Magmatic Processes and the Role of Antecrysts in the Genesis of Corvo Island (Azores Archipelago, Portugal)

Larrea, Patricia; França, Zilda; Lago, M.; Widom, Elisabeth; Galé, Carlos; Ubide, Teresa

doi:10.1093/petrology/egs084

Cited by 54 publications

(42 citation statements)

References 36 publications

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“…Similar chemical anomalies have been found in lava and dike samples (unaffected by eolian fractionation), but containing high proportions of antecrysts, which are large crystals that according to their chemical composition may not have shared common histories or crystallized from the magma in which they are now hosted, but rather may have grown within the same magmatic system but in a more primitive magma than that from which they are found (Larrea et al 2013). Thus, although the whole-rock composition of the ash-rich level (sample CLHE-TF2; Fig.…”

Section: Olivine Composition As Indicator Of Parental Meltsupporting

confidence: 59%

Mafic monogenetic vents at the Descabezado Grande volcanic field (35.5°S–70.8°W): the northernmost evidence of regional primitive volcanism in the Southern Volcanic Zone of Chile

Salas

Rabbia

Hernández

et al. 2016

Int J Earth Sci (Geol Rundsch)

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Section: Olivine Composition As Indicator Of Parental Meltsupporting

confidence: 59%

Mafic monogenetic vents at the Descabezado Grande volcanic field (35.5°S–70.8°W): the northernmost evidence of regional primitive volcanism in the Southern Volcanic Zone of Chile

Salas

Rabbia

Hernández

et al. 2016

Int J Earth Sci (Geol Rundsch)

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“…minerals that were not crystallized from the host magma, but having a genetic linkage to the same magmatic system (Charlier 2005;Davidson et al 2007;Ubide et al 2012;Larrea et al 2012). They could represent recycled crystals of earlier stages of the magmatic system at depth.…”

Section: Discussionmentioning

confidence: 99%

“…In particular, effects of megacrysts on the bulk chemical composition and their meaning have been widely discussed, especially in porphyritic varieties Larrea et al 2012). Recently, the term 'antecrysts' has been systematically used (e.g., Charlier et al 2005;Davidson et al 2007;Jerram & Martin 2008) referring to a specific crystal type that differs from those identified as phenocrysts (larger early-crystallized phases that are in equilibrium with the liquid) and xenocrysts (crystals that are foreign to the magmatic liquid and have no genetic association with it).…”

Section: Introductionmentioning

confidence: 99%

The antecryst compositional influence on Cretaceous alkaline lamprophyre dykes, SE Brazil

et al. 2015

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ABSTRACT:The question of whether the antecryst assemblage affects the bulk composition of lamprophyre dykes, and could be responsible for the compositional zonation between their centers and borders is addressed through a detailed study involving four monchiquite and camptonite dykes (basanites and tephrites) representative of the Arco de Ponta Grossa and Serra do Mar alkaline provinces. In them, antecrysts are interpreted as early-crystallized minerals that are no longer in equilibrium with their host-liquid, albeit still linked to the same magmatic system. They represent recycled crystals of earlier stages of the magmatic system at depth. The antecryst microtextures, such as zoned clinopyroxene megacrysts (augite cores and titanaugite rims) with partly corroded cores, olivine crystals with corroded rims surrounded by biotite coronas, chrome-spinel inclusions in clinopyroxene and olivine megacryst cores, and titanomagnetite crystals surrounded by biotite coronas, suggest chemical re-equilibrium with the matrix. The greatest antecryst cargo in these dykes is found in their centers. After subtracting the antecryst volume from the center analyses of each body, the calculated compositions are very similar to the border analyses. The mafic antecryst cargo of each occurrence proportionally leads to enrichment of MgO, FeO, TiO 2 , CaO, compatible trace elements (Cr, Ni and Co), and depletion of SiO 2 , K 2 O, Na 2 O, Al 2 O 3 and incompatible trace elements (Ba, Sr and REE). The whole-rock geochemical analyses of each dyke represent the combination of accumulated crystals and melt. The compositional zonation of the studied dykes is associated with the antecryst cargo rather than different magmatic pulses. KEYWORDS:Antecrysts; Alkaline lamprophyres; Petrology; Geochemistry. RESUMO: A questão de como a assembleia de antecristais influencia a composição química de diques de lamprófiro e se esta pode ser responsável pelo zoneamento composicional entre núcleos e bordas é abordada por meio de um estudo detalhado em quatro diques de monchiquito e camptonito, representativos das províncias alcalinas Arco de Ponta Grossa e Serra do Mar. Nestes diques, os antecristais são interpretados como minerais cristalizados precocemente que não se encontram mais em equi-

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“…This has informed the premise that many large crystals, rather than being phenocrysts, should be regarded as antecrysts that formed prior to emplacement at depth (Charlier et al, 2005;Davidson et al, 2007;Gill et al, 2006;Hildreth and Wilson, 2007;Jerram and Martin, 2008;Larrea et al, 2013). The complexity within antecrysts implies the existence of complex magma plumbing systems with episodes of contamination, recharge and magma mixing (Francalanci et al, 2012;Sakyi et al, 2012;Ubide et al, 2014a;Ubide et al, 2014b).…”

Section: Introductionmentioning

confidence: 99%

High-resolution LA-ICP-MS trace element mapping of igneous minerals: In search of magma histories

et al. 2015

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Magmatic Processes and the Role of Antecrysts in the Genesis of Corvo Island (Azores Archipelago, Portugal)

Cited by 54 publications

References 36 publications

Mafic monogenetic vents at the Descabezado Grande volcanic field (35.5°S–70.8°W): the northernmost evidence of regional primitive volcanism in the Southern Volcanic Zone of Chile

Mafic monogenetic vents at the Descabezado Grande volcanic field (35.5°S–70.8°W): the northernmost evidence of regional primitive volcanism in the Southern Volcanic Zone of Chile

The antecryst compositional influence on Cretaceous alkaline lamprophyre dykes, SE Brazil

High-resolution LA-ICP-MS trace element mapping of igneous minerals: In search of magma histories

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