loess deposits
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Author(s):  
В. А. Белоус ◽  
С. А. Салмин

В статье рассматриваются конструктивные особенности двух весел-гребков, обнаруженных при раскопках в лессовых отложениях на берегу р. Зрачка (позднее - городского рва), относящихся к периоду Средневековья (до 1375 г.). The article describes the design features of the two paddles (oars) discovered during excavations in loess deposits on the Zrachka river bank (later the city moat), dating back to the period of Middle Ages (before 1375).



2021 ◽  
pp. jgs2021-078
Author(s):  
Jean-Pierre Lefort ◽  
John Renouf ◽  
Guzel Danukalova

Onshore and offshore sedimentological, geochemical, geomorphological, paleontological and geochronological studies of loess deposits located under and around the English Channel revealed that they were transported by katabatic winds generated by the British-Irish Ice Sheet. Katabatic winds, which are low-altitude wind flows, were able to jump over the low southern British hills but were stopped by the higher Brittany and Normandy hills. This regional topography is interrupted by a north-south corridor linking the northern and southern shores of Brittany where loess propagated down to the mouth of Loire River. This long transit shows that the total distance travelled by the katabatic wind was around 750 kilometres, which represents an unusual distance for the propagation of this wind under continental conditions. Strong similarities with Antarctica and Greenland, where well documented cases of katabatic winds are known, show that the transit of the trans-Channel katabatic winds were strongly enhanced by the seasonal drift of storms propagating in an eastward direction along the axis of the English Channel. This increasing strength of the North-South katabatic flux was probably at the origin of the transport of loess particles down to the mouth of Loire River.



2021 ◽  
Vol 60 (4) ◽  
pp. 280-293
Author(s):  
Habib Alimohammadian ◽  
Fereshteh Mahdipour Haskouei ◽  
Jafar Sabouri

Environmental magnetism techniques enable us to reconstruct paleoclimate conditions in some deposition such as losses. The  magnetic properties  of  minerals  are  used  as  proxies  for  environmental  changes. For this study, loess/paleosol sequence of Kolet section at Neka, north-east of Iran were magnetically investigated. We applied environmental magnetism methods, to reconstruct paleoclimate changes. We investigated relationship between paleoclimate changes and environmental magnetism proxies like magnetic susceptibility (?) variation. The laboratory techniques indicated the presence of main factor of magnetic property in loess/paleosol sequence, such as magnetite, maghemite and etc. We also estimated magnetically parameters (like SIRM, HIRM and etc.) to confirm concentrations of both aeolian and pedogenic particles versus variations of magnetic susceptibility enhancement. The ? values show prominent peaks for the three well developed soil and paleosol horizons, Recent Soil (S0), Upper Paleosol (S1) and Lower Paleosol (S2); which refer to warmer and wetter conditions. As result, we concluded that the increase/decreasing of magnetic susceptibility is coinciding with palaeosol/loess sequence, and probably with humid/arid conditions. Moreover, variations of magnetic susceptibility versus lithological column of Kolet section enabled us to recognize paleoclimatically periods known as interglacial/glacial cycles. The obtained  magnetic  data  indicate  that  during over  the  past  50  ka,  there  have  been  at  least  two glacial/interglacial periods and since last 20 ka, there was no main glaciation occurrence, in the study area.



2021 ◽  
Vol 9 ◽  
Author(s):  
Steffen Mischke ◽  
Zhongping Lai ◽  
Galina Faershtein ◽  
Naomi Porat ◽  
Matthias Röhl ◽  
...  

Current conditions in the southern Levant are hyperarid, and local communities rely on fossil subsurface water resources. The timing of more favourable wetter periods and also their spatial characteristics are not yet well constrained. To improve our understanding of past climate and environmental conditions in the deserts of the southern Levant, sedimentary sections including artefact-bearing beds from Jurf ed Darawish on the Central Jordanian Plateau were investigated using sedimentological and micropalaeontological analyses and OSL dating. Grain-size analysis and structures of the clayey-silty sediments show that they mainly represent reworked loess deposits. The OSL ages suggest that these fine-grained sediments were accumulated during Marine Isotope Stages (MIS) 5-3. Recorded ostracod valves (mostly Potamocypris, Ilyocypris and Pseudocandona), remains of aquatic and terrestrial gastropod shells, and charophyte gyrogonites and stem encrustations indicate that an in-stream wetland existed at the location of Jurf ed Darawish during MIS 5-4 which was replaced by a vegetated alluvial plain in MIS 3. The prevailing aggradational setting was replaced by an erosional setting sometime after 30 ka. Abundant artefacts, distributed over a vertical range of up to 40 cm in a bed covered by a sedimentary sequence of 12-m thickness, provide evidence for the presence of humans in the region during a relatively long period from ca. 85 to 65 ka. The reconstruction of an in-stream wetland at Jurf ed Darawish, and the presence of humans at the site and in other desert regions of the Jordanian Plateau, the Wadi Arava/Araba, and the Negev and the Nefud deserts, show that the regional climate in the late MIS 5 and MIS 4 was significantly wetter than today and provided favourable conditions for humans in the Southern Levant and the northwestern Arabian Peninsula.



2021 ◽  
Vol 12 (5) ◽  
pp. 101180
Author(s):  
Yue Li ◽  
Yougui Song ◽  
Dimitris G. Kaskaoutis ◽  
Jinbo Zan ◽  
Rustam Orozbaev ◽  
...  


CATENA ◽  
2021 ◽  
Vol 204 ◽  
pp. 105430
Author(s):  
José M. Plata ◽  
Rafael Rodríguez ◽  
Frank Preusser ◽  
Jaume Boixadera ◽  
J. Carles Balasch ◽  
...  
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