Frequency-dependent Susceptibility Research Articles

Iron Age ceramics from Thracian rock-cut complexes from Bulgaria – Mineral magnetic relics of technological production and use

The Gluhite kamani Thracian rock-cut complex in the Eastern Rhodopes Mountain is famous with its more than 500 rock niches carved in the rock at heights up to 20 m. Continuous habitation starting from the final Chalcolithic (the second quarter of the 4th millenium BCE) until the Late Classical – Early Hellenistic period (late 5th – 4th century BCE) provides unique opportunity for studying diachronic changes in pottery production and use. In this contribution, systematic analysis of a collection of 135 ceramic sherds from five archaeological periods at the site was carried out using a combined mineral magnetic and geochemical approach. Magnetic susceptibility (χ), frequency-dependent magnetic susceptibility (χfd%) and firing temperature (Tfire), determined using the magnetic susceptibility method, were combined with data from elemental XRF analyses. Thermomagnetic measurements, employed for identification of magnetic minerals revealed the dominant presence of (titano)magnetite with low Ti-content and/or a fraction of single-domain magnetite and in few cases hematite. Although varying in a wide range, median χ values of ceramic sherds from the Early Iron Age (EIA) periods show similar distribution, while for Late Iron Age (LIA) with the introduction of the wheel-thrown pottery, χ values are higher, presumably due to decreased amount of silica-rich clastics in the clay. Concurrently, χfd% values decrease in ceramics from the LIA, indicating predominant presence of stable single-domain magnetite in the iron oxide composition of the ceramics. Firing temperatures (Tfire) estimations display a systematic pattern of two groups – higher (Tfire between 760 and 800 °C) and lower (Tfire ∼ 400–––600 °C). During the EIA periods both Tfire groups are present, characterized by systematic gradual decrease of the median value of the low Tfire when going from EIA1 towards the EIA2. Wheel-thrown pottery from the LIA show low Tfire ∼ 400 °C only. Based on the differences in thermomagnetic properties of ceramics, their magnetic parameters and Tfire estimates, two possible hypotheses are suggested to explain the observed changes in EIA ceramic characteristics: i) utilization of two differently sourced clay materials (illite-dominated and montmorillonite-dominated) for production of ceramics fired at higher and lower temperatures, respectively; and ii) utilization of one raw clay source, while using two firing regimes – firing at higher temperature for prolonged time, and fast firing to high temperature with successive stage of longer firing at lower temperature. Differences in thermomagnetic properties of wheel-thrown pottery from the LIA period leads to the assumption for utilization of diverse clay source for their production, as compared clay sources for the Early Iron Age periods.

Coordination number impact on magnetic properties of Schiff base Co(II) complexes

Two mononuclear Co(II) complexes with a tetrahedral and octahedral coordination geometry with a Schiff base ligand L− (anion of 4-[(2-fluoroanilino)-phenyl-methylene]-5-methyl-2-phenyl-pyrazol-3-one) having the formulas [CoL2]·2MeCN (1) and [CoL2(H2O)2]·2MeCN (2) have been synthesized and structurally characterized. Notably, their coordination geometry and magnetic relaxation behaviors can be tuned by variation of reaction conditions. Static magnetic studies reveal that complex 1 exhibits considerable easy-axis magnetic anisotropy. Frequency-dependent susceptibility measurements revealed slow magnetic relaxation behavior with spin-reversal barriers of 79.2 K at an applied external field of 500 Oe. Clear magnetic hysteresis loops were observed for 1 at 2 K. Complex 2 show field-induced slow magnetic relaxation with Raman and direct relaxation processes. The observed magnetic behavior of 1 and 2 is confirmed by high-level ab initio calculations and simulation of χMT(T) curves.

