Book of Abstracts. 16th Castle Meeting: New Trends on Paleo, Rock and Environmental Magnetism, 10-16 June 2018, Chęciny, Poland

Abstract:

This year we have the pleasure to attend already the 16th “Castle Meeting” on Paleo, Rock and Environmental Magnetism. Although 16 is not the right reason to celebrate, these meetings started exactly 30 years ago as meeting on Paleomagnetism, Rock Magnetism and Database Usage.

Abstract:

In the present study sediments cores from the inner part of Thermaikos Gulf are examined by means of magnetic properties. The investigated area covers the gulf and the bay of Thessaloniki, the second biggest city of Greece and metropolitan center in the Balkans.

Abstract:

This work aims to evaluate the use of thermomagnetic curves to identify the presence of iron oxyhydroxysulfates (jarosite type minerals) by their transformation at high temperatures to ferrimagnetic iron oxides.

Abstract:

Obtaining reliable paleointensities from lavas is a notoriously difficult task. Methods to obtain absolute intensities, e.g., Thellier-Thellier or Multi-specimen-style techniques, rely on heating a specimen to demagnetize their thermally acquired Natural Remanent Magnetization (NRM) and replace it with a partial Thermoremanent Magnetization ((p)TRM) arising from an applied external lab field.

Abstract:

First-order reversal curves (FORC) have become an extremely successful method to assess domain states such as single-domain (SD), pseudo-single-domain (PSD), and multi-domain (MD) grains as well as magnetostatic interactions and are therefore an invaluable tool for basic sample characterization. There use to predict remanence acquisition behaviour, however, has traditionally been limited and mostly qualitative. Traditionally, FORC diagrams are interpreted in terms of Preisach theory that breaks the magnetic behaviour of the different domain states down into individual elementary hysteresis loops (hysterons). These effectively depend on a grain’s coercivity and an interaction field, but do not contain any information about a grain’s thermal or viscous (thermoviscous) behaviour. In the case of igneous rocks, natural remanence (NRM) acquisition is, however, (chemical alterations apart) almost always thermoviscous in nature. Hence, in order to use FORC diagrams for NRM analysis, the inclusion of thermal fluctuations in the model is essential.

Abstract:

Stepwise thermal demagnetization and alternating field (AF) demagnetization are commonly used in paleomagnetic studies to isolate remanent magnetic components of different origins. The magnetically hardest, i.e., highest unblocking temperature/peak field component is often interpreted as the primary magnetization and magnetically softer components as subsequent remagnetizations due to geological events posterior to the formation of the rock, such as reheating or formation of new magnetic minerals.

Abstract:

Anisotropy of magnetic properties is related to the crystallographic or shape preferred orientation of minerals, or the distribution of strongly magnetic grains. The preferred alignment of ferromagnetic or remanence-carrying grains is particularly important for paleomagnetic studies, because their anisotropy can deflect the magnetization away from the inducing field, and affect the intensity of magnetization.

Abstract:

The internal geomagnetic field varies over a huge range of timescales but it is only at the longest of these (107 to 109 years) that we expect to encounter a signature of geodynamo forcing from mantle convection and Earth’s secular cooling. Precise and accurate identification of such variations and their causes represents one of the great outstanding challenges for palaeomagnetism and deep Earth science.

Abstract:

Understanding Earth’s earliest magnetic field is of critical interest in part because of the necessary protection provided by the field against solar wind erosion of the atmosphere, allowing for the preservation of liquid water on Earth’s surface.

Abstract:

In this study, more than 200 oriented cores were selected for palaeomagnetic investigation of six metaigneous and one metacarbonate sites from metamorphic Proterozoic – Lower Palaeozoic complex of South-Western Oscar II Land (Western Spitsbergen). Additionally, a comprehensive set of petrological, structural and rock-magnetic methods were applied to obtain detailed information about ferromagnetic carriers and their origin. To increase the resolution of the petro-magnetic data, standard “whole rock” analyses were enhanced by experiments conducted on Fe-containing separates. The results revealed that all primary magmatic ferromagnetic phases of the meta-igneous rocks has been completely replaced by remineralization related to Caledonian (sensu lato) and younger metamorphic events. The dominant ferromagnetic carriers are representing by low/medium coercivity fraction such as pyrrhotite and Ti-magnetite/maghemite. The examination of separated magnetic phases allowed to accurately pointed out ferromagnetic carriers and connected them with particular tectono-thermal stages of investigated rocks. Multiphase metamorphic history of the region corresponding to the complex pattern of the natural remanent magnetization (NRM) of meta- igneous rocks. Obtained palaeomagnetic directions demonstrated no convergence with reference path of Laurussia for syn- to post-Caledonian time. However, the same trend of shifting the palaeomagnetic directions to the east was observed almost in all meta-igneous sites. Similar behavior was noted during previous investigations conducted on other meta-igneous sites from Oscar II Land. To explain this phenomenon several tectonic models were proposed. Our conclusions will be useful for further palaeomagnetic and petrographic interpretations of this region.

Abstract:

The definition of the Jurassic-Cretaceous (J-K) boundary is still not fully established and the boundary is the last system boundary without a GSSP. Conclusions on the calibration of calpionellids, magnetostratigraphy, ammonites and nannofossils are to define a stage base using C. alpina in the middle of M19n.2n (Wimbledon 2014). Recently we have been able to compare paleomagnetic polarity zones of  several studied sections  and demonstrate, using high-resolution magnetostratigraphy, that the J-K boundary sections in the sub-Boreal Realm can be correlated with the Tethyan ones. Currently, we conduct detailed study of the following localities: Štramberk and Kurovice (Czech Republic); Swanage, Cheif Beef, Peveril Point, Portland, Jordans, Bowers, Fresh Water Bay (England); and Le Chouet, St Bertrand’s Spring (Elbra et al. 2017), Charens, Belvedere and Tre Maroua (France). The data are correlated with well-recognized deep-water sections (Brodno) as well as shallow water sections (Le Chouet and Tatric succession) with poorly developed chronostratigraphy.

Abstract:

Methods to derive paleodirections or paleointensities from rocks currently rely on measurements of bulk samples (typically ~10 cc). The process of recording and storing magnetizations as function of temperature, however, differs for grains of various sizes and chemical compositions. Most rocks, by their mere nature, consist of assemblages of grains varying in size, shape, and chemistry. Unraveling the behavior of individual grains is a holy grail in fundamental rock magnetism.

Abstract:

The rock magnetic, mineralogical and Mössbauer spectroscopy studies were undertaken on the Lower Triassic sediments from the West Spitsbergen Fold and Thrust Belt (Bellsund) and the foreland of this orogen (Sassendalen) for a better-constrained interpretation of paleomagnetic results. Magnetic mineralogy here only partly depends on the lithology. SEM and Mössbauer spectroscopy indicated the presence of magnetite and pyrrhotite, both the most probably of secondary origin. Thermomagnetic curves of whole-rock samples show that these rocks exhibit almost pure paramagnetic behavior whereas ferromagnetic separates indicate the presence of magnetite. IRM component analysis (Kruiver et al. 2001) shows three main contributors – magnetite, pyrrhotite, and titanomagnetite or maghemite to the remanence with the significant contribution of iron oxides. Identified ferromagnetic minerals display a wide range of grain-size and magnetic behavior with the domination of PSD particles following the SD-MD mixing line on the Day-Dunlop plot. However, the minor influence of SP and SD particles is also observed. Although presented here, rock magnetic characteristic of both areas is similar, sites in the fold belt the most likely were remagnetized, whereas those in the foreland carry the primary magnetization. Due to many potential carriers of the magnetic remanence displaying a broad range of grain size and various magnetic properties, the paleomagnetism of Triassic rocks in Spitsbergen might be difficult in interpretation.

Abstract:

This study covered investigation of properties of street dust collected from 248 sites in Warsaw. The results revealed that magnetic susceptibility (χ) was in the range of 49– 1025∙10^-8 m³kg^-1 and for most locations reflected traffic intensity. The lowest values were obtained for single-lane, suburban streets and recreational areas. The highest values were obtained for high traffic crossroads with traffic lights and along transition roads from center to residential areas. Generally, the results confirmed that street dust is a good proxy of pollution level but isn’t universally applicable because complication in estimation how long the enhancement of magnetic fraction and heavy metals concentrations were accumulated on road. Using street dust also requires considering different geological properties. Awareness of these difficulties encouraged us to look for new material devoid of disadvantages. As an alternative we offer tool – “passive dust samplers” effectively accumulates traffic pollution and overcomes street dust imperfections.

Abstract:

Ultrafine iron oxides and oxyhydroxides are generated through a variety of processes during soil formation such as for instance weathering or redox cycling. Among these minerals, ferrimagnetic magnetite or maghaemite often dominate the magnetic signature of soils, clearly marking humid periods in loess/paleosol sequences, due to their large spontaneous magnetisation. Most pedogenic iron, however, occurs in anti-ferromagnetic minerals such as haematite and goethite, whose magnetic contribution is easily over-looked, because of their weak spontaneous magnetisation and high coercivity. Because of their different formation paths, a correct discrimination between ferri- and antiferromagnetic pedogenic minerals is important for the correct interpretation of palaeoclimatic archives involving pedogenesis.

