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Soil profile with bog iron ore horizon (Bsm). Three different zones are distinguished in horizon IBsm: (i), (ii), (iii).
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The study focused on determining the micromorphological features of the Bsm horizon in a soil with bog iron ore. The study site is located within an ancient terrace of the Vistula River valley in the Wilanow district of Warsaw. The studied horizon comprised three layers with different microstructure and mineral compositions. The upper Bsm layer con...
Contexts in source publication
Context 1
... study area is located in the Wilanów district of Warsaw, which is widely covered by bog iron ores. The study was focused on soil profile No. 600 ( Fig. 1), located in the Vistula valley within an ancient ox-bow lake, approx. 800 m away from the moraine plateau margin. A representative soil profile containing bog iron ore is the Areni-Mollic Gleysol, petroferric phase (ISSS-ISRIC-FAO-1998) from Holocene alluvial sands [4]. Three undisturbed samples of the Bsm horizon were taken in tins ...
Context 2
... soil profile consists of three distinct macromorphological horizons -Ahc, Bsm, and Cg (Fig. 1). The studied IBsm horizon is a massive, cemented ferruginous layer, approx. 30 cm thick. Ferrihydrite is the main iron mineral in this horizon [6]. The bog iron ore horizon (Bsm) showed high contents of redox-sensitive elements Fe (Fe t -40%, Fe d -40.1%, Fe o -22%), Mn (Mn t -1%) and P (P t -2.12%) ...
Citations
... These are terrestrial deposits of ferrous minerals, especially Fe oxides and hydroxides, and often form in hydromorphic, clayey, sandy, and clayey alluviums and soils (De Geyter et al. 1985;Landuydt 1990). A suitable pedological environment for the formation of this type of ore are gley soils in association with alluvial sands (Kaczorek, Zagórski 2007) with variable redox potentials and constant flow of groundwater-saturated with iron Fe 2+ ions (Graupner 1982; Kaczorek et al. 2004). Environmental preconditions at the Kalinovac -Hrastova greda position, but also in the broader spatial context of the Podravina region, are favourable for the development of bog iron ores, such as ones exploited in the past (Sekelj Ivančan, Marković 2017; Brenko et al. 2020;. ...
... Predictive modelling of the topographic wetness index (Map 3: c) largely corresponds to the situation found during the field inspection, although the algorithm of this analysis basically indicates the soil moisture potential caused by runoff and retention of rainwater and soil moisture at Kalinovac -Hrastova greda can be caused by the height of groundwater compared to the relative depth of the depressions and altitude, given that in the period of high water they reach the humus -accumulative layer. Pedologically, the soil in the entire observed area of the Kalinovac -Hrastova greda position is classified as gleysol (Envi 2021), which is suitable for the formation of bog iron ores (Kaczorek, Zagórski 2007). However, areas where water is retained, are reserved for shallow depressions at this micro-location. ...
The fundamental raw material used for iron production in the Podravina region during late antiquity and the early Middle Ages was the bog iron ore. Analysis of ore properties and deposits can contribute to the understanding of natural mechanisms that conditioned the exploitation and use of ores in the past. However, locating the deposits is challenging, due to the possibility of full exploitation, degradation and inhibited regeneration or development caused primarily by human activities and impact on the environment. In the modern landscape of Podravina, the Kalinovac – Hrastova Greda 1 – 3 position had the highest potential for ore development and the only, partially destroyed ore deposit. Based on its analysis, a model of the formation mechanism, physiognomy and deposit positioning in Podravina is proposed and methods of exploitation and the potential area of the deposit occurrence in relation to the positions of
archaeological sites with iron production remains are discussed. To analyse the technological usability of ore samples with similar properties from the archaeological context, experimental testing of the smelting process was performed with the Kalinovac ore. Based on the results, the factors that could inhibit the production of iron blooms are explained. The latter research also implies a past technological adaptation, ore dressing conditioned by natural preconditions, primarily the variable properties of bog
iron ores and the nature of the deposits. Data from surface field survey, geoarchaeological probing, geospatial analysis, experimental testing and mineralogical (XRD) and chemical analysis (ICP – AES) of samples of ore development stages and slag obtained through experimental smelting are used in the
analysis.
