Geology and geochemistry of the Palaeozoic plutonic bodies of the Trans-Altay Gobi, SW Mongolia: implications for magmatic processes in an accreted volcanic-arc system
Three geological domains (Gobi Tien Shan, Shargyn Gobi and Trans-Altay) have been distinguished in the Trans Altay Gobi (SW Mongolia) consolidated during the Carboniferous and intruded by numerous plutons of the Devonian, Carboniferous and Permian ages. According to relationship to the Variscan orogenic cycle, pre-orogenic, syn-orogenic and post-orogenic intrusive bodies have been recognized. A pre-orogenic phase is represented by the Gurvan Khar Massif composed of geochemically primitive granodiorites that are geologically related to the relics of the Silurian-Devonian oceanic crust in the Zoolen Terrane (Shargyn Gobi Domain). Calc-alkaline intrusive rocks of I-type in the Gobi Tien Shan and Naran Sevest intrusive complexes exposed in the Gobi Tien Shan Domain are syn-orogenic to post-orogenic. Laser ablation U-Pb ICP-MS dating on zircon yielded an Early Carboniferous age for the Zamyn Belgekh Pluton, representing the largest plutonic body in this domain. Other plutons (Bayan Ayrag, Trans-Altay and Ikh Bayan) are of high-K chemistry, have Late Carboniferous to Permian age and are clearly post-orogenic. Minor gabbro massifs and small oval bodies of granites of the Ikh Bayan Massif in the Baytag Terrane (Shargyn Gobi Domain) are spatially related to the Trans-Altay shear zone of Late Carboniferous to Permian age. This zone accommodated dextral lateral movements between the Shargyn Gobi and Trans-Altay domains.
SNIP (Scopus, 2015): 0.700
IF (ISI, 2015): 1.326
Policy: Open Access