Abstract:

The Most Basin is a part of the European Cenozoic Rift System, and formed during late Eocene – early Miocene within the Ohře (Eger) Graben structure (Mach et al. 2013, Ziegler and Dèzes 2007). The erosion remnants of the Most Basin sediments are thickest in several “depocentres” in the former graben axis between cities of Most, Teplice, and Ústí nad Labem. Three drill cores from Teplice and Ústí nad Labem part were sampled at 1 m sampling step. Cored samples were subjected to rock and paleomagnetic analyses, e.g., natural remanent magnetization (NRM) and alternating field demagnetization, magnetic susceptibility (k), its’ anisotropy (AMS) and dependence on field, frequency and temperature, and acquisition and demagnetization of isothermal remanence (IRM).

Abstract:

In 1877 Gauss proved a now famous theorem that allows to uniquely separate external from internal sources of the geomagnetic field via its spherical harmonic expansion. Based on a far-reaching generalization of this theorem it is possible to accomplish an unexpected breakthrough in rock magnetic research. Using potential field theory a new uniqueness theorem is proved, which guarantees for an astonishingly large class of prior source localizations that it is possible by potential field measurements on a surface to differentiate between signals from the separate source regions within. The well-known non-uniqueness of potential field inversion only prevents that the source distributions within the individual regions can be uniquely recovered.

Abstract:

Largely hemipelagic sediments intercalated with a few dropstones (IRD) have recently been collected from the western Svalbard-Barents Sea margins as long Calypso piston cores and MeBo drillcores. Using the automated 2G cryogenic magnetometer at the Geological Survey of Norway, these cores are used to develop a magnetostratigraphic framework for the late Pleistocene in this area. The lack of calcareous organisms in some of the sediment sequences makes it difficult to provide a continuous biostratigraphic framework based on stable oxygen and carbon isotopes. Instead, the available stable isotope stratigraphy is supplemented with new paleomagnetic results, including relative paleointensity variations in the time interval of ca. 10-200 ka. Relative paleointensity variation is obtained by dividing Natural Remanent Magnetization (NRM) intensities by suitable normalizers like derived from magnetic susceptibility, anhysteretic magnetization, or isothermal magnetization. The results indicate that the documented geomagnetic excursions are linked to large fluctuations of the relative paleointensity. The data indicate that paleointensity measurements are a useful additional stratigraphic tool in this climate-sensitive region of the high latitudes.

Abstract:

The ocean floor covers more than 70% of the Earth’s surface and its magnetization patterns preserve plate tectonic motions as well as geomagnetic field variations over the last 180 Ma. The natural remanent magnetization (NRM) of ocean floor basalts is a thermochemical remanent magnetization carried by titanomaghemite and acquired during the very quick cooling of basaltic flows. Its complex nature was already recognized by Nagata and Kobayashi (1963) and triggered a large amount of rock magnetic research on thermochemical remanent magnetization. Bleil and Petersen (1983) discovered the importance of low temperature single-phase oxidation of titanomagnetite for the NRM of ocean floor basalts. Oxidation starts at the grain surface and develops an inhomogenous distribution of the vacancies whereby the outer parts of a particle are more oxidized than its inner core. The corresponding decrease of lattice constant towards the oxidized grain surface generates excessive internal stresses which can generate shrinkage cracks. Such shrinkage cracks have been observed by Gapeev and Tselmovich (1983) and were studied by Petersen and Vali (1987). The diffusion properties of oxidation in titanomagnetite have afterwards been carefully studied by Gapeev and Gribov (1990), who found that – like in magnetite – the diffusion coefficient sharply decreases with increasing oxidation parameter. Although these results qualitatively clarify many aspects of TCRM acquisition in ocean floor basalts, a quantitative model is still missing. Here we develop a theoretical framework that connects all the above details and provides a consistent model of the oxidation process in titanomagnetite grains in oceanic basalts, including the development of the stresses and generation of cracks. Using this theoretical approach also the acquisition and evolution of NRM within the oceanic crust can be studied.

Abstract:

Airborne pollution poses a serious threat to human life due to its associations with a variety of health issues, including damage to not only respiratory and cardiovascular health, but also neurodevelopment and cognitive functions. Metal-based fine (< 10 μm) and ultrafine (< 0.1 μm) particles might be considered as especially hazardous as they can easily invade the human body via inhalation. Due to the large surface area of nanoparticles and their high reactivity with biomolecules and tissues, they may generate adverse health impacts related to potential oxidative stress, inflammation and generation of reactive oxygen species (e.g., Shuster-Meiseles et al. 2016). 

Abstract:

The area of South Spitsbergen National Park is exceptionally vulnerable to degradation caused by human activity due to the pristine condition of the natural ecosystem. Therefore, both environmental assessment and its thorough monitoring is of vital importance.

The present research is concerned with the assessment of topsoil contamination near the Stanisław Siedlecki Polish Polar Station (PPS) in Hornsund, Svalbard. To achieve this, we employed magnetic methods supplemented by chemical analyses and microscopic observations. Laboratory experiments were used to evaluate the concentration, magnetic mineralogy and grain-size distribution of anthropogenic magnetic particles.

Abstract:

Thermomagnetic experiments for indoor dust, outdoor dust, street dust and dust from cabin air filters from cars were conducted for identification of magnetic mineralogy. Firstly, the temperature changes of magnetic susceptibility k(T) in the range of 30–700°C were determined. Secondly, the induced magnetization M(T) in the wider temperature range of 30–800 °C was obtained with applied magnetic field of 500 mT. 

Abstract:

The Mecsek Mountains (southern Hungary) constitute a part of Tisia–Dacia megatectonic unit (Haas and Péró 2004, Császár et al. 2013), one of the key-area for the paleogeographic reconstructions of the Carpathians. Tisia was a separate tectonic unit since the Middle Jurassic after its rifting from the European Platform and prior to the beginning of the nappe-thrusting process in the Late Cretaceous (Turonian–Coniacian).

Abstract:

In contrast to the Western Carpathians, magnetic stratigraphy in the Tithonian–Berriasian has not been applied in the Northern Calcareous Alps (NCA). All formerly investigated sections in the NCA are localized in the Tirolic units and reveal multiphase, syntectonic remagnetization (Pueyo et al. 2007). However, our results from a Tithonian–Berriasian deep-water succession in the Salzburg area confirmed preservation of primary magnetization (Grabowski et al. 2017). Detailed sampling of relatively undeformed latest Tithonian to Early Valanginian succession (Krische et al. 2013) was performed in the Leube quarry SW of Salzburg. Here we present the results from the middle to upper Berriasian part of the succession, 130 m thick (= upper part of the Oberalm Formation and lower part of the Schrambach Formation). Magnetite is the main magnetic mineral in the studied section. However several horizons in the succession are enriched in hematite. Magnetic fabric reveals a simple compactional pattern with bedding parallel foliation and weak lineation in the SE–NW direction. Characteristic component of magnetization of dual polarity with unblocking temperature spectra between 400-550°C was isolated during thermal demagnetization. In combination with high-resolution biostratigraphy the magnetization component could be interpreted as primary and attributed to the magnetozones M17r to M14r (close to the Berriasian/Valanginian boundary). The magnetostratigraphic interpretation correlates perfectly with calpionellid and ammonite age dating (Krische et al. 2013, Bujtor et al. 2013) as well as with newly obtained high resolution δ¹³C curve. It must be concluded that remagnetization of Mesozoic sedimentary rocks in the NCA (Pueyo et al. 2007) was not complete. Due to the fact that in this part of the NCA relatively thick deep-water successions were deposited in contrast to the mostly condensed sections in the Western Tethyan realm there is an enormous potential for application of magnetic stratigraphy and to refine our knowledge of this still controversial early Alpine orogenic events on the base of multiproxy studies. 

Abstract:

Mineral magnetic properties are sensitive indicators for evaluation of mechanisms influencing soil formation. The interpretation of magnetic contribution focuses on discrimination between the lithogenic, pedogenic and anthropogenic origin of minerals. In case of Andosols the interpretation is limited because the lithogenic magnetic signals are masking the anthropogenic and pedogenic magnetic contributions. The main aims of this study are: (i) to assess the link between the distribution of 21 elements on the one side, and mass-specific magnetic susceptibility (χ) and frequency-dependent magnetic susceptibility (χ_FD%) on the other side, along soil depth profiles; (ii) to analyse the relationship between soil organic carbon (Cox) and the χ_FD and χ_FD% with respect to particle-size distribution. We studied 9 profiles (81 soil samples) of Alu-andic Andosols from the French Massif Central, developed on highly magnetic basaltic parent rock (Grison et al. 2017). The statistical evaluation was performed by the principal component analysis and linear regression.

Abstract:

Late Neoarchean to early Paleoproterozoic cratons have traditionally been grouped into ‘clans’ distinguished by their basement ages and supracrustal volcanic-sedimentary cover successions (e.g., Bleeker 2003). However, with the recent development of the large igneous province (LIP)-barcode method of craton juxtaposition, which is based primarily on coeval U-Pb ages of mafic dyke swarms and sill provinces, has suggested a continuity of ancient crust that brings together members of separate clans. One such reconstruction is presented in Gumsley et al. (2017): the Vaalbara supercraton is presented immediately adjacent to the western part of Superior Craton, along with the Wyoming Craton in its rotated reconstruction south of the Superior Craton. However, it is likely that Vaalbara supercraton never existed in its present form, and that instead, one or two large continents existed at this time. If such a scenario, or ‘Kenorland’ supercontinent amalgamation existed in Paleoproterozoic time, it likely assembled during Neoarchean accretion. Such a model predicts a single paleomagnetic apparent polar wander (APW) path for all the constituent cratons, where all of the individual paleomagnetic poles are rotated quantitatively into the reconstruction for the duration of their tectonic continuity.  

