred from the analysis of primary liquid fluid inclusions: mean T h of 213 • C; 0.2-0.4 wt.% NaCl eq. ). Relict quartz-adularia-illite alteration occurs at the surface, in the vicinity of the quartz crystals, and in drillcores from the nearby TK-1 exploration well. Repeated movement on the Paeroa Fault uplifted pyroclastic rocks hosting the quartz crystals, but also provided pathways for "pulses" of hot fluids to move through the system. Quartz precipitation occurred at the edge of the crystals as the reservoir fluids cooled, as indicated by micron-scale alternating CL-dark/CL-bright quartz growth bands, which contain fluid inclusions with T h values of 210 ± 40 • C. Pressure fluctuations were the likely cause of dissolution, marked by corroded crystal edges, with subsequent precipitation of quartz into open space. SEM-CL imaging shows that the quartz crystals contain healed fractures, which trapped low salinity fluids with T h values of 201 ± 6 • C. Low-pH fluids in the near-surface * Corresponding author. G. Bignall et al. / Geothermics 33 (2004) 615-635 setting also rounded the quartz crystals, and coated them with kaolinite and CL-grey amorphous "silica residue".

show abstract

Cathodoluminescence and micro-structural evidence for crystallisation and deformation processes of granites in the Eastern Lachlan Fold Belt (SE Australia)

Cited by 77 publications

References 40 publications

Contact Metamorphism of Precambrian Gneiss by the Skaergaard Intrusion

Contact Metamorphism of Precambrian Gneiss by the Skaergaard Intrusion

The nature of “quartz eyes” hosted by dykes associated with Au-Bi-As-Cu, Mo-Cu, and Base-metal-Au-Ag mineral occurrences in the Mountain Freegold region (Dawson Range), Yukon, Canada

Fluid-rock interaction processes in the Te Kopia geothermal field (New Zealand) revealed by SEM-CL imaging

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