Hydrothermal alteration of the surface volcanic rocks at the Acoculco geothermal field, Mexico: a multi-parametric approach

AbstractThe studies on hydrothermal alteration-induced effects in surface and subsurface rocks provide useful information in the characterization and exploitation of a geothermal reservoir. Generally, these studies are based on traditional, and reliable methods like petrography (primary and secondary minerals, and grade of alteration), and geochemistry (mobility of elements, changes in mass and concentration of elements, and fluid inclusions). Recently, apart from these established methods, some methods based on the geochemical (Chemical Index of Alteration, CIA; Weathering Index of Parkar, WIP; Loss on Ignition, LOI; and Sulfur, S) and rock magnetic properties (magnetic susceptibility, χlf; and percentage frequency-dependent susceptibility, χfd%) are also being applied in the identification of whether a rock is an altered or a fresh one. The Acoculco Geothermal Field (AGF), Mexico, is characterized by high temperature and very low permeability, and it is considered a promissory Enhanced Geothermal System. The following changes are observed in the rocks as a result of an increase in hydrothermal alteration: (1) an increase in CIA, LOI, and S values, and a decrease in WIP; (2) an increase in quartz and quartz polymorph minerals (silicification), and clay minerals (argillization); and (3) decrease in χlf values. At AGF, the most altered surface acid rocks are characterized by entirely quartz and its polymorphs, and clay minerals. The present study also indicates the applicability of the binary plots of major elements (felsic vs mafic component) and rock magnetic parameters (χlf vs. χfd%). The rock with χfd% value of 2–10 and χlf value < 0.5 × 10–6 m3 kg−1 indicate the presence of single domain and stable single domain grains, which in turn suggests that it is an altered rock. These methods are simple to apply, rapid, reliable, and have the potential to become effective tools for the identification of hydrothermally altered rocks during the initial stage of geothermal exploration.

Paleomagnetic chronology and paleoenvironmental records from a drill core in the Liupan Mountain area, NE Tibetan Plateau

The Liupan Mountain area, a north-trending mountain range, located in the northeastern-most active structural margin of the Tibetan Plateau and the convergence zone of the East Asian monsoon region, provides an ideal geological setting for investigating the tectonic events in the northeastern Tibetan Plateau and the Cenozoic evolution of the Asian aridification. We provide magnetostratigraphic and paleoenvironmental records for a Late Cenozoic sedimentary core drilled in the Guyuan in the Liupan Mountain. The lithology of the core can be roughly divided into two parts. The lower part (depths of 795–40 m) is composed of lacustrine sediments and the upper part (depths of 40–0 m) is composed of fluvial deposits. Magnetostratigraphy of the 795 m deep core dates the magnetic polarity sequence between ∼8.2 and 0.03 Ma. The Brunhes/Matuyama, Matuyama/G, and Gauss/Gilbert boundaries are located at depths of 53.55 m, 161.50 m, and 264.75 m, respectively. Four intervals with relatively higher accumulation rates were identified at ca. 7.64–6.03, 5.24–4.18, 3.60–2.58, and 1.07–0.78 Ma. All of this evidence is probably related to the pulses of tectonic uplift of the northeastern (NE) Tibetan Plateau. The frequency-dependent susceptibility values have exhibited obvious decreasing trends since ∼8.2 Ma, indicating obvious aridification in the Guyuan Basin since the Late Miocene, but relatively high values occurred between 4.6 and 3.5 Ma. The enhancement of the aridity in the Liupan Mountain since ∼8.2 Ma was due to the combined effect of global climate cooling and the uplift of the Northern Tibetan Plateau since the Late Miocene.

Temporary Hearing Threshold Shift in California Sea Lions (Zalophus californianus) Due to a Noise Band Centered at 32 kHz

To determine their frequency-dependent susceptibility to noise-induced temporary hearing threshold shift (TTS), two California sea lions (Zalophus californianus) were exposed for 60 min to a continuous one-sixth-octave noise band (NB) centered at 32 kHz as the fatiguing sound, at sound pressure levels of 132 to 156 dB re 1 µPa (sound exposure levels [SELs] of 168 to 192 dB re 1 µPa2s). Using a psychoacoustic technique, TTSs were quantified at the center frequency of the fatiguing sound and at half an octave and one octave above the center frequency (at 32, 44.8, and 63 kHz). When significant TTS occurred, higher SELs resulted in greater TTSs. TTSs and hearing recovery patterns were similar in both sea lions. The mean onset of TTS1-4 min (defined as 6 dB TTS) in sea lion F01 is estimated to occur after exposure to an SEL of 179 dB re 1 µPa2s (at hearing test frequency 44.8 kHz). After exposure to an SEL of 180 dB re 1 µPa2s, a mean TTS1-4 min of 6.7 dB was measured at hearing test frequency 44.8 kHz. In California sea lions, TTS onset levels are not as closely related (especially at the lower and higher frequencies) to the unmasked hearing thresholds (audiograms) as was previously assumed.