Abstract:

For the recognition of the glacier dynamics, it is important to determine its drainage type. For this purpose, hydrological models are applied, that show direction of subglacial water movement, based on supraglacial topography and the results of radar-sounding of the glacier bed. This enables distinguishing main catchments, flow patterns and the main drainage pathway. To define main sources of eroded material we performed independent and multidisciplinary experiments: magnetometry and granulometry providing wider interpretation that include phenomena connected to glacier movement. 

Abstract:

Early Cretaceous sills constituting the Diabasodden Suite (DBS), crop out all over Svalbard, Arctic Canada and Franz Josef Land. They have also been identified offshore on seismic in sedimentary basins in the North Western Barents Sea. Resent dating of the sills using U-Pb and Ar-Ar methods suggest a magmatic event around 125 Ma. The magnetization history of the DBS is rather complex. Sills from eastern Svalbard carry Early Cretaceous paleopoles (reverse polarity). 

Abstract:

Analysis of the reports of the Regional Inspectorate for Environmental Protection in Katowice, allows the exact location of critical points associated with increased emissions of PM10 and PM2.5, consequently also technogenic magnetic particles (TMPs) in Upper Silesia. TMPs are ferrimagnetic iron minerals which arose during high temperature technological processes. Their presence in soils can indicate the soil contamination by potentially toxic elements (PTE) because TMPs due to their structure and well developed surface area have the ability to bind metals and metalloids. In iron analysis very effective tool is Mössbauer spectroscopy because of the high sensitivity of this method and precise phase analysis capabilities. It enables the determination of iron speciation in environmental samples and provides very precise information about the chemical, structural and magnetic properties of material.

Abstract:

Shortly after the first geological pioneering application of the AMS (Ising 1942), Graham (1954) suggested to open a new way based on this approach. For more than 10 years, AMS use was very limited, due to the heavy conditions of measurement and to the necessary use of large samples. The development of new instruments, like the Digico Anisotropy Delineator (by Molyneux) and the Kappabridges (by Jelinek, Suza, and Pokorny) and the use of standard cylindrical samples offered the possibility to obtain results from fast measurements and easier sampling. AMS is now a routine method used in many laboratories over the world. 

Abstract:

Rocks and sediments are composed of various minerals, but ferromagnetic minerals contribute only a small amount to their total volume. The low concentration can make detection through microscopic methods difficult. Since the first studies to understand the remanent magnetization carried by ferromagnetic minerals in volcanic rocks by Koenigsberger (1938) and Thellier (1938), a variety of techniques have been developed to aid in identifying ferromagnetic phases in rocks, sediments and soils, by exploiting the material properties of these minerals. For example, thermomagnetic curves, which are used to define Curie or Néel temperature, help determine mineral composition, whereas hysteresis properties can provide information on domain state, i.e., particle size and concentration. Because geophysical instrumentation and rock magnetic methods allow for detection of very small concentrations, techniques have a validity in other research areas that are interested in identifying ferromagnetic phases with respect to their composition, concentration, and particle size. Methods that aid in distinguishing whether the ferromagnetic particles are either dispersed so as to act as individual particles or in clusters, in which particles magnetically interact, are also of interest in many applications. The number of rock magnetic studies has grown exponentially over the past 20 years. Examples will be shown on how rock magnetic methods can be used in applications that are related to environmental studies and material development. 

Abstract:

Pleistocene subaerial deposits in Ukraine have been paleomagnetically studied in several dozens of loess-paleosol sequences. In some sections the results were frequently fairly contradictory, for example, different authors placed the Matuyama-Brunhes (M/B) boundary – a key magnetostratigraphic benchmark of Pleistocene – in different stratigraphic horizons even within the same sections (Bakhmutov et al. 2017). Independent investigations concerning the magnetic parameters of the rocks and paleomagnetic study of loess-paleosol sections in Volhynian Upland (Boyanychi and Korshiv sections), Black Sea Lowland (Roxolany section) and Dnieper Lowland (Vyazivok section) by the same experimental procedure for comparing the formation of the magnetic properties for these regions and revealing the magnetostratigraphic markers were obtained by the author. According to new results for Roxolany section the M/B boundary is located at a depth of 46.6 m at the contact of buried soils of Lubny (lb) and Martonosha (mr) horizons. The M/B boundary in Vyazivok section lies at a depth of 56.2 m in the lower part of Shyrokino (sh) paleosol horizon (Hlavatskyi 2016). The position of the M/B boundary in Roxolany and Vyazivok sections is controversial following by local stratigraphic schemes, which can be explained both of peculiarities of “magnetic record” in soil and incorrect stratigraphic subdivision of Roxolany section. There are evidences of magnetic event, probably Emperor/Big Lost (560-570 kyr), in both sections, which was detected in Zavadivka (zv) soil. The same zone of reversed polarity was fixed in Zavadivka horizon in other sections of the south of Ukraine (Bakhmutov et al. 2017). The M/B boundary is not revealed in the Volhynian Upland sections and short reversed-polarity episodes or excursions are absent; therefore, magnetostratigraphic correlation of Boyanychi and Korshiv sections with other loess- paleosol sequences is impossible. New correlation stratigraphic scheme of the subaerial formation of Ukraine is proposed.

Abstract:

The Anisotropy of Magnetic Susceptibility (AMS) is in general controlled by all minerals present in a rock. However, the individual magnetic minerals or their groups may behave in different ways in various geological situations and it is therefore desirable to resolve the rock AMS fabric into components corresponding to individual magnetic mineral sub-fabrics. The resolution is based on specific behaviour of suscep-tibility of individual minerals in variable magnetic fields or at variable temperatures.

Abstract:

The aim of this study is to compare pollution of air inside a building (Jeleńska et al. 2017) with pollution of soil and dust street around the building. Magnetic properties such as hysteresis parameters and magnetic susceptibility values, and magnetic mineralogy identification were used for characterization of magnetic particles present in indoor dust, street dust and in soil. Study was carried out in the flat in residential biulding located in the center of Warsaw between two very busy streets and one smaller but very narrow. Dust samples (ID) were collected inside the buildings with a vacuum cleaner. Street samples (DD) were swept up from the surface of the roadway. Soil samples (DS) were digged from the lawns along the street. The samples were taken from 2 or 3 layers: surface, 0-10 cm and 10-20 cm of depth. Two samples of soil were taken from the lawn in the inner yard of the building. 3 samples were taken from the flat located on first floor. Magnetic parameters measured include mass susceptibility, hysteresis loops and volume susceptibility during heating to 700 °C. The values of susceptibility showed that soil taken from the inner yard is contaminated approximately similarly to soil taken along the small street. The highest values of susceptibility are for soil taken around crossroad. Contamination of street dust is lower than soil around crossroad and higher along the streets. Susceptibility of indoor dust is approximately the same as for soil samples taken by the nearest street.

Abstract:

A well known outcome of fire on soil magnetism is extremely high magnetic enhancement of top-most soil depths (Tite and Mullins 1971) compared to non-burnt soil. It was anticipated that due to thermal transformations in iron oxyhydroxides (mainly goethite) during heating a strongly magnetic maghemite is produced. This mechanism is further considered as one of the possible processes causing widely observed soil magnetic enhancement (e.g., Dearing et al. 1996, Evans and Heller 2003). Several studies, however, evidence that vegetation ashes also exhibit high magnetic susceptibility, typical of ferrimagnetic substances (McClean and Kean 1993, Lu et al. 2000, Jordanova et al. 2006, Petrovsky et al. 2018) in spite of diamagnetic nature of the raw vegetation. Thus, it could be supposed that magnetic signature of burnt soils reflects a more complex enhancement processes than previously thought. Apart from this, another major question arising in considering the magnetic properties of fire-affected soils is whether their magnetic enhancement is stable in time since the firing event, or it changes. In order to answer this question, an experimental fire was set up and magnetic susceptibility of samples taken from two depth levels (ash-rich level (0-3 cm) and soil mineral level (3-6 cm)) immediately after the fire was monitored during 2.5 years period. In addition, several samples from these two depth levels were taken after different time span since the firing event and their magnetic susceptibility again was monitored during that period. Besides, soil samples were taken one week after natural wildfires in 2017 year and magnetic susceptibility of samples from different depth intervals was tracked during the following 8 months. Reference soil samples from non-burned soils from the respective sites were included in the collection well. The main results from the study show that: 1) Magnetic susceptibility of burnt soil changes since the firing event and this change depends on the intensity and duration of fire, being more pronounced in soils suffering low-severity fire; 2) Magnetic susceptibility increases in soil samples taken immediately after the fire during the first ~10 days and slowly decreases afterwards for ash-rich samples or remains semi-constant in mineral-rich samples; 3) Magnetic susceptibility increase with time varies in a wide range between 2–3% and almost 40% with respect to the initial value, being higher in mineral-rich samples; 4) Magnetic susceptibility of soil samples taken after high-severity natural wildfire show a weak decrease (varying between 0–4%) with time which is the most pronounced in top-most depths; 5) Magnetic susceptibility of reference non-burnt soil samples practically does not change with time. The most probable reason for the observed fast changes in magnetic susceptibility after fire is related to soil dehydration as revealed by the data of weight loss with time. It is supposed that severe wildfires lasting several days produce more stable new magnetic minerals, while experimental fire and low-severity natural fires generate ultra-fine unstable magnetic grains which continue growing and further oxidize during laboratory monitoring period. Different implications of the observed changes in magnetic enhancement of fired soils related to environmental applications in practice will be discussed.

