Stages in the development of the Darhad dammed lake (Northern Mongolia) during the Late Pleistocene and Holocene

2005 ◽  
Vol 136 (1) ◽  
pp. 83-94 ◽  
Author(s):  
Sergey K. Krivonogov ◽  
Vladimir S. Sheinkman ◽  
Anatoly A. Mistruykov
2008 ◽  
Vol 69 (2) ◽  
pp. 169-187 ◽  
Author(s):  
Alan R. Gillespie ◽  
Raymond M. Burke ◽  
Goro Komatsu ◽  
Amgalan Bayasgalan

Late Pleistocene glaciers around Darhad Basin advanced to near their maximum positions at least three times, twice during the Zyrianka glaciation (at ∼ 17–19 ka and ∼ 35–53 ka), and at least once earlier. The Zyrianka glaciers were smaller than their predecessors, but the equilibrium-line altitude (ELA) difference was < 75 m. End moraines of the Zyrianka glaciers were ∼ 1600 m asl; ELAs were 2100–2400 m asl.14C and luminescence dating of lake sediments confirm the existence of paleolake highstands in Darhad Basin before ∼ 35 ka. Geologic evidence and10Be cosmic-ray exposure dating of drift suggests that at ∼ 17–19 ka the basin was filled at least briefly by a glacier-dammed lake ∼ 140 m deep. However, lake sediments from that time have not yet been recognized in the region. A shallower paleolake briefly occupied the basin at ∼ 11 ka, but between ∼ 11 and 17 ka and after ∼ 10 ka the basin was probably largely dry. The timing of maximum glacier advances in Darhad appears to be approximately synchronous across northern Mongolia, but different from Siberia and western Central Asia, supporting the inference that paleoclimate in Central Asia differed among regions.


2020 ◽  
Author(s):  
Juris Soms ◽  
Zane Egle

&lt;p&gt;In the south-western part of Jersika Plain (SE Latvia), the late Pleistocene aeolian sediments form the inland dune field located at Dviete village. This dune field with surface &gt;112 km&lt;sup&gt;2&lt;/sup&gt; represents the evidence of aeolian activity and landscape evolution during the transition from glacial to post-glacial conditions in this region. The dunes have developed on the surface of glaciolacustrine plain, where subaqueous sedimentation in the N&amp;#299;cgale ice-dammed lake took place during the retreat of glacier, the Pomeranian phase of the last glaciation.&lt;/p&gt;&lt;p&gt;Here, we focus on reconstructing paleoenvironmental conditions in this region, as inferred from landforms morphology, aeolian sand granulometry and geochemistry, and efficient wind directions derived from DEM. It will contribute to better understanding the processes of landscape evolution conditioned by last deglaciation in SE Latvia.&lt;/p&gt;&lt;p&gt;Results indicate that single parabolic dunes typically have U-shaped configuration in planar view. Aeolian landforms also link and override each other, presenting clustered groups. GIS analysis reveals that the dominating wind directions during the development of dunes would have been westerly to easterly. Previously published dates on OSL chronology for this dune field indicate the initial phase of aeolian activity at around 15.5 Ka and 14.5 Ka. Hence, when the studied landforms formed in presumably paraglacial landscape, the Scandinavian Ice Sheet (SIS) was still present, and most likely atmospheric circulation in this region was affected by anticyclone over the SIS.&lt;/p&gt;&lt;p&gt;The mean grain size&amp;#160;&lt;em&gt;M&lt;sub&gt;z&lt;/sub&gt;&lt;/em&gt; of the aeolian deposits forming inland dune field ranges between 143 &amp;#956;m and 256 &amp;#956;m. Hence aeolian landforms are composed mainly of fine-grained sands. It indicates the dominance of saltation and a balance between sand particles and comparatively low energy of local wind power during the aeolian processes. The sediments demonstrate well and moderately well sorting with &amp;#963; values between 0.473 and 0.707 phi. Granulometry elucidates symmetrical distribution of particles of different fraction with small both negative and positive skewness &lt;em&gt;Sk&lt;/em&gt; values ranging from -0.048 to 0.112 phi. For the values of kurtosis &lt;em&gt;K&lt;sub&gt;G&lt;/sub&gt;&lt;/em&gt;, results showed that sand is mainly mesokurtic.&lt;/p&gt;&lt;p&gt;Geochemical analysis points out that elemental composition is rather typical for aeolian sediments, determined by the dominance of quartz and K-silicates. Among REE elements, only Y un Nb were identified in detectable concentrations. Similar geochemical signatures across the dune field suggest the provenance of sediments from one main source, possibly associated with glaciofluvial sediment transportation by extra-glacial waters draining from the already ice-free parts of adjoining uplands to the glacial lake.&lt;/p&gt;&lt;p&gt;As apparent from the limited number of paleosoils, aeolian deposition seems to nearly instantly follow the drainage of the N&amp;#299;cgale ice-dammed lake. It is most likely that cold and dry climate in conjunction with low groundwater tables during the late Pleistocene &amp;#8211; beginning of Holocene were among the main controlling factors which prevented development of vegetation cover in this region and delayed stabilisation of the dunes. In turn, it facilitates the action of wind over glaciolacustrine plain as the main driving process of aeolian morphogenesis during the initial evolution of metastable post-glacial landscape.&lt;/p&gt;


2014 ◽  
Vol 82 (2) ◽  
pp. 430-440 ◽  
Author(s):  
Shao-Yi Huang ◽  
Yue-Gau Chen ◽  
George S. Burr ◽  
Manoj K. Jaiswal ◽  
Yunung Nina Lin ◽  
...  

AbstractWe present a reconstructed lithologic column compiled from a series of lacustrine outcrops along a tributary of the Nyang River, a major tributary of the Yarlung-Tsangpo in southeast Tibet. The deposits were preserved between terraces at altitudes of 2950–3100 m asl. The stratigraphic record features at least two sets of coarsening-upward sequences depicting episodic aggradation and progradation of a glacially dammed lake related delta. Recognized facies changes illustrate the evolution cycles of depositional environments from pro-delta, delta front, to delta plain. Radiocarbon and optically stimulated luminescence dates reveal an aging-downward trend in stratigraphic order and provide an approximate timeline for the formation of glacially dammed lakes in late Pleistocene. This result reflects that the Zelunglung Glacier had progressively advanced to block the Yarlung-Tsangpo river and the dam materials had stepwise stacked up to an altitude of 3095 m asl during Marine Oxygen Isotope Stages 4 to 2.


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