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P-T estimation of the metamorphism of gabbro to garnet amphibolite at Herrestad, Eastern Segment of the Sveconorwegian orogen

Karlstedt, Filippa (2017) In Dissertations in Geology at Lund University GEOR02 20171
Department of Geology
Abstract (Swedish)
Målet med denna studie åir att bestämma tryck och temperatur ftir en del av det Östra Segmentet
i Svekonorvegiska Provinsen. Henestad metabasiten består dels av gabbro och dels av metamorf granatamfibolit.
Gradvisa övergångar mellan dessa ändled kan observeras över korta avståLnd (dm-m). Stuffer fiån två olika områden
togs lor analys. Båda är granatamfiboliter, men W23 har stöme granater (6 mm) och FKI -50C2 innehåller dessutom titanit. Flera olika metoder anvâncles ftir att bestämma tryck och temperatur. För geotermobarometri användes
GTB och TWQ, vilka gav resultaten 600--630"C vid 8-10 kbar respektive 625475"C vid 8-10 kbar. Termodynamisk modellering giordes med Theriak-Domino. Resultatet blev ett stort stabilitetsfÌilt med möjliga... (More)
Målet med denna studie åir att bestämma tryck och temperatur ftir en del av det Östra Segmentet
i Svekonorvegiska Provinsen. Henestad metabasiten består dels av gabbro och dels av metamorf granatamfibolit.
Gradvisa övergångar mellan dessa ändled kan observeras över korta avståLnd (dm-m). Stuffer fiån två olika områden
togs lor analys. Båda är granatamfiboliter, men W23 har stöme granater (6 mm) och FKI -50C2 innehåller dessutom titanit. Flera olika metoder anvâncles ftir att bestämma tryck och temperatur. För geotermobarometri användes
GTB och TWQ, vilka gav resultaten 600--630"C vid 8-10 kbar respektive 625475"C vid 8-10 kbar. Termodynamisk modellering giordes med Theriak-Domino. Resultatet blev ett stort stabilitetsfÌilt med möjliga tryck och temperaturer, men isolinjer for uppmätta värden av mineralens sammansättningar korsade vid ungefÌir 690'C och 9.5
kbar. Det titanit-ftirande provet analyserades med Laser Ablation Inductively Coupled Plasma Mass Spectrometry
(LA-ICP-MS) for zirconium och andra spårämnen. Tillämpning av Zr-i-titanit termometern gav 656--724"C ftir ett
tryck av 8-9.5 kbar. Flera av dessa temperaturvärden är högre än smälttemperaturen lor granit i ett vattenmättat
system. Vatten har troligtvis infiltrerat vid deformation och orsakat omkristalliseringen till amftbolit, men graniten
runt om har inte smält och därfor kan temperaturen inte vara allt ftir hög. Uppskattningsvis är ftirhållandena 610
+40"C oclr 9 +0.5kbar. Datering av metamorf zirkon (Beckman et al. 2017) har givit 970 +7Ma, medan U-Pbdatering av titaniterna i denna studie gav 922 +28 Ma och tolkas som en avkylningsålder. (Less)
Abstract
This study presents the results of P-T estimation of amphibolite facies rocks in the
Eastern Segment of the Sveconorwegian orogen. The investigated Hìrrestad metabasite consists of both unmetamorphosed gabbro and metamorphosed gamlet amphibolite and gradual transitions over a few meters between these end-members. Trio sampl.s *".e collectåd and used in
this study._!ample.W23 i¡ an amphibolite with 6 mm porphyrôblastic garnets. The other sample (FK1-50C2) with smaller garnets is titanite-bearing.^P-t éstimation ívas made using several
methods. Geothermot_arometry using the program GTÞ gave 600-630'C and 8-10 kbãr, while
IWq gave 625-675oC and 8-10 kbar. Thèrmodynamic modelling with Theriak-Domino gave a
large stability_ field, with... (More)
This study presents the results of P-T estimation of amphibolite facies rocks in the
Eastern Segment of the Sveconorwegian orogen. The investigated Hìrrestad metabasite consists of both unmetamorphosed gabbro and metamorphosed gamlet amphibolite and gradual transitions over a few meters between these end-members. Trio sampl.s *".e collectåd and used in