Abstract:

Magnetic enrichment of fire-affected soils is a long – known phenomenon, observed at the birth of environmental magnetism and it was suggested that fire may be responsible for the soil magnetic enhancement of well aerated soils (Tite and Mullins 1971). Since then, several rock magnetic parameters have been proposed for discrimination between natural magnetic enhancement and burnt soils’ enhancement, based on the observation that fire-affected soils show systematically higher concentration of fine grained superparamagnetic magnetite particles (Oldfield and Crowther 2007, Roman et al. 2013). The aim of the present contribution is to examine the effect of complex variations in fire severity, type of vegetation, time since fire and natural soils’ properties on the observed magnetic and geochemical signature of burnt soils from Bulgaria. For that purpose, nine couplets of burnt- natural forest soils under pine forest; four couplets under mixed/broadleaf forest and three soil couplets with grass/bush vegetation have been studied. The wildfire events happened at different times before sampling, encompassing the period 2000–2017. In all profiles sampled, clear distinction of the burnt layer was possible based on the presence of abundant ashes and charcoal. Systematic magnetic enhancement is observed in all fire-affected soil levels, which is expressed not only in increased SP-content, but also enhanced concentration of stable SD particles. It is suggested by the experimental data, that the relative contribution of the two fractions depends on the fire severity in terms of both maximum firing temperature reached in the surface soil and the duration of fire event. Maximum fire-induced magnetic enhancement of susceptibility is obtained for soils developed under pine forest, suffered by strong wildfires. Less intense fire events and mixed or broadleaf vegetation cover induced weaker magnetic enhancement. Along with the enrichment with strongly magnetic iron oxides of the burnt layers, significant increase in the content of total concentration of elements – micronutrients such as Mn, Cu, Zn, P is observed, in line with other studies (Certini 2005, Pereira et al. 2012). Much better log-linear correlation is obtained between total carbon content (Ctot) and anhysteretic remanence (ARM) for burnt soil levels (R² of 0.85) as compared to non-burnt and Ctot – magnetic susceptibility relationships. These findings suggest that wildfire affected soils’ magnetic signature is dominated by magnetic signal of vegetation ashes.

Abstract:

Loess-palaeosol sequences provide one of the most widespread palaeoenvironmental records. Aeolian dust deposition and loess formation dominated in glacial Pleistocene stages, whereas during temperate interglacial (or interstadial) periods the loess surface was altered to soil. The pedogenic processes caused diagnostic changes of iron minerals present in primary loess (e.g., Maher 2011). Primary magnetic fabric of the loess, described by anisotropy of magnetic susceptibility principal directions, fabric magnitude, and a fabric shape, was deformed due to neo-formation of ultrafine superparamagnetic (SP) particles and sediment bioturbation (e.g., Tarling and Hrouda 1993). Additionally, the interglacial (interstadial) flash precipitation events could trigger slope processes and the soft sediment reworking. 

Abstract:

Sudetic ophiolite is formed of three serpentinite massives situated around the Sowie Góry Mts Block: Jordanów-Gogołów Massif (JGSM), Braszowice-Brzeźnica Massif (BBSM) and Szklary Massif (SZM). Chromite Fe-Cr spinels occur in chromium ore (chromitites) in JGSM and BBSM (ore fragments on waste heaps) and as scattered grains in ultramafic rocks. 

Abstract:

The Most Basin is the largest basin within the Ohře Rift in Czech Republic. The Early Miocene Most Formation (topmost part of Most Basin) is divided into 5 members, spinning from Duchcov up to Osek members (Mach et al. 2014), and comprise of lacustrine-, alluvial and fluviodeltaic sediments with interjected coal seams.

Abstract:

Mössbauer spectroscopy is the technique of recoil-free resonant emission and absorption of gamma rays. It has the advantage of being sensitive only for one element. In the case of materials formed on the Earth’s surface, such as soils and clays, the only propitious element is Fe. 

Abstract:

Palaeomagnetic studies of the Upper Jurassic rocks were performed in the Polish part of the western fragment of the Pieniny Klippen Belt (PKB). Red and green radiolarites of the Czajakowa Radiolarite Formation and red nodular limestones of the Czorsztyn Limestone Formation represent the Grajcarek succession. More than 80 oriented cores were collected from the 20-m-thick Stare Bystre succession. Laboratory work was focused on recognizing the natural remanent magnetization (NRM) structure and magnetic carriers, involving thermal and alternating field demagnetization, analysis of magnetic susceptibility and its anisotropy, and the Lowrie (Lowrie and Heller 1982) and S-ratio (Bloemendal et al. 1992) tests. Thermal demagnetization revealed two main components of natural remanent magnetization (NRM). A low-blocking temperature component S of normal polarity is considered of post-tectonic origin. A stable, high-blocking temperature NRM component P shows dual-polarity distribution and is considered as primary. Unfortunately, only some of the samples from the base and top of the succession show the primary magnetization component – their number is insufficient for Fisher statistics. This requires more sampling for further studies. IRM saturation curves show a rapid saturation up to 100 mT and then a slower pace until reaching the maximum value of 1 T, which suggests the presence of magnetite and hematite. These results are confirmed by the thermal demagnetization of the IRM saturated samples – the low coercivity component shows a blocking temperature of ca. 575°C, while the high coercivity component shows the blocking temperature of ca. 675°C. Furthermore, the S-ratio analysis (S_-0.3T) gives most values close to zero, which suggests a significant contribution of hematite. Magnetic susceptibility values (2.11 ×10^-5 [SI] to 1.27×10^-4 [SI]) during thermal demagnetization are stable over the entire temperature range with the exception of slightly lower values near 320°C, which may suggests a low content of iron sulfides.

Abstract:

The measurement of anisotropy of magnetic susceptibility (AMS) becomes one of the most popular structural techniques for precise and quick determination of anisotropic fabric in rocks with lack of macroscopically visible structures. Sometimes, the lack of comprehensive information about the governing processes of AMS in rock can make interpretation difficult. Although it is well-established method and the strain-AMS relationship has been long time under investigation, recent publications have brought more attention to this subject. There is considerable discussion concerning origin of the magnetic fabric, its correlation with the bulk deformation and rock strain memory. The aim of our work is to bring new insights into the time and space relationships between finite strain microstructure and AMS fabric by providing new comparative data from analogue shear zones. Relationship of AMS with increasing strain was experimentally studied in deformed sandstones, plasticine, magnetite bearing sand bonded with cement (Borradaile and Alford 1987, Jackson et al. 1993), during preparation and compaction of calcite and muscovite aggregate (Schmidt et al. 2008a, b) and simple shear experiments on mixture of silicone and wax (Arbaret et al. 2013).

Abstract:

Upwelling systems along the western margin of continents are the most productive marine ecosystems on the earth. In such systems the wind along the coast causes off-shore movement of surface water which results in upwelling of cold, highly CO₂ concentrated, nutrient-rich water to the illuminate zone where photosynthesis occurs. Nutrients and CO₂ concentrations are essential for photosynthesis and their rise results in increased primary productivity in the water surface (growing amount of organic matter). Dead organisms sink to the water/sediments zone where they are decomposed by microbes. In this process oxygen is consumed and strongly reducing conditions are established. The fate of magnetic phases in such an ecosystem is poorly resolved, despite the fact that upwelling systems are widespread and are active over millions of years. Considering such system magnetic phases can be formed, e.g., by biogenic processes or be destroyed by reductive dissolution. 

Abstract:

A primary goal of this palaeomagnetic study was to determine palaeolatitude of the Ediacaran basin, situated at the western part (present-day coordinates) of the East European Platform (EEP). 

Abstract:

Magnetite and hematite are the most common ferromagnetic minerals in rocks and sediments. Many methods have been developed to identify their occurrence in geological material. Because the saturation magnetization of magnetite is much stronger than hematite, it may not be easy to identify both minerals when using induced magnetic methods, e.g., hysteresis loops or thermomagnetic curves. Frank and Nowaczyk (2008) demonstrated that the hematite concentration must be at least 95 wt% of the mixture before a change in coercivity can be detected, and 99.5 wt% before B_cr/B_c is affected. Parameters involving remanent magnetization rather than induced magnetisation, e.g., SIRM or HIRM, noted hematite at concentrations of 90 wt% or higher. In this study, we reexamine mixtures of magnetite and hematite to evaluate the ability of FORC analysis to distinguish mixtures. The end members for the mixtures were magnetosomes of biogenic magnetite (LMU-30) that were provided by the group of Prof. Dirk Schüler from the Department of Microbiology at the University of Bayreuth, Germany. The hematite sample (Hem21) was obtained from Merck. The magnetic properties were defined for these end member samples. Hysteresis loops are closed by 100 mT for mixtures up to 85 wt % hematite; at higher concentration the loop remains open to maximum field. The coercivity, B_c, remains relatively stable with a decrease until above 80 wt % hematite. B_cr shows a gradual decrease up to 80 wt % hematite. M_s shows a linear cdecrease with increasing hematite concentration. Acquisition IRM curves are saturated by approximately 60 mT for the mixtures of magnetite and hematite up to 61 wt %. By 70 wt % hematite, it is clear that the IRM is not saturated, and the non-saturated contribution increases with increasing hematite content. S-ratio, however, remains above 0.95 for all mixtures until 95 wt% hematite, similar to what was found by Frank and Nowaczyk (2008).

