TY - JOUR

T1 - Interactions between dioritic and granodioritic magmas in mingling zones

T2 - Plagioclase record of mixing, mingling and subsolidus interactions in the Gȩsiniec Intrusion, NE Bohemian Massif, SW Poland

AU - Pietranik, Anna

AU - Koepke, Jürgen

N1 - Funding Information: Acknowledgments The research work was supported by grants to AP: 2022/W/ING/07 and KOLUMB by the Polish Science Foundation. We are grateful to Vojtech Janousˇek and Bill Collins for very helpful reviews and editorial comments. Chris Hawkesworth is thanked for valuable comments on an early version of this manuscript, and his suggestions as to how the English might be improved.

PY - 2009/7

Y1 - 2009/7

N2 - Dioritic and granodioritic rocks coexist in the Gȩsiniec Intrusion in SW Poland showing typical relationships in many mafic-felsic mingling zones worldwide, such as dioritic syn-putonic dykes and microgranular enclaves within granodioritic host. Plagioclase zonation from granodioritic rocks suggests late stage mixing probably with dioritic magma, whereas no magma mixing is recorded in plagioclase from dioritic rocks. The diorites seem to show effects of interaction with evolved, leucocratic melts derived from granodiorite, not with the granodioritic melt itself. We conclude that the diorites' compositions were modified after their emplacement within the granodioritic host, when the diorites were essentially solidified and injection of evolved melt from granodiorite did not involve marked modification of plagioclase composition. Compositional zoning patterns of plagioclase in diorites can be modeled by closed system fractional crystallization interrupted by resorption induced probably by decompression. Granodioritic plagioclase seems to be affected by the same resorption event. Plagioclase that crystallized in dioritic magma before the resorption does not record interaction between dioritic and granodioritic magmas, suggesting that both magmas evolved separately.

AB - Dioritic and granodioritic rocks coexist in the Gȩsiniec Intrusion in SW Poland showing typical relationships in many mafic-felsic mingling zones worldwide, such as dioritic syn-putonic dykes and microgranular enclaves within granodioritic host. Plagioclase zonation from granodioritic rocks suggests late stage mixing probably with dioritic magma, whereas no magma mixing is recorded in plagioclase from dioritic rocks. The diorites seem to show effects of interaction with evolved, leucocratic melts derived from granodiorite, not with the granodioritic melt itself. We conclude that the diorites' compositions were modified after their emplacement within the granodioritic host, when the diorites were essentially solidified and injection of evolved melt from granodiorite did not involve marked modification of plagioclase composition. Compositional zoning patterns of plagioclase in diorites can be modeled by closed system fractional crystallization interrupted by resorption induced probably by decompression. Granodioritic plagioclase seems to be affected by the same resorption event. Plagioclase that crystallized in dioritic magma before the resorption does not record interaction between dioritic and granodioritic magmas, suggesting that both magmas evolved separately.

KW - Bohemian Massif

KW - Diorite

KW - Granodiorite

KW - Magma mingling

KW - Magma mixing

KW - Plagioclase

KW - Sr

KW - Subsolidus interactions

UR - http://www.scopus.com/inward/record.url?scp=67349253905&partnerID=8YFLogxK

U2 - 10.1007/s00410-008-0368-z

DO - 10.1007/s00410-008-0368-z

M3 - Article

AN - SCOPUS:67349253905

VL - 158

SP - 17

EP - 36

JO - Contributions to Mineralogy and Petrology

JF - Contributions to Mineralogy and Petrology

SN - 0010-7999

IS - 1

ER -