Estimating the concentration of aluminum‐substituted hematite and goethite using diffuse reflectance spectrometry and rock magnetism: Feasibility and limitations

Hu, Pengxiang; Jiang, Zhaoxia; Liu, Qingsong; Heslop, David; Roberts, Andrew P.; Torrent, J.; Barrón, Vidal

doi:10.1002/2015jb012635

Cited by 35 publications

(36 citation statements)

References 69 publications

(147 reference statements)

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“…Compared with first derivative curves, the band location in second derivative curves is not influenced by other constituents or by the concentration of minerals in mixtures, and the second derivative is more suitable for natural samples (Liu et al, ). Besides natural samples, previous studies have investigated synthetic hematite/goethite samples using DRS and traditional rock magnetic methods and found that the DRS band amplitude in second order derivative curves is a relatively reliable concentration proxy for hematite and goethite (Hu et al, ; Jiang et al, ; Liu et al, ). In this study, we define Rel Hm+Gt to combine the concentration of hematite and goethite.…”

Section: Discussionmentioning

confidence: 99%

“…DRS technology has been used, for example, to identify a combination of hematite and goethite in eolian sediment fractions derived from northwest Africa (Balsam et al, ). Jiang et al () and Hu et al () demonstrated that the combination of DRS and magnetic methods should provide a more reliable approach for determining the concentration of antiferromagnetic minerals in sediments.…”

Section: Introductionmentioning

confidence: 99%

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An Integrated Study of the Eolian Dust in Pelagic Sediments From the North Pacific Ocean Based on Environmental Magnetism, Transmission Electron Microscopy, and Diffuse Reflectance Spectroscopy

Zhang

Liu

et al. 2018

JGR Solid Earth

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Eolian dust is a major terrigenous component in North Pacific Ocean pelagic sediments and is an important recorder of Asian terrestrial environmental evolution and Northern Hemisphere atmospheric circulation. In order to extract and quantify wind‐borne mineral signals and develop a reliable eolian dust proxy for pelagic sediments, we investigated sediments from Ocean Drilling Program Hole 885A, North Pacific Ocean, by integrating results from environmental magnetism, transmission electron microscopy, and diffuse reflectance spectroscopy (DRS). Our results indicate that ferrimagnetic and antiferromagnetic minerals coexist in the sediments. The former includes biogenic magnetite, nano‐sized single domain (titano) magnetite inclusions embedded in silicate hosts, submicron vortex state magnetite, and ultrafine superparamagnetic maghemite. The latter includes hematite and goethite. Our results indicate that magnetic properties can be used to determine an overall trend of increased eolian dust inputs, with additional significant influence from biogenic and volcanogenic components. In contrast, a newly proposed parameter RelHm+Gt (combined hematite and goethite concentration) obtained from DRS measurements extracts precisely the eolian signal and precludes other components. Our DRS results indicate that hematite/goethite and siliceous fractions deposited at Hole 885A were jointly delivered to the North Pacific Ocean from Asian dust sources. Therefore, we suggest that RelHm+Gt is a reliable eolian dust proxy for pelagic sediments in this region.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Integrated Study of the Eolian Dust in Pelagic Sediments From the North Pacific Ocean Based on Environmental Magnetism, Transmission Electron Microscopy, and Diffuse Reflectance Spectroscopy

Zhang

Liu

et al. 2018

JGR Solid Earth

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“…The HIRM, that is, “hard” IRM, is a method used to study the high‐coercivity minerals hematite and goethite (Bloemendal et al, ; Liu et al, ; Thompson & Oldfield, ). The approach of Hu et al () defines the HIRM as

HIRM ((), _{FF, BF}) = ((), {IRM}_{FF} + {IRM}_{BF}) \div 2

…”

Section: Methodsmentioning

confidence: 99%

“…Diffuse reflectance spectroscopy (DRS) is used to interpret the types of magnetic minerals and their concentrations within the paleosols (Deaton & Balsam, ; Hu et al, ; Scheinost et al, ). This method determines sample composition through quantifying the interaction between visible light and the properties imparted to a soil/paleosol by Fe oxides.…”

Section: Methodsmentioning

confidence: 99%

“…These authors identified hematite through the second-derivative amplitude between the~535-nm minimum and thẽ 580-nm maximum. The height of the second derivative peak, that is, the intensity of the wavelength, increases with hematite concentration and the position of the minimum and maximum occurs at different wavelengths as hematite concentration changes and ion substitutions for iron increase (Deaton & Balsam, 1991;Hu et al, 2016;Liu et al, 2011). DRS measurements were made using a Varian Cary 50 photospectrometer fitted with an external integrating sphere.…”

