Grain growth and transformation of pedogenic magnetic particles in red Ferralsols

Long, Xiaoyong; Ji, Junfeng; Balsam, William; Barrón, Vidal; Torrent, J.

doi:10.1002/2015gl064678

Cited by 26 publications

(16 citation statements)

References 41 publications

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“…sequence. The grain growth of FM particles has also been observed in our previous studies on the climosequence with dramatic changes in Hm/(Hm + Gt) (Long et al, 2015). However, the Hm/ (Hm + Gt) values in the two sequences are comparable, and therefore, the difference in the accumulation efficiency of different FM particles should be controlled by the contrasting P/Fe ranges.…”

Section: 1029/2020gl090439supporting

confidence: 76%

“…However, the relative formation efficiency of Mgh and Hm seems to be modulated by water activity (Long et al, 2016) and ligand adsorption of precursor iron oxides (Cabello et al, 2009) due to the similar thermodynamic stability of Mgh and Hm in nanometers (Navrotsky et al, 2008). Our previous study found significant grain growth of Mgh particles and their transformation to Hm in tropical Ferralsol, with a high formation efficiency estimated by Hm/(Hm + Gt) above 0.6 (Long et al, 2015). However, in some red soils and sediments with relatively high chemical weathering intensity formed in warm periods (Fang et al, 2003; Guo et al, 2002; Ren et al, 2020), the asynchronous change of redness and magnetism can also be frequently observed (Chen et al, 2019; Jiang et al, 2015; Nie et al, 2016; Walker et al, 1981), although the Hm/(Hm + Gt) fluctuates slightly below 0.6, and the positive correlation between redness and magnetism is still maintained in these soils and sediments (Balsam et al, 2004; Ding et al, 2001; Ji et al, 2004; Torrent et al, 2006).…”

Section: Introductionmentioning

confidence: 95%

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Different Enrichment Patterns of Magnetic Particles Modulated by Primary Iron‐Phosphorous Input

Ren

Long

et al. 2020

Geophysical Research Letters

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Magnetic particles associated with iron (Fe) oxides are widespread on the surface of Earth and Mars and serve as reasonable climatic indicators. Ferrimagnetic maghemite (Mgh) and antiferromagnetic hematite (Hm), which dominate magnetism and redness, often coexist or compete with each other in soils and sediments. The formation efficiency of Mgh relative to Hm could be modulated by geochemical background besides climate, especially by phosphate (P), which has a high affinity for the surfaces of precursor iron oxides in natural systems. We investigated two Ferralsol sequences around a P mining field with similar climates and contrasting P/Fe ratios. High P/Fe ratios retard iron oxide crystallization, grain growth, and transformation into Hm, thereby promoting more effective accumulation of ferrimagnetic Mgh as an intermediate product. The lack of ligand-protected effects well interprets asynchronous changes in magnetism and redness in soils and sediments across large spatiotemporal scales, especially in highly weathered soils. Plain Language Summary Iron oxides are critical carriers of magnetism and dyeing agents of soils and sediments. The concentration of pedogenic maghemite (Mgh) and hematite (Hm), which dominate magnetism and redness, is considered to be controlled by the primary iron input and climate conditions. However, phosphate exhibits a high affinity for the surfaces of precursor iron oxides, especially in highly weathered soils. We investigated two Ferralsol sequences around a P mining field with contrasting P/Fe ratios but similar climates. High P/Fe ratios are observed to impede iron oxide crystallization, grain growth, and transformation into Hm, thereby promoting more effective accumulation of ferrimagnetic Mgh as an intermediate product. The presence and absence of ligand-protected effects help explain asynchronous changes in magnetism and color in nature systems across large spatiotemporal scales.

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Section: 1029/2020gl090439supporting

confidence: 76%

Section: Introductionmentioning

confidence: 95%

Different Enrichment Patterns of Magnetic Particles Modulated by Primary Iron‐Phosphorous Input

Ren

Long

et al. 2020

Geophysical Research Letters

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“…In the LZ, SP and SD particles have a similar formation rate with magnetic enhancement, whereas in the UZ, the production rate of SP particles is higher than that of SD particles (Figure e). Long et al [] reported that χ FD / χ ARM ratios increase rapidly with low χ (~100–1000 × 10 −8 m 3 kg −1 ) but remain constant at high χ (~1000–3000 × 10 −8 m 3 kg −1 ) in red Ferralsols. However, the different formation rate between SP and SD particles is controlled mainly by water content, temperature, and Fe supply in the soil.…”

