Abstract
A regional shear zone developed during a late stage of the Variscan orogeny in the Moragy Hills, SE Mecsek Mts., Tisza Unit, Hungary. This shear zone brought in contact a Variscan granite suite of Moldanubian lithological affinity (Moragy Granitoid) and a regional metamorphic series (Ofalu series) in which different lithologies with various metamorphic grades are interlaced, displaying a broad range of deformational microtextures. Polyphase garnet-bearing ultramylonites are for the first time petrologically described from this shear zone. Splintery cores of idioblastic garnets are interpreted as relic porphyroclasts from precursor gneiss. Their strongly varying chemical composition indicates amphibolite facies conditions for the parent rock. A new idioblastic garnet generation around these cores reflects compositional growth zoning with a contrasting, homogeneous chemistry pointing to equilibrium conditions. Mineral parageneses and thermobarometric calculations indicate 5.7-6.3 kbar and 450°C peak postkinematic conditions. According to the 40Ar/39Ar analyses on whole rock and biotite-rich concentrates this shearing event took place between 3030 Ma (maximum age) and 270 Ma.
| Original language | English |
|---|---|
| Pages (from-to) | 65-84 |
| Number of pages | 20 |
| Journal | Acta Geologica Hungarica |
| Volume | 43 |
| Issue number | 1 |
| Publication status | Published - 2000 |
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ASJC Scopus subject areas
- Geology
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Late Variscan ultramylonite from the Moragy Hills, SE Mecsek Mts., Hungary. / Lelkes-Felvari, Gy; Frank, W.; Árkai, P.; Nagy, G.
In: Acta Geologica Hungarica, Vol. 43, No. 1, 2000, p. 65-84.Research output: Article
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TY - JOUR
T1 - Late Variscan ultramylonite from the Moragy Hills, SE Mecsek Mts., Hungary
AU - Lelkes-Felvari, Gy
AU - Frank, W.
AU - Árkai, P.
AU - Nagy, G.
PY - 2000
Y1 - 2000
N2 - A regional shear zone developed during a late stage of the Variscan orogeny in the Moragy Hills, SE Mecsek Mts., Tisza Unit, Hungary. This shear zone brought in contact a Variscan granite suite of Moldanubian lithological affinity (Moragy Granitoid) and a regional metamorphic series (Ofalu series) in which different lithologies with various metamorphic grades are interlaced, displaying a broad range of deformational microtextures. Polyphase garnet-bearing ultramylonites are for the first time petrologically described from this shear zone. Splintery cores of idioblastic garnets are interpreted as relic porphyroclasts from precursor gneiss. Their strongly varying chemical composition indicates amphibolite facies conditions for the parent rock. A new idioblastic garnet generation around these cores reflects compositional growth zoning with a contrasting, homogeneous chemistry pointing to equilibrium conditions. Mineral parageneses and thermobarometric calculations indicate 5.7-6.3 kbar and 450°C peak postkinematic conditions. According to the 40Ar/39Ar analyses on whole rock and biotite-rich concentrates this shearing event took place between 3030 Ma (maximum age) and 270 Ma.
AB - A regional shear zone developed during a late stage of the Variscan orogeny in the Moragy Hills, SE Mecsek Mts., Tisza Unit, Hungary. This shear zone brought in contact a Variscan granite suite of Moldanubian lithological affinity (Moragy Granitoid) and a regional metamorphic series (Ofalu series) in which different lithologies with various metamorphic grades are interlaced, displaying a broad range of deformational microtextures. Polyphase garnet-bearing ultramylonites are for the first time petrologically described from this shear zone. Splintery cores of idioblastic garnets are interpreted as relic porphyroclasts from precursor gneiss. Their strongly varying chemical composition indicates amphibolite facies conditions for the parent rock. A new idioblastic garnet generation around these cores reflects compositional growth zoning with a contrasting, homogeneous chemistry pointing to equilibrium conditions. Mineral parageneses and thermobarometric calculations indicate 5.7-6.3 kbar and 450°C peak postkinematic conditions. According to the 40Ar/39Ar analyses on whole rock and biotite-rich concentrates this shearing event took place between 3030 Ma (maximum age) and 270 Ma.
KW - Ar/Ar analyses
KW - Greenschist facies metamorphism
KW - Mecsek Mts., Hungary
KW - Mineral chemistry
KW - Thermobarometry
KW - Ultramylonite
UR - http://www.scopus.com/inward/record.url?scp=0033826925&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033826925&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0033826925
VL - 43
SP - 65
EP - 84
JO - Central European Geology
JF - Central European Geology
SN - 1788-2281
IS - 1
ER -