Temeljna sirovina za proizvodnju željeza tijekom kasne antike i ranoga srednjeg vijeka na prostoru Podravine bila je močvarna željezna ruda. Analiza rudnih ležišta i svojstava ruda može doprinjeti razumijevanju prirodnih mehanizama koji uvjetuju način eksploatacije i uporabu ruda u prošlosti. Međutim, ubikacija ležišta je izazovna zbog mogućnosti degradacije, potpunoga iskorištavanja te inhibicije obnove ili razvoja ležišta, prvenstveno uzrokovanih ljudskom aktivnošću i utjecajem na okoliš. U suvremenome krajoliku Podravine najviši potencijal za razvoj ležišta i jedino, djelomično razoreno ležište, ustanovljeno je na položaju Kalinovac – Hrastova greda 1 – 3. Na osnovi njegove analize izveden je model mehanizma formiranja, fizionomije i položaja ležišta u Podravini te je povedena rasprava o metodama eksploatacije kao i potencijanim prostorima pojave ležišta u odnosu na položaje arheoloških lokaliteta s tragovima proizvodnje željeza. U svrhu analize tehnološke iskoristivosti ruda sličnih svojstava iz arheološkoga konteksta, provedeno je eksperimentalno taljenje kalinovačke rude. Na osnovi rezultata objašnjavaju se čimbenici koji su mogli onemogućiti proizvodnju spužvastoga željeza. Potonje istraživanje ukazuje i na tehnološku prilagodbu u prošlosti, preradu ruda uvjetovanu prirodnim preduvjetima, prvenstveno promjenjivim svojstvima močvarnih željeznih ruda i karakterom ležišta. Pri analizi se koriste podaci dobiveni površinskim terenskim pregledom, geoarheološkim sondiranjem, geoprostornim analizama, eksperimentalnim testiranjem i mineraloškim (XRD) te kemijskim analizama (ICP – AES) uzoraka razvojnih faza rude i zgure dobivene kroz postupak eksperimentalnoga taljenja.
... As the Podravina region is a lowland area of the Drava River valley, with the natural prerequisites for the formation of bog iron ore, it has been assumed that local bog iron ore was exploited and used for iron production during the late Antiquity and early Middle Ages (Sekelj Ivančan and Marković, 2017;Brenko et al., 2020). Bog iron ores are sedimentary accumulations of iron and accompanying elements (Ramanaidou and Wells, 2014), often found in wet lowland environments, such as clayey and alluvial soils, with a groundwater table close to the surface (Kaczorek and Zagórski, 2007). Bog iron ores are usually differentiated into three macromorphological types: (i) bog iron soils; (ii) bog iron nodules and concretions; and (iii) bog iron fragments and continuous, cemented horizons (Thelemann et al., 2017). ...
... Spherical nodular shapes can be seen incorporated inside bog iron fragments, proving the theory that the fragments, as a final development phase, are formed by even further cementation with an Fe-enriched matrix, agglomerating smaller nodules into larger fragments (Fig. 2D). If the cementation process were to continue, the formation of a layered bog iron ore deposit is to be expected (Kaczorek and Zagórski, 2007). The diffraction reflexes of bog iron fragments often contain high background noises which probably indicate the enrichment in the amorphous iron phase (ferrihydrite), a mineral often associated with the bog iron ores (Kaczorek and Zagórski, 2007) that can be found in the soil groundmass. ...
... If the cementation process were to continue, the formation of a layered bog iron ore deposit is to be expected (Kaczorek and Zagórski, 2007). The diffraction reflexes of bog iron fragments often contain high background noises which probably indicate the enrichment in the amorphous iron phase (ferrihydrite), a mineral often associated with the bog iron ores (Kaczorek and Zagórski, 2007) that can be found in the soil groundmass. Extremely high concentrations of Mn were detected in the fragments from the Novigrad Podravski-Milakov Berek site. ...
