Magma mingling, zoning and emplacement in calc-alkaline granitoid plutons

Zorpi, M.J.; Coulon, Christian; Orsini, Jean-Baptiste; Cocirta, Constantin

doi:10.1016/0040-1951(89)90147-9

Cited by 164 publications

(58 citation statements)

References 83 publications

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“…First, linear mixing could explain the two trends only by assuming a different composition of the basic component in each case, whereas the crustal component could have had a roughly constant composition. This seems unlikely, as basic magmas are absent at a regional scale, even less so the occurrence of several basic magma types (or a differentiating basic magma series, as suggested by Zorpi et al, 1989). However, this absence is insufficient to discard open-system models.…”

Section: Microgranular Enclaves In the Lpb: Geochemical Evidence Formentioning

confidence: 99%

“…However, the significance of differences in enclave content and types is difficult to assess, because the enclaves are not classified according to purely descriptive criteria and very different processes are involved in their genesis and evolution. Most often, they have been interpreted either as restites (White and Chappell, 1977;Chen et al, 1989;White et al, 1999) or as hybridized mafic magmas (Vernon 1983(Vernon , 1984Reid et al, 1983;Huppert and Sparks, 1988;Dorais et al, 1990;Castro et al, 1991;Barbarin and Didier, 1991;Moreno-Ventas et al, 1995;Wiebe et al, 1997;Zorpi et al, 1989;Silva et al, 2000;Janoušek et al, 2004;Barbarin, 2005). However, other processes have been suggested to form microgranular enclaves, including early segregation or quench cumulates Borodina, 1977, 1991;Phillips et al, 1981;Clemens and Wall, 1984;Dodge and Kistler, 1990;Dahlquist, 2002), or to contribute to their genesis, such as chemical equilibration, contamination or enclave dissolution in ascending magmas (Dorais et al, 1990;Allen, 1991;Elburg, 1996;García-Moreno et al, 2006).…”

Section: The Significance Of Microgranular Enclaves In the Lpbmentioning

confidence: 99%

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The significance of microgranular enclaves in assessing the magmatic evolution of a high-level composite batholith: A case on the Los Pedroches Batholith, Iberian Massif, Spain

Pascual

Donaire

2008

Geochem. J.

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are partly a consequence of the heterogeneities of the Earth's crust, in most cases requiring a case-by-case study of granitoid genesis. In other instances, however, uncertainties are a consequence of an insufficient integration of geochemical information with other geological data (field, petrographic, geophysical, etc.), either by scarcity or ambiguousness.We present here the case of the Los Pedroches batholith (LPB), one of the largest Variscan batholiths in Spain, as an example in which a number of the usual uncertainties in granite genesis can be overcome by a careful integration of geochemical and isotopic data with field and petrographic evidence.There are several reasons making the LPB of particular interest. The geological setting is very well constrained, as there is both compelling evidence and a wide consensus on its intrusion age, its emplacement style, and its main subdivision in two plutonic suites (Larrea et al., 2004). Also, the LPB is very suitable for a mineralogical and geochemical study, as all of the LPB units contain very fresh rocks. In addition, the LPB rocks are remarkably homogeneous at a large scale, particularly in the case of the granodioritic rocks (LPG). For these reasons, we consider the LPB as a good target to build up a model, which could be of major interest, not only at a regional scale, but also with regard to the general role of microgranular enclaves as indicators of magma genesis (Received May 15, 2007; Accepted October 6, 2007) To evaluate the origin and significance of microgranular enclaves hosted by granites, we present new data on two granitoid series belonging to the Los Pedroches Batholith (LPB), SW Iberian Massif, Spain. The two series in the LPB show a distinct contrast in terms of field, petrographic, mineralogical and geochemical data. This contrast also extends to the enclaves, differing in abundance and other features in each of the series considered. Isotopic measurements, however, including 87 Sr/ 86 Sr, ε Nd and δ 18 O data, show no significant, inter-or intra-series contrast throughout the LPB. These data lend additional support to an origin of all the granitoid rocks in the LPB from a single, isotopically homogeneous, lower crustal source. We also suggest that differences between microgranular enclaves in the two LPB granitoid series cannot be related to a different degree of participation of mafic rocks in the genesis of the respective groups: in both cases, microgranular enclaves are better interpreted as autoliths.

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Section: Microgranular Enclaves In the Lpb: Geochemical Evidence Formentioning

confidence: 99%

Section: The Significance Of Microgranular Enclaves In the Lpbmentioning

confidence: 99%

The significance of microgranular enclaves in assessing the magmatic evolution of a high-level composite batholith: A case on the Los Pedroches Batholith, Iberian Massif, Spain

Pascual

Donaire

2008

Geochem. J.

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“…3). Estas feições são comuns em granitos ediacaranos da Província Borborema (Mariano & Sial, 1990;Galindo, 1993;Galindo et al, 1995;Cavalcante et al, 2014;Nascimento et al, 2015) e em plutons graníticos descritos na literatura (Zorpi et al, 1989;Vernon, 1990Vernon, , 2004Hibbard, 1995;Barbarin, 2005 Nascimento et al, 2015). Outros tipos de enclaves máficos, de particular interesse nos granitos do Stock Flores, são os schlieren elipsoidais, presentes no fácies Tipo II.…”

Section: Geologia Do Stock Floresunclassified

O Stock Flores: Exemplo de magmatismo granítico tipo-A no Domínio Rio Piranhas-Seridó, NE da Província Borborema

