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The behavior of water and salt inside porous sandstone is crucial for determining the durability of stone heritage. This involves multiphase coupled processes, yet previous analyses have paid insufficient attention to the spatial and temporal characterization of solution-crystal phase change. Based on the salt crystallization experiments, theoretical models and numerical computational frameworks are synthesized to simulate multiphase processes. Subsequently, equations are established for coupled water-salt-heat-mechanical interactions in the multiphase media. Then, the critical state of solution-crystal phase change is analyzed through the evolution of saturation, crystallization pressure, and porosity. The findings indicate rapid solution saturation growth at positions with minimal wetting front fluctuations, leading to initial crystallization. Further tracing reveals that crystallization evolves through discrete crystallization, annular crystallization, and crystallization expansion stages. By investigating the crystallization pressure and the crystal morphology, it is possible to quantify the dynamics of crystal pressure on constraint surfaces and solution pressure. In addition, the change in porosity can be observed by simulation of dry and wet cycles to obtain crystallization initiation. The numerical calculations agree well with the experimental results, providing valuable insights into the deterioration mechanism induced by salt crystallization in the porous sandstone of Dazu Rock Carvings. • Saturation of water-salt migration in porous sandstone is analyzed quantitatively. • The stress change of solution-crystal phase change can be judged by simulation. • Critical crystalline shows an annular state of saturation and effective stress. • Pore structure of stone is progressively destroyed by dry-wet cycles of solution. [ABSTRACT FROM AUTHOR]

Cultural values may considerably enhance the significance of a geo(morpho)site, especially from the perspective of geotourism and geopark operations. Typically considered as one of 'additional values', they may in fact strongly influence the identity of a place and distinguish a landform from many others of similar kind. Cultural values may be intangible or associated with past landform modification to suit human needs. In sandstone areas of the Bohemian Cretaceous Basin (Czechia, Germany, Poland) multiple relationships between human activities and erosional scenery exist, leaving a diverse record of human uses and alterations of specific landforms. Seven major categories of added cultural values are recognized. They include the use of landforms to support defensive structures, spiritual (religious) associations, exploitation of stone resources and other industries, inspiration for art, modifications associated with tourism development, dwelling places and transport facilities. They also illustrate changing relationships of humans with geomorphological landscapes from prehistoric times until the present. Within each category specific examples are presented to show variety of uses and alterations. A possibility to include added cultural values in semi-quantitative geosite evaluations is discussed, but it is concluded that this is difficult to achieve satisfactorily. Following previous opinions of Czech researchers, it is suggested that sandstone landscapes offer the most striking and diverse linkages between rock scenery and culture at the global scale, at least in part facilitated by the relative ease of excavating, cutting and carving of the rock, which otherwise also tends to support spectacular erosional landforms of different size and shape. • Multiple interactions between human activities and landforms over time recognized. • Specific features of sandstone landforms dictated specific anthropic modifications. • Relative ease of excavating, cutting and carving the sandstone favoured cultural imprint. • Sandstone landscapes offer some of the most striking linkages between rock scenery and culture at the global scale. [ABSTRACT FROM AUTHOR]

Revealing carved parts in rock art is of primary importance and remains a major challenge for archaeological documentation. Computational geometry applied to 3D imaging provides a unique opportunity to document rock art. This study evaluates five algorithms and derivatives used to compute ambient occlusion and sky visibility on 3D models of Mongolian stelae, also known as deer stones. By contrast with the previous companion work, models are processed directly in 3D, without preliminary projection. Volumetric obscurance gives the best results for the identification of carved figures. The effects of model resolution and parameters specific to ambient occlusion are then evaluated. Keeping tridimensional information intact allows accurate measurement of distance, volume, and depth. Objects augmented by ambient occlusion can easily be manipulated in 3D viewers, for seamless and effortless access to the overall organization of the figures, at the scale of the entire object. Qualitatively speaking, the 2D projected outputs are equivalent to, or even better than, existing archaeological documentation. The proposed workflow should be easily applicable in many situations, particularly as the functions provided for the free R programming software are fully configurable. [ABSTRACT FROM AUTHOR]

The preservation of rock art in open-air contexts is a global issue controlled by several environmental processes, which are less investigated than the cultural significance of engravings and paintings. For that reason, we discuss the age, preservation, and palaeoenvironmental context of petroglyphs discovered on the flat, almost vertical face of a large boulder fallen along the western slope of Jabal Hammah, a rocky hill that borders the oasis of Salut (northern Sultanate of Oman). Geoarchaeological investigation highlighted that, in the region, the preservation of petroglyphs is due to the interplay of two contrasting weathering processes. On one hand, karst dissolution – even if it is a very slow process in arid and semi-arid lands – gradually levels the surface of boulders. On the other hand, a biomineralized Mn- and Fe-rich rock varnish has developed inside the grooves of the engravings, thus sheltering them from extreme dissolution and promoting the preservation of the pristine shape of the representations. Moreover, organics trapped within the rock varnish have been radiocarbon dated to 2600 ± 60 uncal. years BP. This result allows establishing a limit ante quem for the production of these specific engravings and to root it to the Bronze or Iron Age exploitation of the area. This result is of particular relevance in a region where well-dated rock art is virtually absent. Today, the biogeochemical processes leading to the formation of the protective crust are almost inactive, and not consistent with the present dry environmental settings. Their occurrence is in accordance with other local palaeoclimatic record, and suggests Bronze and Iron Age climatic conditions wetter than today. A broader implication of our work is that it shows how a multidisciplinary approach to the study of rock art provides the opportunity of understanding the age of rock art and its paleoenvironmental significance. We demonstrate that physical, chemical, and biological weathering processes are in charge of the preservation and/or destruction of rock art; such processes have to be seriously taken into account in projects of rock art field assessment. [ABSTRACT FROM AUTHOR]

