Mineralogical and clay mineralogical aspects of loess research

Bronger, A.; Heinkele, Th.

doi:10.1016/1040-6182(90)90037-5

Cited by 74 publications

(41 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The more abundant component of the lower portion is~5 μm, while that of the upper portion is~40 μm. As deep weathering could significantly decrease the particle size of the materials (Bronger and Heinkele, 1990;Sun, 2006), changes in particle size distribution of Xuancheng red soils are indicative of a downward increase in degree of weathering, in good agreement with the chemical indices.…”

Section: Bulk Geochemical Composition and Degree Of Weatheringsupporting

confidence: 53%

Red soils with white net-like veins and their climate significance in south China

Hong

Yin

et al. 2010

Geoderma

View full text Add to dashboard Cite

Section: Bulk Geochemical Composition and Degree Of Weatheringsupporting

confidence: 53%

Red soils with white net-like veins and their climate significance in south China

Hong

Yin

et al. 2010

Geoderma

View full text Add to dashboard Cite

“…A map showing the sample locations can be found in Chauvel et al (2014). Mineralogy, provenance and grain-size distribution for these deposits have been reported in previous studies such as Jeong et al (2008) and Bronger and Heinkele (1990) for the mineralogy of the Chinese loesses, Smith et al (2003) and Zárate (2003) for the source location of the Argentinian loesses, and Ding and Ding (2003) for the grain-size distribution of loesses from Tajikistan.…”

Section: Samplesmentioning

confidence: 93%

New perspectives on the Li isotopic composition of the upper continental crust and its weathering signature

Sauzéat

Rudnick

Chauvel

et al. 2015

Earth and Planetary Science Letters

127

View full text Add to dashboard Cite

Editor: M. Bickle Keywords: Li isotopes loess upper continental crust chemical weatheringLithium isotopes are increasingly used to trace both present-day and past weathering processes at the surface of the Earth, and could potentially be used to evaluate the average degree of past weathering recorded by the upper continental crust (UCC). Yet the previous estimate of average δ 7 Li of the UCC has a rather large uncertainty, hindering the use of Li isotopes for this purpose. New δ 7 Li for desert and periglacial loess deposits (windblown dust) from several parts of the world (Europe, Argentina, China and Tajikistan) demonstrate that the former are more homogeneous than the latter, and may therefore serve as excellent proxies of the average composition of large tracts of the UCC. The Li isotopic compositions and concentrations of desert loess samples are controlled by eolian sorting that can be quantified by a binary mixing between a weathered, fine-grained end-member, dominated by phyllosilicates and having low δ 7 Li, and an unweathered, coarse-grained end-member, that is a mixture of quartz and plagioclase having higher δ 7 Li. We use correlations between insoluble elements (REE, Nd/Hf and Fe 2 O 3 /SiO 2 ), Li concentrations (henceforth referred as [Li]), and δ 7 Li to estimate a new, more precise, average Li isotopic composition and concentration for the UCC: [Li] = 30.5 ± 3.6(2σ ) ppm, and δ 7 Li = +0.6 ± 0.6(2σ ). The δ 7 Li for desert loess deposits is anti-correlated with the chemical index of alteration (CIA). Using this relationship, along with our average δ 7 Li, we infer that (1) the present-day CIA of the average UCC is 61 +4 −2 (2σ ), higher than the common reference value of 53, and (2) the average proportion of chemically weathered components is as high as 37 +17 −10 (2σ )% at the surface of the Earth.

show abstract

“…0.8 µm are also observed in the grain size distribution curves of all three end-members. The generation of these fine grain peaks may be due to postdepositional pedogenesis, especially for particles < 2 µm (Bronger and Heinkele, 1990). However, since the dominant modal peaks are much coarser, weaker post-depositional weathering as suggested by MS is unlikely to have had a significant influence on the populations of EM1, EM2, or EM3 at NLK.…”

Section: Genetic Interpretations Of End-members In Loess Grain Sizementioning

confidence: 99%

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

Song

Fitzsimmons

et al. 2018

Clim. Past

View full text Add to dashboard Cite

Abstract. The extensive loess deposits of the Eurasian midlatitudes 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 (χ fd %) 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.

show abstract

Mineralogical and clay mineralogical aspects of loess research

Cited by 74 publications

References 25 publications

Red soils with white net-like veins and their climate significance in south China

Red soils with white net-like veins and their climate significance in south China

New perspectives on the Li isotopic composition of the upper continental crust and its weathering signature

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

Contact Info

Product

Resources

About