2017

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Resumo -O Stock granítico Flores intrude gnaisses paleoproterozoicos, relacionados ao ComplexoCaicó, no Domínio Rio Piranha-Seridó, porção setentrional da Província Borborema, NE do Brasil. Este trabalho tem como objetivo a caracterização petrológica e geoquímica de seu monzogranitos. O Stock Flores compreende duas fácies petrográficas de monzogranitos equigranulares, leucocrá-ticos: i) monzogranitos rosados de granulação media; e ii) monzogranitos cinza rosados de granulação fina. Localmente ocorrem no Fácies Tipo II, enclaves máficos exibindo feições de coexistência de magmas (mixing e mingling), e schlieren elipsoidais, interpretados como estruturas formadas por convecção magmática. Biotita é o máfico principal; titanita, allanita, apatita, zircão e opacos ocorrem como minerais acessórios; fluorita, clorita e saussurita ocorrem como minerais tardios relacionados a fluídos em estágio subsolidus. As análises geoquímicas evidenciam a natureza evoluída do Stock e afinidade alcalina com teores de SiO 2 > 71,0%, e Na 2 O+K 2 O ~ 9,0%. Os diagramas discriminantes de ambiente tectônico demonstram a tipologia de granito Tipo-A. Tais dados são coerentes com a idade U-Pb 553±4 Ma encontrada para o Stock, o colocando dentro do contexto tardi-a pós-tectônico em relação à Orogênese Brasiliana/Pan-Africana na Província Borborema. Palavras-chave: Granito alcalino, Tardi a Pós-tectônico, Província Borborema.Abstract -The Flores Stock: An example of A-type granitic magmatism on Rio Piranhas-Seridó Domain, NE Borborema Province.The Flores granitic stock intrudes paleoproterozoic gneissic related to Caicó Complex, in Rio Piranhas-Seridó Domain, North part of the Borborema Province, NE Brazil. This work focused on the petrological and geochemical characterization of its monzogranites. The Flores Stock comprises equigranular, leucocratic monzogranites, which are divide in two petrografic facies: i) medium grained, pink monzogranites; and ii) fine grained, gray to pink monzogranites. Locally we can find in this type dioritic enclaves displaying magmas coexistence features (mixing and migling), and ellipsoidal schlieren formed by magmatic convection. Mineralogically, the Stock is constitued by biotite as its main mafic; titanite, allanite, apatite, zircon, opaque, and as late minerals, fluorite, chlorite and saussurite, these late ones are interpreted as related to fluids in subsolidus stage. The studied monzogranites show high SiO 2 contents (> 71% wt%) and alkaline affinity with Na 2 O + K 2 O ~ 9,0%. Tectonic discriminant diagrams of tectonic environment suggest a typology of A-type granite related to a post-collisional environment, which is corroborated by U-Pb zircon crystallization age of 553±4 Ma. Thus, the Flores Stock is interpreted as emplaced in a late to post-tectonic stage of the Brasiliana / Pan-African Orogeny in the Borborema Province

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“…Vernon, 1984;Didier and Barbarin, 1991). 최근에 많은 연구에서 고철질 미립상 포유체(mafic microgranular enclave, MME)를 포함하는 화강암질암 (granitoid)은 조성이 서로 다른 두 마그마의 혼합작용 에 의한 결과라고 보고되었다 (Reid et al, 1983;Zorpi et al, 1989;Didier and Barbarin., 1991;Holden et al, 1991;Jwa and Kim, 2000;Kim et al, 2004Kim et al, , 2012Kim et al, 2005).…”

Section: 서 언 맨틀 상부와 지각하부에서 생성된 마그마는 심부 단열에 조합된 심부 통로 즉 화도(Conduit)를unclassified

Field Evidence of Magma Mixing from Concentric Zoning and Mafic Microgranular Enclaves in Bunam Stock, Korea

Hwang¹,

Seo²

2016

The Journal of the Petrological Society of Korea

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The Bunam Stock (29.5 km 2 area) is an outcrop of plutonic complex classified four facies: coarse-grained granite, quartz monzodiorite, granodiorite and fine-grained granite. Three facies except the last one exhibit very irregular boundaries with gradational compositional variations between both facies and show concentric zoning from the central quartz monzodiorite through granodiorite to outer coarse-grained granite. Mafic microgranular enclaves (MME) commonly occur in granodiorite. Some MMEs, have very fine-grained chilled margins and indentedly crenulate contacts, and display horizontally circular and vertically elongate shapes. Their shape and granularity indicate coeval flow and mingling of partly crystalline felsic and mafic magmas. MMEs exhibit dark fine-grained margins giving them a ellipsoidal form that has been attributed to undercooling of a mafic magma as blobs intruded into a felsic magma. The observed relations in the Bunam Stock identify that two endmembers are coarse-grained granite from a felsic magma and quartz monzodiorite from a mafic magma, and hybrid is granodiorite including MMEs.

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Magma mingling, zoning and emplacement in calc-alkaline granitoid plutons

Cited by 164 publications

References 83 publications

The significance of microgranular enclaves in assessing the magmatic evolution of a high-level composite batholith: A case on the Los Pedroches Batholith, Iberian Massif, Spain

The significance of microgranular enclaves in assessing the magmatic evolution of a high-level composite batholith: A case on the Los Pedroches Batholith, Iberian Massif, Spain

O Stock Flores: Exemplo de magmatismo granítico tipo-A no Domínio Rio Piranhas-Seridó, NE da Província Borborema

Field Evidence of Magma Mixing from Concentric Zoning and Mafic Microgranular Enclaves in Bunam Stock, Korea

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