scholarly journals Rock magnetism and soil magnetic susceptibility

2021 ◽  
pp. 4-11
Author(s):  
O.V. Kruglov ◽  
◽  
S.A. Popov ◽  
Keyword(s):  
Magnetic Susceptibility ◽  
High Performance ◽  
Rock Magnetism ◽  
Source Rocks ◽  
Information Support ◽  
Magnetic Characteristics ◽  
Magnetic Minerals ◽  
Parent Rocks ◽  
Profile Distribution

Information support of modern agriculture and ecology forms a demand for ever higher requirements for efficiency and density of the sampling network. This fact determines the spread of high-performance methods of soil research, among which are magnetometric ones. However, these methods have a number of limitations associated with the existence in soils of ferromagnets of non-pedogenic nature. The purpose of the study is to show the patterns of spatial and profile distribution of soils with high values of magnetic characteristics, inherited from parent rocks as a result of pedogenesis. The research used: determination of specific magnetic susceptibility using kappabridge KLY-2, determination of volumetric magnetic susceptibility with kappameter KT-5 and induction of magnetic field by proton magnetometer MP 203. The study was conducted at two objects located in the central part of the Ukrainian shield region. Studies have shown that soils developed on the weathering crust are characterized by certain features of their magnetic properties. First of all, it depends on the petromagnetic parameters of the source rocks. On magnetic rocks, the MS of soils is determined primarily by inherited magnetic minerals. The magnetic susceptibility of such soils has two maxima. The first is in the upper part of the profile, where it is determined by the sum of pedogenic and terrigenous magnets. The second is located in the lower part of the profile, which consists almost entirely of weathering products.

scholarly journals Eolian dust dispersal patterns since the last glacial period in eastern Central Asia: insights from a loess-paleosol sequence in the Ili Basin

2018 ◽  
Vol 14 (3) ◽  
pp. 271-286 ◽  
Author(s):  
Yue Li ◽  
Yougui Song ◽  
Kathryn E. Fitzsimmons ◽  
Hong Chang ◽  
Rustam Orozbaev ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Susceptibility ◽  
Central Asia ◽  
Chinese Loess Plateau ◽  
Magnetic Characteristics ◽  
Magnetic Minerals ◽  
Near Surface ◽  
Siberian High ◽  
End Members ◽  
Eastern Central Asia

Abstract. The extensive loess deposits of the Eurasian mid-latitudes provide important terrestrial archives of Quaternary climatic change. As yet, however, loess records in Central Asia are poorly understood. Here we investigate the grain size and magnetic characteristics of loess from the Nilka (NLK) section in the Ili Basin of eastern Central Asia. Weak pedogenesis suggested by frequency-dependent magnetic susceptibility (χfd%) and magnetic susceptibility (MS) peaks in primary loess suggest that MS is more strongly influenced by allogenetic magnetic minerals than pedogenesis, and may therefore be used to indicate wind strength. This is supported by the close correlation between variations in MS and proportions of the sand-sized fraction. To further explore the temporal variability in dust transport patterns, we identified three grain size end-members (EM1, mode size 47.5 µm; EM2, 33.6 µm; EM3, 18.9 µm) which represent distinct aerodynamic environments. EM1 and EM2 are inferred to represent grain size fractions transported from proximal sources in short-term, near-surface suspension during dust outbreaks. EM3 appears to represent a continuous background dust fraction under non-dust storm conditions. Of the three end-members, EM1 is most likely the most sensitive recorder of wind strength. We compare our EM1 proportions with mean grain size from the Jingyuan section in the Chinese loess plateau, and assess these in the context of modern and Holocene climate data. Our research suggests that the Siberian High pressure system is the dominant influence on wind dynamics, resulting in loess deposition in the eastern Ili Basin. Six millennial-scale cooling (Heinrich) events can be identified in the NLK loess records. Our grain size data support the hypothesis that the Siberian High acts as teleconnection between the climatic systems of the North Atlantic and East Asia in the high northern latitudes, but not for the mid-latitude westerlies.

scholarly journals Analysis of Ultramafic Rocks Weathering Level in Konawe Regency, Southeast Sulawesi, Indonesia Using the Magnetic Susceptibility Parameter

2020 ◽  
Vol 5 (2) ◽  
pp. 73-81
Author(s):  
Jahidin ◽  
LO. Ngkoimani ◽  
LM. Iradat Salihin ◽  
Hasria ◽  
Erzam S. Hasan ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Source Rock ◽  
Ultramafic Rock ◽  
Nickel Content ◽  
Ultramafic Rocks ◽  
Petrographic Analysis ◽  
Magnetic Minerals ◽  
Rock Samples ◽  
Weathering Process

The Konawe region is part of the Sulawesi Southeast Arm ophiolite belt where ultramafic rocks are exposed in the form of dunite and peridotite. The formation of nickel deposits is closely related to the weathering process of ultramafic rocks as a source rock. Ultramafic rocks exposed to the surface will experience weathering which is influenced by many factors, including in the form of climate change, topography, and existing geological structures. The weathering process in the source rock can influence variations in chemical elements and magnetic properties in laterite soil profiles. For example, the chemical weathering might affect magnetic mineralogy and the physical weathering could affect granulometry as well as the quantity of magnetic minerals in the soil. Condition of weathering of ultramafic rocks (initial, moderate and advanced) can affect nickel content in laterite sediments. The weathering profile study of serpentine mineral is an indication of the lateralization process that occurs in ultramafic rocks and is carried out through petrographic analysis of thin cuts and polish cuts. Determination of weathering level like this is based on the level of weathering of the mineral serpentine. In this study, the determination of the weathering level of ultramafic rocks (initial, moderate, and continued) uses magnetic susceptibility parameter. A total of 232 ultramafic rock core samples obtained from 34 hand samples were taken from different places and weathered levels were analyzed. The results of the research have shown that the magnetic susceptibility of ultramafic rocks in the study area varies, from 580 x 10-6 SI to 4.724 x 10-6 SI. Based on the value of magnetic susceptibility, magnetic minerals contained in ultramafic rock samples are hematite and geotite minerals. This means that the weathering level of ultramafic rock samples is the continued weathering level. The level of continued weathering that occurs in ultramafic rocks in the study area produces nickel laterite deposits with a nickel content of 1.65 - 2.40% in the saprolite zone, 0.42% in the saprock zone, and 0.20 - 0.51% in the basic rock zone (bedrock).

Association between magnetic susceptibilities and hydrocarbon deposits in the Barinas-Apure Basin, Venezuela

Geophysics ◽  
2011 ◽  
Vol 76 (6) ◽  
pp. L35-L41 ◽  
Author(s):  
A. Perez-Perez ◽  
L. D’Onofrio ◽  
M. Bosch ◽  
E. Zapata
Keyword(s):  
Magnetic Susceptibility ◽  
Source Rocks ◽  
Magnetic Minerals ◽  
Mean Values ◽  
Magnetic Susceptibilities ◽  
Significant Difference ◽  
The Mean ◽  
Susceptibility Profiles ◽  
Hydrocarbon Deposits ◽  
Basic Statistical Analysis

We have measured the magnetic susceptibility of 5425 drill cuttings, coming from 20 oil wells distributed in eight fields of the Petroliferous Barinas-Apure Basin (Barinas, Venezuela), seeking evidence of magnetic anomalies associated with the presence of hydrocarbon deposits. The rock samples are located between the near earth’s surface and the basement’s top (approximately 4000 m). In the magnetic susceptibility profiles, we observed high magnetic susceptibilities at the top of the sedimentary units corresponding to reservoir and source rocks of oil-producing wells, whereas in the case of nonproducing wells we observed low magnetic susceptibilities. A basic statistical analysis of the magnetic susceptibility measurements shows a significant difference between the mean values across producing and nonproducing wells at the correspondent oil-related formations, with a ratio of [Formula: see text] of producing to nonproducing wells. In the producing wells, we have found a relation between the magnitudes of the magnetic susceptibility and the age of the formation; the larger the magnetic susceptibility, the younger the geological stratum. The age and depth of the formations where the cuts were obtained exclude the presence of cultural (human origin) contamination of the samples, suggesting the evidence of authigenic origin of the magnetic minerals due to the reductive effect of hydrocarbons in rocks.

Fired clay from Neolithic houses – the role of past environment revealed in mineral magnetic properties

2021 ◽  
Author(s):  
Neli Jordanova ◽  
Diana Jordanova ◽  
Deyan Lesigyarski ◽  
Maria Kostadinova-Avramova
Keyword(s):  
Magnetic Susceptibility ◽  
Firing Temperature ◽  
Rock Magnetism ◽  
Neolithic Period ◽  
Early Neolithic ◽  
Magnetic Minerals ◽  
Late Neolithic ◽  
Magnetic Studies ◽  
Study Region ◽  
Mineral Magnetic

<p>Human behavior and especially the use of fire increasingly influence our environment during the Anthropocene epoch. Balkan Peninsula is on the road of the ancient human dispersal during the Neolithic period. Burnt Neolithic remains are often related to ancient houses which ended their existence as a result of extensive fire. Materials from burnt clay remains from house destructions originating from 18 Neolithic sites from Bulgaria were studied using rock magnetism. Mineral magnetic studies and equivalent firing temperature estimates were carried out. The aim of the study was to explore the magnetic signature of fired clay materials in relation to the most important environmental factors. The main magnetic minerals identified were magnetite, maghemite and hematite, in several cases also epsilon-Fe<sub>2</sub>O<sub>3</sub>. Magnetic susceptibility enhancement is dependent on the raw clay mineralogy and the firing intensity, being higher for sites developed on loess materials. Sites located in river valleys from South Bulgaria show lower susceptibility enhancement. Magnetic susceptibility  and percent frequency dependent magnetic susceptibility at site level were considered in relation to the climatic conditions during the Neolithic as revealed by anthracological studies already published for the study region. Firing temperature estimates, comprising 198 single determinations in total, vary in the range 580 – 1050°C across the sites. Estimated average firing temperatures at site’s level showed higher values in Early Neolithic sites (Tfire average=815°C) as compared to Late Neolithic ones (Tfire average = 746°C and 713°C). Several possible hypotheses for the trend observed are considered: difference in climate regimes across the territory leading to different “fire weather”; difference in the vegetation fuel used in house construction; and intentional burning of Early Neolithic houses. This study is financially supported by the project KP-06-COST/2, funded by the Bulgarian National Science Fund.</p>

scholarly journals Analisis Suseptibilitas Dan Histeresis Magnetik Pada Endapan Pasir Besi Di Sulawesi Utara

Jurnal MIPA ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 105
Author(s):  
Gerald Tamuntuan ◽  
Seni H.J. Tongkukut ◽  
Guntur Pasau
Keyword(s):  
Magnetic Susceptibility ◽  
East Coast ◽  
Magnetic Characteristics ◽  
Size Distributions ◽  
Magnetic Minerals ◽  
The West ◽  
North Sulawesi ◽  
Domain State ◽  
Grain Size Distributions ◽  
Different Grain Size

