Mongol Altai 50 - a Development Cooperation Project of Czech Republic with Mongolia in geology (2013-2016)

 

Vladimír Žáček, Petr Bohdálek, Eva Břízová, David Buriánek, Pavel Čáp, Enkhjargal Mijiddorj, Juraj Franců, Gelegjamts Adilbish, Alexandra Guy, Pavel Hanžl, Pavel Havlíček, Eric Henrion, Jan Hošek, Jan Jelének, Ilja Knésl, Jana Karenová, Lenka Kociánová, Jana Kotková, Zuzana Krejčí, Petr Mixa, Jan Mrlina, Vratislav Pecina, Zoltán Pécskay, Alice Prudhomme, Igor Soejono, Martin Svojtka, Zbyněk Šimůnek, Radek Škoda, Kryštof Verner, Lukáš Vondrovic, Tomáš Vorel, Stanislav Vrána, Renata Čopjaková

Geoscience Research Reports 50, 2017, pages 159–166

Full text (PDF, 2.79 MB)

Published online: 10 August 2017

Export to RIS

 

Abstract

Results of the project "Mongol Altai-50"of the Czech Development Cooperation with Mongolia, were successfully defended before the Mongolian Stratigraphic Commission in September 2016, in Ulan Bator. The project was carried out during 2013-2016, and experts from four countries participated in its implementation. The project was located in western Mongolia in the Hovd Department (???? ?????) and the districts (soums) of Munhkhairkhan, Mankhan, and Zereg (Fig. 1). The western part of the Mongolian Altai Range has a mostly character of stepped plateaus, some of which rise above 4000 m a.s.l. There is a different morphology in the lower and peripheral parts of the mountain rejuvenated by deep faults or in places with former glaciation. Rocky ridges and deep gorges and canyons originated due to intensive feedback erosion (Figs. 2a-h). Five base geological maps at a scale of 1 : 50,000 (sheets L_46_28V, L_46_28G, L_46_29V, L_46_29G and L_46_30V) covering an area of 1770 km2 were compiled during the project implementation. The field-work in Mongolia was realised during three main campaigns in 2013-2015, each year 2-3 months long (Figs. 3 a-d). The project also had an educational significance, which involved training of 19 young Mongolian geologists in the field (Figs. 4 a-d). The Final Report (Žáček et al. 2016a) presents 43 new geochronological data, new insights into petrology, geochemistry, mineralogy, structural geology, sedimentology and palaeontology, and also includes a chapter on economic geology, and 50 applied maps showing results of exploration geochemistry. A set of geological maps represents an instructive E-W profile across an area on the contact of Lake, Altai and Hovd terranes (zones), which are part of the Central Asian orogenic belt (CAOB, Badarch et al. 2002), Fig. 5. These terranes are a collage of Lower Palaeozoic volcanic arcs, accretionary wedges, and back-arc basins separated from one another by deep-seated faults. The generally NW-SE trending and relatively steeply dipping lithological contacts, deformational fabrics and morphological pattern are common geological feature of a western Mongolian Altai. Structural record in the rocks is a result of polyphase development of three ductile deformational phases portrayed in varying intensity. The youngest deformation phase is associated with penetrative hydrothermal event, which produced abundant epidote and chlorite, ubiquitous in whole research area. Previous maps of the area on the scale 1 : 200,000 were given by Luvsandanzan et al. (1999) and Baatarhuyag and Gansukh (1999), general and local stratigraphy by Ariunchimeg et al. (2012). The Lake Zone in the E of the research area is formed by mid-Cambrian volcano-sedimentary Baatar Formation. It is intruded in several stages by the Togtokhinshil Igneous Complex, the age of which was newly determined to be Middle Ordovician (gabbros and diorites), and Upper Devonian (granites), Soejono et al. (2016). Thick sequence of folded Lower Palaeozoic sediments prevails in the Hovd and Altai zones. The sediments are ascribed to Zuun Nuruu (Ordovician), Tsetseg (Silurian) and Sagsai (Lower Devonian) formations (see Fig. 5). The age of these sediments decreases generally westwards, but the stratigraphic record is complicated by strong deformation when the same part of the sequence may be repeated. The sediments occur in several developments: deep basinal (shales), common flysh, shallower calcareous flysh, minor volcano-sedimentary, and shallow psammitic. Fossils are rare and poorly preserved, and usually indicate a broader age. The following groups of fossils were found: Graptoloidea, Anthozoa, Crinoidea, Brachiopoda, Bryozoa, Cephalophoda and abundant ichnofossils.(...)