Internal structure of the Supragetic Unit basement in the Serbian Carpathians and its significance for the late Early Cretaceous nappe-stacking

Item

Krstekanić, Nemanja

Fault-related folds and hanging-wall structures reflect the geometry of the main thrusts in foldthrust belts. The results of the structural analysis of the Supragetic Unit metamorphic basement in eastern Serbia at map-, outcrop- and thin-section scale, and its importance for the late Early Cretaceous nappe-stacking are presented in this paper. The Supragetic Unit metamorphic basement includes various volcano-sedimentary rocks of Ordovician-Silurian protolith age. They were metamorphosed to the low greenschist facies with temperatures reaching 300–350°C and pressure reaching 0.3–0.5 GPa. The microscale studies show that quartz and albite demonstrate dominantly bulging and locally subgrain rotation recrystallisation, while chlorite, sericite and muscovite define spaced to continuous foliation recognised both at the outcrop- and the thin-section-scale. The statistical analysis based on the available map data shows low- to high-angle west-dipping foliation which is interpreted as an indicator of flat-ramp geometry of the Supragetic thrust, rather than east-vergent tight to isoclinal folding. At the thin-section scale ductile to semi-ductile C’-S structures indicate top to ESE thrusting. Subsequent kinking, recognised both at the outcrop- and the thin-section-scale, deform the older foliation. Those kink bands are the result of WNW–ESE to NW–SE compression and could represent the later stage of a continuous deformation event during which C’-S structures were formed. The youngest, brittle deformation is represented by subvertical joints with no offset recognised in thin-sections. The structural characteristics of the Supragetic Unit low-grade metamorphic basement in the studied areas, combined with tectonothermal events recognised elsewhere in Dacia mega-unit, could imply a possible initiation of the late Early Cretaceous nappe-stacking in the ductile to semi-ductile/semi-brittle domain.

Цитирање: Krstekanić, Nemanja et al., “Internal structure of the Supragetic Unit basement in the Serbian Carpathians and its significance for the late Early Cretaceous nappe-stacking” у Geološki anali Balkanskoga poluostrva(78).

Contributor

sr Đerić, Nevenka

Creator

sr Krstekanić, Nemanja
sr Stojadinović, Uroš
sr Kostić, Bojan
sr Toljić, Marinko

Date

sr 2017

Identifier

sr 10.2298/GABP1778001K

Publisher

sr University of Belgrade – Faculty of Mining and Geology,Department of Regional Geology and Department of Palaeontology

Source

sr Geološki anali Balkanskoga poluostrva

Subject

sr structural analysis
sr flat-ramp geometry
sr Supragetic Unit
sr late Early Cretaceous thrusting

Abstract

sr Fault-related folds and hanging-wall structures reflect the geometry of the main thrusts in foldthrust belts. The results of the structural analysis of the Supragetic Unit metamorphic basement in eastern Serbia at map-, outcrop- and thin-section scale, and its importance for the late Early Cretaceous nappe-stacking are presented in this paper. The Supragetic Unit metamorphic basement includes various volcano-sedimentary rocks of Ordovician-Silurian protolith age. They were metamorphosed to the low greenschist facies with temperatures reaching 300–350°C and pressure reaching 0.3–0.5 GPa. The microscale studies show that quartz and albite demonstrate dominantly bulging and locally subgrain rotation recrystallisation, while chlorite, sericite and muscovite define spaced to continuous foliation recognised both at the outcrop- and the thin-section-scale. The statistical analysis based on the available map data shows low- to high-angle west-dipping foliation which is interpreted as an indicator of flat-ramp geometry of the Supragetic thrust, rather than east-vergent tight to isoclinal folding. At the thin-section scale ductile to semi-ductile C’-S structures indicate top to ESE thrusting. Subsequent kinking, recognised both at the outcrop- and the thin-section-scale, deform the older foliation. Those kink bands are the result of WNW–ESE to NW–SE compression and could represent the later stage of a continuous deformation event during which C’-S structures were formed. The youngest, brittle deformation is represented by subvertical joints with no offset recognised in thin-sections. The structural characteristics of the Supragetic Unit low-grade metamorphic basement in the studied areas, combined with tectonothermal events recognised elsewhere in Dacia mega-unit, could imply a possible initiation of the late Early Cretaceous nappe-stacking in the ductile to semi-ductile/semi-brittle domain.

Date Available

sr 1

Date Created

sr 15

Date Accepted

sr NULL

Date Copyrighted

sr 10

Date Submitted

sr NULL

Date Issued

sr 78

Date Modified

sr 1

Spatial Coverage

sr Belgrade

Provenance

sr č292

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