A paleomagnetic record in loess–paleosol sequences since late Pleistocene in the arid Central Asia
Abstract Geomagnetic excursions during Brunhes epoch have been brought to the forefront topic in paleomagnetic study, as they provide key information about Earth’s interior dynamics and could serve as another tool for stratigraphic correlation among different lithology. Loess–paleosol sequences prov...
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doaj-ef5265a98e3543409a6d68383b4f37db2020-11-25T00:34:18ZengSpringerOpenEarth, Planets and Space1880-59812018-03-0170111310.1186/s40623-018-0814-8A paleomagnetic record in loess–paleosol sequences since late Pleistocene in the arid Central AsiaGuanhua Li0Dunsheng Xia1Erwin Appel2Youjun Wang3Jia Jia4Xiaoqiang Yang5Guangdong Provincal Key Laboratory of Geodynamics and Geohazards, School of Earth Sciences and Engineering, Sun Yat-sen UniversityMOE Key LABORATORY of Western China’s Environmental Systems, College of Earth and Environmental Sciences, Lanzhou UniversityDepartment of Geoscience, Eberhard Karls Universität TübingenMOE Key LABORATORY of Western China’s Environmental Systems, College of Earth and Environmental Sciences, Lanzhou UniversityMOE Key LABORATORY of Western China’s Environmental Systems, College of Earth and Environmental Sciences, Lanzhou UniversityGuangdong Provincal Key Laboratory of Geodynamics and Geohazards, School of Earth Sciences and Engineering, Sun Yat-sen UniversityAbstract Geomagnetic excursions during Brunhes epoch have been brought to the forefront topic in paleomagnetic study, as they provide key information about Earth’s interior dynamics and could serve as another tool for stratigraphic correlation among different lithology. Loess–paleosol sequences provide good archives for decoding geomagnetic excursions. However, the detailed pattern of these excursions was not sufficiently clarified due to pedogenic influence. In this study, paleomagnetic analysis was performed in loess–paleosol sequences on the northern piedmont of the Tianshan Mountains (northwestern China). By radiocarbon and luminance dating, the loess section was chronologically constrained to mainly the last c.130 ka, a period when several distinct geomagnetic excursions were involved. The rock magnetic properties in this loess section are dominated by magnetite and maghemite in a pseudo-single-domain state. The rock magnetic properties and magnetic anisotropy indicate weakly pedogenic influence for magnetic record. The stable component of remanent magnetization derived from thermal demagnetization revealed the presence of two intervals of directional anomalies with corresponding intensity lows in the Brunhes epoch. The age control in the key layers indicates these anomalies are likely associated with the Laschamp and Blake excursions, respectively. In addition, relative paleointensity in the loess section is basically compatible with other regional and global relative paleointensity records and indicates two low-paleointensity zones, possibly corresponding to the Blake and Laschamp excursions, respectively. As a result, this study suggests that the loess section may have the potential to record short-lived excursions, which largely reflect the variation of dipole components in the global archives.http://link.springer.com/article/10.1186/s40623-018-0814-8Geomagnetic excursionBlake excursionLaschamp excursionRelative paleointensityLoessArid Central Asia |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Guanhua Li Dunsheng Xia Erwin Appel Youjun Wang Jia Jia Xiaoqiang Yang |
spellingShingle |
Guanhua Li Dunsheng Xia Erwin Appel Youjun Wang Jia Jia Xiaoqiang Yang A paleomagnetic record in loess–paleosol sequences since late Pleistocene in the arid Central Asia Earth, Planets and Space Geomagnetic excursion Blake excursion Laschamp excursion Relative paleointensity Loess Arid Central Asia |
author_facet |
Guanhua Li Dunsheng Xia Erwin Appel Youjun Wang Jia Jia Xiaoqiang Yang |
author_sort |
Guanhua Li |
title |
A paleomagnetic record in loess–paleosol sequences since late Pleistocene in the arid Central Asia |
title_short |
A paleomagnetic record in loess–paleosol sequences since late Pleistocene in the arid Central Asia |
title_full |
A paleomagnetic record in loess–paleosol sequences since late Pleistocene in the arid Central Asia |
title_fullStr |
A paleomagnetic record in loess–paleosol sequences since late Pleistocene in the arid Central Asia |
title_full_unstemmed |
A paleomagnetic record in loess–paleosol sequences since late Pleistocene in the arid Central Asia |
title_sort |
paleomagnetic record in loess–paleosol sequences since late pleistocene in the arid central asia |
publisher |
SpringerOpen |
series |
Earth, Planets and Space |
issn |
1880-5981 |
publishDate |
2018-03-01 |
description |
Abstract Geomagnetic excursions during Brunhes epoch have been brought to the forefront topic in paleomagnetic study, as they provide key information about Earth’s interior dynamics and could serve as another tool for stratigraphic correlation among different lithology. Loess–paleosol sequences provide good archives for decoding geomagnetic excursions. However, the detailed pattern of these excursions was not sufficiently clarified due to pedogenic influence. In this study, paleomagnetic analysis was performed in loess–paleosol sequences on the northern piedmont of the Tianshan Mountains (northwestern China). By radiocarbon and luminance dating, the loess section was chronologically constrained to mainly the last c.130 ka, a period when several distinct geomagnetic excursions were involved. The rock magnetic properties in this loess section are dominated by magnetite and maghemite in a pseudo-single-domain state. The rock magnetic properties and magnetic anisotropy indicate weakly pedogenic influence for magnetic record. The stable component of remanent magnetization derived from thermal demagnetization revealed the presence of two intervals of directional anomalies with corresponding intensity lows in the Brunhes epoch. The age control in the key layers indicates these anomalies are likely associated with the Laschamp and Blake excursions, respectively. In addition, relative paleointensity in the loess section is basically compatible with other regional and global relative paleointensity records and indicates two low-paleointensity zones, possibly corresponding to the Blake and Laschamp excursions, respectively. As a result, this study suggests that the loess section may have the potential to record short-lived excursions, which largely reflect the variation of dipole components in the global archives. |
topic |
Geomagnetic excursion Blake excursion Laschamp excursion Relative paleointensity Loess Arid Central Asia |
url |
http://link.springer.com/article/10.1186/s40623-018-0814-8 |
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