Mid-Ordovician and Late Devonian magmatism in the Togtokhinshil Complex: new insight into the formation and accretionary evolution of the Lake Zone (western Mongolia)

0459681 - GLÚ 2017 RIV CZ eng J - Journal Article
Soejono, I. - Buriánek, D. - Svojtka, Martin - Žáček, V. - Čáp, P. - Janoušek, V.
Mid-Ordovician and Late Devonian magmatism in the Togtokhinshil Complex: new insight into the formation and accretionary evolution of the Lake Zone (western Mongolia).
Journal of Geosciences. Roč. 61, č. 1 (2016), s. 5-23. ISSN 1802-6222. E-ISSN 1803-1943
Institutional support: RVO:67985831
Keywords : Central Asian Orogenic Belt * geochemistry * Lake Zone * magmatism * U-Pb zircon dating
Subject RIV: DD - Geochemistry
Impact factor: 0.609, year: 2016

New field, petrographic, geochemical and geochronological data from the Togtokhinshil Complex (western margin of the Lake Zone, Central Asian Orogenic Belt) reveal the presence of two separate Early Palaeozoic magmatic pulses: Mid-Ordovician and Late Devonian. The Mid-Ordovician (c. 460 Ma) magmatism produced various types of mafic plutonic rocks (gabbro-diorite suite) emplaced into the volcanosedimentary sequence of the Baatar Fm. Gabbros to gabbrodiorites have metaluminous and mostly low to normal-K calc-alkaline or possibly tholeiitic character. The majorand trace-element as well as Nd isotopic signatures suggest its magmatic-arc geotectonic setting and imply the derivation either exclusively from the mantle or in part from the juvenile mafic crust. The Late Devonian (c. 376 Ma) granite suite intruded the rocks of both the gabbro-diorite suite and the Baatar Fm. Granites are subaluminous and have a high-K calc-alkaline to shoshonitic character.
Permanent Link: http://hdl.handle.net/11104/0259860