Iron oxide mineralogy in Mollisols, Aridisols and Entisols from southwestern Pampean region (Argentina) by environmental magnetism approach

Chaparro, Marcos A. E.; Moralejo, María del Pilar; Böhnel, Harald; Acebal, S. G.

doi:10.1016/j.catena.2020.104534

Cited by 20 publications

(4 citation statements)

References 35 publications

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“…These ranges fall within the reported values for magnetite (8.0-69.5 mT, Peters and Dekkers 2003). Although H cr may vary with grain size of magnetic minerals, a mixture of low-and high-coercivity minerals may also lead to slight variations in H cr as reported by Chaparro and Sinito (2004), Chaparro et al (2020a), and references therein. Mean (and SD) values are similar for both campaigns and are interpreted in term of a common PM production source: traffic pollution.…”

Section: Magnetic Particles On Lichen's Thallussupporting

confidence: 89%

Magnetic Biomonitoring Using Native Lichens: Spatial Distribution of Traffic-Derived Particles

Gómez

Chaparro

Castañeda-Miranda

et al. 2021

Water Air Soil Pollut

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Air pollution has become a subject of extensive study of several disciplines and it is identified as one of the most damaging factors for the ecosystem and human health. In urban areas, particle emission can be found in suspension and therefore a portion of them is inhalable for humans, or deposited on streets and several surfaces, including lichen's thallus. We studied particulate matter (PM) (by traffic emission) accumulated in native lichens Parmotrema pilosum in order to carry out a magnetic biomonitoring over 2016 and 2017. For this purpose, the environmental magnetism method was complemented with inductively coupled plasma optical emission spectrometry, scanning electron microscopy, and geostatistical methods. The accumulated iron oxides on lichen's thallus include potential toxic elements, such as Ba, Cr, Ni, and V. Fe-rich particles related to vehicle emissions correspond to (ultra)fine magnetite of inhalable sizes (PM 2.5 ). Our results indicate a relation between concentration of magnetic particles and areas with high traffic, as well as the influence of rainfall on magnetic PM records. Magnetic biomonitoring is validated as a low-cost and complementary methodology to determine levels of air magnetic PM pollution in cities.

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Section: Magnetic Particles On Lichen's Thallussupporting

confidence: 89%

Magnetic Biomonitoring Using Native Lichens: Spatial Distribution of Traffic-Derived Particles

Gómez

Chaparro

Castañeda-Miranda

et al. 2021

Water Air Soil Pollut

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“…Hard IRM, or HIRM, signifies the proportion of high-coercivity magnetic minerals. The L-ratio values for the samples of lake L6 remain nearly constant showing only minor variations (1.0–1.21) (Supplemental Figure S2) indicating that the HIRM values are dominantly controlled by the varying concentrations of hematite (Chaparro et al, 2020; Liu et al, 2007). The HIRM values range from 7.05 to 502.85 × 10 −5 A m 2 kg −1 , with an average (±sd) of 40.2 (±64.09) × 10 −5 A m 2 kg −1 (Figure 3).…”

Section: Resultsmentioning

confidence: 99%

A high-resolution record of Mid- to Late-Holocene environmental changes from a land-locked lake in Schirmacher Oasis, East Antarctica

Joju,

Warrier,

Mahesh

et al. 2024

The Holocene

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We present a high-resolution record of environmental changes during the Mid-Late Holocene obtained from a lake sediment core covering the past 4.87 cal kyr BP in the Schirmacher Oasis, East Antarctica. The magnetic signal of Lake L6 was found to be primarily controlled by catchment-derived ferrimagnetic minerals. The period between 4.87 and 3.35 cal kyr BP is marked by several episodes of cold and warm conditions. Warm and wet conditions prevailed in the region from 3.35 to 2.43 cal kyr BP. Magnetic susceptibility values remained generally low indicating the pedogenic formation of fine magnetic grains. The high values of the chemical weathering indices reflected the warm and wet conditions conducive to chemical weathering. A transition to cold and dry conditions was observed at around 2.43 cal kyr BP, representing the Neoglacial cooling, with high values of magnetic concentration-dependent parameters. Following the Neoglacial period, a return to warm and wet conditions was observed at 1.63 cal kyr BP, coeval with the Medieval Climate Anomaly. Our record shows a Late-Holocene cooling marked by a sudden increase in magnetic susceptibility values, which could represent the Little Ice Age, followed by a shift to warmer conditions near the core top.