Section: Diffuse Reflectance Spectroscopymentioning

confidence: 99%

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Constraints on Fe‐Oxide Formation in Monsoonal Vertisols of Pliocene Kenya Using Rock Magnetism and Spectroscopy

Lepre

2019

Geochem Geophys Geosyst

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Pliocene Vertisols from the Turkana Basin of northwest Kenya (~4°N latitude) have been examined using isothermal remanent magnetization (IRM) experiments, susceptibility measurements, and diffuse reflectance spectroscopy. The complete vertical profile of each paleosol is almost intact, measuring >2 m in thickness and being strongly magnetic (IRM at 1.0T ranges from 4 to 25 × 10−3 Am2/kg). Downprofile changes to the proxy indicators suggest uninterrupted pedodevelopment and a lack of stratigraphic inversions caused by argilli‐pedoturbation. Magnetic minerals consist of hematite to a lesser degree, and pedogenic ferrimagnets derived from moisture cycles that were controlled by monsoonal rainfall. Basal pedogenic zones of the paleosols are magnetically intense, and preserve the greatest slickenside development indicating pronounced seasonal wetting and drying. These observations indicate a deeper dry season water table as compared to poorly drained temperate/tropical Vertisols, which suffer reductive dissolution of Fe oxides in basal pedogenic horizons associated with weak magnetic intensities. Magnetic susceptibilities and the well‐represented presence of fine pedogenic ferrimagnets suggest that Pliocene rainfall was greater than the local modern rate of 200 mm/year and may have been within the range of 500–1,000 mm/year. The study highlights the need to expand the database on Vertisols Fe oxides and magnetism, especially considering the anomalously dry and bimodal rainfall seasonality of East Africa.

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Iron pools of the typical loess–palaeosol sequence and their environmental significance in northeastern China

Sun,

Wang,

Jiang

et al. 2023

Earth Surf Processes Landf

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The iron content can be used as a proxy for the intensity of weathering and pedogenesis, which reflect long‐term climate cycles and short‐term climate fluctuations and events. In this study, a typical loess–palaeosol sequence for 19.85 m in thickness deposited since 423 ka BP in northeastern China was investigated, and its iron pools were determined. The results reveal that with increasing depth, the abundances of different forms of iron are consistent with the changes in the magnetic susceptibility. Iron (Fe) in all forms is more abundant in the palaeosol than in the loess. The silicate‐bound Fe pool (Fer = Fet − Fed) accounts for 60.4% of the total Fe (Fet), indicating weak pedogenesis. The Fe in the crystalline oxides (Fec = Fed − Feo) is predominantly free Fe (Fed), with a crystallinity [Fey = (Fed − Feo) × 100 / Fed] of as high as 97.2%. The coefficients of variation of the different forms of iron associated with the soil depth are as follows: Fec > Fed > poorly crystalline Fe (Feo) > Fer > Fet. The distribution of the forms of Fe throughout the profile is a clear indicator of the pedogenesis. The Fed, Fec, and Fe freeness (freeness = Fed × 100 / Fet) correlate with the magnetic susceptibility. The neoformation of iron (Fe) oxides was closely related to the degree of pedogenesis. More crystalline Fe oxides were found in the soil layers corresponding to warm interglacial periods. We detected variations in the abundance of the Fe pools for characterizing climate fluctuations that occurred in a short period of time. In this study, we demonstrated that when used in combination with dating techniques, morphological development indices, and magnetic susceptibility, the measurement of soil Fe pools can be extremely useful for tracing the iron evolution in the Earth's critical zone and reconstructing past climatic events in loess–palaeosol sequences.

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Estimating the concentration of aluminum‐substituted hematite and goethite using diffuse reflectance spectrometry and rock magnetism: Feasibility and limitations

Cited by 35 publications

References 69 publications

An Integrated Study of the Eolian Dust in Pelagic Sediments From the North Pacific Ocean Based on Environmental Magnetism, Transmission Electron Microscopy, and Diffuse Reflectance Spectroscopy

An Integrated Study of the Eolian Dust in Pelagic Sediments From the North Pacific Ocean Based on Environmental Magnetism, Transmission Electron Microscopy, and Diffuse Reflectance Spectroscopy

Constraints on Fe‐Oxide Formation in Monsoonal Vertisols of Pliocene Kenya Using Rock Magnetism and Spectroscopy

Iron pools of the typical loess–palaeosol sequence and their environmental significance in northeastern China

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