Interpretation of wide zircon U–Pb age distributions in durbachite-type Variscan granitoid in the Mórágy Hills

Annamária Kis; Tamás G. Weiszburg; István Dunkl; Friedrich Koller; Tamás Váczi; György Buda

doi:10.1007/s00710-023-00817-2

Interpretation of wide zircon U–Pb age distributions in durbachite-type Variscan granitoid in the Mórágy Hills

Annamária Kis (Corresponding author)
, Tamás G. Weiszburg
, István Dunkl
, Friedrich Koller
, Tamás Váczi
, György Buda

Publications: Contribution to journal › Article › Peer Reviewed

Abstract

In situ U–Pb analyses were performed on SEM-BSE, SEM-CL and Raman mapped zircons from the Variscan granitoids exposed in the Mórágy pluton, Hungary. However, the routinely used LA-ICP-MS could result only in reliable age constraints if the system was not overprinted by multiple geological processes that affect the isotope system of zircons. To overcome the ambiguities the new zircon U–Pb age data were evaluated carefully, first using simple statistical models, then a zircon internal texture related complex approach was applied. This method demonstrates that the U–Pb age in overprinted systems correlates with the structural state; the worse structural state zones showing younger, but still concordant ages. Individual zircon internal texture and structural state based evaluation made it possible to select the least overprinted age components of the system and identify five steps in the evolution of the studied intrusive rock. The two melts (granitoid and mafic) passed the zircon U–Pb isotope closure temperature ~ 355 ± 3 Ma ago during their cooling. Crystallization of the two mingled magmas overarched the 350–340 Ma period, including two intense zircon crystallization peaks (~ 347 Ma, ~ 333 Ma). The cessation of melt crystallization (~ 650 °C) happened ~ 334 ± 4 Ma ago, as indicated by the age of the “normal and long prismatic” zircons. Further confirming this statement, they are embedding in their rims the eutectic mineral assemblage. A Cretaceous post-magmatic event was identified according to slightly discordant U–Pb ages for the Mórágy pluton.

Original language	English
Pages (from-to)	663-683
Number of pages	21
Journal	Mineralogy and Petrology
Volume	117
Issue number	4
DOIs	https://doi.org/10.1007/s00710-023-00817-2
Publication status	Published - 24 Mar 2023

Funding

We express our thanks for a CEEPUS scholarship supporting the field work in Austria. We are indebted to Professor Urs S. Klötzli for the lab work, to ELTE Faculty of Science Research and Instrument Core Facility for the access to the Raman laboratory. Supported By the ÚNKP (1783-3 / 2018 / FEKUTSRAT) New National Excellence Program of the Ministry of Human Capacities. We thank GÖochron Laboratories, University of Göttingen, Germany for the access to the LA-SC-ICP-MS lab. The research was carried out as part of the “More efficient exploitation and use of subsurface resources” project of the University of Miskolc, implemented in the framework of the Thematic Excellence Program funded by the Ministry of Innovation and Technology of Hungary (Grant Contract reg. nr.: NKFIH-846-8/2019). We are grateful for the detailed reviews of Prof. Albrecht von Quadt, and two other reviewers Prof. Fritz Finger and Prof. Jiří Sláma whose suggestions have improved the quality of the manuscript. We express our thanks for a CEEPUS scholarship supporting the field work in Austria. We are indebted to Professor Urs S. Klötzli for the lab work, to ELTE Faculty of Science Research and Instrument Core Facility for the access to the Raman laboratory. Supported By the ÚNKP (1783-3 / 2018 / FEKUTSRAT) New National Excellence Program of the Ministry of Human Capacities. We thank GÖochron Laboratories, University of Göttingen, Germany for the access to the LA-SC-ICP-MS lab. The research was carried out as part of the “More efficient exploitation and use of subsurface resources” project of the University of Miskolc, implemented in the framework of the Thematic Excellence Program funded by the Ministry of Innovation and Technology of Hungary (Grant Contract reg. nr.: NKFIH-846-8/2019). We are grateful for the detailed reviews of Prof. Albrecht von Quadt, and two other reviewers Prof. Fritz Finger and Prof. Jiří Sláma whose suggestions have improved the quality of the manuscript.

Austrian Fields of Science 2012

105116 Mineralogy
105113 Crystallography

Keywords

Metamorphic overprinting
Mórágy granitoid
Tisza Mega-unit
U–Pb concordance
Zircon structural state

Access to Document

10.1007/s00710-023-00817-2

Cite this

@article{dfc7954c457c46fbacabc1ab74354fd8,

title = "Interpretation of wide zircon U{\textendash}Pb age distributions in durbachite-type Variscan granitoid in the M{\'o}r{\'a}gy Hills",

abstract = "In situ U{\textendash}Pb analyses were performed on SEM-BSE, SEM-CL and Raman mapped zircons from the Variscan granitoids exposed in the M{\'o}r{\'a}gy pluton, Hungary. However, the routinely used LA-ICP-MS could result only in reliable age constraints if the system was not overprinted by multiple geological processes that affect the isotope system of zircons. To overcome the ambiguities the new zircon U{\textendash}Pb age data were evaluated carefully, first using simple statistical models, then a zircon internal texture related complex approach was applied. This method demonstrates that the U{\textendash}Pb age in overprinted systems correlates with the structural state; the worse structural state zones showing younger, but still concordant ages. Individual zircon internal texture and structural state based evaluation made it possible to select the least overprinted age components of the system and identify five steps in the evolution of the studied intrusive rock. The two melts (granitoid and mafic) passed the zircon U{\textendash}Pb isotope closure temperature \textasciitilde{} 355 ± 3 Ma ago during their cooling. Crystallization of the two mingled magmas overarched the 350{\textendash}340 Ma period, including two intense zircon crystallization peaks (\textasciitilde{} 347 Ma, \textasciitilde{} 333 Ma). The cessation of melt crystallization (\textasciitilde{} 650 °C) happened \textasciitilde{} 334 ± 4 Ma ago, as indicated by the age of the {\textquotedblleft}normal and long prismatic{\textquotedblright} zircons. Further confirming this statement, they are embedding in their rims the eutectic mineral assemblage. A Cretaceous post-magmatic event was identified according to slightly discordant U{\textendash}Pb ages for the M{\'o}r{\'a}gy pluton.",

