Inter-profile correlation of the Chinese loess/paleosol sequences during Marine Oxygen Isotope Stage 5 and indications of pedogenesis

Liu, Qingsong; Banerjee, Subir K.; Jackson, Michael J.; Deng, Changzhou; Pan, Yongxin; Zhu, Rixiang

doi:10.1016/j.quascirev.2004.07.021

Cited by 59 publications

(59 citation statements)

References 74 publications

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“…Moreover, these excursions are well correlated with those discovered globally in both volcanic and/or sedimentary paleomagnetic records (e.g., Langereis et al, 1997;Lund et al, 2006;Singer et al, 2002;Oda, 2005). Furthermore, some paleomagnetic studies with dense sampling demonstrate that loess units are capable of recording geomagnetic paleosecular variation (PSV) (e.g., Zhu et al, 1998Zhu et al, , 2000Heslop et al, 1999;Liu et al, 2005a). These observations suggest that Chinese loess-paleosol deposits have the potential to record geomagnetic episodes as short as a few kyr or less in duration, as well as long term reversal patterns.…”

Section: Introductionmentioning

confidence: 68%

“…It is now recognized that dust from the Gobi and other deserts in north and northeast China began to accumulate in response to increased uplift of the Tibetan Plateau, and the associated changes in Asian atmospheric circulation patterns that resulted from this uplift (Fang et al, 1999;Sun and An, 2002). Magnetostratigraphy (Heller and Liu, 1982, 1984, 1986Sun et al, 1997;Ding et al, 2001;Evans and Heller, 2001;Qiang et al, 2001;Wang et al, 2006;Liu et al, 2010) and detailed rock magnetic studies (Maher and Thompson, 1991;Banerjee et al, 1993;Introduction Chapter 1 4 1984, 1986;Kukla et al, 1988;Hovan et al, 1989;Ding et al, 2002) and short-term climate instability Zhu et al, 2004;Liu et al, 2005a), have been obtained for the last 2.6 Ma from Chinese loess/paleosol sequences. Liu (1984, 1986) first recognized that low-field magnetic susceptibility variations in Chinese loess/paleosol sequences correlate with marine oxygen isotope records.…”

Section: A Brief History Of Loess Studiesmentioning

confidence: 99%

“…More work needs to be done to adequately understand how Chinese loess records paleomagnetic information. It has been claimed that Chinese loess can record relative geomagnetic paleointensity variations (Liu et al, 2005a). This possibility needs testing in light of experimental work to determine the remanence acquisition mechanism(s) in Chinese loess.…”

Section: Paleointensitymentioning

confidence: 99%

“…These climate changes are recorded over the last 2.6 million years (Ma) in loess/paleosol sequences Liu, 1982, 1984;Liu et al, 1988a;Rutter et al, 1990) and back to 22 Ma in the underlying Red Clay sequences . High loess accumulation rates preserve paleoclimate signals that can be analysed at high resolution, including millennial-scale climate changes (e.g., Liu et al, 2005a).…”

Section: Introductionmentioning

confidence: 99%

“…However, several attempts to determine relative paleointensity have been published for the Chinese loess (Zheng et al, 1995;Zhu et al, 1999;Pan et al, 2001;Liu et al, 2005a). and Liu et al (2005a) concentrated on the S1 interval.…”

Section: Introductionmentioning

confidence: 99%

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How does Chinese loess become magnetized?

Zhao

Roberts

2010

Earth and Planetary Science Letters

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Thick loess deposits on the Chinese Loess Plateau provide an outstanding archive of paleoclimate, geomagnetic field and paleoenvironmental changes over at least the last 2.6 Ma. Much work on magnetic polarity reversals, pedogenic magnetic enhancement and climatic change has been carried out over the past 30 years. However, questions about how Chinese loess becomes magnetized remain unanswered. In this thesis, I have sought to address key questions concerning magnetization processes in the Chinese loess. To understand magnetization processes, it is important to understand which magnetic minerals are present and the processes that caused them to be present. Magnetic and other analyses of both loess and paleosol samples indicate that pedogenic superparamagnetic and single domain magnetite and hematite can be present. The mass concentration of hematite can exceed 90% of the magnetic particle assemblage. An eolian dust deposition simulator designed for laboratory redeposition experiments was then used to demonstrate that both a depositional remanent magnetization (DRM) and a post-depositional remanent magnetization (PDRM) can be acquired by Chinese loess. Water content significantly affects the efficiency of PDRM acquisition. No significant PDRM was observed when the water content was below a critical threshold of 40%. Published paleomagnetic data from the Chinese loess indicate the widespread occurrence of inclination error. Detailed paleomagnetic studies of U-channel samples from the last loess/paleosol sequence at Yuanbao were made to assess whether the Chinese loess can accurately record geomagnetic relative paleointensity variations. Three normalized remanence records were determined using conventional normalization as well as the pseudo-Thellier method. Strong coherence among the normalized remanence records indicate that the whole range of magnetic minerals has been affected by pedogenesis. Poor similarity among published normalized remanence records from the Chinese loess, as well as with marine relative paleointensity records indicate that the Chinese loess is not suitable for relative paleointensity determinations. The range of magnetic minerals present and their varying distribution within loess and paleosol sediments indicate that the magnetization is due to a mixture of remanence acquisition mechanisms including DRM, PDRM, chemical remanent magnetization (CRM) and viscous remanent magnetizations, which also indicates complexities in remanence acquisition that will complicate attempts to extract relative paleointensity information. This thesis has provided an improved understanding of the mechanisms of Chinese loess magnetization, and re-emphasizes the importance of pedogenic CRM acquisition.

