Ascent and emplacement of pegmatitic melts in a major reverse shear zone (Sierras de Córdoba, Argentina)

Demartis, Manuel; Coniglio, Jorge E.; Tubía, José María; Aragón, Eugenio; Insúa, Leonardo Alfredo Agulleiro

doi:10.1016/j.jsg.2011.06.008

Cited by 36 publications

(41 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The accumulation of volatile-rich melts could efficiently stimulate the hydraulic opening of the fractures. Fluid super-saturated magma had been easily moved to these extensional fractures according to the magma pumping mechanism (Demartis et al 2011). The original melt may have had the composition of the felsic component.…”

Section: Origin Of the Parent Melt/fluid To The Fluorapatite-rich Veinmentioning

confidence: 99%

Age and origin of fluorapatite-rich dyke from Baranec Mt. (Tatra Mts., Western Carpathians): a key to understanding of the post-orogenic processes and element mobility

Gawęda¹,

Szopa²,

Chew³

et al. 2016

Geologica Carpathica

View full text Add to dashboard Cite

Abstract:On the southeastern slope of the Baranec Mount in the Western Tatra Mountains (Slovakia) an apatite-rich pegmatite-like segregation was found in the subvertical fault zone cutting metapelitic rocks. Two zones: felsic (F) and mafic (M) were found, differing in mineral assemblages and consequently in chemistry. Fluorapatite crystals yield a LA-ICP-MS U-Pb age of 328.6 ± 2.4 Ma. A temperature decrease from 634 °C to 454 °C at a pressure around 500 to 400 MPa with oxygen fugacity increasing during crystallization are the possible conditions for formation of the pegmatite-like segregation, while secondary alterations took place in the temperature range of 340 -320 °C. The Sr-Nd isotope composition of both apatite and whole rock point toward a crustal origin of the dike in question, suggesting partial melting of (P, F, H 2 O)-rich metasedimentary rocks during prolonged decompression of the Tatra Massif. The original partial melt (felsic component) was mixed with an external (F, H 2 O)-rich fluid, carrying Fe and Mg fluxed from more mafic metapelites and crystallizing as biotite and epidote in the mafic component of the dyke.

show abstract

Section: Origin Of the Parent Melt/fluid To The Fluorapatite-rich Veinmentioning

confidence: 99%

Age and origin of fluorapatite-rich dyke from Baranec Mt. (Tatra Mts., Western Carpathians): a key to understanding of the post-orogenic processes and element mobility

Gawęda¹,

Szopa²,

Chew³

et al. 2016

Geologica Carpathica

View full text Add to dashboard Cite

show abstract

“…These rocks are characterized by a fine-grained matrix composed of recrystallized biotite + quartz + K-feldspar + sillimanite, defining a mylonitic foliation that wraps around porphyroclasts of garnet and quartz + K-feldspar aggregates 0.2-2.0 mm in diameter. Syntectonic granites and pegmatites intruded along the GCSZ domain (Demartis et al 2011).…”

Section: Geological Settingmentioning

confidence: 99%

“…The pegmatites are mainly hosted by mylonitized gneisses, migmatites, and minor amphibolites from the GCSZ. These pegmatites were emplaced during the main shearing event of the GCSZ, showing evidence of deformation over a wide range of conditions (Demartis et al 2011).…”

Section: The Comechingones Pegmatitic Fieldmentioning

confidence: 99%

“…Pegmatites from the CPF consist of composite pegmatitic dykes, up to 1000 m long and 200 m wide, internally made up of a large number of lens-or sheetshaped pegmatitic bodies of relatively small size (less than 50 m thick and 200 m long, Demartis et al 2011). The main rock-forming minerals are quartz, K-feldspar, muscovite, and plagioclase, and each pegmatite sheet tends to preserve its internal zonation.…”

Section: The Comechingones Pegmatitic Fieldmentioning

confidence: 99%

“…Like many pegmatites in the CPF, it consists of a large composite dyke, with a maximum width of 50 m and a length of more than 1000 m in outcrop, which strikes almost N-S and dips variably, from 40 to 65° toward the east and west. It is internally made up of several subparallel lens-or sheet-shaped pegmatitic bodies of relatively small size (from 5 to 30 m thick and ~200 m long) emplaced beside each other (Demartis et al 2011). Each pegmatitic body displays an almost symmetrical zoning pattern, which generally consists of the following textural and paragenetic zones, from the contacts inward: fine-to medium-grained muscovite + quartz ± albite grading to medium-to coarse-grained quartz + muscovite ± microcline ± albite, defining the wall zone.…”

Section: The áNgel Pegmatite and Its Replacement Unitmentioning

confidence: 99%

See 2 more Smart Citations

Extreme F Activities in Late Pegmatitic Events as a Key Factor for Lile and Hfse Enrichment: The Ángel Pegmatite, Central Argentina

et al. 2014

Self Cite

View full text Add to dashboard Cite

The Ángel pegmatite forms part of the Comechingones pegmatitic field, in central Argentina, which is made up of pegmatites characterized by low to intermediate degrees of fractionation, classified as beryl-columbite-phosphate subtype pegmatites. These pegmatites are syntectonic with a regional shear zone. The Ángel pegmatite contains associations with quartz, microcline, plagioclase, a first generation of muscovite (muscovite I), beryl, members of the columbite group, triplite, and montebrasite. This association is locally affected by two stages of replacement. The first replacement stage is characterized by early albitization, followed by the development of associations of cleavelandite, quartz, Fe-rich elbaite (elbaite I), a second generation of muscovite (muscovite II), topaz, lacroixite, fluorapatite, pollucite, columbite-(Mn), and Hf-rich zircon. Muscovite II replaces montebrasite and muscovite I, and is characterized by slight enrichments in F, Rb, and Cs. The second replacement stage generated a new mineral association characterized by muscovite III, Fe-poor elbaite (elbaite II), Cs-micas, and U-rich hydroxykenomicrolite. Muscovite III replaces muscovite II and is characterized by strong enrichments in F, Cs, and, to a lesser extent, Rb. In turn, muscovite III is replaced by the Cs-micas sokolovaite and nanpingite. The high F content of the nanpingite suggests that this could be the F-analogue of nanpingite, which would be a new mineral. The sequence of replacement is indicative of an increase in the F activity in the latest pegmatitic fluids. The high F activity of these fluids favored the transport of Ta, U, Bi, Hf, Rb, Cs, and Li, and the formation of F-rich micas could be the mechanism for precipitating these LILE and HFSE elements. The syntectonic emplacement of this pegmatite in a large shear zone could be a decisive factor in the migration of these late evolved fluids rich in F, LILE, and HFSE.

show abstract

Lithium Mineralization, Contributions of Paleoclimates and Orogens

GLOAGUEN,

MELLETON,

GOURCEROL

et al. 2023

Metallic Resources 2

View full text Add to dashboard Cite

Ascent and emplacement of pegmatitic melts in a major reverse shear zone (Sierras de Córdoba, Argentina)

Cited by 36 publications

References 42 publications

Age and origin of fluorapatite-rich dyke from Baranec Mt. (Tatra Mts., Western Carpathians): a key to understanding of the post-orogenic processes and element mobility

Age and origin of fluorapatite-rich dyke from Baranec Mt. (Tatra Mts., Western Carpathians): a key to understanding of the post-orogenic processes and element mobility

Extreme F Activities in Late Pegmatitic Events as a Key Factor for Lile and Hfse Enrichment: The Ángel Pegmatite, Central Argentina

Lithium Mineralization, Contributions of Paleoclimates and Orogens

Contact Info

Product

Resources

About