Topsoil's magnetic and electrical properties in a volcanic and tropical region.

Environmental monitoring by measuring topsoil's magnetic and electrical properties is one practical, quick, and low-cost approach. This method has been used worldwide as a proxy for the presence of potentially toxic elements. However, additional research must be conducted on diverse soil types, geology, and climates. We determined the magnetic and electrical properties of urban and agricultural topsoils in a volcanic region and analyzed them as possible proxies of potentially toxic elements for environmental monitoring. To identify topsoil characteristics, we employed the measurements of magnetic susceptibility and hysteresis, electrical conductivity, total dissolved solids, power of hydrogen (pH), particle morphology, and element contents that were statistically analyzed to identify relevant properties. The result was able to differentiate volcanic soils from urban, industrial, and agricultural areas as well. The value of low-frequency magnetic susceptibility (χLF) in soils from urban areas is higher than 866.0±249.9 ×10-8 m3 kg-1, while the value of χLF in agricultural areas is 208.0±67.8 ×10-8 m3 kg-1. This is reinforced by the relationship between low-frequency and frequency-dependent magnetic susceptibility (χLF-χFD%) in samples from urban areas that fall within the same cluster dominated by coarse-grained magnetic minerals originating from anthropogenic processes. In contrast, the agricultural area forms a separate cluster primarily influenced by pedogenic processes from acid igneous rock minerals. Caution is required for interpreting the magnetic signal due to the high contents of lithogenic magnetic particles inherited from the parent materials of Andisols.

Similar susceptibility to temporary hearing threshold shifts despite different audiograms in harbor porpoises and harbor seals.

When they are exposed to loud fatiguing sounds in the oceans, marine mammals are susceptible to hearing damage in the form of temporary hearing threshold shifts (TTSs) or permanent hearing threshold shifts. We compared the level-dependent and frequency-dependent susceptibility to TTSs in harbor seals and harbor porpoises, species with different hearing sensitivities in the low- and high-frequency regions. Both species were exposed to 100% duty cycle one-sixth-octave noise bands at frequencies that covered their entire hearing range. In the case of the 6.5 kHz exposure for the harbor seals, a pure tone (continuous wave) was used. TTS was quantified as a function of sound pressure level (SPL) half an octave above the center frequency of the fatiguing sound. The species have different audiograms, but their frequency-specific susceptibility to TTS was more similar. The hearing frequency range in which both species were most susceptible to TTS was 22.5-50 kHz. Furthermore, the frequency ranges were characterized by having similar critical levels (defined as the SPL of the fatiguing sound above which the magnitude of TTS induced as a function of SPL increases more strongly). This standardized between-species comparison indicates that the audiogram is not a good predictor of frequency-dependent susceptibility to TTS.

Vortex Dynamics and Pinning in CaKFe4As4 Single Crystals from DC Magnetization Relaxation and AC Susceptibility

Among various “families” of iron-based superconductors, the quite recently discovered AeAFe4As4 (where Ae is an alkali-earth metal and A is an alkali metal) has high critical current density, a very high upper critical field, and a low anisotropy, and has recently received much interest for the possibility of high magnetic field applications at the liquid hydrogen temperature. We have performed DC magnetization relaxation and frequency-dependent AC susceptibility measurements on high-quality single crystals of CaKFe4As4 with the aim of determining the pinning potential U*. The temperature dependence of U* displays a clear crossover between elastic creep and plastic creep. At temperatures around 27–28 K, U* has a very high value, up to 1200 K, resulting in an infinitesimally small probability of thermally activated flux jumps. From the dependence of the normalized pinning potential on irreversible magnetization, we have determined the creep exponents in the two creep regimes, which are in complete agreement with theoretical models. The estimation of the pinning potential from multifrequency AC susceptibility measurements was possible only near the critical temperature due to equipment limitations, and the resulting value is very close to the one that resulted from the magnetization relaxation data. Magnetic hysteresis loops revealed a second magnetization peak and very high values of the critical current density.