Abstract:

In early 2016, the Lake Ohau Climate History (LOCH) project recovered an 80-metre sedimentary sequence from Lake Ohau on the south island of New Zealand, containing a ~17,000-year record of environmental and magnetic variability (Levy et al. in press). The LOCH project aims to produce a detailed history of regional palaeoclimate and palaeoenvironment, which are strongly influenced by variations in southern-hemisphere westerly winds. Preliminary palaeosecular variation and relative palaeointensity results were presented at the EGU General Assembly 2017 (Lurcock et al. 2017), and proved to be heavily affected by a presumed drilling overprint and gyromagnetic remanences. In order to better constrain and characterize these effects, and to investigate the enviromagnetic record of the Lake Ohau sediments, we are undertaking a detailed rock magnetic study of the 6-metre Mackereth core 6m_1a, retrieved from Site 2 in Lake Ohau preliminary to the main LOCH coring project. Our analyses aim at a thorough rock magnetic characterization of the sediments using measurements of hysteresis loops, temperature dependence of magnetic susceptibility, first-order reversal curves, remanent coercivity spectra, and stepwise IRM demagnetization. Previous NRM demagnetization and ARM acquisition studies on this core have already shown good potential for palaeomagnetic interpretation. Our rock magnetic studies will inform understanding of the palaeomagnetic results from both the 6m_1a core and the full-length LOCH-2A core obtained from the same site. In addition, they will provide a valuable enviromagnetic contribution to the ongoing multi-proxy palaeoenvironmental studies on the Lake Ohau cores. Initial studies have already shown that magnetic parameters in the 6m_1a cores are correlated with palaeoenvironmental proxies such as neodymium isotopes, and our full rock magnetic study will provide further insights into variations in sediment provenance, inflow events, and conditions at the sediment-water interface.

Abstract:

The Neogene infilling of the Orava Basin constitutes a sedimentary record postdating the formation of thrust-and-fold belt of Outer Carpathians and its contact with Inner Carpathians. After the main underlying structural units (Magura Nappe, Pieniny Klippen Belt, and Podhale Synclinorium) were formed, the area underwent uplift and erosion. The considerable horizontal movements including strike-slip tectonics were noted since Lower/Middle Miocene resulting in origin of local depressions. The sedimentary succession and deformation history of the Orava Basin provide an excellent data for the understanding the neo-alpine evolution of the Orava and Podhale regions.

Abstract:

Soil magnetic properties mainly reflect the iron-mineral composition. As ferromagnetic properties sensu stricto are exhibited only by metallic iron (αFe), which is not formed under natural environmental conditions, ferrimagnetic minerals like magnetite, maghemite, pyrrhotite or greigite dominate the bulk magnetic properties of natural soils. Only if ferrimagnetic minerals are lacking, antiferromagnetic minerals such as hematite, goethite, lepidocrocite, ferrihydrite or paramagnetic iron containing aluminosilicates noticeably influence soil magnetic properties. 

Abstract:

Abstract

Magnetic method is suitable instrument in assessment environmental problems. Recently we’ve received promising results in the studying of hydrocarbon areas (Menshov et al. 2016) and polluted territories in Ukraine (Menshov 2017). The correct planning of agriculture areas is fundamental for a sustainable future in Ukraine. 

Abstract:

In the years 1999-2016 Laboratory of Palaeomagnetism of the Institute of Geophysics, Polish Academy of Sciences coordinated numerous palaeomagnetic field investigations in different parts of Svalbard Archipelago. More than 950 independently oriented palaeomagnetic samples were collected from 156 sites representing all three Svalbard Caledonian Terranes (Harland and Wright 1979) as well as post-Caledonian, pre-Eurekan cover of Spits-bergen and Edgeøya. Palaeomagnetic samples were collected during following expeditions: (a) XXII PAS Polar Wintering Expedition to Hornsund (1999-2000; Wedel Jarlsberg Land and Torell Land), (b) IGF PAS palaeomagnetic field investigations of Torell Land (2002), (c) IGF PAS palaeomagnetic field investigations of Wedel Jarlsberg Land, Torell Land, and Sørkapp (2004), (d) Joined expedition of IGF PAS/University of Greenwich (UK) along western and northern coasts of Spitsbergen (2006; Kongsfjorden, Ny Friesland), (e) Palaeomagnetic field investigations of Caledonian Terranes of Svalbard organized in the course of PALMAG NCN project (2012-2013; Oscar II Land, Kongsfjorden, Ny Friesland, Nordaustlandet), (f) “Trias North”project joined expedition of UNIS and Statoil to Edgeøya (2016).

Abstract:

The North Atlantic Ocean has been an area of intensive research on the causes and effects of climate change on different time scales. This location bias is based on the high sensitivity of this region to changes in continental ice volume, given the high ratio of continental to oceanic surface, and in the vigour of the Meridional Overturning Circulation, whose engine is deep-water mass production in these regions. On the contrary, research in equatorial and tropical latitudes is scarce, despite their high potential of preserving atmospheric signals due to their high sensitivity to meridional shifts in the Inter Tropical Convergence Zone (ITCZ). Dust production and transport from the African Sahel and Sahara Desert is strongly dependent on the position and strength of the ITCZ, with large implications for lithogenic inputs in remote areas of the ocean, cloud formation, as well as albedo and radiative effects.

Abstract:

The Earth’s magnetic field is generated in the liquid outer core. So-called absolute paleointensities, i.e., a field intensity in mT for a given location that can be converted to a virtual (axial) dipole moment, are tedious to obtain and therefore remain rather scarce, in particular for periods older than the Holocene. The Holocene field intensity is considered (unusually?) high; it is reasonably well constrained by data from lavas and archaeological artefacts, at least for considerable portions of the northern hemisphere. The average intensity of the Brunhes Chron is ~20% higher than most of the underlying Matuyama Chron (Ziegler et al. 2011). Longer term trends within the Brunhes Chron, however, are surprisingly poorly characterised. It seems that the period between ~200 and ~400 ka featured a lower field intensity as determined for Hawaii (Pacific Ocean, USA; Tauxe and Love (2003)) and the Eifel (Germany; Monster et al. 2018) but data paucity precludes firm inferences. Regional full-vector PSV curves are essential to further our understanding of geodynamo operation. Such curves typically lack palaeointensity information. Here, we present new paleointensty data from El Hierro, Canary Islands. The Canary Islands are part of the Canary Island Seamount Province which developed on ancient ocean crust, the oldest Atlantic Ocean crust Jurassic in age, relatively close to a continent, Africa. El Hierro and La Palma represent the youngest islands with ages of < 2 Ma (e.g., Guillou et al. 1996). We sampled 28 lava flows (age range c. 150 to 450 ka) from a section along the Camino de Jinama, about 4.5 km to the south of a section sampled by Széréméta et al. (1999) for an analysis of directional PSV. Individual flows range in thickness between 1 and several meters, and are usually easily distinguished by the presence of scorias, pyroclastic layers, or paleosols. Three groups of flows are recognized, referred to as the upper group (UG), the middle group (MG) and the lower group (LG). In line with earlier results (Széréméta et al. 1999), we observe an easterly declination deviation of c. 14° for the middle and lower part of our section. We relate this to under-sampling of the complete PSV spectrum; rotation of El Hierro since c. 500 ka is deemed unlikely. Attempts to date the flows with the ⁴⁰Ar/³⁹Ar method on a state-of-the-art multi-collector instrument were unsuccessful due to the presence of copious amounts of methane in the extracted gases. 

Abstract:

Sedimentary environments preserve a record of climate change as reflected in the variations in magnetic mineralogy through time. Deconvolving the complex bulk magnetic signal is one of the primary challanges facing environmental magnetism. 

Abstract:

A paleomagnetic study of a Middle/Upper Jurassic stromatolite section from the Zalas quarry was conducted and revealed a well-defined structure of natural remanent magnetisation (NRM) comprising: (1) a viscous component (20–100°C), (2) a normal secondary component (100–275°C), and (3) normal and reversed primary components (275–500°C). Scanning electron microscopy (SEM) studies of magnetic extracts revealed that the vast majority of the recovered magnetic mineral fraction consists of spherulitic iron-nickel grains of 10 to 300 µm in diameter. These spherules are identified as micrometeorites. We present a comprehensive rock magnetic and microscopy study of the micrometeorites and discuss their potential as NRM recorders. 

