Petrology and geochemistry of granitoids and their mafic micogranular enclaves (MME) in marginal part of the Małopolska Block (S Poland)

2012
journal article
article
6
cris.lastimport.wos2024-04-09T18:57:14Z
dc.abstract.enGranitic plutons (the Dolina Będkowska valley and Pilica area) were found in a few boreholes in the Małopolska Block (MB). These granitic rocks may represent apical parts (apophyses) of a great magmatic bodies (batholiths) located in deeper level of the Ediacaran/Paleozoic basement. They are described as ‘stitching intrusions’, generated during/after collision in Carboniferous/Permian period (~300 Ma) between the Upper Silesian Block (USB) and the Małopolska Block (MB). These rocks are fresh, unaltered granodiorites that are pale grey in colour. They have holocrystalline, medium- to coarse-grained structure and massive texture. For the first time, several mafic microgranular enclaves (MME), varying in size and colour, were found in the granodioritic host (HG). The occurrence of MME in the host granodioritic rocks is evidence of a mingling process between mafic and felsic magmas. The MME are pale/dark grey in colour, fine-grained rocks with ‘porphyritic’ textures. They consist of large megacrysts/xenocrysts of plagioclase, quartz, alkali feldspars and the fine-grained groundmass of pseudo-doleritic textures (lath-shaped plagioclases, blade-shaped amphiboles/biotites). According to their modal/mineral composition, they represent Q-diorites and tonalites. The MME, similar to the host granodiorites (HG), are I-type rocks, exhibit high Na2O content >3.2 wt%; normative diopside or normative corundum occurs (mainly <1%). They are metaluminous to slightly peraluminous (ASI <1.1) and have calc-alkaline, medium-K to high-K character. They generally belong to magnesian series (#Mg=0.20-0.40) and have low agpaitic index (<0.87). They are low evolved magmatic rocks. The rocks studied are enriched in LREEs (La, Ce, Sm) compared to HREEs. The Eu* negative anomaly and high Sr contents point to varying degrees of plagioclase fractionation connected to the mixing process rather than simple fractional crystallization. Both rocks studied (HG and MME) are characterized by a high content of LILEs (K, Ba, Rb) in normalized patterns and a low HFS/LIL elements ratio (Ta, Nb)/(K, Rb, La). The projection points of the rocks studied plot in different fields of various petrochemical diagrams: mainly in the arc granites that are rare in the pre-collisional granites as well as the syn-subductional to post-collisional granites fields. For the first time, inner textures in rock-forming minerals related to mixing processes are described both in the granodioritic host (HG) and in the MME. Mantled boxy cellular plagioclase megacrysts with ‘old cores’ of labradorite composition, and amphibole aggregates with titanite and opaque minerals, represent peritectic rather than primary residual minerals. The plagioclase, quartz and alkali feldspar megacrysts/xenocrysts were mechanically transferred from the granodioritic host (HG) to MME. The presence of lath-shaped plagioclases, blade-shaped amphiboles/biotites and acicular-shaped apatites in the groundmass of the MME is evidence of undercooling of hot mafic blobs in a relatively cold granodioritic magma chamber. The MME were hybridized by leucocratic melt squeezed from the granodioritic magma in a later stage of the mixing process (quartz and alkali crystals in the interstices in the MME groundmass). In the granodiorites (HG), the spike and spongy cellular zones as well as biotite/amphibole zones in plagioclase megacrysts are connected to the mixing process. Both of the rocks studied are characterized by different amounts of major elements (SiO2, Na2O and K2O), trace elements (Ni, Cr, V, Ti and P), #Mg and modified alkali–lime index (MALI) that is related to their origins from different sources. On the other hand, they have similar chondrite-normalized patterns (for trace elements and REE), LILEs contents (Sr, Ba, Rb), aluminum saturation index (ASI) and isotopic signatures (high 86Sr/87Sr (0.079-0.713) and low 143Nd/144Nd (0.512) values but lower than in continental crust), which are evidence of the strong hybridisation of mafic enclaves by the granodioritic host magma. The parental rocks of both rocks studied have a similar mafic signature but were generated in different sources: the host granodiorites (HG) magma in lower continental crust rocks, and the MME magma in enriched upper mantle. The MME crystallized from strongly hybridized magma of intermediate compositions (Q-diorite, tonalite) rather than from primary mafic magma. The host granodiorites (HG) originated from completely homogenized crustal granodioritic magma which inherited its geochemical signature from ancient arc-rocks in a subduction-related setting.pl
