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The Proterozoic pre-Ediacaran metamorphie basement of the southern Tajik(North Afghanistan) continental block and the adjacent Band-e-Bayan zone is exposed in the Ghor Province of Central Afghanistan.It is predominantly composed of the EW-striking supracrustal succession consisting of interbedded felsic schists and gneisses(metapsammites).amphibolites(metabasalts),calcite and dolomite marbles.The metamorphie facies changes from greenschist in the Band-e-Bayan zone to amphibolite facies in the Tajik block.The supracrustal rocks of the Band-e-Bayan zone and Tajik block possess common features suggesting that the former represents a tectonized part of the latter.The geochemical characteristics of metapsammites indicate derivation of the clastic material from a continental arc and,partly from a passive continental margin,whereas the composition of metabasalts suggests their possible formation in a continental rift basin.The tectonic setting of supracrustal unit could be interpreted as a back-arc type basin.We presume that the Tajik microcontinent split off the Gondwana supercontinent along an ancient rift zone during the late Paleozoic.
The Proterozoic pre-Ediacaran metamorphie basement of the southern Tajik (North Afghanistan) continental block and the adjacent Band-e-Bayan zone is exposed in the Ghor Province of Central Afghanistan. It is predominantly composed of the EW-striking supracrustal succession consisting of interbedded felsic schists and gneisses (metapsammites) .amphibolites (metabasalts), calcite and dolomite marbles. The metamorphie facies changes from greenschist in the Band-e-Bayan zone to amphibolite facies in the Tajik block. The supracrustal rocks of the Band-e-Bayan zone and Tajik block possess common features suggesting that the former represents a tectonized part of the latter. The geochemical characteristics of metapsammites indicate derivation of the clastic material from a continental arc and, partly from a passive continental margin, whereas the composition of metabasalts suggests their possible formation in a continental rift basin. The tectonic setting of supracrustal unit could be interpreted as a ba ck-arc type basin. We presume that the Tajik microcontinent split off the Gondwana supercontinent along an ancient rift zone during the late Paleozoic.