Apparent timing and duration of the <scp>M</scp>atuyama‐<scp>B</scp>runhes geomagnetic reversal in <scp>C</scp>hinese loess

Zhao, Hui; Qiang, Xiaoke; Sun, Youbin

doi:10.1002/2014gc005497

Cited by 10 publications

(14 citation statements)

References 84 publications

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“…This is much more complex than those seen in North Atlantic sediments (Channell et al 2010), and also differs from the reconstruction of the dynamics of geomagnetic field reversals recently reported by Valet et al (2012). Further, the duration lasts too long to match with other recent records for the duration of M-B transition on the southern and central CLP Zhao et al 2014;Zhou et al 2014). The VGPs repeatedly bounce back and forth between northern and southern polar regions and lack almost any intermediate directions, and thus may not represent the true geomagnetic field behaviour.…”

Section: Constraints On the Mbb Of The Yushan Sectioncontrasting

confidence: 84%

“…More recently, high-resolution paleomagnetic records from the marginal areas of the CLP (western and NE/SE CLP) showed significantly varying M-B transition records and apparently complex remanence acquisition processes in the loess (Wang et al 2014). Zhao et al (2014) analysed the paleomagnetic records of the previously published high-resolution results of four loess sections (Luochuan, Xifeng, Lingtai, and Baoji) from the central to southern CLP, showing apparently consistent features of the M-B transition over these sections including the location of the MBB in the L8/S8 transition.…”

mentioning

confidence: 99%

“…Liu 1985). The Quaternary loess in the Lantian Basin is characterized by a relatively low sedimentation rate, approximately 4.7-6.7 cm ka −1 (Bloemendal & Liu 2005;Wu et al 2010); thus, the basic structure of M-B transition could be easily obtained because its duration may have been probably >10 ka (Hyodo et al 2006;Yang et al 2010;Wang et al 2014;Zhao et al 2014), even though the duration may change with the latitude of observation (Clement 2004). Therefore, a highresolution and continuous paleomagnetic record in this area may help to locate and uncover details of the polarity transition across the M-B reversal boundary in loess.…”

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confidence: 99%

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Magnetic stratigraphy constraints on the Matuyama–Brunhes boundary recorded in a loess section at the southern margin of Chinese Loess Plateau

Zhu

Qiu

et al. 2015

Geophys. J. Int.

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S U M M A R YAlthough the Matuyama-Brunhes boundary (MBB) in the Chinese Loess Plateau (CLP) is very important in reliably correlating Quaternary loess with other sediments in the world, particularly with marine and polar ice cores, its exact stratigraphic position remains controversial. Previous investigations usually placed the MBB between paleosol unit S8 and loess unit L8 in various locations. To better understand the spatial differences in the MBB position, a high-resolution paleomagnetic study was conducted in a loess section of the Lantian Basin at the southern margin of the CLP. The results show that the MBB is situated in the middle of the relatively weak paleosol unit S7, consistent with a recent report on the MBB based on a 10 Be study from the Xifeng and Luochuan loess sections of the central CLP. However, the regional anomalously low magnetic susceptibility in paleosols S7 and S8 indicates that it is more reliable to determine the paleoclimate boundaries between loess and paleosol horizons of this segment with median grain size. Then, the MBB in the Yushan section can be correlated with the bottom of paleosol S7, corresponding to the older part of interglacial marine isotope stage 19. This result temporally reconciles the striking discrepancy of the position of the MBB recorded in between loess and other typical sedimentary sequences, and further confirms that the stratigraphic position of the MBB could spatially vary to a certain extent due to regional sedimentary or paleoclimatic conditions in the marginal areas of the CLP. In the Yushan section, the high-frequency variations of paleomagnetic directions during a long period of ∼31 ka before the MBB, however, could not be attributed to a genuine response to the true geomagnetic behaviour. Moreover, the climate offset defined by the magnetic susceptibility and median grain size of the section can be preliminarily attributed to the regional geology and paleoenvironment background. A multiproxy-based stratigraphic division is considered very necessary when paleomagnetic and climatic boundaries are defined exactly in a specific area of the southern CLP.

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Section: Constraints On the Mbb Of The Yushan Sectioncontrasting

confidence: 84%

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confidence: 99%

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confidence: 99%

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Magnetic stratigraphy constraints on the Matuyama–Brunhes boundary recorded in a loess section at the southern margin of Chinese Loess Plateau

Zhu

Qiu

et al. 2015

Geophys. J. Int.