Abstract:

Measurements of the anisotropy of whole-rock magnetic susceptibility (AMS) have been conducted to define the palaeowind strength and directions. For the AMS studies more than 1000 geographically oriented cylindrical samples were taken from 22 loess sections located in the area between the Vistula and Dnipr rivers, and the Black Sea. In order to define sources of dust and to verify directions of wind obtained from the AMS studies the U-Pb ages of detrital zircons extracted from 20 loess horizons have been also estimated. An oblate magnetic fabric is prevalent in all the horizons of loess studied. Such a feature is characteristic of loess sediments. The value of anisotropy P is proportional to the foliation parameter F, indicating a subordinate role of lineation. There is an inverse relationship between half-angular uncertainty in the direction of maximum susceptibility (e₁₂) and the magnetic lineation parameter L, and between half-angular uncertainty in the direction of minimum susceptibility (e₂₃) and the magnetic foliation parameter F caused by increased measurement errors for weak lineations (foliations). On the other hand, the absence of correlation between e₁₂ and foliation indicates that the lineation and foliation sub fabric are probably defined by the orientation distribution of separate minerals. Only part of the samples had statistically significant magnetic lineations, with F12 > 4 and  e₁₂ < 22.5^o. The AMS of the loess from the Black Sea region is very weak, i.e., almost 5 times weaker than noted in the periglacial loess of Western Ukraine and Poland, and comparable to that noted in the Chinese loess. The imbrication of Kmin axes is not so distinct in the older loess horizons, probably because of compaction. Nevertheless in this case also, the distribution of magnetic susceptibility axes allows to define prevailing wind directions. Migration of the Kmax axes due to variable wind strength limit their usefulness for the determination of aeolian transport directions. They may not be used alone for this purpose, but may support the information obtained from the imbrication directions of the Kmin axes. 

Abstract:

Paleomagnetic studies of lunar samples collected during the Apollo missions suggest the Moon had an active core dynamo for at least 2 billion years (Tikoo et al. 2017). The early lunar dynamo (4.25–3.56 Ga) was intense, recording paleointensities of 20–110 µT (Garrick-Bethell et al. 2009, Shea et al. 2012, Suavet et al. 2013, Weiss and Tikoo 2014). The lunar dynamo field subsequently declined to 5±2 µT at 2.5–1 Ga (Tikoo et al. 2017). The strength and longevity of this dynamo field is challenging to explain via a single mechanism. Thermal convection could not have driven a dynamo for such a sustained period of time, whilst thermochemical convection during core solidification is unlikely to have started so early (Christensen et al. 2009, Nimmo 2009). Alternative mechanisms of dynamo generation, such as mechanical stirring driven by gravitational coupling to the Earth may also be plausible (Dwyer et al. 2011). 

Abstract:

Our goal was to investigate rockmagnetic properties of two lithofacies of Silurian gas-bearing shales from Northern Poland: Pelplin Formation and Jantar Member which both represent a potential source of unconventional hydrocarbons. The studied rocks are characterized by similar burial evolution, but different amounts of organic matter (Jantar – up to 7 percent, while in Pelplin not exceed 1.5 percent). Moreover, in the Pelplin Formation spherical calcareous concretions were examined. The differences in magnetic minerals composition, if any occur, may help better understand the determinants, which control water chemistry at the bottom of sedimentary basin and thus the preservation of organic matter. 

Abstract:

Magnetic hysteresis loops are an important tool in theoretical and applied rock magnetism with applications to paleointensities, paleoenvironmental analysis, and tectonic studies, among many others. Hence, information derived from these data is amongst the most ubiquitous rock magnetic data used in the Earth science community. Despite their prevalence, there are no general guidelines to aid scientists in obtaining the best possible data and no widely available software to allow the efficient analysis of hysteresis loop data using the most advanced and appropriate methods. Here we provide a brief outline of detrimental factors and simple approaches to measuring better hysteresis loops as well as introducing a new MATLAB software package called Hysteresis Loop analysis box (HystLab) for processing and analyzing loop data. This graphical user interface software is capable of reading the wide range of data formats that are generated by the multiple types of equipment typically used to measure hysteresis loops. HystLab provides an easy-to-use interface allowing users to visualize their data and perform advance processing, including loop centering, drift correction, linear and approach to saturation high-field slope corrections, as well as loop fitting to improve the results from noisy specimens. A large number of hysteresis loop properties and statistics are calculated by HystLab and can be exported to text file for further analysis or can be explored using the in-built bi-plot functionality of HystLab. All plots generated by HystLab are customizable and user preferences can be saved for future use. In addition, all plots can be exported to encapsulated postscript files that are publication ready with little or no adjustment, greatly enhancing the workflow productivity when processing and analyzing large data sets.

Abstract:

The effect of wood-ash fertilization on forest soils has been assessed mainly through geochemical methods (e.g., content of soil organic matter or nutrients). However, a simple and fast method of determining the distribution of the ash and the extent of affected soil is missing. In this study we present the use of magnetic susceptibility, which is controlled by Fe-oxides, in comparing the fertilized soil in the forest plantation of pine and oak with intact forest soil. Spatial and vertical distribution of magnetic susceptibility was measured in an oak and pine plantation next to stems of young plants, where wood-ash was applied as fertilizer. Pattern of the susceptibility distribution was compared with that in non-fertilized part of the plantation as well as with a spot of intact natural forest soil nearby. Our results show that the wood-ash samples contain significant amount of ferrimagnetic magnetite and has susceptibility higher than that of typical forest soil. Clear differences were observed between magnetic susceptibility of furrows and ridges. Moreover, the dispersed ash remains practically on the surface, does not penetrate to deeper layers. Finally, our data suggest significant differences in surface values between the pine and oak plants. Based on this study we may conclude that magnetic susceptibility may represent a simple and approximate method of assessing the extent of soil affected by wood-ash.

Abstract:

Airborne particulate matter (PM) that originates from the combustion of fossil fuels is of concern due to adverse effects on the environment and human health (Rogula-Kozłowska 2015). Classic monitoring methods based on PM collectors and subsequent chemical analyses are expensive and time consuming. As a result, time- and cost-effective methods were in demand. Results from several studies have identified spider webs as an excellent source of biomonitors (Flanders 1994, Rybak 2015). Spider webs accumulate pollutants to which humans are exposed; thus, they are a reliable source of information about the quality of the environment in a way that is similar to other bioindicators. Compared to conventional atmospheric pollution monitoring, the assessment of air quality with the use of spider webs is cheap, non-invasive and easy as webs are abundant and they are woven in secluded locations, which prevents them from exposure to rain and wind. The basis of the present study was an assumption that because spider webs are diamagnetic (with negative magnetic susceptibility), the increased value of their magnetic susceptibility that results from exposure to the polluted atmosphere may be a sign of contamination by particulates (of which some are metallic). Therefore, the proposed hypothesis is that magnetic susceptibility of spider webs reflects the level of ambient air pollution.

Abstract:

The studies that we have achieved in the last 40 years in the Danube – Danube Delta – Black Sea hydrosedimentary system have revealed strong connections between the characteristics of sedimentary environment, sediment quality and their magnetic properties. The paper analyses a large magnetic susceptibility (MS; k) database resulting from ca. 20 expeditions carried out during 1981–2015 time period in the lakes of two aquatic units of the Danube Delta (DD), i.e., Gorgova – Uzlina and Lumina – Roşu Depressions. These are placed in the DD southern wing, westwards and respectively, eastwards of the Caraorman Sand Ridge.

Abstract:

The Paleoproterozoic is a fascinating period of Earth history. Inception of plate tectonics, first supercontinents, inner core nucleation, eukaryote appearance, atmospheric great oxigenation event and other first order global processes likely ocurred during this period. Reliable and well-dated paleomagnetic data from the Paleoproterozoic is scarce, which hampers global paleogeographic and geodynamic models. The characteristics of the Earth Magnetic field in such old times are also known very schematically due to data paucity. In order to contribute to a better understanding of the Paleoproterozoic paleogeographic, geodynamic and geomagnetic evolution, a systematic paleomagnetic study is being carried out on a series of numerous late to post-tectonic igneous bodies of mid-Paleoproterozoic age exposed in the Piedra Alta terrane of Uruguay, which is considered as the core of the Rio de la Plata craton (e.g., Oyhantçabal et al. 2018 and references therein). First results from this research were published by Rapalini et al. (2015) who presented a schematic apparent polar wander path for this craton for the late Rhyacian to the early Orosirian, based on three paleomagnetic poles obtained from three of these plutons. They also suggested that when compared with coeval data from the Sao-Francisco, Guyana and West Africa cratons it supported an unorthodox configuration of the hypothetical Atlantica continent. Available U-Pb (both SHRIMP and LA-ICPMS) from several of these igneous bodies strongly suggest that they were intruded in a relatively short period between ca. 2.1 and 2.05 Ga. Further paleomagnetic results on several other plutons are presented. After stepwise AF and/or thermal demagnetization, consistent characteristic magnetic components were isolated from the Cufré-Cerro Albornoz granites (2.086 Ga), Carreta Quemada Gabbro (2.086 Ga), Arroyo Marincho Granite (2.081 Ga) and the yet undated Tía Josefa Tonalite, Arroyo Grande Granite and GM4 pluton. Our results permit to compute individual paleomagnetic poles from each body that together with those already published from Mahoma (2.1 Ga), Isla Mala (2.076 Ga) and Soca (2.056 Ga) plutons are distributed along a simple track composed of eight poles. It suggests that the Río de la Plata craton was at polar latitudes during the mid-Paleoproterozoic but experiencing a fast displacement and rotation. Only the Tia Josefa pole seems to be an outlier of this single track. Most bodies show a unique polarity, either normal or reverse, which, according to their position along the track, suggest at least five reversals of the Earth Magnetic Field during that time span and a dominant dipolar field. Since all reliable radiometric datings are U-Pb, precise magnetization ages depend on the cooling rates of these bodies. Few thermo-barometric determinations suggesting shallow intrusive levels and old Rb-Sr ages on these igneous bodies falling in the range 1.95–2.1 (with large uncertainties between 50 and 75 Ma) point to a relatively fast cooling. Comparison with coeval poles from other blocks in South America and Africa support the unorthodox Atlantica reconstruction and point to magnetizations ages somewhat 20 to 30 Ma younger than U-Pb ages. Ar-Ar datings on amphibole are under way to better constrain the magnetization ages of these plutons.

