气候变化领域集成服务门户(CCPortal): Particle-size dependent magnetic properties of Scotia Sea sediments since the Last Glacial Maximum: Glacial ice-sheet discharge controlling magnetic proxies

CCPortal

DOI	10.1016/j.palaeo.2020.109906
	Particle-size dependent magnetic properties of Scotia Sea sediments since the Last Glacial Maximum: Glacial ice-sheet discharge controlling magnetic proxies
	Shin J.Y.; Kim S.; Zhao X.; Yoo K.-C.; Yu Y.; Lee J.I.; Lee M.K.; Yoon H.I.
发表日期	2020
ISSN	0031-0182
卷号	557
英文摘要	The strong glacial–interglacial similarity between the magnetic susceptibility (MS) of Southern Ocean sediments and Antarctic ice core dust records has often been used to reconstruct Southern Hemisphere atmospheric variability. Although evaluation of various magnetic properties is essential for identifying the magnetic carriers linked to sedimentological variation, detailed magnetic studies are not sufficient in the Scotia Sea. Here we investigate the bulk and particle-size dependent magnetic properties of Scotia Sea sediments over the past ~22 kyr, to determine the main sediment transport mechanism driving bulk magnetic proxies including MS. In bulk sediments, MS is highest during the last glacial period and is accompanied by an increase in the concentration and grain size of ferrimagnetic and antiferromagnetic minerals. For magnetic mineral assemblages, coarse detrital magnetite is dominant. Of three particle-size fractions (>63, 16–63, and <16 μm), the coarse silt fraction (16–63 μm) is responsible for the magnetic properties of bulk glacial sediments. Such dominant contribution of coarse silts rules out a major input of dust, which is expected as finer silt and clay. The silt fraction exhibits a co-varying magnetic mineral concentration with that of the sand fraction (>63 μm) throughout the last deglaciation, indicating a close linkage between their input mechanisms. Thus, the sediment particles ranging from sand to coarse silt, which control the bulk glacial magnetic proxies, are most plausibly transported by iceberg-rafted debris (IRD). As hematite is relatively concentrated in the sand fraction, the hematite contribution in the bulk sediment can highlight IRD-related magnetic signals rather than magnetite. The bulk hematite contribution simultaneously varies with the deglacial influx of coarse IRD particles (>1 mm) in Scotia Sea sediments, although their glacial inconsistency possibly suggests a different IRD input mechanism during the advancement and retreat of the ice sheet. Consequently, the glacial increase in the bulk magnetic concentration indicates vigorous iceberg calving activity in the Scotia Sea and further suggests the coupled cryosphere–atmosphere system. © 2020 Elsevier B.V.
英文关键词	Glacial period; Iceberg-rafted debris; Magnetic property; Particle-size dependence; Southern Ocean
语种	英语
scopus关键词	glacial-interglacial cycle; hematite; ice core; iceberg calving; last deglaciation; Last Glacial Maximum; magnetic mineral; magnetic susceptibility; magnetite; marine sediment; particle size; sediment transport; sedimentology; size distribution; Southern Hemisphere; Atlantic Ocean; Scotia Sea; Southern Ocean
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150366
作者单位	Deep-sea Mineral Resources Research Center, Korea Institute of Ocean Science and Technology, Busan, 49111, South Korea; Korea Polar Research Institute, Incheon, 21990, South Korea; Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia; Department of Astronomy, Space Science, and Geology, Chungnam National University, Daejeon, 34134, South Korea
推荐引用方式 GB/T 7714	Shin J.Y.,Kim S.,Zhao X.,et al. Particle-size dependent magnetic properties of Scotia Sea sediments since the Last Glacial Maximum: Glacial ice-sheet discharge controlling magnetic proxies[J],2020,557.
APA	Shin J.Y..,Kim S..,Zhao X..,Yoo K.-C..,Yu Y..,...&Yoon H.I..(2020).Particle-size dependent magnetic properties of Scotia Sea sediments since the Last Glacial Maximum: Glacial ice-sheet discharge controlling magnetic proxies.Palaeogeography, Palaeoclimatology, Palaeoecology,557.
MLA	Shin J.Y.,et al."Particle-size dependent magnetic properties of Scotia Sea sediments since the Last Glacial Maximum: Glacial ice-sheet discharge controlling magnetic proxies".Palaeogeography, Palaeoclimatology, Palaeoecology 557(2020).