气候变化领域集成服务门户(CCPortal): Palaeo- and rock magnetic investigations of Late Quaternary sediments from the Upper Congo deep-sea fan: on the difficulty in obtaining palaeomagnetic secular variation records from low latitudes

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DOI	10.1007/s00531-018-1653-3
	Palaeo- and rock magnetic investigations of Late Quaternary sediments from the Upper Congo deep-sea fan: on the difficulty in obtaining palaeomagnetic secular variation records from low latitudes
	Frank U.; Nowaczyk N.R.; Frederichs T.; Liu J.; Korte M.
发表日期	2019
ISSN	14373254
起始页码	267
结束页码	285
卷号	108 期号:1
英文摘要	We report here on results of palaeo- and rock magnetic investigations of two sediment cores from the Upper Congo deep-sea fan. The sediments have a high organic content and contain a heterogeneous Fe-mineral assemblage with biogenic magnetite and detrital (Ti-)magnetite as the main magnetic carrier minerals. Pyrite, hematite, and Fe-oxyhydroxides were identified by comparing high-temperature magnetic susceptibility curves with those from Fe-minerals of known composition. According to AMS 14 C dates, the 6.8 m-long profile spans the last 37 kyr. Sediments older than 20 ka are affected by reductive diagenesis that has led to a loss of the fine-grained magnetic mineral fraction. Sediments younger than 20 ka have stable magnetizations. Characteristic remanent magnetization records of inclination and declination were obtained for each core. There is a little agreement between these records, modelled curves, and other sediment records from Equatorial Africa, so no composite record could be established. The cores are not ideal relative palaeointensity recorders and estimates using different normalizers did not yield consistent signals from both cores. Normalization methods used for relative palaeointensity estimation were not developed for sediments that contain large amounts of ultra-fine-grained biogenic magnetite; therefore, the relative palaeointensity estimates should be considered with caution. However, in view of the incoherent picture given by the scarce available palaeointensity information from the region off South-West Africa, the GeoB6517-2 record may provide a tentative relative palaeointensity record for comparison, at least for the past 10 kyr. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Late quaternary; Magnetic mineralogy; Palaeointensity; Palaeomagnetic secular variation; Upper Congo deep-sea fan
语种	英语
scopus关键词	magnetic susceptibility; magnetite; magnetization; paleointensity; paleolatitude; paleomagnetism; Quaternary; secular variation; sedimentary rock; submarine fan; Atlantic Ocean; Congo Canyon; Gorgonacea
来源期刊	International Journal of Earth Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/147888
作者单位	GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Faculty of Geosciences, University of Bremen, Klagenfurter Strasse, Bremen, 28359, Germany
推荐引用方式 GB/T 7714	Frank U.,Nowaczyk N.R.,Frederichs T.,et al. Palaeo- and rock magnetic investigations of Late Quaternary sediments from the Upper Congo deep-sea fan: on the difficulty in obtaining palaeomagnetic secular variation records from low latitudes[J],2019,108(1).
APA	Frank U.,Nowaczyk N.R.,Frederichs T.,Liu J.,&Korte M..(2019).Palaeo- and rock magnetic investigations of Late Quaternary sediments from the Upper Congo deep-sea fan: on the difficulty in obtaining palaeomagnetic secular variation records from low latitudes.International Journal of Earth Sciences,108(1).
MLA	Frank U.,et al."Palaeo- and rock magnetic investigations of Late Quaternary sediments from the Upper Congo deep-sea fan: on the difficulty in obtaining palaeomagnetic secular variation records from low latitudes".International Journal of Earth Sciences 108.1(2019).