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Map showing the physical geography of the Chinese Loess Plateau and pattern of modern Asian atmospheric circulation. The main map corresponds to the area within the rectangle in the index map. ArcGIS 9.3 was used to create the base map and the SRTMDEMUTM 90 M data were obtained from: http://www. gscloud.cn/.  

Map showing the physical geography of the Chinese Loess Plateau and pattern of modern Asian atmospheric circulation. The main map corresponds to the area within the rectangle in the index map. ArcGIS 9.3 was used to create the base map and the SRTMDEMUTM 90 M data were obtained from: http://www. gscloud.cn/.  

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Magnetic paleoclimatic records often represent mixed environmental signals. Unmixing these signals may improve our understanding of the paleoenvironmental information contained within these records, but such a task is challenging. Here we report an example of numerical unmixing of magnetic hysteresis data obtained from Chinese loess and red clay se...

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... within Lingtai County, in the central CLP (Fig. 1). The section is ~300 m thick, with the upper 175 m EM1---hysteresis and EM2---hysteresis are the end members derived from the hysteresis unmixing model, while EM1---IRM and EM2---IRM are from the IRM unmixing model. selected (50 samples from loess-paleosol sequence and 50 samples from red clay sequence). The selected loess and red clay ...

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In recent years, increasing interest in loess studies has focused on qualitative and quantitative paleoclimatic reconstruction using the imperfect antiferromagnetic mineral hematite. However, the linkage between the hematite formation and climatic variables remains controversial. Here we present the results of a comprehensive investigation of the m...

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... The characterization of distinct coercitivity populations present in a rock from magnetization measurements has been used to elucidate the origin of natural mineral assemblages and to reveal different environmental processes (Jackson et al., 1993;Channell and McCabe, 1994;Tauxe et al., 1996;Tauxe, 1998;Heslop;2015), establishing the unmixing of hysteresis loops into individual components as a key concern for rock-magnetism research. Several models have been suggested for decomposing magnetic hysteresis loops, like those which apply approximation by multi-variate functions (Thompson, 1986), Fourier analysis (Willcock and Tanner, 1983;Upda and Lord, 1985;Josephs et al., 1986;Jackson et al., 1990), second-order rational functions (Rivas et al., 1981), hyperbolic basis functions (von Dobeneck, 1996); singular value decomposition (Carter-Stiglitz et al., 2001), sigmoid logistic functions (Jackson and Solheid, 2010) and numerical estimation of end-members (Heslop and Roberts, 2012;Zhang et al., 2016). However, sometimes these are difficult to implement and the availability of software packages for processing and analysing magnetic hysteresis data is still scarce (von Dobeneck, 1996;Paterson et al., 2018). ...
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... Previous researches showed that the windblown dust deposits started accumulation from the Late Oligocene to Early Miocene at 25-22 Ma in the western CLP (Guo et al., 2002;Hao et al., 2008;Qiang et al., 2010) and the Late Miocene at 8-7 Ma in the central and eastern CLP (Ao et al., 2016;Qiang et al., 2001;Song et al., 2001Song et al., , 2007Sun et al., 1998aSun et al., , 2010. The continuous and thick red clay sequences provide new information about East Asian Monsoon (EAM) evolution and the Asian inner aridification during the late Miocene-Pliocene period Chen et al., 2007;Nie et al., 2014a;Sun et al., 2010;Sun and An, 2002;Zhang et al., 2016). However, the record of Miocene-Pliocene evolution of the EAM preserved in the Neogene red clay sequence is still not well understood. ...
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Magnetic hysteresis loops are important in theoretical and applied rock magnetism with applications to paleointensities, paleoenvironmental analysis, and tectonic studies, among many others. Information derived from these data is among the most ubiquitous rock magnetic data used by the Earth science community. Despite their prevalence, there are no general guidelines to aid scientists in obtaining the best possible data and no widely available software to allow the efficient analysis of hysteresis loop data using the most advanced and appropriate methods. Here we outline detrimental factors and simple approaches to measuring better hysteresis data and introduce a new software package called Hysteresis Loop analysis box (HystLab) for processing and analyzing loop data. Capable of reading a wide range of data formats, HystLab provides an easy-to-use interface allowing users to visualize their data and perform advanced processing, including loop centering, drift correction, high-field slope corrections, and loop fitting to improve the results from noisy specimens. A large number of hysteresis loop properties and statistics are calculated by HystLab and can be exported to text files for further analysis. All plots generated by HystLab are customizable and user preferences can be saved for future use. In addition, all plots can be exported to encapsulated postscript files that are publication ready with little or no adjustment. HystLab is freely available for download at https://github.com/greigpaterson/HystLab and in combination with our simple measurement guide should help the paleomagnetic and rock magnetic communities get the most from their hysteresis data.
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... Unmixing and principal component analysis of spectrumtype data such as remanence curves, hysteresis loops and FORC distributions can more readily provide evidence of multiple components. These approaches are increasingly undertaken to characterize changes in contributions to the total remanent magnetization and in magnetic grain size of sedimentary archives of various origins from past and present continents and oceans (e.g., Abrajevitch and Kodama, 2011;Lascu et al., 2012;Chen et al., 2014;Nie et al., 2014;Hyland et al., 2015;Fabian et al., 2016;Maxbauer et al., 2016c;Zhang et al., 2016). However, obtaining mineral compositions of an ensemble of components via these methods is only possible indirectly through a series of assumptions or a priori knowledge. ...
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