1 3 Int J Earth Sci (Geol Rundsch) DOI 10.1007/s00531-015-1198-7 ORIGINAL PAPER Detrital zircon U–Pb geochronology of the Siwalik Group of the Nepal Himalaya: implications for provenance analysis Upendra Baral 1,2 · Ding Lin 1 · Deepak Chamlagain 3 Received: 20 October 2014 / Accepted: 14 May 2015 © Springer-Verlag Berlin Heidelberg 2015 a link with the Higher Himalaya and lower Lesser Hima- laya. Therefore, the provenance of the Siwalik Group in the Nepal Himalaya might have witnessed a mixed type of provenance similar to the northwestern Himalaya. Keywords U–Pb geochronology · Provenance · Siwalik Group · Nepal Himalaya Introduction The world-famous Himalayan mountain chain, extending about 2400 km from the Nanga Parbat in the west to the Brahmaputra River in the east, is a typical continent–con- tinent collision zone in between the Indian and Eurasian plates (Gansser 1964; Patriat and Achache 1984). During the course of mountain building, the sediments deposited at the northern tip of the Greater India have been reworked, recy- cled, metamorphosed and were subsequently exhumed and transported along major south-propagating thrusts (Robinson et al. 2006; Khanal and Robinson 2013). The synorogenic clastic sedimentary rocks in the foreland basin of the con- vergent tectonic system represent direct detrital input from the tectonically evolving Himalayan orogen. Sedimentologi- cal, petrologic, thermochronologic, geochronological, and geochemical studies can provide much information on sedi- mentary geology such as exhumation, fluvial environment and facies, rates of sedimentation and sediment provenance (Nakayama and Ulak 1999; Huyghe et al. 2005; Ravikant et al. 2011; Chirouze et al. 2012; Guilbaud et al. 2012). In this regard, foreland basin sediments of the Siwalik Group have been extensively studied to reconstruct the paleoge- ography (Miall 1995; DeCelles and Giles 1996; Sinclair 1997; DeCelles et al. 1998a), constrain the rate and timing of Himalayan exhumation (Dickinson 1985; DeCelles and Abstract This paper deals with the provenance analysis of the Neogene foreland basin sediments of the Siwalik Group in the Nepal Himalaya. This study adopts the techniques of the optical petrography and detrital zircon U–Pb ages from two river sections: the Koshi Nadi in eastern Nepal and the Surai Khola in western Nepal Himalaya. The optical petrography data and resulting QFL plot show a “recycled orogeny” field for the studied sandstone samples, indicat- ing northern lithotectonic units; Tethys Himalaya, Higher Himalaya and Lesser Himalaya as the source of the foreland basin sediments. The detrital zircon geochronological data set has clearly revealed that the cluster ages are younger than ~1000 Ma; however, the older grains (>1000 Ma) are significantly fewer. The obtained age spectrum is similar to the Tethys Himalaya and the upper Lesser Himalaya, but the lower Lesser Himalayan rocks were not distinct, which indi- cates that sediments in the Neogene foreland basin of the Nepal Himalaya were primarily sourced from the Tethys Himalaya and upper Lesser Himalaya. The minor subordi- nate scattered peaks that roughly correspond to the age of the Higher Himalaya and lower Lesser Himalaya may indi- cate that a lower proportion of the sediments might have Electronic supplementary material The online version of this article (doi:10.1007/s00531-015-1198-7) contains supplementary material, which is available to authorized users. * Upendra Baral upendrabaral@gmail.com 1 Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, and Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China 2 University of Chinese Academy of Sciences, Beijing, China 3 Department of Geology, Tri Chandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal