Red Bole Research Articles

Effect of Potassium Fertigation Levels on Jalapeno Pepper Growth in Red Bole Soil under Polyhouse Conditions

A field experiment was conducted at Instructional Farm Polyhouse, Dr. Sharadchandra Pawar College of Agriculture, Baramati during June 2023 to September 2023. The study aimed to investigate the Influence of Graded levels of Potassium Fertigation on Growth of Jalapeno Pepper Grown in Red Bole Soil Under Polyhouse. The experiment was laid out in Randomized Block Design (RBD) with four replications. The treatments were five, viz., T1- Control, T2- Recommended dose of fertilizer, T3- Recommended dose of nitrogen and phosphorus (RDNP) + 125% Recommended dose of potassium (RDK), T4- Recommended dose of nitrogen and phosphorus (RDNP) + 150% Recommended dose of potassium (RDK) and T5- Recommended dose of nitrogen and phosphorus (RDNP) + 175% Recommended dose of potassium (RDK). Data were taken on growth contributing characters and the collected data were statistically analyzed for evaluation of the treatment effects. Data on growth parameters, including plant height, leaf area and chlorophyll content, were recorded at 20, 35, 50 and 65 days after transplanting (DAT) and analyzed statistically. The results indicated that the maximum plant height (95.65 cm), leaf area (61.61 dm²) and chlorophyll content (58.83) at 65 DAT were significantly higher in treatment T5 (RDNP + 175% RDK). This study concludes that the application of RDNP + 175% RDK via fertigation from 10 DAT to 60 DAT is optimal for the growth of Jalapeno pepper in red bole soil under polyhouse conditions, highlighting its potential for improving crop yield and quality.

Origin of clays in the interbasaltic red boles of Deccan Volcanics: Pedogenesis versus palagonitization

Red-coloured clay-rich beds (bole beds) occur at flow breaks in parts of the Deccan volcanic province (DVP). These boles in the Deccan province retain paleoenvironmental information that prevailed at the K-T boundary, including the timing of the Deccan eruption synchronous with the K-T mass extinction. This contribution assesses the origin of clays in various red boles, selected based on their field appearances, physical properties, and relation with bounding units. The saprolitic red bole, fragile red bole and grey bole capping red bole have kaolinite and smectite clay with broad 001 peaks (FWHM>0.62°). The selective dissolution of grey bole reveals the highest Alo, Sio and Feo/Fed (>3) characteristics of short-range ordered alumino-silicates and oxyhydroxide. Both red and grey boles show relative enrichment in immobile elements, indicating leaching within the incipient stage of weathering (saprolite equivalent). Clays from these boles show FeFe and AlAl segregated domains in the octahedral sheet, features characteristic of short-range ordered clay, indicative of a pedogenesis. Smectite in these boles shows Fe > 0.3 apfu with trans vacant (tv) nature, suggesting oxidizing conditions at low temperatures. The STEM-EDS of clay FIB section reveal smectite laths with multiple chemistries in each sample, indicating re-equilibrating conditions in a closed system due to fluctuating wet and dry seasons. Contrary to the above two red boles, indurated-structure less and indurated-laminated red boles have glass shards with yellowish rinds and smectite clay (FWHM<0.5°), indicating palagonitization. The cation occurrence probability in the smectite octahedral sheets of later boles has values characteristic of randomly distributed cations, suggesting a relatively higher temperature of interacting solution. We envisage two processes of clay formation in red boles: a) pedogenesis and b) palagonitization of basalt flow top and/or mafic volcanoclastic deposits.

Palaeoclimatic Imprints as Revealed from the Studies of Intrabasaltic Bole Beds of the Deccan Traps, Maharashtra, India

Geochemical characteristics of four Deccan intrabasaltic bole bed profiles occurring around Yelapur area of Sangli District (Maharashtra, India) were used in deducing the palaeoclimatic conditions prevailed during their formation. Higher Chemical Index of Weathering (CIW) values for all the four red boles indicate considerable chemical weathering and much leaching of the bases while the values of Parker's Weathering Index (PWI) show slight variations. Almost similar Mean Annual Temperature (MAT) values for all the red boles suggest their formation under moderate temperatures while Mean Annual Precipitation (MAP) values indicate slight variations in rainfall. Although quite variable the Iron Species Ratio values indicate oxidizing conditions while Product Index values suggest somewhat acidic conditions during the formation of red boles. Hydrolysis values in red boles indicate mostly humid conditions while values of Salinization are well below unity indicating that the red boles were formed under fairly leached conditions. A–CN–K plots for all four red bole profiles point their weathering trends towards smectite formation while SiO2– Al2O3–Fe2O3 plots indicate kaolinization stage for bole beds suggesting their incipient weathering without lateritization. Thus, these four red bole profiles were formed under somewhat humid, fairly leached, relatively well-drained and rather acidic conditions under variable rainfall. Keywords: Intrabasaltic Bole Beds, Palaeoweathering, Geochemistry, Deccan Traps, India.

Electrical Resistivity Imaging in Parts of Nandurbar District, Deccan Volcanic Province, Maharashtra, India

Abstract Exploration of groundwater resources in basaltic hard-rock terrain has always remained a challenging task for hydrogeologists as the potential groundwater zones/recharge pockets in such areas are associated with differential weathering, anisotropy, heterogeneities, fractured and fissured geological features etc. The thickness of the weathered/fractured layer overlying the compact rocks in such terrain plays a vital role in groundwater prospects. Paucity of water in the semi-arid trap covered areas of north Maharashtra necessitated to locate sources of groundwater almost all over the region. This has driven hydrogeologists to determine the role of dykes in the occurrence, movement and storage of groundwater. The study area is situated in Nandurbar district of Maharashtra bordering Narmada-Tapi rift zone. Two-dimensional (2D) electrical resistivity imaging (ERI) was used to generate subsurface resistivity models for delineating the availability of groundwater in the dyke-infested basaltic region of Nandurbar. The available dug well/borehole lithology suggests that the top layer is comprised of red bole, laterite or black soil followed by weathered/fractured rock. Results from the 2D inverted models of resistivity variation with depth suggest the occurrence of aquifers mostly in weathered/fractured zones within the traps or beneath it. The resistivity models suggest that the northern part of the study area represents a promising aquifer zone with reasonable thickness of weathered formation.

A red bole zircon record of cryptic silicic volcanism in the Deccan Traps, India

Abstract Silicic magmas within large igneous provinces (LIPs) are understudied relative to volumetrically dominant mafic magmas despite their prevalence and possible contribution to LIP-induced environmental degradation. In the 66 Ma Deccan LIP (India), evolved magmatism is documented, but its geographic distribution, duration, and significance remain poorly understood. Zircons deposited in weathered Deccan lava flow tops (“red boles”) offer a means of indirectly studying potentially widespread, silicic, explosive volcanism spanning the entire period of flood basalt eruptions. We explored this record through analysis of trace elements and Hf isotopes in zircon crystals previously dated by U–Pb geochronology. Our results show that zircon populations within individual red boles fingerprint distinct volcanic sources that likely developed in an intraplate setting on cratonic Indian lithosphere. However, our red bole zircon geochemical and isotopic characteristics do not match those from previously studied silicic magmatic centers, indicating that they must derive from yet undiscovered or understudied volcanic centers associated with the Deccan LIP.

A simple recipe for red bole formation in continental flood basalt provinces: weathering of flow-top and flow-bottom breccias

Continental flood basalt (CFB) provinces such as the Deccan Traps show numerous inter-flow horizons called boles, most commonly red or brown. These have been variably interpreted as altered glassy bases of basalt flows, paleosols developed on exposed flow tops, altered volcanic ash beds, or local inter-flow sediments. We believe that each of these mechanisms may apply, singly or in combination, to specific red boles, and propose an additional mechanism, namely the weathering of flow-top and flow-bottom breccias. The breccias are inherently highly prone to weathering, and evidence for the mechanism is a close observed correspondence between breccia zones and red boles. The mechanism explains the absence of red boles in the compound pāhoehoe flows which characteristically lack breccias, and their abundance in rubbly pāhoehoe and ‘a’a lava flows. The latter observation has been misinterpreted as indicating significant eruptive hiatuses and a low eruption frequency. Importantly, even all breccia-derived boles do not have the same significance: those derived from flow-top breccias are paleosols, formed by subaerial weathering during eruptive breaks. Those derived from flow-bottom breccias, thus not in contact with the atmosphere, were formed due to groundwater ingress along flow contacts and fractures. These boles have developed slowly over long time periods. Significant development of all bole types must also have occurred in post-volcanism time and is arguably ongoing even today in the exposed and unexposed parts of CFB sequences. Recognizing multiple and complex origins of superficially similar-looking red boles is of critical importance in CFB volcanology and flow stratigraphy, and a warning sign to straightforward application of mineral chemical, mineral magnetic, geochemical, and similar data on boles to interpreting paleoweathering, paleoclimates, and paleoenvironments.

Stabilization of Red soil and Black Cotton soil using Iron Slag and Fly Ash

The infrastructure is increasing day by day which leads to construction in the space where soil is not much of good strength and the Safe Bearing Capacity of soil is very low. In such areas soil stabilization can prove to be good alternative for improvement in its properties. The stabilization has been found to be effective in improvement of strength and compressibility. If soil is used for any construction purpose like pavement construction or embankments then such constructions may prove to be cost effective. Mixer like what is used in concrete making can be employed to mix the soil with different admixtures (Iron slag and fly ash) and then placing a mix soil for making road and embankment. If such constructions are done without stabilization then it will lead to decrease in strength and also increase in construction cost. The structures built upon such soil may also lead to failure. Initially cement and lime have been used to stabilize the soil but now we need to find other alternatives as there is lot of CO2 emission in the production of cement which is not safe for our environment. The alternatives to be used should not harm to the environment. In the present study we have used fly ash and iron slag in different proportion for red soil which obtained by the weathering of basalt (It is termed as red bole in Geological terms). The percentage of iron slag is used as 2%,4%,6%,8% and 15%by weight of soil and fly ash is used in 10%, 15%, 20% and 25%by weight of soil. After procuring the soil the Standard Proctor Tests were conducted to determine the Optimum Moisture Content and Maximum Dry Density. Red bole soil and black cotton soil are stabilized using iron slag and fly ash and then the results of various tests have been compared. Consistency Limits, Specific Gravity, Free Swell Index, Standard Proctor, Permeability, Direct Shear, Unconfined Compression Strength and Swelling Pressure tests were performed on each soil (i.e. red bole and black cotton). The tests were performed using the standard codes and the methodology as per various IS codes.

The geological site characterisation of the Mandla region, Eastern Deccan Volcanic Province, Central India

Detailed geological studies were carried out on the basaltic sequences along the Jabalpur–Niwas, Jabalpur–Chutka and Jabalpur–Mandla traverses covering an area of about $$12\hbox { km} \times 15\hbox { km}$$ to characterise various basaltic lava flows and their behaviour on seismotectonics and geodynamic setting of their formation in the Mandla region of the Eastern Deccan Volcanic Province (EDVP). The studies involve an analysis of the satellite images for the identification of lineaments/faults and field geological studies consisting of geological controls such as ground check, thickness of fractures and orientation along the acknowledged lineaments/faults. The results of the present research comprising 65 lineaments/faults mainly belonging to two geometric groups, minor and major dominantly in the NW–SE and the NE–SW and altered strata varying lithology (weathered to compact basalts) are recognised in the study area. Based on their extent, 57 lineaments have been classified as minor ( 300 km) lineaments are noticed in the study region. The field geological investigations have facilitated the recognition of 10 flows with different characteristic features and a variety of volcanic structures such as columnar, vesicular, amygdaloidal, inflated pahoehoe lava flows and red bole interflow horizons have been documented. Basement rocks of these Deccan basalt lavas are represented by Tirodi Biotite gneisses, quartzite, quartz–mica schists and crystalline limestone in the SE part of the study area of the Mandla region. The present study will help evaluate the localised site characterisation for urban planning and setting up major civil structures.

