Paleo-shoreline changes in moraine dammed lake Khagiin Khar, Khentey Mountains, Central Mongolia
- 9 Downloads
The formation and evolution of glacier moraine-dammed lakes are closely related to past glacier expansion and retreat. Geomorphic markers such as lacustrine terraces and beach ridges observed in these lakes provide important evidence for regional paleoenvironment reconstruction. We document the magnitude of paleo-shoreline fluctuations and timings of highstands of lake water by using cosmogenic 10Be surface exposure dating and optically stimulated luminescence (OSL) dating on samples collected from lacustrine sediment and bedrock strath in Lake Khagiin Khar. The lake was initially impounded by glacier moraine at the Global Last Glacial maximum (gLGM; 21–19 ka), and the lake reached its maximum paleo-shoreline level of 1840 m at sea level (a.s.l.). At that time, the stored lake water amount was up to seven times greater and the surface area was three times larger than the present values. The paleolake experienced higher shoreline levels at 1832, 1822, and 1817 m a.s.l. and reached the present lake level after 0.4 ka. We interpret that decrease in the paleolake level was caused by spillover. The increase in melt water after the gLGM and the Late Glacial exceeded the storage threshold of the lake, and the paleolake water overflowed across the lowest drainage divides. The lake spilled over across the lowest bedrock ridge at 15.9 ± 0.6 ka, and the outlet was incised since that time at a rate of 3.72 ± 0.15 mm/yr. The initial stream of the Khiidiin Pass River was disturbed by LGM moraine damming and was rerouted into the present course running through moraine after the spillover at 15.9 ± 0.6 ka.
KeywordsMoraine-dammed lake Lake Khagiin Khar Shoreline Spillover 10Be exposure dating
Unable to display preview. Download preview PDF.
This work was supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (grant NRF-2018S1A5A2A01031348 awarded to Y.B. Seong). We express sincere thanks to two anonymous reviewers for their constructive and helpful comments.
- Adamiec G, Aitken MJ (1998) Dose-rate convertion factors: Ancient TL 16: 37–50.Google Scholar
- Aitken MJ (1985) Thermoluminescence Dating. London: Academic Press.Google Scholar
- Batima P, Natsagdorj L, Gombluudev P, et al. (2005) Observed climate change in Mongolia. Assessments of Impact and Adaptations to Climate Change (AIACC) Working Papers 12: 1–26.Google Scholar
- Costa JE, Schuster RL (1988) The formation and failure of natural dams. Geological Society of America Bulletin 100: 1054–1068. https://doi.org/10.1130/0016-7606(1988)100<1054:TFAFON>2.3.CO;2 CrossRefGoogle Scholar
- Hilbig W (1995) The vegetation of Mongolia: SPB Academic Publishing, Amsterdam.Google Scholar
- Kelty TK, Yin A, Dash B, et al. (2008) Detrital-zircon geochronology of Paleozoic sedimentary rocks in the Hangay-Hentey basin, north-central Mongolia: Implications for the tectonic evolution of the Mongol-Okhotsk Ocean in central Asia. Tectonophysics 451: 290–311. https://doi.org/10.1016/j.tecto.2007.11.052 CrossRefGoogle Scholar
- Khandsuren P, Seong YB, Oh JS, et al. (2019) Late Quaternary glacial history of the Khentey Mountains, central Mongolia. Boreas (in press): https://doi.org/10.1111/bor.12386. ISSN 0300-9483.
- Lehmkuhl F, Lang A (2001) Geomorphological investigations and luminescence dating in the southern part of the Khangay and the Valley of the Gobi Lakes (Central Mongolia). Journal of Quaternary Science 16: 69–87. https://doi.org/10.1002/1099-1417(200101)16:1<3C69::AID-JQS583>3E3.0.CO;2-OCrossRefGoogle Scholar
- Limnological catalog of Mongolian lakes (2018) Mongolian Lakes Project. https://doi.org/www.geodata.es/mongolian_lakes/map/mongolia-map.php?lang=en Google Scholar
- Mejdahl V (1979) Thermoluminescence dating: Beta-dose attenuation in quartz grains. Archaeometry 21: 61–72. https://doi.org/10.1111/j.1475-4754.1979.tb00241.x CrossRefGoogle Scholar
- MLDB (2014) Seenkataster 2.0. Mongolian Lake Data Base. https://doi.org/www.monnature.org/MOLARE/Different_Topics/Eintrage/2014/4/25_Mongolian_Lake_Data_Base.html (Accessed on February 2019)Google Scholar
- MS map (2019) Microsoft map for windows (Accessed on January 2019)Google Scholar
- Murray AS, Olley JM (2002) Precision and accuracy in the optically stimulated luminescence dating of sedimentary quartz: A stats review. Geochronometria 21: 1–16.Google Scholar
- NAGG (1969) Topographic map of Mongoila 1:100000. National Agency of Geodesy and Cartography.Google Scholar
- O’Connor JE, Baker VR (1992) Magnitudes and implications of peak discharges from glacial Lake Missoula. Geological Society of America Bulletin 104: 267–279. https://doi.org/10.1130/0016-7606(1992)104<3C0267:MAIOPD>3E2.3.CO;2. CrossRefGoogle Scholar
- Schneider U, Becker A, Finger P, et al. (2016) GPCC full data reanalysis version 7.0: Monthly land-surface precipitation from rain gauges built on GTS based and historic data. Research data archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory.Google Scholar
- Tomurtogoo O (1999) Geological map of Mongolia. Map Scale 1.Google Scholar
- Walther M, Enkhjargal V, Gegeensuvd Ts, et al. (2016) Environmental changes of Orog Nuur (Bayan Khongor Aimag, South Mongolia) lake deposits, paleo-shorelines and vegetation history. Erforschung biologischer Ressourcen der Mongolei 13: 37–57.Google Scholar