53 ABSTRACT Unmanned aerial vehicles (UAVs) or drones have revolutionized scientific research in multiple fields. Drones provide us multiple advantages over conventional geological mapping or high-altitude remote sensing methods, in which they allow us to acquire data more rapidly of inaccessible or risky outcrops, and can connect the spatial scale gap in mapping between manual field techniques and airborne, high- altitude remote sensing methods. Despite the decreased cost and technological developments of platforms, sensors and software, the use of drones for geological mapping in Mongolia has not yet been utilized. In this study, we present using of drone in two areas: the Chandman area in which eclogite is exposed and the Naran massif of the Khantaishir ophiolite in the Altai area. Drone yields images with high resolution that is reliable to use and reveals that it is possible to make better formulation of geological mapping. Our suggestion is that (1) Mongolian geoscientists are encouraged to add drones to their geologic toolboxes and (2) drone could open new advance of geological mapping in Mongolia in which geological map will be created in more effective and more detailed way combined with conventional geological survey on ground. Keywords: remote sensing, inaccessible outcrops, geological map ARTICLE INFO Article history: Received 1 September 2018 Accepted 26 December 2018 DRONE BRINGS NEW ADVANCE OF GEOLOGICAL MAPPING IN MONGOLIA: OPPORTUNITIES AND CHALLENGES Otgonbayar Dandar * , Atsushi Okamoto, Masaoki Uno, Undarmaa Batsaikhan, Burenjargal Ulziiburen, Noriyoshi Tsuchiya Graduate School of Environmental Studies, Tohoku University, Japan *Corresponding author. Email: Otogo@geokankyo.tohoku.ac.jp Dandar et al. Mongolian Geoscientist 47 (2018) 53-57 DOI: https://doi.org/10.5564/mgs.v0i47.1063 Mongolian Geoscientist © The Author(s). 2017 Open access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and source, provide a link to the Creative Commons license, and indicate if changes were made. INTRODUCTION In the last decade, unmanned aerial vehicles (UAVs) or drones have become widely available for use in a broad range of disciplines (Watts et al., 2012). Drones are reforming scientific research in multiple fields including detailed geological mapping (Piras et al., 2017), environmental science (e.g. Mlambo et al., 2017), forestry (e.g. Sankey et al., 2017), geological education (Jordan, 2015), geothermal research (e.g. Nishar et al., 2016), hydrology (Bandini et al., 2017), natural hazards (e.g. Mateos et al., 2017), structural geology (e.g. Bemis et al., 2014) and etc. Geological mapping is a complex and time-consuming activity, especially when performing in mountain area (e.g., Joyce et al., 2014). Expert geologists can accomplish ground mapping but they do not Scientific communication