Temperature- and frequency-dependent magnetic susceptibility on archaeological ceramics of the Tlatilca culture (Mexico City): A pilot study towards an archaeointensity approach

Temperature-dependent susceptibility curves are commonly used in archaeointensity studies to identify changes in the magnetic mineralogy of archaeological ceramics. In this pilot study, we investigated the low- and high-temperature thermomagnetic behavior and frequency-dependent susceptibility of eight ceramics from a Tlatilca culture archaeological site in Mexico City, after heating them at five different temperatures (from 120 to 440 °C). Our objective is to establish a correlation between the thermomagnetic behavior and the parameters that determine the magnetic grain-size and magnetic domain in similar style of ceramics from different occupations of the site. Our findings show that superparamagnetic grains (SP) degrade with increasing reheating temperature in ceramics, and we conclude that this behavior is related to details in artifact processing, such as the use of pastillage to represent headdresses, and an important aspect to consider when working with samples for archaeointensity procedures.

Sensitivity analysis of magnetic susceptibility under different climatic conditions during the late Pleistocene-Holocene period

Understanding the climate change experienced by the Loess Plateau in China from the end of the late Pleistocene to the Holocene is helpful for exploring global palaeoclimate change and predicting future climate change. However, sensitivity studies on palaeoclimate proxies under different geological periods and different climatic conditions are still lacking, which affects the accurate identification of palaeoclimate changes and the precision with which future climate change predictions can be made. Three soil profiles in Luochuan County were sampled, and the magnetic susceptibility (χlf), frequency-dependent susceptibility (χfd%), clay content (<0.005 mm), clay/coarse silt ratio, calcium carbonate content (CaCO3), and total content of organic carbon (TOC) of the profiles were analysed. The results showed that the climate changed from dry and cold to warm and wet to dry and cool since the end of the late Pleistocene. The precipitation (MAP) and temperature (MAT) since the end of the late Pleistocene were reconstructed by using the magnetic susceptibility of different soil particle size fractions (>2 mm, 2–1 mm, 1–0.5 mm, 0.5–0.25 mm, <0.25 mm), and the results were compared with those from other researchers. The results showed that the magnetic susceptibility of the fine fraction (<0.25 mm) was more sensitive at 0–3200 cal. yr. BP, 8500–13,000 cal. yr. BP, and 15,000–25,000 cal. yr. BP, while that of the coarse fraction (>0.25 mm) was more sensitive at 3200–8500 cal. yr. BP. Based on this finding, the precipitation and temperature of this period were reconstructed. This study provides a research method for selecting suitable climate proxies to describe climate changes in different geological periods to accurately conduct quantitative or semiquantitative assessments of climate change.

The firing temperatures of burnt clay from the Chinese neolithic cultural relics and its paleoenvironmental imprints

The impact of human-induced fires on the surrounding environment has been particularly significant during the Anthropocene epoch. Neolithic burnt clay, which is widely distributed in the archaeological relics of ancient civilizations across the Eurasian continent, provides pivotal information about the ancient firing stories. However, understanding of the paleoenvironmental imprints of fire in burnt clay has been largely limited by the lack of sufficient analytical data on comprehensive knowledge of ancient firing conditions. In this study, a detailed magnetic analysis was conducted on burnt clay materials from a Neolithic site in Fujian, southeastern China, which presented a burnt clay-based record of the Neolithic firing temperature in relation to paleoenvironmental conditions. Based on magnetic analysis, the ancient firing temperature was determined to be approximately 620 °C, which is comparable with other records from Eurasian Neolithic sites. Frequency-dependent magnetic susceptibility provides alternative indicative information for ancient firing conditions in addition to conventional magnetic susceptibility. Furthermore, magnetic properties of burnt clay may decode the in-situ source characteristics with respect to geological background. In addition, a potential link between temporal variations in ancient firing temperatures in burnt clay and surrounding paleoenvironmental changes is tentatively interpreted by local environmental feedback of temperature-moisture conditions and anthropogenic activity. This study further confirms the archaeological potential of thermomagnetic properties as useful indicators in paleoenvironmental studies. More work combining paleoenvironmental and archaeological archives is critically essential to understand ancient firing history in the context of environmental conditions.

