scholarly journals Eolian dust dispersal patterns since the last glacial period in eastern Central Asia: insights from a loess-paleosol sequence in the Ili Basin

2018 ◽  
Vol 14 (3) ◽  
pp. 271-286 ◽  
Author(s):  
Yue Li ◽  
Yougui Song ◽  
Kathryn E. Fitzsimmons ◽  
Hong Chang ◽  
Rustam Orozbaev ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Susceptibility ◽  
Central Asia ◽  
Chinese Loess Plateau ◽  
Magnetic Characteristics ◽  
Magnetic Minerals ◽  
Near Surface ◽  
Siberian High ◽  
End Members ◽  
Eastern Central Asia

Abstract. The extensive loess deposits of the Eurasian mid-latitudes provide important terrestrial archives of Quaternary climatic change. As yet, however, loess records in Central Asia are poorly understood. Here we investigate the grain size and magnetic characteristics of loess from the Nilka (NLK) section in the Ili Basin of eastern Central Asia. Weak pedogenesis suggested by frequency-dependent magnetic susceptibility (χfd%) and magnetic susceptibility (MS) peaks in primary loess suggest that MS is more strongly influenced by allogenetic magnetic minerals than pedogenesis, and may therefore be used to indicate wind strength. This is supported by the close correlation between variations in MS and proportions of the sand-sized fraction. To further explore the temporal variability in dust transport patterns, we identified three grain size end-members (EM1, mode size 47.5 µm; EM2, 33.6 µm; EM3, 18.9 µm) which represent distinct aerodynamic environments. EM1 and EM2 are inferred to represent grain size fractions transported from proximal sources in short-term, near-surface suspension during dust outbreaks. EM3 appears to represent a continuous background dust fraction under non-dust storm conditions. Of the three end-members, EM1 is most likely the most sensitive recorder of wind strength. We compare our EM1 proportions with mean grain size from the Jingyuan section in the Chinese loess plateau, and assess these in the context of modern and Holocene climate data. Our research suggests that the Siberian High pressure system is the dominant influence on wind dynamics, resulting in loess deposition in the eastern Ili Basin. Six millennial-scale cooling (Heinrich) events can be identified in the NLK loess records. Our grain size data support the hypothesis that the Siberian High acts as teleconnection between the climatic systems of the North Atlantic and East Asia in the high northern latitudes, but not for the mid-latitude westerlies.

High-resolution records of climate change in arid eastern central Asia during MIS 3 (51 600-25 300 cal a BP) from Wulungu Lake, north-western China

2016 ◽  
Vol 31 (6) ◽  
pp. 577-586 ◽  
Author(s):  
Xiaonan Zhang ◽  
Aifeng Zhou ◽  
Can Zhang ◽  
Shengtun Hao ◽  
Yongtao Zhao ◽  
...  
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Central Asia ◽  
Western China ◽  
Mis 3 ◽  
North Western ◽  
Eastern Central Asia

scholarly journals SOKOLOWIA HORIZON OF THE ZIARAT FORMATION (EASTERN ALBORZ, IRAN): BIOSTRATIGRAPHIC AND PALEOGEOGRAPHIC IMPLICATIONS

2019 ◽  
pp. 15-27
Author(s):  
Mehdi Hadi ◽  
Amir Salahi ◽  
Yaghub Nasiri ◽  
Hossein Mosaddegh
Keyword(s):  
Central Asia ◽  
Tarim Basin ◽  
Genetic Relationship ◽  
Benthic Foraminifera ◽  
Middle Eocene ◽  
Southeastern Europe ◽  
Larger Benthic Foraminifera ◽  
Central Asian ◽  
Apparent Similarity ◽  
Eastern Central Asia

