scholarly journals Spatial variations of magnetic susceptibility of Chinese loess for the last 600 kyr: Implications for monsoon evolution

2005 ◽  
Vol 110 (B12) ◽  
Author(s):  
Qingzhen Hao ◽  
Zhengtang Guo
Keyword(s):  
Magnetic Susceptibility ◽  
Spatial Variations ◽  
Chinese Loess

National-scale spatial variations of soil magnetic susceptibility in Brazil

2021 ◽  
Vol 108 ◽  
pp. 103191
Author(s):  
Julierme Zimmer Barbosa ◽  
Giovana Poggere ◽  
Sérgio Henrique Godinho Silva ◽  
Marcelo Mancini ◽  
Antonio Carlos Vargas Motta ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Spatial Variations ◽  
National Scale ◽  
Soil Magnetic Susceptibility

Reconsidering the paleoclimate implications of magnetic susceptibility records of Holocene loessic soils

2021 ◽  
Author(s):  
Diana Jordanova ◽  
Neli Jordanova
Keyword(s):  
Magnetic Susceptibility ◽  
Parent Material ◽  
Chinese Loess Plateau ◽  
Absolute Difference ◽  
Physical Parameters ◽  
Soil Profiles ◽  
Chinese Loess ◽  
Loess Area ◽  
River Terraces ◽  
Paleoclimate Proxy

<p>Mass specific magnetic susceptibility variations with depth along soil profiles developed on loess parent material is one of the most frequently used physical parameters in local, regional and global correlations of loess deposits. It is also utilized as a paleo-precipitation proxy, defined either as absolute difference between susceptibilities of the enhanced B-horizon and parent loess, or as relative enhancement using ratios of magnetic parameters. These different approaches in the application of magnetic susceptibility as paleoclimate proxy lead us to perform a comparative study on a number of Holocene soil profiles developed on loess from European loess area and the Chinese Loess Plateau (CLP). We made a compilation of data including 20 profiles from North Bulgaria, 28 profiles from Eastern and Central Europe; and 26 profiles from the CLP. Minimum magnetic susceptibilities of the last glacial loess (X<sub>min</sub>) from the compiled data base for European and Chinese profiles show climate related variability, revealing multi linear relationship with both present day MAP and MAT values for the corresponding locations. Strong deviations of X<sub>min</sub> from this dependence display sites located at low elevation river terraces, Black sea coast and possessing large content of coarse silt and sand fractions. Pedogenic magnetic susceptibility (X<sub>pedo</sub>) defined as (X<sub>max</sub> - X<sub>min</sub>) with  X<sub>max</sub> determined from the youngest part (last 1500 – 2000 years B.P.) of the Holocene magnetic susceptibility records of Chinese sections and absolute X<sub>max</sub> of the European sites show systematic dependence on modern MAP and MAT values. This dependence is uniform for all sites with steppe vegetation, while higher scatter and steeper regression trends are observed for sites under mixed (steppe – forest) and forest vegetation. The study is financially supported by project No KP-06-N34/2 funded by the Bulgarian National Science Fund.</p>

High-Resolution Paleoclimatic Information from Chinese Eolian Sediments Based on Grayscale Intensity Profiles

2000 ◽  
Vol 53 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Stephen C. Porter
Keyword(s):  
Magnetic Susceptibility ◽  
High Resolution ◽  
Digital Camera ◽  
Dune Sand ◽  
Laptop Computer ◽  
Chinese Loess ◽  
Proxy Records ◽  
Eolian Sediments ◽  
Highly Correlated ◽  
Two Parameters

AbstractGrayscale intensity profiles from photographic images offer a rapid means of obtaining paleoclimate proxy records from Chinese loess, dune sand, and paleosols. Although the data can be obtained using conventional 35-mm film images, a digital camera and laptop computer will produce a high-resolution grayscale profile at a field site within minutes. Comparison of grayscale profiles with profiles of magnetic susceptibility measured down loess and dune-sand sections at sites on the Loess Plateau and Tibetan Plateau in a range of altitudes and climatic regimes shows that the two parameters are highly correlated. Therefore, grayscale intensity is a convenient alternative to magnetic susceptibility for generating paleoclimatic data in the loess and desert-margin regions of China. The resolution of both grayscale and susceptibility profiles ultimately is limited by bioturbation, which is most pronounced in paleosols.