A Raman microspectroscopy-based comparison of pigments applied in two gothic wall paintings in Slovenia

The present study deals with the characterisation of pigments used in two overlaid gothic wall paintings from the former 13 th century Minorite church of St. Francis of Assisi (Koper, Slovenia), in order to define differences in the technologies used. Paint layer samples were analysed via Raman microspectroscopy, supported by SEM/EDS and FT-IR analysis, when necessary. The results revealed that the 14 th century mural was painted mainly a fresco with final elements a secco, a technique typical of Italian mediaeval wall painting. In contrast, the 15 th century painting was executed mostly a secco , a technique often applied in Northern Europe and the Alpine region. The differences between the two paintings are especially obvious in the pigments applied. While the earlier painting is characterised by azurite, carbon black, red and yellow ochres, lime white and green earth, the palette used for the younger painting is much broader. In addition to red and yellow ochres, carbon black and lime white, lead pigments such as lead white, red lead and lead-tin yellow type I were also determined, as well as a number of expensive pigments including cinnabar, azurite and malachite. Also found in the younger painting was the rare orange yellow pigment vanadinite. In both layers, azurite was applied a secco for the background area. Gilding was confirmed in both layers, carried out as application of gold leaves on red bole (in the earlier mural) and on mordant (on a younger, superimposed (overlaid painting), which is quite exclusive and rare for Slovene mediaeval painting. In the younger layer also a use of tin foil for secondary elements was discovered.

Weathering Controlled Landslide in Deccan Traps: Insight from Mahabaleshwar, Maharashtra

Landslide is one of the devastating natural phenomenon that threatens human life and property. Every year a number of persons lost their lives due to the landslides. Therefore, a better understanding and characterization of landslide is very essential for adopting mitigation strategies to contain the adversities of this natural hazard. Information on landslides from different climatic setup are very essential for better understanding of the influence of weathering, rainfall, or topography on landslide generation. Weathering is one of the important causative factor for landslide generation in the moderate topography or inactive mountainous terrain. The Western Ghats including the Deccan Traps, an inactive mountain range, receives torrential rainfall. Intense rainfall in these areas enhances the weathering processes and fabricates thick soil covers. Mahabaleshwar area, Maharashtra was chosen as a case study, where high elevated part is covered by lateritic layer and each lava flow unit is separated by a thin weathered bed of red bole. The area experiences series of landslides during the summer monsoon months. Mainly two types of landslides have been identified in the area confined with the red bole bed and powdery lateritic soil. The first type of landslides occur at higher elevations (≥1200m) where horizontal beds of permeable laterites underlined by impermeable thick basalt beds. The rain water infiltrates down and spread laterally within the permeable lateritic beds. It finally spouts at lower plateau elevations and triggers mainly debris flows. The other category of landslides occurs where the weathered red bole bed separates two successive lava flows. The percolating water from the secondary porosities (joints and inter connected vugs) comes out from the contact zones of basalt and red bole bed in the form of seepages. It erodes the red bole bed and as a result the overlying masses hang and consequently lead to rock fall. The Chemical Index of Alteration (CIA) of the representative samples from landslide locations indicates significant weathering. The CIA values for the fine lateritic soil are up to 98% whereas for the red bole bed it varies from 77 to 85%. This suggests a high chemical weathering and higher erodibility. The association of active landslide locations with the red bole bed and fine lateritic soil suggests a close relation between weathering and landslide occurrences in the area.

Trace element behavior in moderately weathered boles from the Deccan volcanic province: Implications for paleoenvironment

