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Mapping lithological units and conducting mineral exploration in a relatively short time and at a reduced cost, requires high-resolution satellite data and state-of-the-art image processing approaches and methods. In this regard, the current paper aims to test an integration of visible-near infrared imagery from WorldView-3 (WV-3) and object-based classification for mapping potential deposits of ocher in Hormuz Island, southern Iran. A combination of field observations, spectroscopy, microscopic mineralogy, and geochemical-based XRD and XRF analyses were conducted on the samples collected throughout the study area. The reflectance and absorption features of the ocher were extracted from spectroscopic measurements of samples from well-known ocher mines at the area, and were then convolved to the WV-3 bands. Results showed that the spectral characteristics of ocher are governed by iron oxides and clay minerals with a presence of distinct strong absorption and high reflectance features in the 510–625 nm and 630–745 nm wavelength regions, respectively. These features are complemented by molecular vibration processes of water O–H intramolecular stretching and H–O–H bending that generate absorption features in the 1440–1940 nm region. Additional absorption features in the 2210–2300 nm are most likely due to the Al-OH and CO3−2 vibrations. The absorptions centered at 480 nm, 540 nm, and 820 nm correspond to bands 2, 3, and 7 of the WV-3, respectively, whereas the high reflectance feature centered near 700 nm corresponds to band 6. These four bands, which were considered as index bands of ocher in this study, were used to assign the segmentation weights and to create the thresholds during image processing. Brightness, density, compactness, and homogeneity features were the primary factors for selecting the training areas in the index bands. The ocher-rich areas were enhanced by using a two-stepapproach of object-based image analysis (OBIA) and image classification, for suitable threshold selection. The information about the feature variables of the ocher within the image and lithological object hierarchy were obtained to evaluate the features of ocher deposits. Information extracted from the index bands provided an important description of the object features, including mean, standard deviation, minimum and maximum pixel values, hue, saturation, and intensity, while the training areas obtained information from the three known ocher mines. Considering the fixed numerical range of ocher mines as a reference, the fixed numerical range of general and specific features of ocher in index bands of WV-3 were achieved. The numerical ranges of pixels were used for creating threshold conditions when applying the "assign class" algorithm in bands 2, 3, and 7 are 815–975 nm, 930–1052 nm, and 1721–1904 nm, respectively. The presented OBIA approach shows a high potential with an overall accuracy of 88 % to discriminate deposits of ocher based on compatibility between ocher mines and identified ocher-bearing pixels. [ABSTRACT FROM AUTHOR]

The multilayer sites Kovrizhka-IV and Bol’shoi Yakor’-I, Kovrizhka-III (Baikal-Patom Highlands, Lower Vitim) make it possible to characterize the Late Upper Paleolithic (LUP) at the early, 19–17 Kyr BP, and late, 15–13 Kyr BC, stages, respectively. The high information potential makes it possible to highlight the culture and activities of the inhabitants in terms of lithic production and microblade splitting, living features, settling, hunting, the transportation of mineral resources from remote sources, sign-symbolic activity and art. Th e lithic assemblages of LUP appearance, in general, show continuity from the early stage to the late one. In microblade splitting, this is expressed in the translation of the Kovrizhka and Yubetsu-Bol’shoi Yakor’ techniques for preparing the wedge-shaped microcore and reducing the biface. For the early stage, chisel-shaped tools are more typical than for the late stage, for the late stage - transversal burins. On Kovrizhka-IV (early stage), the remains of dwelling features were found, art objects were discovered as well as numerous evidence of the use of ocher. Bol’shoi Yakor’-I and Kovrizhka-III (late stage) show various hearth complexes and specifi c structures made of gneiss slabs. Culturally and typologically, the LUP of the Lower Vitim correlates with the Studenovskaya culture of Southern Transbaikalia at an early stage, the Dyuktai culture of Yakutia, and the Verkholenskaya culture of Southwestern Cisbaikalia at a later stage. In the early Holocene, LUP traditions were continued in a number of sites. However, already along with the appeared complexes of the Mesolithic appearance.

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The high amount of carbon dioxide produced by using cement as a component in concrete has led to environmental issues. Additionally, the amount of cement used in high-performance concrete (HPC) is considerable. As an alternative, slag is being used to reduce cement consumption. This study presents the development of HPC with minimal use of cement without significant strength reduction. The cementitious materials comprise 85% slag, 5% hydrated lime, and 10% ordinary Portland cement (OPC). Replacing cement with slag at high percentages always reduces the strength of concrete. Therefore, appropriate additives were used to achieve the strength of conventional concrete made of OPC. Calcium chloride was used as the most well-known accelerator of hydration, as well as ocher (red clay) due to its Fe2O3 content. Compressive strength and four-point flexural tests at the ages of 7 and 28 days, and Thermogravimetric Analysis (TGA), scanning electron microscopy (SEM), and X-ray diffraction (XRD) tests were performed. The results showed that the mixture which included 2% calcium chloride with 2% ocher, provided the highest compressive and flexural strengths of 93.2 and 8.1 MPa, respectively. These values were 99% of the compressive strength and 96% of the flexural strength of the concrete sample made of OPC only. The microstructural analysis showed that this mixing design had the highest content of calcium-silicate-hydrate (C–S–H) and other vital phases. Also, due to the role of chloride ions in steel corrosion, the electrical resistance test was performed on the sample that contained 2% calcium chloride and the sample with OPC only. The results showed that calcium chloride used as an accelerator will not cause corrosion of steel bars in the concrete. [ABSTRACT FROM AUTHOR]

Among the artist's iron-based natural earth pigments, the so-called terra di Siena (raw sienna), terra di Siena bruciata (burnt sienna) and terra d'ombra (umber) have been among the yellow-brown and reddish-brown earth pigments most widely used by Italian and European painters since the Renaissance. We present the history of discovery, designation, and production of these famous pigments, their geological, lithological, and geochemical characterization, and the recognition of their genesis and places of origin, based on new geological field surveys, and on the critical analysis of textual documents and rock sample collections assembled during the eighteenth and nineteenth centuries. In particular, the terra di Siena earth pigment exclusively originated at, and was extracted from, late Pleistocene paleo-lake basins surrounding the Monte Amiata volcano. This earth pigment consists of primarily lacustrine sediments composed of hydrated iron oxide (limonite/goethite) produced by biochemical authigenic precipitation from fresh waters rich in metal solutes. [ABSTRACT FROM AUTHOR]

Iron-containing earth minerals of various hues were the earliest pigments of the prehistoric artists who dwelled in caves. Being a prominent part of human expression through art, naturederived pigments have been used in continuum through ages until now. Studies reveal that the primitive artist stored or used his pigments as color cakes made out of skin or reeds. Although records to help understand the technical details of Indian painting in the early periodare scanty, there is a certain amount of material from which some idea may be gained regarding the methods used by the artists to obtain their results. Considering Indian wall paintings, the most widely used earth pigments include red, yellow, and green ochres, making it fairly easy for the modern era scientific conservators and researchers to study them. The present knowledge on material sources given in the literature is limited and deficient as of now, hence the present work attempts to elucidate the range of earth pigments encountered in Indian wall paintings and the scientific studies and characterization by analytical techniques that form the knowledge background on the topic. Studies leadingto well-founded knowledge on pigments can contribute towards the safeguarding of Indian cultural heritage as well as spread awareness among conservators, restorers, and scholars. [ABSTRACT FROM AUTHOR]

Copyright of Stratum Plus Journal is the property of P.P. Stratum plus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of ochre has been documented in many Middle Stone Age sites of Southern Africa. However, the literature on the exploitation of ochre within the archaeological contexts of Later Stone Age (LSA) rock art sites is scarce. Despite the discovery of several painted shelters within the Erongo Mountains (Namibia), no archaeological study of ochre assemblages has been conducted in the region. Here, we present the archaeological ochre assemblage recovered from a LSA sequence at the rock art shelter of Leopard Cave (Erongo, Namibia), spanning ca. 5,700 to 2,100 cal. BP. The use-wear traces present on some ochre fragments and the stone tools bearing red residues are indicative of different stages of ochre processing at the site. The presence of other artifacts, such as ostrich eggshell and bone beads with red residues, and the existence of rock paintings in the cave are pointers to the importance of ochre for understanding the sociocultural behaviors of the LSA populations in central Namibia. [ABSTRACT FROM AUTHOR]

The appearance of rich and diverse funerary practices is one of the hallmarks of the Late Epipalaeolithic Natufian in the Levant. Numerous burials at a number of sites excavated mostly in the Mediterranean zone of the southern Levant have fed into the interpretation of the Natufian as a sedentary society of complex hunter-gatherers. Here, we report on the human remains recovered from Shubayqa 1, a well-dated early to late Natufian site in northeast Jordan. The majority of the minimum of 23 individuals that are represented are perinates and infants, which represents an atypical population profile. Ground stone artifacts and traces of colorants are associated with some of these individuals, providing a rare insight into funerary treatment of subadults in Natufian contexts. We interpret the Shubayqa 1 evidence in the light of current and ongoing debates concerning Natufian burial practices and the issue of social complexity. [ABSTRACT FROM AUTHOR]

The Filanthropinon monastery church is regarded the birthplace of the "Epirus/NW Greece School" of painting as it bears the oldest wall paintings of this very school. Surviving inscriptions bear no painter name(s), yet they testify that the murals were executed in three phases between 1531/2 and 1560. The bulk of the technical and typological characteristics of the latter paintings are typical of post-Byzantine religious art, while OM, SEM-EDX, and micro-Raman probing reveals the existence of a number of idiomorphic characteristics that might be viewed as part of the microscopic fingerprint of the "Epirus school." A microscopic fingerprint of the school is important because current attributions of relevant works to specific painters are mostly stylistic ones, as pertinent signatures are rare. The latter characteristics include the application of a "charcoal plus blue smalt" substrate in the paintings' background and the employment of a possibly local (: Epirus), unusual ochre pigment. Sophisticated segregation of pigment grains, employment of glauconite, and the extensive use of San Giovanni white were also documented. Analytical data support the following scheme as regards artistic identities: the 1531/2 nave paintings were executed by a single painter, possibly assisted by a pupil who also contributed to the 1542 paintings. The paintings of the 1542 and 1560 phases are apparently the outcome of another—yet related to the nave painter—workshop; there are clues which indicate employment of Georgios and Frangos Kontaris in both of these commissions. Finally, remnants of four different overpaintings were also revealed: pertinent pigments indicate successive interventions during an extended period of time, which reflect the will of Filanthropinon votaries to retain the murals vivid. [ABSTRACT FROM AUTHOR]

Though many European Upper Palaeolithic sites document early examples of symbolic material expressions (e.g., cave art, personal ornaments, figurines), there exist few reports on the use of earth pigments outside of cave art–and occasionally Neanderthal–contexts. Here, we present the first in-depth study of the diachronic changes in ochre use throughout an entire Upper Palaeolithic sequence at Hohle Fels cave, Germany, spanning from ca. 44,000–14,500 cal. yr. BP. A reassessment of the assemblage has yielded 869 individual ochre artefacts, of which 27 show traces of anthropogenic modification. The ochre artefacts are from all Upper Palaeolithic layers, stemming from the earliest Aurignacian horizons to the Holocene. This wide temporal spread demonstrates the long-term presence and continuity of ochre use in a part of Europe where it has not been systematically reported before. The anthropogenic modifications present on the ochre artefacts from the Gravettian and Magdalenian are consistent with pigment powder production, whereas the only modified piece from the Aurignacian displays a possible engraved motif. The non-modified artefacts show that more hematite-rich specular ochres as well as fine-grained deep red iron oxide clays were preferred during the Gravettian and Magdalenian, while the Aurignacian layers contain a broader array of colours and textures. Furthermore, numerous other artefacts such as faunal elements, personal ornaments, shells, and an ochre grindstone further strengthen the conclusion that ochre behaviours were well established during the onset of the Aurignacian and subsequently flourished throughout the Upper Palaeolithic at Hohle Fels cave. [ABSTRACT FROM AUTHOR]

The conducted studies have proven the possibility of the directed control of operational properties of epoxy composites, due to the addition of finely-ground ocher into their composition, and the use of microwave modification of the epoxy composition. The rational content of ocher as a modifying additive (0.5 parts by mass) and a filler (75 parts by mass) of the epoxy composition has been selected, which ensures the improvement of the studied complex of physical-mechanical properties. It has been proven that ocher affects the structure formation processes and the structure of the epoxy composite, thus increasing its thermal, heat and fire resistance. During the research, the application efficiency has been proven, and the optimal parameters of the microwave modification (power—350 W; duration—30 s) of epoxy compositions filled with ocher, which increase physical-mechanical characteristics of composites, have been selected.

Nine ancient Egyptian sarcophagi of the twenty-fifth to twenty-sixth dynasty, one Ptolemaic Hawk Mummy, and one Amarna fresco were examined in the collections of the San Diego Museum of Man. Binding media, pigments, wood identification, deterioration and alteration products were identified. The pigment palette represents the basic suite of ancient Egyptian pigments: charcoal black, red ochre, yellow ochre, Egyptian blue, green earth, calcite, and gypsum. In the case of the Hawk mummy, oxammite was identified as a degradation product, together with magnesium phosphate, the first identification of oxammite in ancient artefacts. In a child’s coffin, realgar and orpiment were additionally identified. The binding media for practically all of the coffins studied was confirmed as gum Arabic with only one example of gum tragacanth found from a wall plaque from Amarna. Wood identification showed that Ficus sycomorus had been used, rather than the assumed cedar of Lebanon for coffin manufacture. One unidentified species of shrubby wood was also found. Some of the coffins had been restored, with one having a completely repainted face, in rutile, and the child’s coffin has an attached foot-box with modern screws. Possible indications of ancient reuse were found during the study. [ABSTRACT FROM AUTHOR]

A study is presented based on the use of entirely non-destructive spectroscopic techniques to analyze the chemical composition of the painted surface layer of archaeological pottery. This study aims to define both the raw materials and the working technology of ancient potters. Energy-dispersive X-ray analysis, micro-Raman spectroscopy, visible and near infrared (NIR) diffuse reflection spectroscopy and external reflection Fourier-transform infrared (FTIR) spectroscopy were applied to matt-painted bichrome pottery sherds (VIII-VII century B.C.) from the site of Incoronata near Metaponto in southern Italy. Two different raw materials, ochre and iron-rich clay, were recognized for the red decoration, while the dark areas resulted to have been obtained by the so-called manganese black technique. In any case, it was demonstrated that the decoration was applied before firing, in spite of its sometimes grainy aspect that could suggest a post-firing application. For the samples with a more sophisticated decorative pattern a red/black/white polychromy was recognized, as the lighter areas correspond to an “intentional white” obtained by the firing of a calcium-rich clay. Reflection spectroscopy in the visible-NIR and mid-IR as well as micro-Raman spectroscopy were then employed to characterize the decoration of an intact ceramic urn from the Etruscan town of Chiusi, evidencing a post-firing painting based on the use of red ochre, carbon black and lime, possibly imitating the “fresco” technique used in wall paintings. [ABSTRACT FROM AUTHOR]

Although the exploitation of ochre and its role in the emergence of modern human behaviour has been afforded substantial academic consideration, inquiries into ochre procurement strategies remain limited. Since the systematic exploitation of red ochre is widely viewed as symptomatic of increasing cognitive complexity, the persistence of this behaviour amongst extant sub-Saharan African groups is significant in terms of human behavioural aspects observed in the archaeological record. The aim of this paper is to provide insight into prehistoric ochre procurement strategies by presenting an account of the methods implicated in the extraction of red ochre by the Ovahimba of the Kunene Region, north-western Namibia. I draw correlations between prehistoric and modern traditional mining practices and show that ethnoarchaeological research provides a basis for the formulation and assessment of archaeological research questions. I focus on the primary source of red ochre in the Kunene Region, the Ombumbuu ochre quarries, and employ visible spectroscopy, energy-dispersive X-ray fluorescence (ED-XRF), X-ray diffraction (XRD) and scanning electron microscopy and energy dispersive X-ray spectrometry (SEM-EDS) to characterise ochre from this resource. I also explore the evolutionary impact that the habitual exploitation of red ochre might have had on prehistoric human adaptive strategies and assert that these played an important role in increasing human survivability and cumulative cultural capacity. [ABSTRACT FROM AUTHOR]

Upper Palaeolithic yellow and red ochre samples recovered in the last 40 years at Tagliente rock-shelter in the Lessini Mountains (Verona, NE Italy) were analysed by means of conventional X-Ray Powder Diffraction (XRPD) and compared with goethite- and hematite-based natural geomaterials coming from geological deposits within a distance of approximately 20 km from the archaeological site. XRPD allowed the yellow ochre sourcing area to be focused on the basis of characteristic and distinctive mineral assemblages. In addition, several samples clearly demonstrated that archaeological red ochre was obtained by thermal treatment of yellow ochre as shown by characteristic peak intensities, shape and the presence of maghemite (γ-FeO). XRPD was a very powerful tool for a preliminary discrimination and grouping of a large quantity of archaeological ochre, in order to outline a preliminary hypothesis on the provenance area and to narrow down the number of samples to be studied in the next future through geochemical and structural analysis in order to confirm the proposed interpretation. [ABSTRACT FROM AUTHOR]

Provenance research of archaeological ocher contributes to understanding the capabilities of prehistoric humans to select, process, and treat suitable raw materials for symbolic and utilitarian purposes. The western part of the Lessini Mountains in the Veneto region of northeast Italy is an ideal location for this type of study as it features several different Fe-rich deposits, and many examples of archaeological ocher have been found in the nearby Fumane Cave and Tagliente Rockshelter Upper Paleolithic sites. Sourcing areas are often identified through the use of geochemical studies; however, microscopic techniques can also be used with the benefit of providing more detailed information about accessory minerals and textural characteristics of the material. One of the goals of our study was to demonstrate the potential in using polarizing light microscopy supported by scanning electron microscopy coupled with an energy dispersive X-ray spectrometer in research of this type. We studied geological source samples and archaeological materials from the sites, the results of which are very promising in terms of shedding light on the sourcing of prehistoric ocher in this region. [ABSTRACT FROM AUTHOR]

Ochre is found at numerous Middle Stone Age (MSA) sites and plays a key role in early modern human archaeology. Here we analyse the largest known East African MSA ochre assemblage, comprising 40 kg of ochre, found at Porc-Epic Cave, Ethiopia, spanning a period of at least 4,500 years. Visual characterisation of ochre types, microscopic identification of traces of modification, morphological and morphometric analysis of ochre pieces and modified areas, experimental reproduction of grinding processes, surface texture analysis of archaeological and experimentally ground ochre facets, laser granulometry of ochre powder produced experimentally on different grindstones and by Hamar and Ovahimba women from Ethiopia and Namibia respectively, were, for the first time, combined to explore diachronic shifts in ochre processing technology. Our results identify patterns of continuity in ochre acquisition, treatment and use reflecting both persistent use of the same geological resources and similar uses of iron-rich rocks by late MSA Porc-Epic inhabitants. Considering the large amount of ochre processed at the site, this continuity can be interpreted as the expression of a cohesive cultural adaptation, largely shared by all community members and consistently transmitted through time. A gradual shift in preferred processing techniques and motions is interpreted as reflecting cultural drift within this practice. Evidence for the grinding of ochre to produce small quantities of powder throughout the sequence is consistent with a use in symbolic activities for at least part of the ochre assemblage from Porc-Epic Cave. [ABSTRACT FROM AUTHOR]

With the aim to obtain iron tubular microstructures attractive for various applications, we have used a natural biogenic iron ochre as a raw material and explore various procedures and experimental conditions to achieve our goal. Our experiments included reduction, nitridation and characterization of microtubes derived from biogenic iron ochre. Various temperatures of reduction under streams of H/N or NH were tested. Our results show that the tubular structure is maintained after reduction of the natural material under H/N. In addition, ammonia was not produced under our experimental conditions, and as expected, hydrogen reduced the material. However, the treatment under NH reduces the material and allows the incorporation of nitrogen into the structure of the solid yielding iron nitride microtubes. Reduced and nitrided microstructures were successfully obtained from natural biogenic iron ochre. A temperature of 500 °C seems to be suitable to expose the calcined biogenic iron ochre under H/N for 4 h or under ammonia for 8 h to obtain reduced or nitrided microtubes, respectively. The stability of the tubular structure during reduction/reduction-nitridation is maintained under both treatments. Further interesting applications of this natural biomaterial could be envisaged. [ABSTRACT FROM AUTHOR]

A historical paint manufactory in Staicele, Latvia (1967), was using local resources -- colour earth. Oil paint composition consisted of pigment, drying oil, varnish and siccative. It had two different tones that are obtained by using natural colour earth pigments: ochre and its burnt form (burnt umber). Pigment quality was analyzed using historical documents, modern pigment tests, and manufactory technology. Chemical composition, particle size, and pigment tone were determined, and the coating ability was calculated. A palette of oil paints based on the historical recipes for restoring Staicele oil paints was created. Properties of colour earth pigments were compared to specimens taken from the local source of iron that is located near the old paint factory. Results provide a historical and technological insight as well as insight in the properties of the basic paint composition. [ABSTRACT FROM AUTHOR]

We describe colour, hardness, grain size, geological type and surface modifications of ochre pieces excavated, first by Malan and later by Harper, from the Middle Stone Age (MSA) of Rose Cottage Cave, 96, 000 to 30, 000 years ago. Soft, bright-red shales are abundant, and most ochre has clayey or silty grain sizes. The post-Howiesons Poort layers contain the most ochre pieces, but the Howiesons Poort layers have the highest frequency of ochre per sediment volume. The pre-Howiesons Poort layers have the highest utilization rate. Use-traces include rubbing, grinding, combined grinding and rubbing, and rare instances of scoring. The processing techniques are proxies for ochre use. Rubbing transfers red ochre powder directly onto soft surfaces, such as human skin, or animal hide. This is appropriate when skin colouring and marking or skin protection (for example from sun, insects or bacteria) is the purpose. Grinding produces ochre powder that can be used for a variety of tasks. It can be mixed with water or other products to create paint, cosmetics or adhesives. Multiple uses of ochre powder and ochre pieces are therefore implied at Rose Cottage and changes through time are apparent. [ABSTRACT FROM AUTHOR]

This analyzes the effect of submersion in the formation of ochre biofilm in geotextile filters used in drainage systems. The chemical microbiological aspects involved in ochre formation and clogging of drainage systems are discussed. Clogging by ochre may be considered a major threat in the performance of filters and drainage systems. This process has been observed in the field and demonstrated in laboratory tests under well-controlled conditions. Oxygen is needed for ochre formation and is available at the water–air interface of the filters. If the filters are submerged, oxygen may also be available dissolved in the water, with higher concentrations close to the surface due to the diffusion process. Column filter tests with the introduction of iron bacteria under three different filter submersion conditions were carried out. Woven geotextile filters were used in all tests. Biofilm formation on the geotextile filters were evaluated through the analysis of EDS (Energy Dispersive X-ray detector) and scanning electron microscopy. Ochre formation was verified in all tests, confirming that ochre formation can occur even under submerged conditions. The formation of ochre biofilm decreased with the depth of the geotextile filter in relation to the water surface, following the expected reduction of available oxygen below the water surface. [ABSTRACT FROM AUTHOR]

The Kenya Rift Valley contains many ochre sources that are currently used by indigenous peoples for adornment, rituals, and art. Ochre pigments occur in rock art and archaeological sites spanning over 250,000 years. Chemical analysis for provenience of geological sources is the first step in the process of reconstructing provenance of archaeological artifacts for cultural heritage, archaeological, and paleoanthropological research. Development of an ochre source chemical composition database can facilitate reconstruction of social interaction networks and cultural heritage conservation efforts in this region. Techniques such as Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) and Instrumental Neutron Activation Analysis (INAA) are often used for compositional analysis and sourcing of ferruginous mineral pigments. Sourcing has proven challenging due to the diverse range of rocks and minerals that are classified as red and yellow ochres, and the diverse processes that induce variation in composition, including modes of formation, sedimentary transport of parent materials, and diagenesis. Attribution of samples to specific sources is possible only when variation within sources is less than differences between sources (the Provenience Postulate). Here we present the results of a study using LA-ICPMS to determine inter- and intra-source geochemical variations for ten ochre sources associated with three large volcanic centers in the central Rift Valley of Kenya. Our results show that differences in chemical composition among sources are greater than variation within sources, both at the scale of large volcanic centers and of individual ochre outcrops within these centers. Clear differentiation of source chemical fingerprints at local and regional scales satisfies the Provenience Postulate, and suggests that provenance studies of ochre artifacts, residues, and rock art in Kenya will be feasible. [ABSTRACT FROM AUTHOR]

The archaeological site Pedra do Cantagalo I is a sandstone shelter displaying rupestrian inscriptions. It is located in the rural area of the municipality of Piripiri, in the northern region of the Piauí state, Brazil. The site was found as being originally decorated with more than 1,900 prehistoric rupestrian paintings, along with engravings, lithics, ceramic fragments and mineral pigments forming reddish and yellowish ochres. Materials of these ochres, collected from recent excavations in this archaeological site, were analyzed by energy dispersive X-ray fluorescence (EDXRF); backscattering and transmission Fe-Mössbauer spectroscopy at 298 K and 25 K and powder X-ray diffraction (XRD), in an effort to assess the chemical and mineralogical characteristics of these sources of pigments that composed the ancient paint materials of the site. The iron contents (expressed as Fe O ) for the reddish ochres were found to range from ∼60 to ∼68 mass%; for the yellowish ochres the corresponding content was ∼34 mass%, as determined by EDXRF. From the Mössbauer spectra for these red ochre samples, hematite ( αFe O ) or a mixture of hematite and goethite ( αFeOOH) were identified. Actually, the spectra at room temperature for the yellow ochres are rather complex, as it is usual for most soil clay materials. At least part of the intense central doublet was assumed to be from superparamagnetic iron oxides in very small particles. The Mössbauer patterns at 25 K allowed confirming this assumption, as the superparamagnetic relaxation effects were virtually suppressed; the spectral contributions due to goethite could be thus more easily separated. [ABSTRACT FROM AUTHOR]

The Lessini Mountains carbonate plateau (Venetian Prealps, Italy) is one of the most important karst areas in Italy. Along with alpine-type caves and well-developed karst landscapes, palaeokarst features are also common. In most cases, palaeokarst is represented by caves and fissures filled by limonitic-haematitic palaeosols (ochres) in which fossiliferous arenite layers are sometimes embedded. These features developed and fossilised during a late Eocene-middle Miocene phase of emersion. Between the Palaeocene and the Oligocene, over a time span partially overlapping the development of palaeokarst, basaltic volcanism took place in the Lessini Mountains. Along with ochre fills, cave passages that were intruded by basalt provide further evidence that a well developed karst network existed in the Lessini Mountains area in the middle-late Palaeogene. Moreover, basalt intrusions provide the only available data for the dating of palaeokarst in the central Lessini Mountains, where fossiliferous layers in ochre beds have not been found. we have started a new survey on palaeokarst in the Lessini plateau, with the aim of identifying ancient features on the basis of unusual fills (namely, ochre and basalt) and morphologies. New instances of basalt intrusions in three caves, Spigola di Canova, Covoli di Velo, and Covolo della Croce, have been recognised; evidence of pre-existing karst features filled by basalt in a previously studied cave (Grotta A Veja) has been identified, and an unusual basalt outcrop that might relate to palaeokarst has also been observed. This paper aims to document the new findings and to discuss previous ones. At the same time, we would like to point out some cautionary observations to prevent a "basalt = palaeokarst" misunderstanding. [ABSTRACT FROM AUTHOR]

The treatment of mine drainage-impacted waters generates considerable amounts of sludge, which raises several concerns, such as storage and disposal, stability, and potential social and environmental impacts. To alleviate the storage and management costs, as well as to give the mine sludge a second life, recovery and reuse have recently become interesting options. In this review, different recovery and reuse options of sludge originating from active and passive treatment of mine drainage are identified and thoroughly discussed, based on available laboratory and field studies. The most valuable products presently recovered from the mine sludge are the iron oxy-hydroxides (ochre). Other by-products include metals, elemental sulfur, and calcium carbonate. Mine sludge reuse includes the removal of contaminants, such as As, P, dye, and rare earth elements. Mine sludge can also be reused as stabilizer for contaminated soil, as fertilizer in agriculture/horticulture, as substitute material in construction, as cover over tailings for acid mine drainage prevention and control, as material to sequester carbon dioxide, and in cement and pigment industries. The review also stresses out some of the current challenges and research needs. Finally, in order to move forward, studies are needed to better estimate the contribution of sludge recovery/reuse to the overall costs of mine water treatment. [ABSTRACT FROM AUTHOR]

Ochre is a common feature at Middle Stone Age (MSA) sites and has often been interpreted as a proxy for the origin of modern behaviour. However, few ochre processing tools, ochre containers, and ochre-stained artefacts from MSA contexts have been studied in detail within a theoretical framework aimed at inferring the technical steps involved in the acquisition, production and use of these artefacts. Here we analyse 21 ochre processing tools, i.e. upper and lower grindstones, and two ochre-stained artefacts from the MSA layers of Porc-Epic Cave, Dire Dawa, Ethiopia, dated to ca. 40 cal kyr BP. These tools, and a large proportion of the 4213 ochre fragments found at the site, were concentrated in an area devoted to ochre processing. Lower grindstones are made of a variety of raw materials, some of which are not locally available. Traces of use indicate that different techniques were employed to process ochre. Optical microscopy, XRD, μ-Raman spectroscopy, and SEM-EDS analyses of residues preserved on worn areas of artefacts show that different types of ferruginous rocks were processed in order to produce ochre powder of different coarseness and shades. A round stone bearing no traces of having been used to process ochre is half covered with residues as if it had been dipped in a liquid ochered medium to paint the object or to use it as a stamp to apply pigment to a soft material. We argue that the ochre reduction sequences identified at Porc-Epic Cave reflect a high degree of behavioural complexity, and represent ochre use, which was probably devoted to a variety of functions. [ABSTRACT FROM AUTHOR]