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“…Dunlop, 1995, Heider et al, 1996Roberts, et al, 2000;Evans and Heller, 2003;Hrouda, 2011;Jordanova, 2016). However, the low χ, χ ARM , and IRM values suggest that these finer magnetic phases likely take the form of the magnetically weaker hematite or goethite rather than magnetite, as suggested by the high Fecontent, high L-ratio, and low S-Ratio values (Liu et al, 2007b;Chaparro et al, 2020;Stine et al, 2020) (Figures 2,3). The presence of SP phases within a magnetically depleted soil can be explained as an initial process of pedogenic formation of SPmagnetite grains, most of which are sequentially converted (oxidized) into a magnetically weaker phase with increasing weathering intensity, potentially due to relatively high soil temperature (Schwertmann, 1958;Liu et al, 2012;Wang et al, 2013;Jiang et al, 2018).…”

Section: Effects Of Provenance and Varying Weathering Intensity On Magnetic Enhancement Vs Magnetic Depletion In The Blackwater Draw Formmentioning

confidence: 99%

The Effect of Differential Weathering on The Magnetic Properties of Paleosols: A Case Study of Magnetic Enhancement vs. Magnetic Depletion in the Pleistocene Blackwater Draw Formation, Texas

et al. 2021

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The type-section of the Blackwater Draw Formation (BDF) consists of a series of five paleosol horizons developed on eolian deposits and an overlying surficial soil. Previous work has shown that magnetic properties (e.g., χ, ARM, and IRM) as a function of depth in this type-section, display both magnetically enhanced and magnetically depleted signals for different paleosols. To better understand the magnetic mineralogy responsible for these varying responses, various rock-magnetic experiments, scanning electron microscopy, and Mössbauer spectroscopy were conducted on representative samples from the six soil units which constitute the BDF type-section. Our results show that sub-micron hematite [with a minor contribution from single-domain sized hematite (Hc = ∼500 mT) dominates all the soils in terms of weight percent concentration. Whereas, low coercivity (Hc = ∼35 mT or less) magnetite/maghemitized-magnetite grains, largely in the PSD state (Mr/Ms=∼0.14 +/– 0.03588, Hcr/Hc=∼2.68 +/– 0.298789), dominate the magnetic signal. Magnetically depleted soils show a relatively higher proportion of goethite, while magnetically enhanced soils show an increased contribution from SP/SSD magnetite/maghemite phases.By combining our data-set with geochemically-derived climofunctions, we have correlated the magnetically preserved, depleted, and enhanced sections of the type-section to three distinct environmental phases (I-III). The basal sediments of Phase I displays relatively homogenous (neither enhanced nor depleted) magnetic properties due to relatively arid conditions and minimal alteration of southerly derive eolian sands. Conversely, Phase II-III represents a change in weathering intensities and provenance, resulting in a mix of southerly derived sands and northerly derived silts. Phase II, experienced greater precipitation levels, resulting in the dissolution of Fe-oxide phases and thus magnetic depletion. The uppermost Phase III experienced intermediate precipitation intensities resulting in magnetic enhancement.Using previously published age models we tentatively interpret these changing environmental conditions to be influenced by the Middle-Pleistocene Transition (1.2-0.7 Ma), where the Earth’s climatic cycles shifted from a ∼41 kyr to ∼100 kyr cycles. However, ambiguities persist due to uncertainties in the currently published age model. Due to the complexity of the magnetic signal, we recommend future studies utilize a holistic approach, incorporating rock-magnetic, geochemical, and microscopy observations for more accurate reconstruction of regional paleoenvironments.

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Iron oxide mineralogy in Mollisols, Aridisols and Entisols from southwestern Pampean region (Argentina) by environmental magnetism approach

Cited by 20 publications

References 35 publications

Magnetic Biomonitoring Using Native Lichens: Spatial Distribution of Traffic-Derived Particles

Magnetic Biomonitoring Using Native Lichens: Spatial Distribution of Traffic-Derived Particles

A high-resolution record of Mid- to Late-Holocene environmental changes from a land-locked lake in Schirmacher Oasis, East Antarctica

The Effect of Differential Weathering on The Magnetic Properties of Paleosols: A Case Study of Magnetic Enhancement vs. Magnetic Depletion in the Pleistocene Blackwater Draw Formation, Texas

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