The present study examines the behavior of trace elements in moderately weathered boles of three different colors (i.e., red, brown and green) from the Deccan Traps in order to understand paleoenvironmental conditions during periods of quiescence between successive eruptions of Deccan flood volcanism (DFV). The minimal (<40%) losses/gains of trace elements, including rare earth elements (REE), in the brown and red boles indicate their low mobility either due to limited release from primary minerals and/or due to sorption on secondary clay minerals and Fe-Mn oxides under near neutral pH (~5.5 to 8) conditions. The green bole shows a greater loss of trace elements, on average ~40–70%, including the REE and the typically immobile elements V and Zr. The low concentrations of V and Zr in the green bole are in accordance with low Ti and high SiO2, K2O and Rb concentrations that suggest addition of petrogenetically evolved volcanic ash (e.g., andesitic composition) compared to the lower flow basalt.A negative Ce anomaly and enrichment of the light REE (LREE) in the green bole indicate precipitation of soluble trivalent LREE desorbed from Fe-Mn oxide surfaces preferentially to insoluble oxidized tetravalent Ce. This is interpreted to indicate more reducing conditions at depth, with Fe-Mn oxides in a more oxidized upper saprolite/soil horizon were eroded prior to trapping of the green bole by the upper lava flow. The light red bole, weathered under a more pervasively oxidative environment, shows loss of Mn oxides that might have initially scavenged cerianite leading to a negative Ce anomaly preserved in the residual bole. Positive Ce anomalies in the dark red and brown boles, are consistent with their gain and negligible loss of Mn, respectively, indicating Ce precipitation on the Mn oxide surfaces relative to the other trivalent LREE in an oxidizing environment. Overall, the boles show weathering signatures suggestive of near neutral pH conditions and locally changing redox, some of which may have largely escaped post-eruptive acidic precipitation possibly due to the transport of acidic gases into the upper atmosphere (stratosphere) under arid conditions.

Mineralogy and geochemistry of various colored boles from the Deccan volcanic province: Implications for paleoweathering and paleoenvironmental conditions

Boles are markers of hiatus in successive eruptions of the Deccan flood volcanism (DFV) emplaced at the Cretaceous-Paleogene boundary that are interpreted to retain paleoenvironmental information from their subaerial exposure. To evaluate paleoenvironment during these hiatuses, mineralogy and geochemistry of three different colors of boles, i.e., red (dark = 10R-3/6 and light = 10R-4/8), brown (5YR-4/4) and green (5G-6/2) were examined. The plagioclase index of alteration (PIA) (loss of Ca and Na relative to Al) was between 76 and 81 for all the boles, indicating moderate chemical weathering that is probably due to their short subaerial exposures. Mass balance calculations show significant enrichments of K, Si, Mg and Rb in green and brown boles suggesting an allochthonous input that is interpreted as volcanic ash fallout. Mineralogically, the red bole is dominated by montmorillonite and hematite, the brown bole of ferruginous smectite and montmorillonite, and the green bole of celadonite and nontronite.Montmorillonite and hematite genesis in red boles indicates leaching in an oxidative environment at near neutral pH (~5.5 to 8) conditions. Further, heating of the altered basalt from emplacement of upper lava flows under subaerial-dry conditions could have also promoted the formation of hematite in red boles. The hydrothermal alteration of K and Mg enriched volcanic ash admixed with the altered lower flow basalt under slightly reducing oxidation potential led to the genesis of nontronite and celadonite in the green bole. The aluminous Fe-smectite in brown bole occurred from hydrothermal alteration of aluminous clays (e.g., montmorillonite). The different colored boles, therefore, suggest a range of weathering processes including chemical leaching to hydrothermal alteration in oxidative to reducing environmental conditions throughout DFV emplacement that could reflect changing surficial conditions associated with volcanically forced changes to the environment.

A 1251m-thick Deccan Flood Basalt Pile Recovered by Scientific Drilling in the Koyna Region, Western India

ABSTRACT A 1251 m thick succession of Deccan lava flows has been recovered by scientific drilling in the Koyna region, western part of the Deccan Volcanic Province (DVP). Forty-six lava flows, starting with the first flow overlying the granitic basement in the region, have been identified through mesoscopic studies of cores obtained from a 1500 m deep borehole KBH7 in Panchgani village of Patan sub-division. Mesoscopic observations supported by petrographic studies bring out the characteristics of the basaltic pile. The salient findings are as follows. The thickness of Deccan trap in the Panchgani area is 1251.20 m, comprising a succession of 40 simple lava flows and 6 compound lava flows. The contact with the underlying granitic basement occurs over a short span of 90 cm. Infra-trappean sediments are absent. Overall, ∼74% of the basaltic pile is constituted of massive basalt and ∼24% vesicular/amygdaloidal basalt. Red bole horizons are observed in 7 flows. Nine giant plagioclase basalt (GPB) flows are identified in the single vertical section. The long basalt core may serve as a model Deccan trap section for correlation with the flows exposed at the surface in the Koyna and surrounding region and support detailed investigations to constrain the duration of Deccan volcanism.