Abstract:

Palaeomagnetic studies of deep marine sediments have made a significant contribution to the development of secular variation and relative paleointensity records which are useful to both understand the behaviour of the geomagnetic field and to date marine sediments at very different time scales. However, the complex mechanisms of remanence acquisition in sediments, involving complex sequences of interactions between Depositional Remanent Magnetisation (DRM), Post-Depositional Remanent Magnetisation (PDRM) and early Chemical Remanent Magnetization (CRM) commonly results in inclination errors and in a time discrepancy between the magnetic and stratigraphic ages. Subsequently, the validation of individual records requires the acquisition of detailed palaeomagnetic, rock-magnetic and geochemical data to detect the occurrence of different magnetic phases and their lock-in ages.

Abstract:

The Chichinautzin Volcanic Field (ChVF) is located at the southern boundary of the Trans-Mexican Volcanic Belt (TMVB), in central Mexico. It shows an E–W trend, c.a. 1000 km long volcanic arc, from the Pacific Ocean to the Gulf of México (Gómez-Tuena et al. 2007). The ChVF volcanism is related to the subduction of Cocos under North American plate. Their ages range from 1.25 Ma to < 05 Ka (Arce et al. 2013). Paleomagnetic cores were collected from 22 sites through the entire volcanic field. Rock magnetic experiments, such as susceptibility vs. temperature, hysteresis curves and FORC were done to identify the magnetic carriers of magnetization and the thermal stability during a heating-cooling processes. AF and termal demagnetization processes were conducted to investigate the mean paleomagnetic direction: Declination = 356.4°, Inclination = 49.7°, α₉₅ = 5.2 and Kappa = 49.6. The paleointensity process was conducted using the Thellier-Thellier method (Thellier 1959). Results will contribute to develop a secular variation curve for Central Mexico, mainly the results of the youngest lavas (< 5 Ka). 

Abstract:

The growth of the South Atlantic Magnetic Anomaly (SAMA) during the last 2 centuries has generated very large geomagnetic secular variation in Chile (Roperch et al. 2015). Most global geomagnetic models suggest very low secular variation in southern South America during most of the Holocene but this result may simply be due to the lack of data to constrain the models. In order to better describe the poorly known secular variation during the late Pleistocene-Holocene, we sampled 21 dated lava flows or pyroclastic flows from several Chilean volcanoes (Lonquimay, Llaima, Solipulli, Villarrica, Mocho-Choshuenco, Osorno, Calbuco) located in the southern volcanic zone (~39°S–41°S). We also sampled 56 sites in Holocene lava flows with only relative ages with respect of the dated units. The paleomagnetic results obtained in the present study indicate little geomagnetic secular variation in direction during the Holocene except near 750–1000 AD. The steepest inclination of the geomagnetic field (-71.6°) and the highest intensity (70µT±5) are recorded in a pyroclastic flow from the Osorno volcano (calibrated age range of 782–966 AD) (Roperch et al. 2014). A dated lava flow (720–980 AD) to the north of the Llaima volcano records also a steep inclination. The corresponding VGPs are not much different from the VGP recorded at European sites suggesting a significant dipole wobble at that time.

Abstract:

A Late Jurassic 30° gap in the Apparent Polar Wandering Path (APWP) of the North American plate has been recently evidenced (Kent and Irving 2010, Kent et al. 2015), and is interpreted by these authors in term of plate motion (referred as to the “Jurassic monster shift”). This unusually fast plate motion was previously undetected or only resulted in smooth variations around the Jurassic/Cretaceous boundary in previous composite APWPs, due to the smoothing of data intrinsic to the method of construction, or in the inclusion of lower quality Jurassic paleopoles. The Jurassic shift started between 183 (Pliensbachian-Toarcian boundary) and 160 Ma (Oxfordian) and ended between 151 (early Tithonian) and 145 Ma (Tithonian/Barremian) (Kent and Irving 2010, Muttoni et al. 2013).

Abstract:

The complex magnetic mineralogy of fluvial sediments reflects the environmental and climatic evolution of their catchments and is thereby a potential source of information in areas were no other archives are available. However, the analysis of these sediments with rock magnetic methods is a challenging task. The contributions from various sources along the course of the rivers results in a multi-component magnetic mineralogy. Additionally, variable and frequently unsteady redox-conditions during multiple burial-transportation cycles may alter individual grains differently. As a result of these diverse pathways, grain size variations of the bulk sediment material as well as of the magnetic components induce further complications to the analyses. Nevertheless, the identification of the magnetic mineralogy is vital for both, palaeo-magnetic investigations, and enviromagnetic analyses. 

Abstract:

Several drill cores were studied in order to correlate Sokolov and Most basins.

Both magnetostratigraphy and cyclostratigraphic investigation was conducted on the drill core JP585. The new drill core from of opencast coal mine Jiří in the Sokolov Basin. Both basins are parts of eastern segment of the European Cenozoic Rift System (ECRIS). The sediments in both basins are of Burdigalian age (lower Miocene). Their lithology mainly comprises fossil-free clays/silts above the main coal seam, with three phosphatic horizons with mineral crandallite in the Most Basin and several greigite layers in the Sokolov Basin.

Abstract:

Five sections in the Vocontian basin have been studied for magnetostratigraphy and biostratigraphy (Le Chouet, Charens, Tre Maroua, Haute Beaume (Belvedere), and St Bertrand’s Spring). The profiles together provide a robustly connected composite sequence across the J/K boundary.

Abstract:

Magnetostratigraphy is an important building block for age-models of scientific cores. Due to the rotational movement of the coring process the azimuthal orientations of the cores is lost hindering the construction of magnetostratigraphy based of correctly orientated paleomagnetic samples. For high latitudes a high quality magnetostratigraphy can still be reconstructed on the basis of the inclination of the paleomagnetic direction alone. For example in northern latitudes a downward inclination is interpreted as normal and an upwards inclination as reversed paleomagnetic directions of the core samples.

Abstract:

Submarine slope failure and associated mass movements are common processes worldwide, some of them with high economic impact and societal consequences. This work represents an approach to the more suitable proxy’s in order to identify and characterize mass movement deposits and the respective deformation. As case study was selected the Portimão Bank, a submarine E–W elongated structural high with prominent slide scars, located offshore southern Portugal in the Gulf of Cadiz. The used methodologies enabled a two different scales approach. On a broad scale, we look for the occurrence of mass movements deposits through accurate geomorphological mapping and seismic interpretation. At local and detailed scale we looked for the vertical characterization and development of MMDs along piston core (PC-07, 338 cm long retrieved in the centre of a slide scar) by means of sedimentological, environmental magnetism, paleomagnetism and magnetic fabric studies, complemented by bioturbation analysis and C¹⁴ dating. Our results show that: i) The Portimão bank is characterized by a series of important on-going landslides; ii) The sedimentary column retrieved from piston core is replicated; iii) Anisotropy of magnetic susceptibility is able to identify a segment with approximately 90 cm that accommodated the deformation associated with the replication of the sedimentary column. Important to emphasize that such deformation goes unnoticed by mesoscopic analysis; iv) in the deformed segment, the AMS lineation represents an intersection lineation that can not be interpreted as the preferred direction of grain alignment. This work was supported by project FCT UID/GEO/50019/2013 to Instituto Dom Luiz.

Abstract:

Anisotropy of magnetic susceptibility (AMS) and anisotropy of anhysteretic remanent magnetization (AARM) data have been obtained from a vertical, two meters thick, mafic dyke (intruding volcanic lava flow pile dated between 190 and 125 ka – Costa et al. (2015), Silva et al. (2018)), located on the southern margin of the Pico Island (Azores Archipelago). Its central part is constituted by different volcanic “facies” characterized by discontinuous cores with concentric rings. Locally, the latter form an almost circular sub-horizontal “structure”. This “composite” magmatic “dyke” seems to correspond to a sequence of lateral magma pulses. Comparison between AMS and AARM fabrics indicate that inverse fabric related to single-domain grains has negligible effects on AMS. According to the scale used, different interpretations of the flow regime are possible.