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“…A similar strategy was proposed to deal with the long-standing discrepancy of Matuyama-Brunhes boundary (MBB) between Chinese loess and marine sediments (e.g., Wang et al 2006;Liu et al 2008;Jin and Liu 2011b). These adjustments would bring the marine and terrestrial records into better age agreements for both the TJ and MBB but might result in a confused correlation of Chinese loess-paleosol sequences and marine sediments (e.g., Zhao et al 2014;Zhou et al 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, numerous studies have focused on the exact identification and/or detailed processes of geomagnetic reversals (Heller and Liu 1982;Sun et al 1993;Zhu et al 1994;Spassov et al 2001Spassov et al , 2003Pan et al 2002;Liu et al 2008;Yang et al 2005Yang et al , 2014Liu 2010, 2011b;Wang et al 2014;Zhao et al 2014;Zhou et al 2014) and excursions (Zhu et al 1998Fang et al 1997;Pan et al 2002;Yang et al 2004Yang et al , 2007aYang et al , 2007bYang et al , 2008Jin et al 2012;Sun et al 2013) recorded in Chinese loess.…”

Section: Introductionmentioning

confidence: 99%

A sedimentary paleomagnetic record of the upper Jaramillo transition from the Lantian Basin in China

Ouyang

Qiu

et al. 2015

Earth Planet Sp

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The termination of the Jaramillo (normal to reverse) subchron is a key chronostratigraphic marker for dating global Pleistocene sedimentary sequences. However, the stratigraphic position of the geomagnetic polarity reversal varies greatly across the Chinese Loess Plateau (CLP), from near the bottom of paleosol unit S9 to the middle-upper part of S10. Here, we present paleomagnetic and rock magnetic results from high-resolution sampling of the Yushan loess section of the Lantian Basin located within the southern CLP. Our combined analyses determine that the polarity reversal is located in the middle-lower part of the paleosol unit S10. This stratigraphic position is lower than most of other studies conducted throughout the CLP. We attribute the difference in the location of the reversal to a deeper lock-in depth of remanence acquisition, which may have occurred from postdepositional processes under favorable hydrothermal conditions along the southern margin of CLP. It is important to note that age determinations through magnetic stratigraphy on sedimentary sections, particularly in discontinuous and/or imperfect sequences, should be treated with caution; there are significant differences with respect to the location of the polarity reversal throughout the CLP.

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Occurrence of greigite in the Pliocene sediments of Lake Qinghai, China, and its paleoenvironmental and paleomagnetic implications

Bloemendal

Qiang

et al. 2015

Geochem Geophys Geosyst

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Lake Qinghai in North China is the largest interior plateau lake in Central Asia and is climaticallysensitive. An almost continuous 626 m long sediment core was drilled in an infilled part of the southern lake basin of Lake Qinghai. The magnetic susceptibility record reveals the presence of two distinct peaks within an interval of fine-grained lacustrine sediments of Lower Pliocene age. We selected a depth interval of approximately 40 m spanning the magnetic susceptibility peaks for detailed rock magnetic and geochemical analyses in order to identify the magnetic mineralogy responsible and to assess its possible paleoenvironmental and paleomagnetic implications. Rock magnetic, X-ray diffraction analysis, scanning electron microscopy (SEM), and energy dispersive analysis of X-ray (EDAX) analyses reveal that the main magnetic carrier is greigite (Fe 3 S 4 ). The greigite is of early diagenetic origin and formed in an inerval of high lake level and inferred relatively warm, humid climate. The greigite-enriched zones are separated by an interval of relatively high total sulfur and organic carbon content, and we infer that in the adjacent greigite-bearing zones, the lower concentrations of sulfur and organic carbon, and high levels of reactive iron, arrested the process of pyritization resulting in the preservation of the greigite on a time scale of several million years. The greigite zones contain narrow intervals of normally magnetized sediments which may be previously unrecognized cryptochrons within the Gilbert Chron, or alternatively they may reflect the continued formation of greigite long after the age of deposition of the surrounding sediment matrix.

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Apparent timing and duration of the Matuyama‐Brunhes geomagnetic reversal in Chinese loess

Cited by 10 publications

References 84 publications

Magnetic stratigraphy constraints on the Matuyama–Brunhes boundary recorded in a loess section at the southern margin of Chinese Loess Plateau

Magnetic stratigraphy constraints on the Matuyama–Brunhes boundary recorded in a loess section at the southern margin of Chinese Loess Plateau

A sedimentary paleomagnetic record of the upper Jaramillo transition from the Lantian Basin in China

Occurrence of greigite in the Pliocene sediments of Lake Qinghai, China, and its paleoenvironmental and paleomagnetic implications

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