Volcanology and Lava Flow Morpho-types from the Koyna-Warna Region, Western Deccan Traps, India

ABSTRACT Flow mapping and physical volcanology of 15 basaltic lavas exposed in three critical road pass sections (ghats) in the Koyna-Warna region of the western Deccan Traps is presented in this paper. Transitional lavas like rubbly pahoehoe are most common morpho-type exposed in these ghat sections. Sinking of rubbly breccia into flow interiors and formation of breccia-cored rosette are common in some lava flows. Few rubbly lavas exhibit slabby tendencies. The amount and nature of the associated rubble is variable and result from the mechanical fracturing and auto-brecciation of the upper vesicular crust in response to distinctive stages in the cooling, crystallization and emplacement history of individual lava flows. Occurrence of aa and pahoehoe morpho-types in the lava flow sequence is subordinate. Three prominent pahoehoe flows separated by red bole horizons are seen in the upper parts of the Kumbharli ghat. These are thick, P-type sheet pahoehoe. The pahoehoe lavas represent compound flow fields that grew by budding, endogenous lava transfer and inflation. Presence of pahoehoe lavas in the Koyna-Warna region hints at possible hitherto unrecorded southern extension of Bushe-like flow fields. This study reconfirms the existence of pahoehoe-slabby-rubbly-aa flow fields and transitions even in the upper echelons of the Deccan Trap stratigraphy. The study of morphology and internal structure of lava flows exposed at the ghat sections in the Koyna-Warna region could guide sub-surface core-logging that is critical in deciphering the physical volcanology and emplacement dynamics of basaltic lava flows penetrated by drill holes sunk under the scientific deep drilling programme.

Evidence for a chondritic impactor, evaporation-condensation effects and melting of the Precambrian basement beneath the ‘target’ Deccan basalts at Lonar crater, India

The ∼1.88km diameter Lonar impact crater formed ∼570ka ago and is an almost circular depression hosted entirely in the Poladpur suite of the ∼65Ma old basalts of the Deccan Traps. To understand the effects of impact cratering on basaltic targets, commonly found on the surfaces of inner Solar System planetary bodies, major and trace element concentrations as well as Nd and Sr isotopic compositions were determined on a suite of selected samples composed of: basalts, a red bole sample, which is a product of basalt alteration, impact breccia, and impact glasses, either in the form of spherules (<1mm in diameter) or non-spherical impact glasses (>1mm and <1cm). These data include the first highly siderophile element (HSE) concentrations for the Lonar spherules. The chemical index of alteration (CIA) values for the basalts and impact breccia (36.4–42.7) are low while the red bole sample shows a high CIA value (55.6 in the acid-leached sample), consistent with its origin by aqueous alteration of the basalts. The Lonar spherules are classified into two main groups based on their CIA values. Most spherules show low CIA values (Group 1: 34.7–40.5) overlapping with the basalts and impact breccia, while seven spherules show significantly higher CIA values (Group 2: >43.0). The Group 1 spherules are further subdivided into Groups 1a and 1b, with Group 1a spherules showing higher Ni and mostly higher Cr compared to the Group 1b spherules. Iridium and Cr concentrations of the spherules are consistent with the admixture of 1–8wt% of a chondritic impactor to the basaltic target rocks. The impactor contribution is most prominent in the Group 1a and Group 2 spherules, which show higher Ni/Co, Ni/Cr and Cr/Co ratios compared to the target basalts. In contrast, the Group 1b spherules show major and trace element compositions that overlap with those of the impact breccia and are characterized by high EFTh (Enrichment Factor for Th defined as the Nb-normalized concentration of Th relative to that of the average basalt) as well as fractionated La/Sm(N), and higher large ion lithophile element (LILE) concentrations compared to the basalts. The relatively more radiogenic Sr and less radiogenic Nd isotopic composition of the impact breccia and non-spherical impact glasses compared to the target basalts are consistent with melting and mixing of the Precambrian basement beneath the Deccan basalt with up to 15wt% contribution of the basement to these samples. Variations in the moderately siderophile element (MSE) concentration ratios of the impact breccia as well as all the spherules are best explained by contributions from three components – a chondritic impactor, the basaltic target rocks at Lonar and the basement underlying the Deccan basalts. The large variations in concentrations of volatile elements like Zn and Cu and correlated variations of EFCu-EFZn, EFPb-EFZn, EFK-EFZn and EFNa-EFZn, particularly in the Group 1a spherules, are best explained by evaporation-condensation effects during impact. While most spherules, irrespective of their general major and trace element composition, show a loss in volatile elements (e.g., Zn and Cu) relative to the target basalts, some spherules, mainly of Group 1, display enrichments in these elements that are interpreted to reflect the unique preservation of volatile-rich vapour condensates resulting from geochemical fractionation in a vertical direction within the vapour cloud.

