Mineral chemistry and chemical zoning in tourmalines, Pampa del Tamboreo, San Luis, Argentina

Henry, Darrell J.; Brodtkorb, Milka K. de

doi:10.1016/j.jsames.2009.03.001

Cited by 13 publications

(9 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Henry, unpubl. data 4) Eclogites, mafic granulites, amphibolites and blackwalls Morgan & London (1987), Henry & Dutrow (1990), , Bosi et al (2010) 5) Tourmalinites, quartz-tourmaline veins and greisens Abraham et al (1972), Willner (1992), London & Manning (1995), Laurs et al (1996), Houzar et al (1998), Béziat et al (1999), Francis et al (1999), Pesquera et al (1999), , Yu & Jiang (2003), Henry & de Brodtkorb (2009) 6) Calcareous metasediments and magnesite rocks Donnay et al (1967), Otroshchenko et al (1971), Dunn (1977aDunn ( , 1977b, Sahama et al (1979), Schmetzer et al (1979), Povondra & Novák (1986), Cotkin (1989) petrological environments in which Li is likely to be relatively low, tourmalines are normalized on the basis of 15 Y + Z + T cations (Henry & Dutrow 1996, Clark 2007 A series of compositional criteria were used to screen the data to identify the better-quality tourmaline data for further consideration. For those samples for which a complete chemical analysis has been made (or can be calculated), the dataset is considered unacceptable if the sum of the oxides is outside the range 98.3-101.7%.…”

Section: Normalization and Quality Control Of Tourmaline Datamentioning

confidence: 99%

The incorporation of fluorine in tourmaline: internal crystallographic controls or external environmental influences?

Henry¹,

Dutrow²

2011

The Canadian Mineralogist

View full text Add to dashboard Cite

show abstract

Section: Normalization and Quality Control Of Tourmaline Datamentioning

confidence: 99%

The incorporation of fluorine in tourmaline: internal crystallographic controls or external environmental influences?

Henry¹,

Dutrow²

2011

The Canadian Mineralogist

View full text Add to dashboard Cite

show abstract

“…However, the presence of scheelite may confirm that tourmalinites developed by contact metasomatic processes near granitoid intrusions, and such lithologies are significant indicators of Sn-W greisen ore deposits (e.g. Raith 1988;Slack 1996;Henry and Brodtkorb 2009;Marks et al 2013). Low-Si, high-Ti white mica inclusions in albite can also be interpreted as a pre-Alpine relict phase.…”

Section: Primary Assemblage(?)mentioning

confidence: 96%

Magmatic and metamorphic evolution of tourmaline-rich rocks of the Sopron area, Eastern Alps

Spránitz¹,

Józsa²,

Kovács³

et al. 2018

J. Geosci.

View full text Add to dashboard Cite

Tourmaline-rich pegmatitic orthogneisses, tourmalinites, kyanite-chlorite-muscovite schists and quartzites crosscut by subordinate quartz-tourmaline veins and layers were newly described from the Sopron area, Western Hungary. The orthogneisses mainly consist of quartz, plagioclase, tourmaline, garnet and white mica. In smaller amounts K-feldspar, beryl, Mg-rich chlorite, kyanite, lazulite, florencite, monazite and apatite also are present. Magmatic cores and two generations of metamorphic tourmaline (Fe-rich and Mg-rich) were distinguished. Tourmaline in tourmalinites is generally large (several cm), deformed, contains chlorite inclusions and shows oscillatory zoning or polygonal fabric. Large tourmaline crystals often contain dark brown mica-shaped relic areas with higher amount of Ti and Fe than the adjacent parts, interpreted as relics of micas from the protolith. Besides tourmaline, quartz, white mica, plagioclase, apatite, garnet, rutile, ilmenite, scheelite, zircon and monazite are also present in the tourmalinites. Deformed tourmaline-quartz bands and veins occur in kyanite-chlorite-muscovite schists and quartzites. Euhedral, zoned and deformed schorl-dravite is accompanied with kyanite, Mg-chlorite (leuchtenbergite), rutile muscovite and sillimanite. Narrow colorless tourmaline rims enriched exclusively in Mg (FeO < 1 wt. %) can be identified. Coarse-grained orthogneisses with a significant amount of primary tourmaline-beryl assemblage indicates a fluid-rich, B-Be-bearing environment during the final crystallization of the Variscan peraluminous leucogranite. The formation of tourmalinites can be explained by the related boron metasomatism. Phengitic white mica rims and calcic garnet rims in orthogneisses and tourmalinites indicate high-pressure Alpine metamorphic overprint. The presence of REE-rich phosphate mineralisation and leuchtenbergite in the orthogneisses imply that high salinity fluids metasomatized the orthogneisses along the pre-existing shear zones after the Alpine metamorphic peak. Tourmaline grains in kyanite-bearing quartzites and schists may have originated from a micaschist that underwent a strong Mg-metasomatism during the formation of leucophyllites described from the area.