keywords = "Metamorphic overprinting, M{\'o}r{\'a}gy granitoid, Tisza Mega-unit, U{\textendash}Pb concordance, Zircon structural state",

author = "Annam{\'a}ria Kis and Weiszburg, \{Tam{\'a}s G.\} and Istv{\'a}n Dunkl and Friedrich Koller and Tam{\'a}s V{\'a}czi and Gy{\"o}rgy Buda",

note = "Publisher Copyright: {\textcopyright} 2023, The Author(s).",

year = "2023",

month = mar,

day = "24",

doi = "10.1007/s00710-023-00817-2",

language = "English",

volume = "117",

pages = "663--683",

journal = "Mineralogy and Petrology",

issn = "0930-0708",

publisher = "Springer-Verlag Wien",

number = "4",

}

TY - JOUR

T1 - Interpretation of wide zircon U–Pb age distributions in durbachite-type Variscan granitoid in the Mórágy Hills

AU - Kis, Annamária

AU - Weiszburg, Tamás G.

AU - Dunkl, István

AU - Koller, Friedrich

AU - Váczi, Tamás

AU - Buda, György

PY - 2023/3/24

Y1 - 2023/3/24

N2 - In situ U–Pb analyses were performed on SEM-BSE, SEM-CL and Raman mapped zircons from the Variscan granitoids exposed in the Mórágy pluton, Hungary. However, the routinely used LA-ICP-MS could result only in reliable age constraints if the system was not overprinted by multiple geological processes that affect the isotope system of zircons. To overcome the ambiguities the new zircon U–Pb age data were evaluated carefully, first using simple statistical models, then a zircon internal texture related complex approach was applied. This method demonstrates that the U–Pb age in overprinted systems correlates with the structural state; the worse structural state zones showing younger, but still concordant ages. Individual zircon internal texture and structural state based evaluation made it possible to select the least overprinted age components of the system and identify five steps in the evolution of the studied intrusive rock. The two melts (granitoid and mafic) passed the zircon U–Pb isotope closure temperature ~ 355 ± 3 Ma ago during their cooling. Crystallization of the two mingled magmas overarched the 350–340 Ma period, including two intense zircon crystallization peaks (~ 347 Ma, ~ 333 Ma). The cessation of melt crystallization (~ 650 °C) happened ~ 334 ± 4 Ma ago, as indicated by the age of the “normal and long prismatic” zircons. Further confirming this statement, they are embedding in their rims the eutectic mineral assemblage. A Cretaceous post-magmatic event was identified according to slightly discordant U–Pb ages for the Mórágy pluton.

AB - In situ U–Pb analyses were performed on SEM-BSE, SEM-CL and Raman mapped zircons from the Variscan granitoids exposed in the Mórágy pluton, Hungary. However, the routinely used LA-ICP-MS could result only in reliable age constraints if the system was not overprinted by multiple geological processes that affect the isotope system of zircons. To overcome the ambiguities the new zircon U–Pb age data were evaluated carefully, first using simple statistical models, then a zircon internal texture related complex approach was applied. This method demonstrates that the U–Pb age in overprinted systems correlates with the structural state; the worse structural state zones showing younger, but still concordant ages. Individual zircon internal texture and structural state based evaluation made it possible to select the least overprinted age components of the system and identify five steps in the evolution of the studied intrusive rock. The two melts (granitoid and mafic) passed the zircon U–Pb isotope closure temperature ~ 355 ± 3 Ma ago during their cooling. Crystallization of the two mingled magmas overarched the 350–340 Ma period, including two intense zircon crystallization peaks (~ 347 Ma, ~ 333 Ma). The cessation of melt crystallization (~ 650 °C) happened ~ 334 ± 4 Ma ago, as indicated by the age of the “normal and long prismatic” zircons. Further confirming this statement, they are embedding in their rims the eutectic mineral assemblage. A Cretaceous post-magmatic event was identified according to slightly discordant U–Pb ages for the Mórágy pluton.

KW - Metamorphic overprinting

KW - Mórágy granitoid

KW - Tisza Mega-unit

KW - U–Pb concordance

KW - Zircon structural state

UR - https://www.scopus.com/pages/publications/85150636256

U2 - 10.1007/s00710-023-00817-2

DO - 10.1007/s00710-023-00817-2

M3 - Article

AN - SCOPUS:85150636256

SN - 0930-0708

VL - 117

SP - 663

EP - 683

JO - Mineralogy and Petrology

JF - Mineralogy and Petrology

IS - 4

ER -

Interpretation of wide zircon U–Pb age distributions in durbachite-type Variscan granitoid in the Mórágy Hills

Abstract

Funding

Austrian Fields of Science 2012

Keywords

Access to Document

Other files and links

Fingerprint

Cite this