The present study deals with molluscan accumulations of the Sokolowia horizon, which is a key-bed in the middle Eocene of the Kalateh section (Ziarat Formation, Eastern Alborz, Iran). The age of this “key horizon” is at-tributed to Bartonian based on presence of larger benthic foraminifera species such as Nummulites lyelli (D'Archiac & Haime), Orbitoclypeus zitteli (Checchia-Rispoli) and Asterocyclina stella stella (Gümbel) immediately below it. The paleogeographic distribution of Sokolowia occurrence from Tarim Basin in eastern Central Asia to the Transylvanian Basin in southeastern Europe indicates a middle Eocene seaway along the southern margin of an Eurasian epicontinental sea. In particular, the comparison of middle Paleogene sequences in different Central Asian regions reveals an apparent similarity between those basins pointing to their genetic relationship.

scholarly journals Annotated bibliography of the subclass Archosauria (Class : Reptilia) : Jan 1960 - Dec 1984

2021 ◽  
Author(s):  
◽  
John R. Lavas
Keyword(s):  
Central Asia ◽  
Scientific Collaboration ◽  
World Wide ◽  
Field Work ◽  
Annotated Bibliography ◽  
Gobi Desert ◽  
Central Asian ◽  
The Us ◽  
The 1960S ◽  
Eastern Central Asia

<p>The subclass Archosauria includes some of the most successful vertebrates to have evolved. Although traditionally viewed as 'cold-blooded' (= ectothermic) and therefore evolutionarily inferior to 'warm-blooded' (= endothermic) mammals and birds, data collected since the 1960s has resulted in significant re-evaluations and a complete reassessment of archosaur evolution, taxonomy, and inferred physiology and behaviour. Much of the relevant data emanates from the results of post WWII field work conducted in eastern Central Asia (particularly the Gobi Desert) by Russian, Polish and Mongolian palaeontologists. However, due to political, cultural and/or other reasons, there remained little scientific collaboration between them and western (particularly US) scientists until very recently. As a consequence, there developed a dichotomy in this field of archosaur research, not only between east and west, but also between Europe and the US. This thesis reviews the literature on archosaurs published world-wide from Jan 1960 - Dec 1984, with the emphasis on the important Central Asian/Gobi contributions, in order to evaluate the academic discussions that have arisen regarding archosaur evolution, physiology, behaviour, their relationship to the Aves, and the evolution of avian endothermy and flight.</p>

scholarly journals Moisture Sources Associated with Precipitation during Dry and Wet Seasons over Central Asia

2020 ◽  
Vol 33 (24) ◽  
pp. 10755-10771
Author(s):  
Dongdong Peng ◽  
Tianjun Zhou ◽  
Lixia Zhang
Keyword(s):  
Central Asia ◽  
Lagrangian Model ◽  
Northern Eurasia ◽  
Formation Mechanisms ◽  
Wet Season ◽  
Moisture Sources ◽  
Western Asia ◽  
The Times ◽  
Western Eurasia ◽  
Eastern Central Asia

AbstractIdentifying the origin of moisture is a key process in revealing the formation mechanisms of precipitation, but the moisture sources for central Asia have not been well documented in previous studies. In this work, we employ the Lagrangian model FLEXPART over 2011–19 to address this question. Multiple observational products indicate that the times of dry and wet seasons are opposite for western and eastern central Asia bounded by 75°E. The wet season is November–April (NDJFMA) for western central Asia but May–October (MJJASO) for eastern central Asia, while the opposite is true for the dry season. The main moisture source regions for western central Asia are local regions (with a contribution of 49.11%), western Eurasia (21.47%), and western Asia (11.37%) during MJJASO and local regions (33.92%), western Asia (27.50%), and western Eurasia (17.60%) during NDJFMA. For eastern central Asia, moisture mainly originates from local regions (52.38%), western central Asia (25.22%), and northern Eurasia (9.26%) during MJJASO and western central Asia (30.86%), local regions (30.82%), western Asia (10.31%), and western Eurasia (10.26%) during NDJFMA. The differences in moisture sources between dry and wet seasons mainly occur in local regions and western Asia for western central Asia but in local regions for eastern central Asia. The moisture from northern Eurasia, western Eurasia, and western central Asia is transported into target regions by the westerly and southwesterly winds that are associated with a deep low trough over central Asia. Moisture is transported from western Asia by the anticyclone occurs over North Africa and western Asia in the lower and middle troposphere.

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