Determination of Magnetic susceptibility of hydrocarbon contaminated soils in Port Harcourt and Bonny Island, Rivers State, Nigeria

In this study, determination of magnetic susceptibility were carried out on 366 soil samples using MS2B magnetic susceptibility meter connected to a computer system using MULTISUS2 software. The soil samples were selected from six sites namely: Shell environment, Nigeria Liquefied Natural Gas environment, Port Harcourt Refining Company James Hart, New Jerusalem and Port Harcourt respectively. Three of the six sites; Shell, NLNG and Port-Harcourt Refining Company environments have their soils contaminated with hydrocarbon. One hundred and ninety two (192) soil samples were collected from these hydrocarbon contaminated sites and 174 from non-hydrocarbon contaminated soil (control samples). The magnetic susceptibility values obtained from Shell environment and for hydrocarbon samples showed higher (enhanced) magnetic susceptibility with average values of 117.54x10-8 m3kg-1 and 2016.39x10-8 m3kg-1 and a moderate magnetic susceptibility for with an average value of 20.83x10-8 m3kg-1 in comparison to magnetic susceptibility values obtained from the control samples whose average values were 2.39x10-8 m3kg-1, 12.42x10-8 m3kg-1 and 3.31x10-8 m3kg-1 for James Hart, New Jerusalem and Port Harcourt respectively. This means that the hydrocarbon sites are highly magnetic which could be indication of pollution. The results of the percentage frequency dependent susceptibility (χFD%) obtained in the hydrocarbon samples showed about 16% of the samples had percentage frequency dependent susceptibility (χFD%) values between 0-2%, 53% had values of χFD% between 2-10% and 31% had χFD% between 10-12% and above while about 21% of the control samples had χFD% values between 0-2%, 58% between 2-10% and 21% between 10-12% and above. The high magnetic susceptibility value in the hydrocarbon soil samples is an indication of pollution due to hydrocarbon deposit. The Government is therefore advised to monitor the location and activities of the oil companies and initiate quick mop up strategies should be put in place in the eventuality of oil spillage.

The fall of volcanic material from Mount Lawu, Central Java: a case study of magnetic susceptibility

Mount Lawu was recorded to have erupted last on November 28, 1885, releasing volcanic material including magnetic minerals. The material settles in various places carried by the wind and river flow. The movement of wind and river flow is very influential in the process of transporting volcanic material. Large material directly falls around the mountain, usually in the form of large rocks, and undergoes physical and chemical weathering. Small-sized materials such as volcanic ash and small-mass rocks will be carried by the wind and river flows in all directions. However, the displacement does not remove the magnetic minerals contained in it. Magnetic minerals can be evaluated by the method of rock magnetism using MS. Bartington MS2 device with a dependent MS2B sensor by mass. From this tool, the low field susceptibility values in the range of 1467.5 x 10−8 m3/Kg – 5262.1 x 10−8 m3/Kg and high field susceptibility in the range of 1467,1 x 10−8 m3/Kg. The volcanic material of Mount Lawu belongs to the Ilmenite (FeTiO3) group and belongs to the group of weak magnetism. Then further review the frequency-dependent susceptibility (%) to see the magnetic domains contained in the sample. From the magnetic susceptibility data, the percentage of frequency-dependent susceptibility (%) is less than 2%. From these data, the sample is not included in the superparamagnetic (SP) and in general the sample is classified as a multidomain item (MD).

A detailed magnetic characterization of combustion products from various metamorphic grade coals

The magnetic properties of combustion products from various metamorphic grade coals including lignite, flame coal, gas coal, fat coal, baking coal and lean coal and anthracite coal, were analyzed. This study was carried out by means of basic magnetic parameters, thermomagnetic and hysteresis measurements. The mass magnetic susceptibility (χ) values ranged from 327 × 10−8 m3/kg to 1722 × 10−8 m3/kg, with an average value of 892 × 10−8 m3/kg, demonstrating a considerable amount of ferrimagnetic minerals in these burned coal samples. The lower χ and SIRM values for the burned lignite were probably due to the lower content of magnetite. A characteristic feature of combustion products was their high values of frequency dependent susceptibility (χfd%), indicating the presence of a large amount of superparamagnetic grains of ferrimagnetic minerals within the combustion products. Thermomagnetic analyses of various combustion products showed the dominant role of magnetite-like phase. Moreover, a significant amount of hematite was also only identified in the combustion product from Flame coal. While the combustion products from Flame coal and Fat coal were characterized by a relatively narrow loop, characteristic of magnetically soft ferrimagnetic minerals, other combustion products including lignite, gas coal, baking coal, lean coal and anthracite coal displayed wasp-waisted loops, indicating the presence of two or more coercivity fractions.

Magnetic Susceptibility of Pumice at Mount Singgalang, West Sumatera

Volcanic activity produces eruptions that release pyroclastic material at the time of the explosion. Mount Singgalang is a volcano that has experienced an eruption after 1600. Several types of volcanic rocks around the Mount Singgalang area are Basalt, Andesite, Tuff Breccia, Lava Breccia, and Pumice Tuff. Pumice is formed when saturated liquid magma gas bursts like a carbonated beverage and soon cools, causing the froth that results to solidify into a glass full of gas bubbles. Some minerals contained in pumice are obsidian, cristobalite, feldspar, and tridymite. Pumice contains magnetic minerals, namely ilmenite (FeTiO3), and magnetite (Fe3O4). The purpose of this study is to quantify the magnetic susceptibility and quantity of pumice on Mount Singgalang in West Sumatera. When utilizing the Bartington Magnetic Susceptibility Meter to analyze a sample, magnetic susceptibility parameters are utilized to pinpoint the features of a magnetic rock mineral. The value of the magnetic susceptibility of pumice on Mount Singgalang, in West Sumatera has a value that varies between 2763.3 x 10-8m3/kg - 2192.1 x 10-8m3/kg. The results showed that the tested samples had antiferromagnetic magnetic mineral properties with frequency-dependent susceptibility values (χfd), indicating that all of the measured samples contained almost no superparamagnetic (SP) grains and were generally dominated by multi-domain (MD) grains.

Rock Magnetic and Mineralogical Properties of Lateritic Soil Profiles Developed on Two Different Parent Rocks in Northern Kerala, South-Western India

The rock magnetic and mineralogical properties of two lateritic soil profiles developed on two different parent rocks (khondalite and granite) in northern Kerala, south-western India were investigated to better understand pedogenic processes under tropical climate. Field investigations reveal the presence of various horizons in the lateritic profiles, such as saprolite, mottled zone, pebble horizon and top soil. The particle size, rock magnetic, Vibrating Sample Magnetometer (VSM), Scanning Electron Microscopy (SEM)-Energy-Dispersive X-ray Spectrometer (EDS) and X-Ray Diffraction (XRD) analyses were performed on samples collected from different horizons of the two profiles. Magnetic susceptibility (χlf) values of the lateritic profiles vary from 9.97 to 1717.04 x 10-8 m3 kg-1, with the granitic profile exhibiting overall higher values. The percentage frequency-dependent susceptibility (χ %) ranges between 0 % and 13.9 %. The XRD data reveal the presence of kaolinite, gibbsite (except for top soil layer) and quartz along with magnetic minerals like magnetite, hematite and goethite. The upper horizons (top-soil and pebble horizon) exhibit high values for concentration dependent magnetic parameters like χlf and χfd%, whereas, the lower horizons (saprock, saprolite, pallid zone horizons) exhibit low values. The tropical soils in the region have undergone a higher degree of pedogenesis with increased magnetic mineral concentration compared to temperate soils. The magnetic enhancement in the topsoil may be due to the neoformation of ultra fine-grained SP magnetite/maghemite (with minor anti-ferro magnetic component), aided by sufficient Fe supply, alternate wetting and drying cycles, dehydration, oxidation and redox conditions. Keywords: Lateritic Soils; Soil Magnetism; XRD; SEM; Magnetic Enhancement; Pedogenesis; Southern India

Mineral magnetic properties of surface soils from the Broknes and Grovnes Peninsula, Larsemann Hills, East Antarctica

This study presents the mineral magnetic, particle size, and organic content data of surface soils from Larsemann Hills, East Antarctica. The analysis of isothermal remanent magnetization and the high specific magnetic susceptibility values –mean (±S.D.) values of 117.7 (±175.0) × 10−8m3kg−1 for Broknes Peninsula and of 330.9 (±217.4) × 10−8m3kg−1 for Grovnes Peninsula– indicate high concentrations of low-coercivity magnetic minerals. The magnetic minerals are coarse-grained in the multidomain and pseudo-single domain range, and the significant correlation between some magnetic parameters suggests the dominant control of multidomain grains. The remanent acquisition coercivity H1/2 shows mean (±S.D.) values of 38.2 (±4.9) for Broknes and 38.3 (±3.7) mT for Grovnes soils suggesting magnetite dominance. The soils lie in the sand and loamy sand textural classes, and the concentration of organic matter is very low. Values of percentage frequency-dependent susceptibility indicate insignificant proportions of superparamagnetic grains, and therefore no significant evidence for pedogenic magnetic minerals was observed in these soils. The magnetic signal of Larsemann Hills soils was primarily terrigenous with no contributions from bacterial magnetite, authigenic greigite and anthropogenic magnetic minerals.

Frequency-Dependent Magnetic Susceptibility and Chemical Composition of Estuary Mangrove Sediment as Environmental Indicator of Ecosystem Degradation

Frequency-Dependent Magnetic Susceptibility and Chemical Composition of Estuary Mangrove Sediment as Environmental Indicator of Ecosystem Degradation

Identification of Sediment Formation Based on Magnetic Content and Element Composition of Mud Volcano in Sangiran Sediment using VSM and X-Ray Fluorescence

Based on trace geological history and several studies, the Sangiran mud volcano provides insight into the geology and hydrology of the region, aquifer system in the basin, groundwater flow patterns and characteristics, rock lithology, hydrogeology condition, and saltwater trap mapping. Related to these conditions, studies were conducted on the magnetic content and composition of the major oxide compounds in the Sangiran sediments. Sample analysis was based on geochemical methods. The methods consist of frequency dependent magnetic susceptibility and vibrating sample magnetometer (VSM) analysis. Geochemical analyses using x-ray fluorescence (XRF) analysis have been conducted and various elemental grades have been determined. VSM results confirm that the magnetic content of Sangiran sediments is partly dominated by Fe (17.66 percent) contained in hematite (Fe2O3). At the same time, the samples of Sangiran sediment were enriched by Si, Fe, Al, Ca, Cl, Ti, and K according to XRF measurements. The samples exhibited the highest Si and Fe concentrations in samples T1 (Si is 29.48 percent and Fe is 13.66 percent) and T7 (Si is 24.95 percent and Fe is 12.01 percent). Meanwhile, in the T4 sample, the highest concentrations were Si and Ca, 23.45 percent and 13.45 percent, respectively. Retrieved from the magnetic susceptibility measurement, this paper confirm that Fe content is one of the components of volcanic ash in the Sangiran sediment.DOI: 10.17977/um024v8i12023p009

Identification of Sediment Formation Based on Magnetic Content and Element Composition of Mud Volcano in Sangiran Sediment using VSM and X-Ray Fluorescence

Based on trace geological history and several studies, the Sangiran mud volcano provides insight into the geology and hydrology of the region, aquifer system in the basin, groundwater flow patterns and characteristics, rock lithology, hydrogeology condition, and saltwater trap mapping. Related to these conditions, studies were conducted on the magnetic content and composition of the major oxide compounds in the Sangiran sediments. Sample analysis was based on geochemical methods. The methods consist of frequency dependent magnetic susceptibility and vibrating sample magnetometer (VSM) analysis. Geochemical analyses using x-ray fluorescence (XRF) analysis have been conducted and various elemental grades have been determined. VSM results confirm that the magnetic content of Sangiran sediments is partly dominated by Fe (17.66 percent) contained in hematite (Fe2O3). At the same time, the samples of Sangiran sediment were enriched by Si, Fe, Al, Ca, Cl, Ti, and K according to XRF measurements. The samples exhibited the highest Si and Fe concentrations in samples T1 (Si is 29.48 percent and Fe is 13.66 percent) and T7 (Si is 24.95 percent and Fe is 12.01 percent). Meanwhile, in the T4 sample, the highest concentrations were Si and Ca, 23.45 percent and 13.45 percent, respectively. Retrieved from the magnetic susceptibility measurement, this paper confirm that Fe content is one of the components of volcanic ash in the Sangiran sediment.DOI: 10.17977/um024v8i12023p009