scholarly journals Reconstruction of 130-kyr Relative Geomagnetic Intensities from 10Be in Two Chinese Loess Sections

Radiocarbon ◽  
2010 ◽  
Vol 52 (1) ◽  
pp. 129-147 ◽  
Author(s):  
Weijian Zhou ◽  
Feng Xian ◽  
J Warren Beck ◽  
A J Timothy Jull ◽  
Zhisheng An ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Potential Application ◽  
Chinese Loess ◽  
Geomagnetic Excursion ◽  
The Past ◽  
Mis 3 ◽  
Good Agreement ◽  
Geomagnetic Intensity

Efforts to extract weak geomagnetic excursion signals from Chinese loess-paleosol 10Be have generally been unsuccessful due to the complexities of its accumulation, because the geomagnetic and climate (precipitation and dust) signals contained in loess-paleosol sequence are tightly overprinted. Here, we present a reconstruction of geomagnetic relative paleointensities for the past 130 kyr from 10Be records in 2 Chinese loess-paleosol sections using a correction based on the correlation of 10Be with magnetic susceptibility (SUS) to remove the climatic contamination. Both these records reveal the Laschamp and Blake events, which lie in the loess and paleosol (L1SS1 and S1SS3) horizons corresponding to mid-MIS 3 and 5e, respectively. The good agreement between our results and other geomagnetic intensities reconstructions from Atlantic and Pacific sediments indicates that our method is robust. Our study suggests the potential application of loess-paleosol 10Be for reconstructing geomagnetic intensity variations spanning the whole Quaternary.

Mineralogic and Climatic Interpretations of the Luochuan Loess Section (China) Based on Diffuse Reflectance Spectrophotometry

2001 ◽  
Vol 56 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Junfeng Ji ◽  
William Balsam ◽  
Jun Chen
Keyword(s):  
Magnetic Susceptibility ◽  
Summer Monsoon ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Relative Proportion ◽  
Chinese Loess Plateau ◽  
Early Pleistocene ◽  
Chinese Loess ◽  
Near Ultraviolet ◽  
Reflectance Data

AbstractWe examined the top 135 m, that is, the entire Pleistocene, of the classic Luochuan section on the Chinese Loess Plateau with a diffuse reflectance spectrophotometer from the near ultraviolet, through the visible, and into the near infrared. From the reflectance data we calculated sample brightness which, with some caveats, is a reasonable proxy for magnetic susceptibility. Mineralogic changes were identified by factor analyzing the first derivative of the percent reflectance data and examining samples with high factor scores. Two factors which explain about 96% of the cumulative variance are distinguished by the relative proportion of hematite and goethite, the minerals that are responsible for the color changes in the loess sequence. Both hematite and goethite are present in both loess and paleosol but goethite dominates in loess whereas hematite dominates in paleosol. The goethite factor exhibits an inverse correlation with magnetic susceptibility; the hematite factor exhibits a weak positive correlation with susceptibility. Paleoclimatic interpretations are drawn from comparison of susceptibility to the concentration of spectrally identified hematite. Based on this comparison, paleosols in the early Pleistocene Wucheng Formation are characterized by conditions that are drier than today, a “dry summer monsoon”, whereas later Pleistocene paleosols are characterized by a “wet summer monsoon”.

scholarly journals Time-Transgressive Nature of the Magnetic Susceptibility Record across the Chinese Loess Plateau at the Pleistocene/Holocene Transition

PLoS ONE ◽  
2015 ◽  
Vol 10 (7) ◽  
pp. e0133541 ◽  
Author(s):  
Yajie Dong ◽  
Naiqin Wu ◽  
Fengjiang Li ◽  
Linpei Huang ◽  
Wenwen Wen
Keyword(s):  
Magnetic Susceptibility ◽  
Loess Plateau ◽  
Chinese Loess Plateau ◽  
Chinese Loess ◽  
The Chinese Loess Plateau
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