Abstract:

Magnetic nanoparticles (MNP) have a wide range of application. They are used for instance as contrast agent for magnetic resonance imaging, as drug delivery vehicle, for magnetic hyperthermia, for sewage treatment, as ink for bank notes, in high-quality loud-speakers or for research purposes. The demand for custom tailored MNPs fosters the development of new MNPs with specific biological and physical properties. Accurate and precise magnetic property characterisation is thus required for quality control of newly developed MNPs at laboratory scales but also for optimising scale-up production procedures, i.e., the production of MNPs in commercial quantities. International standards for definition and measurement of the magnetic properties of MNPs do not exist. This reduces the trust of magnetic nanoparticle consumers in safety, reliability and functionality of magnetic nanoparticle products and increasingly hampers the market chances of magnetic nanoparticle producers. 

Abstract:

Long-term variations (> 10 Ma) in Earth’s magnetic field have been postulated to reflect the influence of mantle forcing, bound to changes in heat flow at the core mantle boundary. One of the best documented records of long-term changes in Earth’s magnetic field is the Geomagnetic Polarity timescale (GPTS). Examination of the GPTS demonstrates that the occurrence of polarity reversals is stochastic, however there is evidence that the frequency of magnetic field reversals varies in a periodic manner. This observation is the foundation for the 200 Ma cyclicity hypothesis, which proposes that periods where the field undergoes rapid transition from a highly unstable state (high reversal frequency) to a more stable state (superchrons) is on a 200 Ma cycle, hypothesized to reflect periodic superplume growth and collapse in Earth’s mantle (Amit and Olson 2015, Olson and Amit 2015). Documented transitions from a highly unstable state to a more stable state are observed between the Middle Jurassic (high-reversal frequency) and the Early Cretaceous (Cretaceous Normal Superchron). Other records of extended non-reversal have been recognized in the Phanerozoic, and they appear to follow a ~200 Ma periodicity. However, better records documenting magnetic reversal frequency preceding these intervals, particularly in the Paleozoic, are needed to appropriately test this hypothesis.

Abstract:

The river sediments have high cappasity to acumulate heavy metal pollutions originated a.o. from industrial wastewater, fossil fuel combustion and atmospheric deposition. The purpose of this research was to estimate the concentration of magnetic particles to assess the level of heavy metal pollution using magnetic methods. 

Abstract:

The aim of this work was to determine impact of a former glasswork using magnetic methods, conductivity and electrical resistivity tomography (ERT) as well as to distinguish between soil pollution from long-range (LRTAPs) and local transport of atmospheric pollutants using soil magnetometry supported by geochemical analyses (i.e., content of the potentially toxic elements – PTEs). The study area was located in the Izery region of Poland – the Izery Mountains (within the “Black Triangle” region, which is the nickname for one of Europe’s most polluted areas, where Germany, Poland, and the Czech Republic meet) and examined soils were developed from the Izera granite. The major site of the study area was situated in the Forest Glade and was exposed to the anthropogenic pressure from a former glasswork that was active here from 1754 until 1891. Whereas, the second site of the study area was located on a neighboring hill (Granicznik), whose western, north-western, and south-western parts of the slope were exposed to the long-range transport of atmospheric pollutants from the Czech Republic and Germany. Our results indicate that the Forest Glade site was characterized by many anthropogenic translocations and confirmed by a relatively high value (0.61) of the Topsoil Transformation Factor – TTF (Łukasik et al. 2015). Moreover, TTF and the initial study of ERT revealed existence of anthropogenic layer of wastes, dumping during the glasswork activity. The highest contents of Cu, Ni, Pb, Sn, and Zn in the Forest Glade site correspond to the local sources of pollutants and anthropogenic influence (i.e., former glasswork), whereas, the highest concentration of As, Cd, Hg, In, Mo, Sb, and Se on the Granicznik Hill site are likely a result of long-range transport of atmospheric pollutants. The principal component analyses (PCA) analysis showed that χ value is inversely correlated with the contents of Nb, Th, U, and Zr, indicating a natural origin of these elements. 

Abstract:

An updated catalogue of Italian palaeomagnetic data published in international journals and small archaeological reports or university thesis during the last decades has been compiled. The new dataset includes data from both archaeological artifacts and volcanic rocks and aims to better constrain the full vector geomagnetic field secular variation (SV) in Italy during the last 8000 years. In respect to the previously published Italian directional SV curve, 24 new directional data from archaeological baked clays have been added while the contribution of directions coming from volcanic rocks importantly enrich the dataset mainly for the last millennium. One of the main problems with the Italian volcanic data is their precise dating and for this reason all data coming from lava and pyroclastic flows have been controlled. Only data with undisputable age have been accepted for further considerations. The available intensity dataset from Italy still remains poor, even when the intensities from volcanic rocks are included. The updated dataset shows that reliable considerations about the SV in Italy can be done only for the last three millennia while data from older periods are extremely scarce for any further elaboration. Comparison of the Italian data with the predictions of European and global geomagnetic field models shows a good agreement suggesting the great potential of the Italian SV dataset for reliable dating of archaeological artifacts, and lava flows emplaced during the last 3000 years.

Abstract:

The first directional archaeomagnetic results from Cyprus are presented, based on the study of seven baked clay structures excavated at the copper smelting site of Agia Varvara- Almyras, situated some 20 km south of Nicosia. This ancient copper working site represents a unique example of complete primary production of the copper metal in Cyprus. In total five furnaces, one ore roasting pit and an oven were sampled in situ for an archaeomagnetic investigation. All the studied structures are well dated, based on pottery finds and radiocarbon analyses, with ages ranging from 600 BC to 50 BC. Several rock magnetic experiments were performed to determine the main magnetic carrier and to investigate the thermal stability of the studied material. The direction of the Characteristic Remanent Magnetization (ChRM) for each structure has been determined by demagnetization of 7 to 15 specimens in alternating magnetic fields up to 100–120 mT. Mean directions were calculated assuming a Fisherian distribution and are very well defined for five out of the seven structures studied. The new directions are compared with the few directional data available for the area, mainly coming from Greece, and with the predictions of global geomagnetic field models. They are an important contribution to improving our knowledge of the geomagnetic field variations in the eastern Mediterranean and emphasize the need for more directional data from well dated structures in order to acquire a better understanding of the geomagnetic field’s short-term variations in this region.

Abstract:

Balkan-Carpathia Ophiolite is the dismembered pieces of ancient oceanic crust cropping out in Romania, Serbia and Bulgaria. Although a pioneering work dated the Bulgarian Cherni Vrah massif as Late Neoproterozoic (von Quadt et al. 1998), more recent studies reported Early Devonian ages for multiple massifs in the ophiolite (Zakariadze et al. 2012, Balica et al. 2014, Plissart et al. 2017, Kiselinov et al. 2017). Consequently, little is established for the tectonic history of the ophiolite. We investigated the paleomagnetism of the gabbroic rocks and sheeted dykes in the Cherni Vrah massif sampled near the village of Gorni Lom. Both types of rocks exhibit similar characteristic remanence direction with West declination and moderate negative inclination (geographic coordinate). Natural remanent magnetization (NRM) are completely demagnetized by 150 mT of alternating field (AF), indicating that titanomagnetite is the primary remanence carrier. Gabbros are stable against AF demagnetization with median destructive field often exceed 50 mT. Microscopic observations revealed that rare, unaltered plagioclase in gabbros contain fine rods of exsolved magnetite. It is yet to be investigated if these exsolved magnetite are the voluminously important carrier of the stable NRM in gabbros. Anisotropy of magnetic susceptibility of gabbros revealed consistent pattern of magnetic foliation with c. 50° strike and c. 50° dip to the South. Assuming that this AMS fabric approximate the paleohorizontal, the characteristic remanence direction after tilt correction shows inclination of c. -38°. 

Abstract:

Industrial emissions are very important source of technogenic magnetic particles (TMPs) – mainly, oxides and hydroxides of Fe. TMPs introduced by Magiera et al. (2011, 2013), thanks their specific mineral and magnetic properties, and well developed specific surface area, are characterized by an affinity for some elements like heavy metals. They are generated in a wide variety of high temperature industrial processes where different iron minerals, present in raw materials, fuels and additives are transformed to highly magnetic iron oxides. TMPs are emitted to the atmosphere and then deposited on the soil, plant, and building surfaces. 

Abstract:

Cenozoic collision between India and Eurasia produced the Himalayan-Tibetan orogen, which is commonly considered as the archetypical orogen for continent-continent collision systems. However, there is still no consensus on the amount and mechanism of post-collisional convergence, as well as on the roles of the numerous tectonic terranes comprising the orogen (Jagoutz et al. 2015, 2016; Replumaz et al. 2013, Royden et al. 2008, van Hinsbergen et al. 2011). The West Burma block exhibits a unique geodynamic evolution within this system, influenced by oblique subduction of the Indian plate and significant strike-slip motions along the dextral Sagaing Fault. Furthermore, it is at a key location for paleoenvironmental reconstructions (Cai et al. 2016, Licht et al. 2013). Despite this, robust paleomagnetic data from the West Burma block is largely absent.

Abstract:

In-situ conversion process for recovery of hydrocarbons from shales requires heating the rock formation to 320°C in order to break down kerogen polymer into fragments small enough to permeate toward collection facility. Thermal analysis is essential for understanding the properties of shales as they change during heating to the target temperature (Grębowicz 2014).