this study._!ample.W23 i¡ an amphibolite with 6 mm porphyrôblastic garnets. The other sample (FK1-50C2) with smaller garnets is titanite-bearing.^P-t éstimation ívas made using several
methods. Geothermot_arometry using the program GTÞ gave 600-630'C and 8-10 kbãr, while
IWq gave 625-675oC and 8-10 kbar. Thèrmodynamic modelling with Theriak-Domino gave a
large stability_ field, with isolines of almandine, þyrope and albite-intersecting at 690"C uñ¿ q.S
kbar. Trace element_a¡alysis was made with fasèr ÁUtation Inductively Coípled plasma Mass
Spectrometry (LA-ICP-MS) on the sample with titanite. The temperature was calculated using
Zhconium in titanite^thermometry to be 656-724"C. These temperatures are generally highei
than the wet solidus _for granite. Hydraulic fluids were present anà caused the añrphibolitizaiion
of some parts of the Hemestad gabbro. Sunounding granitic gneisses have not und.rgor," partial
melting which implies that the temperature must hãvl been ãround 630"C at 8 kbar ór 60^0.C at l0 kbar. Thepreferred estimate estimation is 610 +40"C and 9 +O.skbar. The metamorphiczir-
:9n i. 970 +7Ma (Beckman et al.2017) U-Pb dating of titanite in rhis study yieldedbZZ +Zt
Ma, interpreted as dating cooling. (Less)
Please use this url to cite or link to this publication:
author
Karlstedt, Filippa
supervisor
organization
alternative title
Bestämning av tryck och temperatur under metamorfos av gabbro till granatam{ibolit i Herrestad, Småland, Svekonorvegiska provinsen
course
GEOR02 20171
year
type
H2 - Master's Degree (Two Years)
subject
publication/series
Dissertations in Geology at Lund University
report number
520
language
English
id
8966347
date added to LUP
2019-01-11 15:52:52
date last changed
2019-01-11 15:52:52
@misc{8966347,
  abstract     = {This study presents the results of P-T estimation of amphibolite facies rocks in the
Eastern Segment of the Sveconorwegian orogen. The investigated Hìrrestad metabasite consists of both unmetamorphosed gabbro and metamorphosed gamlet amphibolite and gradual transitions over a few meters between these end-members. Trio sampl.s *".e collectåd and used in
this study._!ample.W23 i¡ an amphibolite with 6 mm porphyrôblastic garnets. The other sample (FK1-50C2) with smaller garnets is titanite-bearing.^P-t éstimation ívas made using several
methods. Geothermot_arometry using the program GTÞ gave 600-630'C and 8-10 kbãr, while
IWq gave 625-675oC and 8-10 kbar. Thèrmodynamic modelling with Theriak-Domino gave a
large stability_ field, with isolines of almandine, þyrope and albite-intersecting at 690"C uñ¿ q.S
kbar. Trace element_a¡alysis was made with fasèr ÁUtation Inductively Coípled plasma Mass
Spectrometry (LA-ICP-MS) on the sample with titanite. The temperature was calculated using
Zhconium in titanite^thermometry to be 656-724"C. These temperatures are generally highei
than the wet solidus _for granite. Hydraulic fluids were present anà caused the añrphibolitizaiion
of some parts of the Hemestad gabbro. Sunounding granitic gneisses have not und.rgor," partial
melting which implies that the temperature must hãvl been ãround 630"C at 8 kbar ór 60^0.C at l0 kbar. Thepreferred estimate estimation is 610 +40"C and 9 +O.skbar. The metamorphiczir-
:9n i. 970 +7Ma (Beckman et al.2017) U-Pb dating of titanite in rhis study yieldedbZZ +Zt
Ma, interpreted as dating cooling.},
  author       = {Karlstedt, Filippa},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {P-T estimation of the metamorphism of gabbro to garnet amphibolite at Herrestad, Eastern Segment of the Sveconorwegian orogen},
  year         = {2017},
}