Kherlen River

{{Short description|River in China and Mongolia}} {{Infobox river | name = Kherlen River | native_name ={{native name|mn|Хэрлэн гол}} | name_other = {{Lang|zh|克鲁伦河}} (Kèlǔlún hé) | name_etymology = Mongolian: kherlen, "hederated"  | image = Kherlen_River.jpg | image_size = | image_caption = Near Ondorkhaan | map = Kherlenrivermap.png | map_size = | map_caption = | pushpin_map = | pushpin_map_size = | pushpin_map_caption = | mapframe = yes | mapframe-zoom = 5  | subdivision_type1 = Country | subdivision_name1 = Mongolia, People's Republic of China | subdivision_type2 = Mongolian Aimags | subdivision_name2 = Khentii, Dornod | subdivision_type3 = Chinese Region | subdivision_name3 = Inner Mongolia | subdivision_type4 = Chinese Prefecture | subdivision_name4 = Hulunbuir | subdivision_type5 = | subdivision_name5 =  | length = {{convert|1254|km|mi|abbr=on}} | width_min = | width_avg = | width_max = | depth_min = | depth_avg = | depth_max = | discharge1_location= | discharge1_min = | discharge1_avg = | discharge1_max =  | source1 = | source1_location = Burkhan Khaldun, Khentii Mountains | source1_coordinates= | source1_elevation = | mouth = Hulun Nuur | mouth_location = | mouth_coordinates = {{coord|48|44|N|117|5|E|display=inline,title}} | mouth_elevation = | progression = | river_system = | basin_size = | tributaries_left = | tributaries_right = | custom_label = | custom_data = | extra = }}

'''Kherlen River''' (also known as '''Kerülen'''; {{Langx|mn|Хэрлэн гол}}; {{Lang-zh|c=克鲁伦河|p=Kèlǔlún hé}}) is a 1,254 km river in Mongolia and China.<ref name="Brutsaert">{{cite journal |last1= Brutsaert |first1= Wilfried |author1-link=  |last2= Sugita |first2= Michiaki |title= Is Mongolia's groundwater increasing or decreasing? The case of the Kherlen River basin |journal= Hydrological Sciences Journal |volume= 53 |issue= 6 |pages= 1221–1229 |publisher= Taylor & Francis Informa Ltd |location= London |date= December 2008 |url= https://zenodo.org/record/896803 |doi= 10.1623/hysj.53.6.1221 |s2cid= 128674944 |access-date= 19 January 2015 |doi-access= free }}</ref> It is also one of the two longest rivers in Mongolia, along with the Orkhon River.<ref name=":0">{{Cite book |editor-last= Yembuu |editor-first= Batchuluun |date= 2021 |title= The Physical Geography of Mongolia |location= Cham |publisher= Springer International Publishing |series= Geography of the Physical Environment |language= en |doi= 10.1007/978-3-030-61434-8 |isbn= 978-3-030-61433-1 |url= https://link.springer.com/10.1007/978-3-030-61434-8 }}</ref>

==Course== The river originates in the south slopes of the Khentii mountains,<ref name=":0"/> near the Burkhan Khaldun mountain in the Khan Khentii Strictly Protected Area, about {{convert|180|km|mi|0|disp=or}} northeast of Ulaanbaatar.<ref name="Brutsaert"/> This area constitutes the divide between the Arctic (Tuul River) and Pacific (Kherlen, Onon) basins and is consequently named "Three River Basins".

From there the Kherlen flows in a mostly eastern direction through the Khentii ''aimag''. Further downriver, it crosses the eastern Mongolian steppe past Ulaan Ereg and Choibalsan, entering China at {{Coord|48|3|N|115|36|E|}} and emptying into Hulun Nuur after another {{convert|164|km|mi|0|disp=or}}.

The mean streamflow of Kherlen River has decreased by more than a half from 2000 to 2008 when compared with prior decades.<ref>{{cite journal |last1= Orkhonselenge |first1= Alexander |last2= Bulgan |first2= Odmaa |date= 2021 |title= Geochemical studies and lacustrine geomorphology of Lake Yakhi basin in eastern Mongolia |journal= Géomorphologie |volume= 27 |issue= 3 |pages= 231–242 (see section 5.2. "Changes in lake area", § 33) |doi= 10.4000/geomorphologie.15873 }}</ref>

===Kherlen-Ergune-Amur=== In years with high precipitation, the normally exitless Hulun Lake may overflow at its northern shore, and the water will meet the Ergune River after about {{convert|30|km|mi|0|disp=or}}.<ref name="Brutsaert"/> The Ergune marks the border between Russia and China for about {{convert|944|km|mi|0|disp=or}}, until it meets the Amur River. The system Kherlen-Ergune-Amur has a total length of {{convert|5,052|km|mi|0|disp=or}}.

