Open AccessCarboniferous continental margin mafic-ultramafic sheeted dyke complex in the West Magnitogorsk zone (Southern Urals)
Author(s) -
А. В. Рязанцев,
И. А. Новиков,
А. А. Разумовский
Publication year - 2019
Publication title -
izvestiâ vysših učebnyh zavedenij. geologiâ i razvedka
Language(s) - English
Resource type - Journals
eISSN - 2618-8708
pISSN - 0016-7762
DOI - 10.32454/0016-7762-2019-3-42-50
Subject(s) - geology , gabbro , mafic , geochemistry , ultramafic rock , ordovician , devonian , petrology , continental margin , rift , precambrian , carboniferous , amphibole , basalt , paleontology , tectonics , quartz , structural basin
In the West of the aHochthon of Magnitogorsk zone thrusted onto the Precambrian complexes of the Uraltau zone, the Devonian island-arc complexes overlap stratigraphicalry the Ordovician and Silurian chert-basalt sequences and serpentine melange. Melange and Ordovician strata are intruded by dyke swarms and sheeted dykes («dyke in dyke») which are composed of mafic and ultramafic rocks. The dykes, composed by gabbro-dolerite, amphibole K-feldspar gabbro, hornblendite, picrite and lamprophyre, predominate. The composition of the ultramafic rocks corresponds to the composition of picrite and komatiite. The 40Ar/39Ar age of the magmatic amphibole from gabbro is 357 ± 8 m.y. The formation of dykes is related to the Early Carboniferous rift-related magmatism on an active continental margin.