Transitioning from Svecofennian to Transcandinavian Igneous Belt (TIB) magmatism in SE Sweden: Implications from the 1.82 Ga Eksjö tonalite
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Transitioning from Svecofennian to Transcandinavian Igneous Belt (TIB) magmatism in SE Sweden : Implications from the 1.82 Ga Eksjö tonalite. / Åhäll, Karl-Inge; Connelly, James N.; Brewer, Tim S.
In: GFF, Vol. 124, No. 4, 2002, p. 217-224.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Transitioning from Svecofennian to Transcandinavian Igneous Belt (TIB) magmatism in SE Sweden
T2 - Implications from the 1.82 Ga Eksjö tonalite
AU - Åhäll, Karl-Inge
AU - Connelly, James N.
AU - Brewer, Tim S.
N1 - Funding Information: ated assistance during planning and evaluation, and to Frank Beunk, Per-Olof Persson and Joakim Mansfeld for valuable review comments. R. Kelly, E. Mansley and N. Marsh are thanked for assistance with geochemical analyses at the University of Leicester. The study was financially supported by the Geological Survey of Sweden, grant 03-1101/2000 (KIÅ).
PY - 2002
Y1 - 2002
N2 - The Eksjö intrusion forms a major tonalitic body in the Oskarshamn-Jönköping belt (OJB), SE Sweden. This is a NW-SE unit of dominantly intermediate granitoid intrusions, bound by felsic rocks of the Transscandinavian Igneous Belt (TIB). Previous U-Pb data for the Eksjö tonalite (1754±10 Ma) implied that subduction-related magmatism occurred in SE Sweden during a period of time when other data required that such magmatism had already moved further west. New U- Pb zircon dating establishes that the Eksjö tonalite crystallised at 1823±2 Ma and that subduction-related, granitoid magmatism of the OJB occurred in the 1834-1823 Ma interval. Field observations and geochemistry implies fractional crystallisation in either a continental arc or a mature island arc system. Although major portions of the Eksjö intrusion are well preserved, it is cut by NW-trending shear zones attributed to block-related movements that remained active until at least 1.80 Ga. Available constraints for the OJB support models of recurring convergent-margin tectonism along the southwestern margin of Baltica between 1.85-1.82 Ga and, hence, prior to onset of voluminous TIB 1 magmatism (1.81-1.77 Ga). Such a scenario accounts for recurring deformation in SW Finland (1.84-1.80 Ga), broadly coeval deformation in south-central Sweden, and apparent steps in Moho depths between the OJB and the pre-1.85 Ga margin of Baltica.
AB - The Eksjö intrusion forms a major tonalitic body in the Oskarshamn-Jönköping belt (OJB), SE Sweden. This is a NW-SE unit of dominantly intermediate granitoid intrusions, bound by felsic rocks of the Transscandinavian Igneous Belt (TIB). Previous U-Pb data for the Eksjö tonalite (1754±10 Ma) implied that subduction-related magmatism occurred in SE Sweden during a period of time when other data required that such magmatism had already moved further west. New U- Pb zircon dating establishes that the Eksjö tonalite crystallised at 1823±2 Ma and that subduction-related, granitoid magmatism of the OJB occurred in the 1834-1823 Ma interval. Field observations and geochemistry implies fractional crystallisation in either a continental arc or a mature island arc system. Although major portions of the Eksjö intrusion are well preserved, it is cut by NW-trending shear zones attributed to block-related movements that remained active until at least 1.80 Ga. Available constraints for the OJB support models of recurring convergent-margin tectonism along the southwestern margin of Baltica between 1.85-1.82 Ga and, hence, prior to onset of voluminous TIB 1 magmatism (1.81-1.77 Ga). Such a scenario accounts for recurring deformation in SW Finland (1.84-1.80 Ga), broadly coeval deformation in south-central Sweden, and apparent steps in Moho depths between the OJB and the pre-1.85 Ga margin of Baltica.
KW - Arc magmatism
KW - Baltica
KW - Eksjö tonalite
KW - Geochemistry
KW - Paleoproterozoic growth
KW - Sweden
KW - U-Pb geochronology
U2 - 10.1080/11035890201244217
DO - 10.1080/11035890201244217
M3 - Journal article
AN - SCOPUS:3843150730
VL - 124
SP - 217
EP - 224
JO - G F F
JF - G F F
SN - 1103-5897
IS - 4
ER -
ID: 333880935