The use of powdered bismuth in Late Gothic painting and sculpture polychromy

Abstract This paper presents a material study of the altarpiece in the chapel at Křivoklat (Purglitz) Castle called Křivoklat Ark (around 1480–1490), located in Central Bohemia, Czech Republic. The Křivoklat Altarpiece is one of the most important works of Jagiellonian courtly art in Bohemia. It is decorated with polychrome sculptures and panel paintings. An initial investigation of the gilded and silvered parts of the paintings, sculptures and architectural decor of the altarpiece was undertaken using a portable X-ray fluorescence analyser. Not only the expected metallic elements gold and silver were identified, but also bismuth. This surprising result led on to a complex study of the altarpiece, focused on the layered structure and the method by which bismuth was used the paint layers under the metal-coated areas (under the gold and silver plating). The coating technique using bismuth powder in the Late Gothic period has already been described in scientific publications. However, our paper deals with a rare technique, i.e. the use of powdered bismuth in red bole and its plating with gold and silver leaf. Several micro-samples were therefore taken from carefully selected parts of the altarpiece. Only a minimum amount of sample material was taken, due to the significance of altarpiece. The samples were then analyzed with optical and electron microscopy, EDS analysis, micro-XRF, and other methods. The quantitative element mapping on the cross-section of a micro-sample with gilding showed distributions of several elements (Bi, Au, Fe, Al, Ca); this means that the presence of bismuth grains in the red layer under the gilding leaf was proven. Interdisciplinary cooperation and a combination of microscopic and spectral methods have enabled us to describe this unique late Gothic gilding technique, in which metallic bismuth was intentionally used to affect the color scheme of the coated areas in paintings and polychrome sculptures.

Electrical resistivity imaging for aquifer mapping over Chikotra basin, Kolhapur district, Maharashtra

Electrical resistivity study assumes a special significance for mapping aquifers in hard rock areas. A two-dimensional (2D) resistivity survey of Chikotra basin, southern part of Kolhapur district in the Deccan Volcanic Province of Maharashtra was conducted. The aim of this work was to determine the aquifer zones of the study area using electrical resistivity imaging technique. The hydro-geological section derived from the available dug well/borehole lithology suggests that the top layer comprises red bole, laterite or black soil followed by weathered/fractured rock grading into compact basalts. The sources of groundwater appear to be available in weathered and fractured basalt trapped between weathered overburden and hard rock. Results from the 2D inverted models of resistivity variation with depth suggest the occurrence of aquifers mostly in weathered/fractured zones within the traps or beneath it. The resistivity models suggest that the northern part of the study area represents a promising aquifer zone with reasonable thickness of weathered basement. The models further indicate that there are several locations throughout the basin for possible groundwater exploration as it exhibited strong water-bearing potential in the subsurface rocks.