dc.affiliationWydział Biologii i Nauk o Ziemi : Instytut Nauk Geologicznychpl
dc.contributor.authorWolska, Anna - 132729 pl
dc.date.accession2016-03-08pl
dc.date.accessioned2016-03-08T09:12:05Z
dc.date.available2016-03-08T09:12:05Z
dc.date.issued2012pl
dc.date.openaccess0
dc.description.accesstimew momencie opublikowania
dc.description.additionalBibliogr. s. 112-127pl
dc.description.number1-2pl
dc.description.physical3-127pl
dc.description.versionostateczna wersja wydawcy
dc.description.volume43pl
dc.identifier.doi10.2478/v10002-012-0003-5pl
dc.identifier.eissn1899-8526pl
dc.identifier.issn1899-8291pl
dc.identifier.projectROD UJ / Ppl
dc.identifier.urihttp://ruj.uj.edu.pl/xmlui/handle/item/21951
dc.identifier.weblinkhttp://www.degruyter.com/view/j/mipo.2012.43.issue-1-2/v10002-012-0003-5/v10002-012-0003-5.xmlpl
dc.languageengpl
dc.language.containerengpl
dc.rightsUdzielam licencji. Uznanie autorstwa - Użycie niekomercyjne - Bez utworów zależnych 3.0 Polska*
dc.rights.licenceCC-BY-NC-ND
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/pl/legalcode*
dc.share.typeotwarte czasopismo
dc.subject.enthe Małopolska Block (MB)pl
dc.subject.enhost granodiorites (HG)pl
dc.subject.enmafic microgranular enclaves (MME)pl
dc.subject.enQ-dioritespl
dc.subject.entonalitespl
dc.subject.enmixingpl
dc.subject.enminglingpl
dc.subject.enhybridisation processpl
dc.subtypeArticlepl
dc.titlePetrology and geochemistry of granitoids and their mafic micogranular enclaves (MME) in marginal part of the Małopolska Block (S Poland)pl
dc.title.journalMineralogiapl
dc.typeJournalArticlepl
dspace.entity.typePublication
cris.lastimport.wos
2024-04-09T18:57:14Z
dc.abstract.enpl
Granitic plutons (the Dolina Będkowska valley and Pilica area) were found in a few boreholes in the Małopolska Block (MB). These granitic rocks may represent apical parts (apophyses) of a great magmatic bodies (batholiths) located in deeper level of the Ediacaran/Paleozoic basement. They are described as ‘stitching intrusions’, generated during/after collision in Carboniferous/Permian period (~300 Ma) between the Upper Silesian Block (USB) and the Małopolska Block (MB). These rocks are fresh, unaltered granodiorites that are pale grey in colour. They have holocrystalline, medium- to coarse-grained structure and massive texture. For the first time, several mafic microgranular enclaves (MME), varying in size and colour, were found in the granodioritic host (HG). The occurrence of MME in the host granodioritic rocks is evidence of a mingling process between mafic and felsic magmas. The MME are pale/dark grey in colour, fine-grained rocks with ‘porphyritic’ textures. They consist of large megacrysts/xenocrysts of plagioclase, quartz, alkali feldspars and the fine-grained groundmass of pseudo-doleritic textures (lath-shaped plagioclases, blade-shaped amphiboles/biotites). According to their modal/mineral composition, they represent Q-diorites and tonalites. The MME, similar to the host granodiorites (HG), are I-type rocks, exhibit high Na2O content >3.2 wt%; normative diopside or normative corundum occurs (mainly <1%). They are metaluminous to slightly peraluminous (ASI <1.1) and have calc-alkaline, medium-K to high-K character. They generally belong to magnesian series (#Mg=0.20-0.40) and have low agpaitic index (<0.87). They are low evolved magmatic rocks. The rocks studied are enriched in LREEs (La, Ce, Sm) compared to HREEs. The Eu* negative anomaly and high Sr contents point to varying degrees of plagioclase fractionation connected to the mixing process rather than simple fractional crystallization. Both rocks studied (HG and MME) are characterized by a high content of LILEs (K, Ba, Rb) in normalized patterns and a low