== Soda lakes, uranium and associated geology ==

Near the city of Choibalsan in the Dornod province (far Northeast Mongolia), the Kherlen river feeds several soda lakes,<ref> {{cite journal |last1= Linhoff |first1= Benjamin S. |last2= Bennett |first2= Philip C. |last3= Puntsag |first3= Tamir |last4= Gerel |first4= Ochir |date= March 2011 |title= Geochemical evolution of uraniferous soda lakes in Eastern Mongolia |journal= Environmental Earth Sciences |volume= 62 |issue= 1 |pages= 171–183 (see Abstract) |doi= 10.1007/s12665-010-0512-8 |url= https://www.researchgate.net/publication/227280613_Geochemical_evolution_of_uraniferous_soda_lakes_in_Eastern_Mongolia |access-date= 2024-07-18 |hdl= 2152/43997 |hdl-access= free }} </ref> located (geologically) in the north Kerulen Block{{efn| In the new tectonic division of Mongolia, the Kerulen block is the new name for what used to be called the Ereendavaa block. It extends eastward into Russia and northeast China and connects with the Erguna Block.<ref>{{cite journal |last1= Zhao |first1= Pan |last2= Jia |first2= Zhenhua |last3= Xu |first3= Bei |last4= Xu |first4= Yan |last5= Sukhbaatar |first5=Turbold |last6= Appel |first6= Erwin |last7= Chen |first7= Yan |date= August 2023 |title= Late Triassic initial closure of the Mongol-Okhotsk Ocean in the western segment: Constraints from sedimentological, detrital zircon ages and paleomagnetic evidence |journal= Gondwana Research |volume= 125 |issue= 1 |pages= 9 |doi= 10.1016/j.gr.2023.08.007 |url= https://insu.hal.science/insu-04191545/file/1-s2.0-S1342937X23002216-main.pdf |access-date= 2024-07-25 }}</ref> }} of the Central Mongolian Fold System.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 3 |loc= "Introduction" > "Regional geology" }} They are closed lakes fed by groundwater,{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 4 |loc= "Introduction" > "Uranium geochemistry" }} with hardly any surface inflow or outflow,{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 10 |loc= "Discussion" > "Evolution of lakes" }} in basins formed in basalt, pyroclastic material and rhyolite erupted from the Choibalsan–Onon volcanic chain during the late Cretaceous;<ref name="mironov"> {{cite journal |last1= Mironov |first1= Y |date= 2006 |title= Uranium of Mongolia |journal= Centre for Russian and Central EurAsian Mineral Studies |location= London }} Cited in {{harvnb|Linhoff|Bennett|Puntsag|Gerel|2011|loc= "Introduction" > "Regional geology"}}. </ref> among these lakes are the Tsaidam lakes, the Gurvany lakes and the Shar Burdiin lake.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 5-6 |loc= "Results" }} The groundwater that feeds the soda lakes comes from a shallow unconfined aquifer recharged by rainfall and snowmelt, and from precipitation in the highlands north of the lakes. But the local climate is semi-arid, with only 207 mm mean annual precipitation distributed unequally throughout the year. This means that groundwater recharge is relatively rare: only the largest precipitation events and snowmelt periods result in significant recharge.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 8 |loc= "Discussion" > "Groundwater evolution" }}

The Kherlen River is the regional discharge point and also represents a hydrogeological divide for the shallow unconfined aquifer, as groundwater flows south along the topographic gradient. The lakes in their shallow closed basins act as evaporative discharge points.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 9 |loc= "Discussion" > "Groundwater evolution" }}

Several of these lakes are exceedingly rich in uranium;{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 4 and 12 |loc= "Introduction" > "Uranium geochemistry", and "Discussion" > "Uranium geochemistry" }} in one location of the Shar Burdiin lake, uranium concentration has been measured at 62.5 μM,{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 7 |loc= table 4 }}{{efn|The World Health Organization (WHO) provisional guideline value for uranium is 0.063 μM L<sup>−1</sup> (15 μg L<sup>−1</sup>).{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 6 |loc= "Results" > "Water chemistry" }} or ~15,000 ppb U{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 12 |loc= "Discussion" > "Uranium geochemistry" }} }} which may be the highest reported naturally occurring U concentration in a surface water body.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 4 |loc= "Introduction" > "Uranium geochemistry" }} Shar Burdiin is also the most highly evaporated lake.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 10 |loc= "Discussion" > "Evolution of lakes" }}

No uranium deposits have been identified within their catchment area. However, approximately 100 km north of the lakes, there are several deposits of uraninite (pitchblende) / coffinite assemblages{{efn|These uranium-rich mineral deposits, 100 km north of the lakes, were mined during the 1970s when Mongolia was aligned with the USSR. Several of the old mines were reopened during the years 2000.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 3 |loc= "Introduction" > "Regional geology" }} }} within conglomerates and sandstones.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 3 |loc= "Introduction" > "Regional geology" }} Devitrification of volcanic glass is a potential source of uranium in the region's groundwater and soda lakes.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 10 |loc= "Discussion" > "Groundwater evolution" }} Contamination may also result from large dust storms, which are frequent during the spring when the soda lakes are driest.

It has been noted that Shar Burdiin lake shows the maximum concentration in uranium (with, only a short distance away, Gurvany-2 lake not far behind in uranium concentration); and that said concentration decreases while the distance from that area increases, as seen from Tsaidam-2 lake and Gurvany-1 lake which are over 15 km from Shar Burdiin Lake. So another possibility for the contamination is that of wind-blown salts from Shar Burdiin lake and Gurvany-2 lake, reaching the lakes and groundwaters in other parts of the area.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 13 |loc= "Discussion" > "Source for uranium in soda lakes and groundwaters" }}

The Khuduu Aral, a 30 kilometre long and 20 km wide plain on the Kherlen river, is home to Genghis Khan's Ikh Aurag (palace). Nearby it there is a small lake that is high in carbonate, soda, and chlorine. Its water has a reputation for treating nerve disorders.<ref>{{cite web |title= Khuduu Aral |website= mongolian.travel |url= https://www.mongolian.travel/khuduu-aral/ |access-date= 2024-07-25 }}</ref>

In central Mongolia, a soda lake was found in 2008 to also have high amounts of uranium in its salts.{{sfn|Linhoff|Bennett|Puntsag|Gerel|2011|p= 13 |loc= "Implications" }}

== See also == * List of rivers of Mongolia

== Notes == {{notelist}}

== References == {{reflist}}

Kherulen river Category:International rivers of Asia