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Section: Introductionmentioning

confidence: 68%

Section: A Brief History Of Loess Studiesmentioning

confidence: 99%

Section: Paleointensitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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How does Chinese loess become magnetized?

Zhao

Roberts

2010

Earth and Planetary Science Letters

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Timing and lock‐in effect of the Laschamp geomagnetic excursion in Chinese Loess

Sun

Qiang

Liu

et al. 2013

Geochem Geophys Geosyst

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[1] The Laschamp geomagnetic excursion (LGE, at 41 ka) is a critical age control for hemispherical comparison of paleoclimate records from various kinds of geological archives (e.g., ice core, marine, and lake sediments). The timing of the LGE in Chinese Loess, however, remains poorly constrained due to the lack of a reliable chronology and the complex acquisition processes of natural remanent magnetization. Here, we systematically compare the paleomagnetic results of three optically stimulated luminescence dated loess sequences on the Chinese Loess Plateau. Our results indicate that the timing of the LGE in the northwestern Loess Plateau is slightly older than the absolute radiometric age determination and the timing inferred from Greenland ice core ( 10 Be flux) and marine (i.e., relative paleointensity and authogenic 10 Be/ 9 Be stack) records, but younger than the counterparts in the central Loess Plateau. We attribute the different timing of the LGE in the three loess sections to a progressive southeastward increase in the lock-in depth caused by the combined effects of postdepositional processes (e.g., surface mixing, chemical weathering, and lock-in delay) on the remanence acquisition process. We conclude that caution is needed to use the LGE in Chinese Loess as a reliable tie-event for highresolution chronological correlation to marine and ice core records, only if the potential lock-in effect can be precisely determined.

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Estimating the concentration of aluminum‐substituted hematite and goethite using diffuse reflectance spectrometry and rock magnetism: Feasibility and limitations

Jiang

Liu

et al. 2016

JGR Solid Earth

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Hematite and goethite in soils are often aluminum (Al) substituted, which can dramatically change their reflectance and magnetic properties and bias abundance estimates using diffuse reflectance spectroscopy (DRS) and magnetic techniques. In this study, synthetic Al‐substituted hematites and goethites and two Chinese loess/paleosol sequences were investigated to test the feasibility and limitations of estimating Al‐hematite and Al‐goethite concentration. When Al substitution is limited (Al/(Al + Fe) molar ratio < ~8%), the reflectance spectrum provides a reliable estimate of the goethite/hematite concentration ratio. New empirical relationships between the DRS band intensity ratio and the true concentration goethite/hematite ratio are estimated as goethite/hematite = 1.56 × (I425 nm/I535 nm) or goethite/hematite = 6.32 × (I480 nm/I535 nm), where I425 nm, I480 nm, and I535 nm are the amplitudes of DRS second‐derivative curves for characteristic bands at ~425 nm, ~480 nm, and ~535 nm, respectively. High Al substitution (> ~8%) reduces DRS band intensity, which leads to biased estimates of mineral concentration. Al substitution and grain size exert a control on coercivity distributions of hematite and goethite and, thus, affect the hard isothermal remanent magnetization. By integrating DRS and magnetic methods, we suggest a way to constrain hematite and goethite Al substitution in natural loess. Results indicate that hematite and goethite in Chinese loess have Al contents lower than ~8% and, thus, that DRS can be used to trace hematite and goethite concentration variations.

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Inter-profile correlation of the Chinese loess/paleosol sequences during Marine Oxygen Isotope Stage 5 and indications of pedogenesis

Cited by 59 publications

References 74 publications

How does Chinese loess become magnetized?

How does Chinese loess become magnetized?

Timing and lock‐in effect of the Laschamp geomagnetic excursion in Chinese Loess

Estimating the concentration of aluminum‐substituted hematite and goethite using diffuse reflectance spectrometry and rock magnetism: Feasibility and limitations

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