show abstract

“…However, there is a significant amount of dispersion of the data around the reference diagonal suggesting additional substitutions influence the tourmaline compositions. An implication of the likely Al = Cr substitution is that these two cations can be treated as similar cations such that the addition of Cr+Al is essentially a condensation down the CrAl -1 exchange vector (see Henry et al 2002Henry et al , 2008Medaris et al 2003;Henry and de Brodtkorb 2009). This permits investigation of the other substitutions that contribute to the dispersion of the data.…”

Section: Site Substitutionsmentioning

confidence: 99%

“…The low-Cr and higher-Fe tourmalines of Charbagh are displaced even further in accordance with the (Al,Cr)Fe 3+ -1 exchange vector, but the intrasample variation is consistent with the [AlO] [Mg(OH)] -1 exchange vector. Of particular note is that this latter vector represents a mechanism for deprotonation of the OH 1-to O 2-on the W site of tourmaline (Henry et al , 2002(Henry et al , 2008Henry and de Brodtkorb 2009).…”

Section: Site Substitutionsmentioning

confidence: 99%

Cr-bearing tourmaline associated with emerald deposits from Swat, NW Pakistan: Genesis and its exploration significance

Arif

Henry

Moon

2010

American Mineralogist

View full text Add to dashboard Cite

Carbonate-talc altered ultramafic (and mafic) rocks of the obducted oceanic lithosphere along the Main Mantle Thrust in the Swat Valley host emerald deposits and are invaded by quartz veins and stockworks. Both the quartz veins and carbonate-talc altered rocks contain discrete grains and clusters of tourmaline crystals, which may be associated with emerald and/or chromian muscovite. Tourmalines from the Mingora and Gujar Kili emerald mines and the Spin Obo-Kuh area are Nibearing, Cr-rich dravites and "oxy-dravites" that exhibit substantial chemical variability with 2.0-2.5 atoms per formula unit (apfu) Mg, relatively low Al (4.8-5.8 apfu), high Cr (0.5-1.8 apfu), high Cr/(Cr+Al) ratios of 0.08-0.28, significant amounts of Ni (up to 0.11 apfu), and variable calculated W site O 2-(0.2-0.8 apfu). The mechanisms that appear to control the tourmaline chemistry at these localites are combinations of the dominant substitution Al = Cr with lesser amounts of the Mg+OH 1-= (Al,Cr)+O 2-and Al 3+ = Fe 3+ substitutions. Relative to the Mingora, Gujar Kili, and Spin Obo-Kuh areas, the Charbagh tourmalines are "oxy-dravites" that have comparable Mg contents (2.2-2.3 apfu) with variable calculated W site O 2-(0.6-0.9 apfu), but are more Fe-rich (0.5 apfu) and Al-rich (6.0-6.3 apfu) with low Cr (0.00-0.01 apfu) and Ni contents (0.01-0.02 apfu). The mechanism that appears to control the variable chemistry of the Charbagh tourmalines is primarily Mg+OH 1-= Al+O 2-. The chemical characteristics of tourmalines from the various localities relate most clearly to differences in host rock chemistry.Tourmalines from the carbonate-talc altered ultramafic-mafic rocks and the invasive quartz veins have a common hydrothermal origin associated with emplacement and crystallization of younger granitoids. Furthermore, the occurrence of Swat emeralds in quartz-tourmaline (±chromian muscovite) veins suggests that the tourmaline is cogenetic with emerald formation. The quality and quantity of Swat emeralds depend on the: (1) host rock composition and (2) nature of the hydrothermal fluids. Large deposits of gem-quality emerald occur in carbonate-altered ultramafic rocks, which also contain Cr-rich dravites and "oxy-dravites." This suggests that the presence of high-Cr magnesian tourmalines, particularly in magnesite-talc altered ultramafic rocks, can represent a criterion for further emerald exploration in the lower Swat region of Pakistan and comparable ultramafic-hosted emerald-producing regions.

show abstract

Mineral chemistry and chemical zoning in tourmalines, Pampa del Tamboreo, San Luis, Argentina

Cited by 13 publications

References 17 publications

The incorporation of fluorine in tourmaline: internal crystallographic controls or external environmental influences?

The incorporation of fluorine in tourmaline: internal crystallographic controls or external environmental influences?

Magmatic and metamorphic evolution of tourmaline-rich rocks of the Sopron area, Eastern Alps

Cr-bearing tourmaline associated with emerald deposits from Swat, NW Pakistan: Genesis and its exploration significance

Contact Info

Product

Resources

About