The formation of loess deposits in the Tashkent region and parts of Central Asia; and problems with irrigation, hydrocollapse and soil erosion

Smalley, Ian; Mavlyanova, N. G.; Rakhmatullaev, Kh.L.; Shermatov, M.Sh.; Machalett, Björn; Dhand, Ken O. 'Hara; Jefferson, Ian

doi:10.1016/j.quaint.2005.12.002

Cited by 71 publications

(18 citation statements)

References 16 publications

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“…In recent years, international Quaternary geologists have paid much attention to the loess sediments in Tajikistan and southern Kazakhstan, which are situated in the southern part of Central Asia [17][18][19][20][21][22][23][24]. Previous studies show that paleoenvironment information recorded in south Central Asia loess sediments is very comparable with that recorded in Chinese loess.…”

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confidence: 99%

Loess magnetic properties in the Ili Basin and their correlation with the Chinese Loess Plateau

Song

Shi

Fang

et al. 2010

Sci. China Earth Sci.

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Over the past two decades, magnetoclimatological studies of loess-paleosol sequences in the Chinese Loess Plateau (CLP) have made outstanding achievements, which greatly promote the understanding of East Asian paleomonsoon evolution, inland aridification of Asia, and past global climate changes. Loess magnetic properties of the CLP have been well studied. In contrast, loess magnetic properties from outside the CLP in China have not been fully understood. We have little knowledge about the magnetic properties of loess in the Ili Basin, an intermontane depression of the Tianshan (or Tien Shan) Mountains. Here, we present the results of rock magnetic measurements of the Ili loess including mass magnetic susceptibility (χ) and anhysteretic remanent magnetization (ARM), high/low temperature dependence of susceptibility (TDS) and hysteresis, as well as X-ray diffraction (XRD) for mineral analysis. Based on the comparison with loess-paleosol sequences in the CLP (hereafter referred to as the Chinese loess), we discuss the possible magnetic susceptibility enhancement mechanism of the Ili loess. The results show that 1) the total magnetic mineral concentration of the Ili loess is far lower than that of the Chinese loess, though they have similar magnetic mineral compositions. The ferrimagnetic minerals in the Ili loess are magnetite and maghemite, and the antiferromagnetic mineral is hematite; XRD analysis also identifies the presence of ilmenite. The ratio of maghemite is lower in the Ili loess than in the Chinese loess, but the ratios of magnetite and hematite are higher in the Ili loess than in the Chinese loess.2) The granularity of magnetic minerals in the Ili loess, dominated by pseudo-single domain (PSD) and multi-domain (MD) grains, is generally much coarser than that of the Chinese loess. Ultrafine pedogenically-produced magnetic grains have a very limited contribution to the susceptibility enhancement. Rather, PSD and MD particles of magnetite and maghemite are the main contributors to the enhancement of susceptibility in the Ili loess. 3) The susceptibility enhancement mechanism for the Ili loess is complicated and superimposes both a wind velocity/vigor model (Alaskan or Siberian model) and the in situ ultrafine grain pedogenic model; the former might play an important role in the Ili loess. 4) Magnetic susceptibility enhancements of the Ili loess are related not only to the eolian input of the source area, but also to the local climate, landform, and geological background. Therefore, great care should be taken when reconstructing paleoclimate using magnetic susceptibility data from the Ili loess. loess, magnetic property, magnetic susceptibility, the Ili Basin, the Chinese Loess Plateau Citation: Song Y G, Shi Z T, Fang X M, et al. Loess magnetic properties in the Ili Basin and their correlation with the Chinese Loess Plateau.

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confidence: 99%

Loess magnetic properties in the Ili Basin and their correlation with the Chinese Loess Plateau

Song

Shi

Fang

et al. 2010

Sci. China Earth Sci.

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“…Hydroconsolidation, also described as filtration consolidation (Liszkowski 1971), is a typical process to which loess is subjected due to calcium carbonate and clay matter content (Rogers et al 1994, Smalley et al 2006, Smalley and Markowic 2014). Hydroconsolidation is defined as the destruction of loess microstructure under the influence of water, resulting in the slumping of loess (Rogers et al 1994).…”

Section: Record Of Diagenetic Processes and Assessment Of The Morpholmentioning

confidence: 99%

“…The main factor triggering hydroconsolidation is the wetting of loess. The presence of carbonates and clay is the key element for the hydroconsolidation of loess (Smalley et al 2006, Smalley andMarkovic 2014). Changes in microstructure (e.g.…”

Section: Introductionmentioning

confidence: 99%

Grain-size and microstructure of the loess from closed depressions in the Nałęczów Plateau (East Poland)

Kołodyńska‐Gawrysiak

2019

pjss

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<p>The investigation was conducted in the eastern part of the Nałęczów Plateau, a region of the Lublin Upland, in eastern Poland. The loess cover of this region was formed mainly during the last glaciation, and loess accumulation lasted until 15,000–12,000 BP. The undulating loess plateau with numerous oval-shaped closed depressions (CDs) is the main landform in the study area. Particle size distribution and SEM analyses were conducted for loess profiles under the bottoms and on the slopes of 4 CDs. Grain-size distribution characteristics as well as qualitative and quantitative micromorphological characteristics of the the loess forming the bottoms and slopes of the depressions were compared and discussed. It was documented that the differences between the loess forming the bottoms and slopes of the depressions are insignificant in the case of clay fraction content, but are considerable in the case of microstructure characteristics. The differences documented result from the impact of syn- and post-depositional diagenetic processes related mainly to suffosion and hydroconsolidation occurring under the influence of water. A quantitative assessment of the morphological effects of these processes was carried out in the context of the origin of closed depressions. The morphological effect of Holocene diagenetic processes was manifested in the deepening of the initial closed depressions formed previously under the influence of primary morphogenetic processes.</p>

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“…In 2006, she also came to Nottingham with Royal Society support. These visits resulted with several good papers on the Central Asian loess (Jefferson et al, 2004;Smalley et al, 2006aSmalley et al, , 2006b. In 2006, Ian again visited the Danube loess, this time in Novi Sad, Serbia.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Ian Smalley: The genius of loess of the loess world

Marković

O’Hara-Dhand

McLaren

2015

Quaternary International

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The formation of loess deposits in the Tashkent region and parts of Central Asia; and problems with irrigation, hydrocollapse and soil erosion

Cited by 71 publications

References 16 publications

Loess magnetic properties in the Ili Basin and their correlation with the Chinese Loess Plateau

Loess magnetic properties in the Ili Basin and their correlation with the Chinese Loess Plateau

Grain-size and microstructure of the loess from closed depressions in the Nałęczów Plateau (East Poland)

Ian Smalley: The genius of loess of the loess world

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