HFS/LIL elements ratio (Ta, Nb)/(K, Rb, La). The projection points of the rocks studied plot in different fields of various petrochemical diagrams: mainly in the arc granites that are rare in the pre-collisional granites as well as the syn-subductional to post-collisional granites fields. For the first time, inner textures in rock-forming minerals related to mixing processes are described both in the granodioritic host (HG) and in the MME. Mantled boxy cellular plagioclase megacrysts with ‘old cores’ of labradorite composition, and amphibole aggregates with titanite and opaque minerals, represent peritectic rather than primary residual minerals. The plagioclase, quartz and alkali feldspar megacrysts/xenocrysts were mechanically transferred from the granodioritic host (HG) to MME. The presence of lath-shaped plagioclases, blade-shaped amphiboles/biotites and acicular-shaped apatites in the groundmass of the MME is evidence of undercooling of hot mafic blobs in a relatively cold granodioritic magma chamber. The MME were hybridized by leucocratic melt squeezed from the granodioritic magma in a later stage of the mixing process (quartz and alkali crystals in the interstices in the MME groundmass). In the granodiorites (HG), the spike and spongy cellular zones as well as biotite/amphibole zones in plagioclase megacrysts are connected to the mixing process. Both of the rocks studied are characterized by different amounts of major elements (SiO2, Na2O and K2O), trace elements (Ni, Cr, V, Ti and P), #Mg and modified alkali–lime index (MALI) that is related to their origins from different sources. On the other hand, they have similar chondrite-normalized patterns (for trace elements and REE), LILEs contents (Sr, Ba, Rb), aluminum saturation index (ASI) and isotopic signatures (high 86Sr/87Sr (0.079-0.713) and low 143Nd/144Nd (0.512) values but lower than in continental crust), which are evidence of the strong hybridisation of mafic enclaves by the granodioritic host magma. The parental rocks of both rocks studied have a similar mafic signature but were generated in different sources: the host granodiorites (HG) magma in lower continental crust rocks, and the MME magma in enriched upper mantle. The MME crystallized from strongly hybridized magma of intermediate compositions (Q-diorite, tonalite) rather than from primary mafic magma. The host granodiorites (HG) originated from completely homogenized crustal granodioritic magma which inherited its geochemical signature from ancient arc-rocks in a subduction-related setting.
dc.affiliationpl
Wydział Biologii i Nauk o Ziemi : Instytut Nauk Geologicznych
dc.contributor.authorpl
Wolska, Anna - 132729
dc.date.accessionpl
2016-03-08
dc.date.accessioned
2016-03-08T09:12:05Z
dc.date.available
2016-03-08T09:12:05Z
dc.date.issuedpl
2012
dc.date.openaccess
0
dc.description.accesstime
w momencie opublikowania
dc.description.additionalpl
Bibliogr. s. 112-127
dc.description.numberpl
1-2
dc.description.physicalpl
3-127
dc.description.version
ostateczna wersja wydawcy
dc.description.volumepl
43
dc.identifier.doipl
10.2478/v10002-012-0003-5
dc.identifier.eissnpl
1899-8526
dc.identifier.issnpl
1899-8291
dc.identifier.projectpl
ROD UJ / P
dc.identifier.uri
http://ruj.uj.edu.pl/xmlui/handle/item/21951
dc.identifier.weblinkpl
http://www.degruyter.com/view/j/mipo.2012.43.issue-1-2/v10002-012-0003-5/v10002-012-0003-5.xml
dc.languagepl
eng
dc.language.containerpl
eng
dc.rights*
Udzielam licencji. Uznanie autorstwa - Użycie niekomercyjne - Bez utworów zależnych 3.0 Polska
dc.rights.licence
CC-BY-NC-ND
dc.rights.uri*
http://creativecommons.org/licenses/by-nc-nd/3.0/pl/legalcode
dc.share.type
otwarte czasopismo
dc.subject.enpl
the Małopolska Block (MB)
dc.subject.enpl
host granodiorites (HG)
dc.subject.enpl
mafic microgranular enclaves (MME)
dc.subject.enpl
Q-diorites
dc.subject.enpl
tonalites
dc.subject.enpl
mixing
dc.subject.enpl
mingling
dc.subject.enpl
hybridisation process
dc.subtypepl
Article
dc.titlepl
Petrology and geochemistry of granitoids and their mafic micogranular enclaves (MME) in marginal part of the Małopolska Block (S Poland)
dc.title.journalpl
Mineralogia
dc.typepl
JournalArticle
dspace.entity.type
Publication
Affiliations

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