Telah dilakukan pengukuran suseptibilitas dan hysteresis magnetic untuk mengetahui karakteristik magnetic endapan pasir besi pada beberapa lokasi di Sulawesi Utara. Lokasi pengambilan sampel dalam penelitian ini adalah tiga lokasi di pesisir timur semenanjung utara Pulau Sulawesi yaitu daerah Belang, Hais, dan Minanga, serta tiga lokasi di wilayah pesisir barat yaitu daerah Lalow, Inobonto, dan Lolan. Hasil yang diperoleh menunjukkan bahwa nilai suseptibilitas magnetic pada sampel-sampel pasir yang diukur bervariasi dari 7,73 × 10-8 m3kg-1 hingga 436,38 × 10-8 m3kg-1. Pengukuran suseptibilitas magnetik pada empat distribusi ukuran bulir pasir yang berbeda menunjukkan bahwa nilai rata-rata tertinggi suseptibiltas adalah pada pasir berukuran halus (fine grains). Secara umum, pasir besi pada daerah pantai timur semenanjung utara Pulau Sulawesi memiliki nilai suseptibilitas magnetik yang lebih tinggi dibandingkan dengan daerah pantai barat. Konsentrasi mineral superparamagnetik tertinggi berada pada daerah Belang. Mineral magnetik yang dominan dari sampel-sampel pasir besi yang diteliti adalah magnetit dengan domain statepseudo-single domain.Magnetic susceptibility and hysteresis parameters of iron sand deposits at several locations in North Sulawesi have been measuredin order to determine their magnetic characteristics. Samples were taken from six locations which is three locations on the east coast of the northern arm of Sulawesi Island (Belang, Hais and Minanga) and three othersfrom the western coastal areas (Lalow, Inobonto and Lolan).The result shows that magnetic susceptibility of the sand samples vary from 7,73 × 10-8 m3kg-1to 436,38 × 10-8 m3kg-1.Measurement of magnetic susceptibility in four different grain size distributions shows that fine grainsand have the highest susceptibility value.In general, magnetic susceptibility valueof Iron sand samplesfrom the east coast of the northarm of Sulawesi Island was higher than the west coast. Concentration of superparamagnetic mineral from Belang area was higher than other locations. The predominant magnetic minerals of the iron sand samples are magnetite with the domain state pseudo-single domain.

scholarly journals Diagenesis of Magnetic Minerals in Active/Relict Methane Seep: Constraints From Rock Magnetism and Mineralogical Records From Bay of Bengal

2021 ◽  
Vol 9 ◽  
Author(s):  
Virsen Gaikwad ◽  
Firoz Badesab ◽  
Pawan Dewangan ◽  
Mahender Kotha
Keyword(s):  
Magnetic Susceptibility ◽  
Bay Of Bengal ◽  
Rock Magnetism ◽  
Sediment Cores ◽  
Cold Seep ◽  
Fault System ◽  
Iron Sulfides ◽  
Magnetic Minerals ◽  
Fine Grained ◽  
Sediment Magnetism

In this study, we conducted a comprehensive investigation of rock magnetic, mineralogical, and sedimentological records of sediment cores supplemented by a high resolution seismic data to elucidate the controls of structural and diagenetic (early vs. late) processes on the sediment magnetism in active and relict cold seep sites in the Bay of Bengal. Two distinct sediment magnetic zones (Z-I and Z-II) are defined based on the down-core variations in rock magnetic properties. The sediment magnetism is carried by complex magnetic mineral assemblages of detrital (titanomagnetite, titanohematite) and authigenic (fine-grained greigite) minerals. Overall, the magnetic susceptibility varies over one order of magnitude with highest values found in relict core. Uppermost sediment magnetic zone (Z-I) is characterized by higher concentration of magnetite as seen through elevated values of magnetic susceptibility (χlf) and saturation isothermal remanent magnetization (SIRM). A systematic gradual decrease of χlf and IRM1T in Z-I is attributed to the progressive diagenetic dissolution of iron oxides and subsequent precipitation of iron sulfides. Magnetic grain size diagnostic (ARM/IRM1T) parameter decreases initially due to the preferential dissolution of fine-grained magnetite in the sulfidic zone (Z-I), and increases later in response to the authigenic formation of magnetite and greigite in methanic zone (Z-II). Distinct low S-ratio and χlf values in methanic zone of relict core is due to increased relative contribution from highly preserved coercive magnetic (titanohematite) grains of detrital origin which survived in the diagenetic processes. A strong linkage between occurrence of authigenic carbonates and greigite formation is observed. Two plausible mechanisms are proposed to explain the formation and preservation of greigite in Z-I and Z-II: 1) decline in methane flux due to massive hydrate accumulation within the active fault system and formation of authigenic carbonate crust in the sub-surface sediments hindered the supply of upward migrating fluid/gas; thereby limiting the sulfide production which preferentially enhanced greigite formation in Z-I and 2) restricted supply of downward diffusing sulfide by the carbonate layers in the uppermost sediments created a sulfide deficient zone which inhibited the pyritization and favoured the formation of greigite in the methanic zone (Z-II).

Sign in / Sign up

Export Citation Format

Share Document