Palaeoweathering characteristics of an intrabasaltic red bole of the Deccan Flood Basalts near Shrivardhan of western coast of India

An intrabasaltic red bole horizon is studied for its weathering characteristics with respect to the underlying and overlying basalts. The study indicates that all the three units have been considerably weathered; the red bole unit, however shows some distinctive characteristics. The red boles show a higher cation exchange capacity (CEC) and lower sodium adsorption ratio (SAR) and organic carbon (OC) as compared to the weathered basalts. The lower values of Al2O3, TiO2 and Fe2O3(T) in red boles indicate their lesser weathering than the underlying and overlying basalts, which is further corroborated by the weathering intensity measured by the indices like chemical index of alteration (CIA) and statistical empirical index of chemical weathering (W). It is also evident that the red bole samples show more retention of original mafic and felsic components. While K2O exhibits an erratic behaviour, the MgO and CaO do not show much leaching in red boles. Lesser leaching and salinity in the red boles is indicated by the higher values of calcification and lower values of salinization. The SiO2–Al2O3–Fe2O3 plot indicates that red bole samples are close to the basalt field, while the weathered upper basalt is more kaolinized than the weathered lower basalt. These observations reveal that the post-formational weathering processes have least affected the original palaeoweathering characters of the red bole horizon and hence the intrabasaltic palaeosols (weathering horizons) can effectively be used to constrain the palaeoweathering and palaeoclimates during the continental flood basalt episodes in the geologic past.

The Louvre Crucifix by Giotto – Unveiling the original decoration by 2D-XRF, X-ray radiography, Emissiography and SEM-EDX analysis

Giotto (1266–1337) and his workshop realized c. 1315 the large Crucifix now in the Louvre Museum. The conservation of this masterpiece in 2010–2013 in the C2RMF studios gave the opportunity for a comprehensive investigation of the execution technique through a characterization of the paint layers. The first examinations revealed an original gilding and decoration surrounding the Christ which was repainted during the 19th C., raising the question of the original decoration appearance. The original decoration still present underneath was unveiled. The different imaging analytical techniques applied brought complementary results allowing us to reconstruct the original decoration. Elemental images of selected areas on the Crucifix were obtained using bi-dimensional X-ray fluorescence imaging technique (2D-XRF) with a prototype XRF spectrometer mounted on a motorized X-Y system. The head of the instrument was moved over a 150 x150 mm2 area with 1 mm steps, using a 1 mm beam spot and acquisition time of 2 seconds per pixel. The XRF spectra of each pixel provided semi-quantitative elemental maps of the layers: gilding and pigments even at low concentrations could be recognised. The XRF maps achieved were completed by X-ray radiographs and emissiographs of the Crucifix. Some micro-samples analyzed with the scanning electron microscope (SEM-EDX) allowed a better understanding of the stratigraphy. The comparison of the direct light and the X-ray pictures enabled us to distinguish the repaint from the original pattern. The visible metallic leaf is a thin gold leaf applied on a mordant gilding while the original one is a double leaf of gold and silver (Zwischgold) applied on a red bole. As for the painting, the visible decoration is composed of brown earth and organic greenish color whereas the original is made of red lake, copper green, azurite and vermillion. The 2D-XRF maps evidenced two levels of copper that could be ascribed to two different copper pigments, a blue and a green one. A complementary methodology combining classical X-ray imaging, sample analysis and 2D-XRF was applied to large areas of the Giotto’s crucifix. This approach allowed us to distinguish the underlying original composition from the 19th C. overpainted decoration.

Materials applied in Bernardo Martorell’s painting analysed by portable XRF

Bernardo Martorell was a leading artist of the 15th century in Catalonia . His panel painting the Ascension of the Virgin is one of the oldest in the collection of Fine Arts Museum of Seville. This is why it was chosen for the analysis among several other panels which form part of a bigger project between the Museum and the National Centre of Accelerators. The research work is dedicated to the characterization of materials applied in the Spanish paintings in the 15th and 16th centuries. The painting was studied by non-destructive techniques (UV light and a portable X-Ray fluorescence) to obtain information on materials applied and possible later interventions. The results showed that the original pigments applied are common for that period of time: lead white (Pb) yellow and red ochres (Fe), massicot, (Pb), umbra (Mn, Fe), vermillion (Hg), azurite (Cu) and a copper based green pigment (Cu). The thin layer of gold, confirmed by Au peaks, is applied over the surface, on top of a red bole layer. Some black areas over the gilded surface contain Ag. Retouches contain Ti, Zn, Cr and Cd that confirm the use of modern pigments, such as titanium-zinc white, chrome green or cadmium red.