Section: Discussionmentioning

confidence: 99%

“…Although fine magnetic particles were formed, the topsoil had a lower χ than the parent basalt. Recently, Long et al [] investigated the magnetic properties of three red Ferralsols from localities with MAP from 1440 to 1650 mm/yr and noted that χ is generally 3–20 times higher than that of unweathered basalt and ferrimagnetic material becomes enriched as the hematite (Hm) content increases in the profile. Due to soil drainage and leaching processes, magnetic properties differ greatly among these red soils, despite their similar parent material.…”

Section: Introductionmentioning

confidence: 99%

Magnetism of a red soil core derived from basalt, northern Hainan Island, China: Volcanic ash versus pedogenesis

Liu

Wei

et al. 2017

JGR Solid Earth

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Similar to loess‐paleosol sequences in northwestern China, terrestrial sedimentary sequences (red soils) in southern China also provide sensitive Quaternary records of subtropical/tropical paleoclimate and paleoenvironment. Compared with red clay sequences originated from eolian dust, red soils derived from bedrock have received little attention. In this study, a long core of red soil derived from weathered basalt in northern Hainan Island, China, was systematically investigated by using detailed magnetic measurements and rare earth element analyses. The results show that an extremely strong magnetic zone with a maximum magnetic susceptibility (>10 × 10−5 m3 kg−1) is interbedded in the middle of the core profile. This layer contains a significant amount of superparamagnetic magnetite/maghemite particles that primarily originated from volcanic ash, with secondary contributions from pedogenesis. The former has an average grain size of ~19 nm with a normal distribution of volume, and the latter has a much wider grain size distribution. The presence of volcanic ash within the red soil indicates that these Quaternary basalts were not formed by continuous volcanic eruptions. Moreover, the magnetic enhancement patterns differ between the upper and lower zones. The upper zone is more magnetically enhanced and experienced higher precipitation and temperature than the lower zone. Discrimination of superparamagnetic particles originating from pedogenic processes and volcanic ash thus provides a sound theoretical base for accurate interpretation of magnetism in red soils in this region.

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“…The classic viewpoint (Schwertmann and Taylor, 1989) argues that the hematite forms by dehydrating ferrihydrites and thus high temperature and dry climate favor formation of hematite. on the other hand, some authors propose that the production of hematite results from the aging of maghemite grains that are in turn produced by the aging of ferrihydrites (Torrent et al, 2006;Liu et al, 2008Liu et al, , 2012Long et al, 2015). Therefore, future studies need to continue to focus on clarifying the formation mechanisms of hematite and goethite.…”

Section: Future Research Directionsmentioning

confidence: 99%

A Review of Recent Advances in Red-Clay Environmental Magnetism and Paleoclimate History on the Chinese Loess Plateau

2016

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The red-clay sequence on the Chinese Loess Plateau (CLP) was deposited during the late Miocene-Pliocene and is encoded with important information of past climate changes. However, it has received much less study in comparison to the overlying Pleistocene loess-paleosol sequence. In this paper, we review recent progress in characterizing the environmental magnetic parameter-based paleoclimate history recorded by the red-clay sequence. Several key conclusions are as follows. (1) the red-clay and the loess-paleosol sequences have similar magnetic enhancement mechanisms but magnetic minerals in the red-clay sequence have experienced a higher degree of oxidation than in the loess-paleosol sequence. (2) The CLP experienced a cooling and wetting trend from 4.5 to 2.7 Ma, caused by ice sheet expansion and East Asian summer monsoon intensification, respectively. (3) The above conclusions benefit from backfield remanence curve unmixing and comparison of magnetic grain size/concentration records, which are particularly useful in separating the temperature from the precipitation signal. A clear need in future studies is to explore the concentration and the grain size variations of hematite and goethite in the red-clay sequence and their formation mechanisms. The payback would be a clear understanding of climate history during the late Miocene-Pliocene, a possible analog for future warmer climate.

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Grain growth and transformation of pedogenic magnetic particles in red Ferralsols

Cited by 26 publications

References 41 publications

Different Enrichment Patterns of Magnetic Particles Modulated by Primary Iron‐Phosphorous Input

Different Enrichment Patterns of Magnetic Particles Modulated by Primary Iron‐Phosphorous Input

Magnetism of a red soil core derived from basalt, northern Hainan Island, China: Volcanic ash versus pedogenesis

A Review of Recent Advances in Red-Clay Environmental Magnetism and Paleoclimate History on the Chinese Loess Plateau

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