Throughout the Podravina region, NE Croatia, over one hundred locations with signs of iron production, dating to the late Antique period and the Middle Ages, have been discovered in the last 30 years. Recently, signs of various bog iron ore types and formations were discovered throughout the area. This study investigates the mineralogical and geochemical characteristics of local bog iron and roasted iron ores. Furthermore, statistical clustering of different geochemical components in the ores is presented, while the abundance and distribution of macro-, micro- and rare earth elements (REE) and how they correlate within the bog iron ores and roasted iron ores is considered. A total of 15 samples acquired from geological investigations and 13 samples found during archaeological excavations were analysed using geochemical and mineralogical methods. In bog iron ores, X-ray diffraction (XRD) confirmed goethite and quartz as the primary mineral phases, while roasted iron ores contained several Fe minerals and had variable quartz and clay mineral contents. Chemical analyses confirmed high Fe contents in both bog iron ores (up to 70.89 mass. %) and roasted iron ores (up to 84.97 mass. %), with a distinct differentiation of Fe and Si between the different bog iron ore types. Scanning electron microscopy with attached EDS detector (SEM-EDS) showed features of laminar Fe and Mn mineralization, confirming the theory that bog iron ore forms as seasonal precipitation from groundwater. Using the hierarchical clustering analysis, a geochemical correlation of the iron component in bog iron ores and roasted iron ores was compared to other major oxides, micro- and REEs. It was established that the iron component has very little influence on REE and microelements behaviour. Therefore, microelements and REEs were used as a tracer for establishing a geographical connection between the bog iron ores and roasted iron ores in the Podravina region.
... %. Bog iron ore is often found in Gleysols associated with alluvial sands (Kaczorek and Zagórski, 2007). The middle part of the soil profile at Kalinovac-Hrastova Greda between 60 and 80 cm depth shows similarity to the first macromorphological type of bog iron ore ("soft bog iron") (Kaczorek and Sommer, 2005;Banning, 2008). ...
This study brings evidence for possible bog iron ore formation in soils of the Podravina region, NE Croatia. During decades of archaeological investigations in the region, numerous sites with iron smelting workshops, furnaces and iron slag materials were found in the region. As archaeological evidence indicates the presence of near-by bog iron excavation sites, a total of 44 soil profiles were drilled in the vicinity of the archaeological sites. Six soil profiles, consisting of five Gleysols and one Fluvisol, were selected for further mineralogical, geochemical and textural analyses due to their visible redoximorphic features. The X-ray diffraction (XRD) analyses confirmed goethite, quartz, clay minerals, plagioclase, feldspars and dolomite. Chemical analyses indicate Fe content above median values for the Podravina region. The Kalinovac-Hrastova Greda profile showed the highest content of Fe2O3, (31.52%) at 60-80 cm depth, while the other investigated profiles show Fe2O3 contents between 3.97 and 10.90%. Contents of As (1.8-563.6 ppm) and P (484-4513 ppm) indicate high accumulations of these elements in the soils. Textural analyses indicate a high amount of silt and, sporadically, sand in all profiles, while showing a relatively small amount of clay. The enrichment factor of Fe2O3 shows significant enrichment in the Kalinovac-Hrastova Greda profile, indicating a possible ore formation. Based on the microelement distribution of Ce, Cs, Hf, La, P and Zr, all soils show a common parent material, but significant differences in contents of Fe and other major oxides indicate different formation processes. This is attributed to differences in the soil texture of the selected soil profiles, oscillations of the groundwater table and changes between oxidative and reductive conditions. The results of this study indicate that the Podravina region is a suitable area for the formation of bog iron ore, although recent conditions inhibit the formation of bog iron ore due to changes in agriculture and melioration which are altering groundwater levels.
The studied sequence is 150 m thick of siliciclastic strata, well-exposed as a prominent escarpment that extends along 25°:45ʺN at the southern flank of Sirt Basin and dated as of Late Eocene age. It is built up from the base to top by three sedimentary units: (i) very fine sandstones and mudstones called New Idam Unit (NIU), (ii) medium-grained sandstones called Lower Sarir Unit (LSU) and (iii) very coarse to microconglomeratic sandstones called Upper Sarir Unit (USU). Pedogenic modifications which are differentially recurring from the base to the top of this sequence have not been paid sufficient attention in the previous studies. This study benefited the widespread macroscopic pedogenic features, introduced them and discussed their usefulness for estimating the continuity of the sedimentation and thus inferring the paleoclimate responsible for their formation.
The exposed pedogenic features characteristic of each unit are described and then discussed in light of the documented modern and ancient analogues and case studies in order to comprehend the depositional continuity through time. The discussion is passed via analysing the prevailed climate because it is the fundamental factor controlling the formation of these features. Ultimately, this research allowed, for the first time, the recognition of a major (end Eocene) unconformity embedded within the sequence. This is certainly of interest for the hydrocarbon exploration in and around the basin.
