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| Titel |
Preliminary structural and geochemical data from the Serbo-Macedonian massif (south Serbia, southwest Bulgaria and Macedonia) |
| VerfasserIn |
Milorad Antic, Alexandre Kounov, Branislav Trivić, Irena Peytcheva, Albrecht Von Quadt, Ianko Gerdjikov, Todor Serafimovski, Goran Tasev |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250053886
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| Zusammenfassung |
| The last twenty years brought a significant amount of new knowledge concerning the
palaeographic position and tectonic evolution of a number of crystalline terrains (e.g. Tisza,
Rhodopes) previously considered to be ancient micro-continents trapped within the Alpine
orogenic belt. These recent works revealed that such terrains are complex collages of
reworked continental (and locally oceanic) crust and sediments actively involved in several
phases of Alpine deformation. Among these terrains, the position of the Serbo-Macedonian
massif (SMM), outcropping in eastern Serbia, southwest Bulgaria, Macedonia, and partially
in Greece, however still remains enigmatic. Its affiliation to European or African plate
basement is still questionable due to the lack of reliable geochronological dating and detailed
structural investigation of its boundaries. This massif is a key area to understand the
bipolarity of the Alpine orogenic system including the northeast-vergent eastern Alps
and Carpathians, and the southwest-vergent Dinarides and Hellenides as well as
the interaction of the Pannonian and Aegean back-arc extension during Cenozoic
time. Moreover, recent studies in the Greek part of the massif reveal a complicated
metamorphic and tectonic history, including an intense Alpine overprint which shows
that probably the Serbo-Macedonian massif does not present one-single tectonic
unit.
Our new project is aiming to unravel the origin of the crystalline basement of the
Serbo-Macedonian massif by determining its protolith age and resolving its complicated
tectonic evolution. For this purpose detailed structural studies and mapping will be combined
with a wide range of isotope-geochemical and geochronological methods including
U/Pb, 40Ar/39Ar and fission-track analyses of basement rocks as well as clastic
sediments.
Our preliminary field data provide structural evidence for the existence of at least two
deformational phases present in both, the Upper (low-grade) and the Lower (high-grade),
units of the SMM. The first phase is related to the formation of isoclinal folds and generally
eastward dipping foliation, whereas the second one is presented by open folds with vertical
axial cleavage. The sense-of-shear criteria related to the first phase indicate general
top-to-east shear.
Geochemical analysis of twenty five igneous and metamorphic rock samples from SE
Serbia and NE Macedonia give evidences for at least two different magma sources for the
magmatics of the region. Basalts derived layered amphibolites and undeformed
diabases show a distinctive MORB tholeitic signature while the plutonic rocks which
intrude this volcano-sedimentary succession, belong to a volcanic arc environment. |
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