Rock surfaces covered with desert varnish frequently feature petroglyphs and thus comprise an important resource for the artistic expression of ancient societies. Knowledge about the processes of varnish formation would be helpful to assess the production, regeneration and durability of this "natural canvas" and related rock art. We performed a multidisciplinary study of rock varnish associated with petroglyphs at the archaeological site of La Proveedora (Sonora, Mexico) that has been occupied by humans for at least 4500 years. An inventory and mapping of these ancient engravings revealed 5873 individual images on 1331 rock surfaces. Classification of these motifs showed that geometric forms were the most commonly featured, followed by zoomorphic and anthropomorphic designs. Colorimetric measurements according to the L*a*b* system confirmed that the carvings have a strong color contrast with the background patina. Petrographic observations revealed the variable thickness of the varnish coating, which penetrates deeper into the granitic rock at contacts with plagioclases and ferromagnesian minerals, forming a "rooted" configuration of the lower boundary. Under SEM thin globular laminae were observed; plagioclase and biotite adjacent to the varnish showed signs of alteration. EDS microanalysis, LIBS and X-ray diffraction demonstrated that the patina consists of Fe and Mn oxihydroxides and clay minerals with differing amounts of Fe and Mn within the coating. These results support the polygenetic model of rock varnish development. Weathering of granite and eolian particles give rise to clay mineral formation, whereas Fe and Mn mobilization and reprecipitation is controlled by microorganisms. Varnish formation was more intensive under moister conditions which prevailed in Sonora during the terminal Pleistocene. Thus, rock varnish comprised a non-renewable resource for ancient artists, being a relict feature. The Holocene rates of patina development were too slow to re-pigment engravings, so the petroglyphs represent a persistent element of a cultural landscape. We attribute the surprising durability of the dark coatings to the "rooted" configuration of their lower boundaries that could be important for petroglyph preservation. [ABSTRACT FROM AUTHOR]

The Palaeolithic rock engravings that are located along the Nalón river basin in Northern Spain (central area of Asturias) have been studied from various perspectives (morphology, depth, style, manual range), but no use-wear studies on the stone tools used to produce such engravings have ever been undertaken. This paper aims to explore a new approach to this type of incisions based on use-wear analysis of experimental lithic tools used to engrave limestone blocks and slabs. Our results show that the use-wear traces generated by engraving limestone are well-developed and can be defined with specific criteria. The principal objective of this study was to provide the first experimental reference collection of use-wear resulting from engraving limestone using flint and quartzite experimental tools to compare with the traces that appear on tools in the archaeological record in contexts with parietal and portable art and, more specifically, to add a new approach to the multidisciplinary study of the La Viña rock shelter. • Experimental collection of use-wear resulting from engraving limestone. • Description of macro and micro traces and residues involving in the stone working. • Combination of SEM and OM to analyse use-wear traces in quartzite and flint tools. [ABSTRACT FROM AUTHOR]

One of the most common problems encountered in research on open-air petroglyph sites is determining the age of the imagery. Most images are not covered by calcite or other deposits which can be directly dated. Archaeological layers located under petroglyph panels may allow connections between imagery and datable cultural contexts to be established. When archaeological layers are lacking, the analysis of stylistic elements of petroglyphs themselves can be highly significant for temporal and cultural attribution. We regard style a Bos including not only artistic characteristics of images but also the ways in which rock panels were modified as well. Technological features can be important for understanding the broader concept of style in rock art. As illustrated by the open-air Kalgutinsky Rudnik site in the Russian Altai region, natural substrate characteristics often demanded specific technological adaptations that can be revealed by the analysis of anthropogenic and natural traces on rock surfaces. These data supplement the discussion of dating the earliest petroglyphs from the Kalgutinsky Rudnik rock art site. [ABSTRACT FROM AUTHOR]

• Detection in a cultural heritage context and a challenging environment is addressed. • A new dataset for markerless detection of ancient rock carvings is presented. • Two methods for detection are employed and compared visually and numerically. • Non-linear embeddings validate the usefulness of a proposed distance measure. In this paper, we discuss the problem of object detection in a cultural heritage application context. In particular, the objects to be detected are ancient rock carvings, discovered at the archaeological site of Vathy, Astypalaia in Greece. Without the help of a marker or a human expert, the rock carvings are extremely difficult for a visitor of the site to discern from their surroundings. We explore the possibility of using a computational method that could replace the human expert and detect the rock carvings of interest without the aid of a specific marker. We present a dataset of images that is comprised of annotated photographs of the rock carvings, taken in situ and under differing poses and lighting parameters. Two methods for detection are applied; the first method makes use of a supervised, deep learning-based model, while the other relies on feature point-based matching to an annotated template, in the context of which we propose a simple image matching distance. We show that each method is applicable under different conditions, and evaluate their effectiveness with numerical trials. [ABSTRACT FROM AUTHOR]

In the rock art of Fennoscandia, the economy of the population from the late Mesolithic to the paleometal age looks as follows. In the images we find only hunting, marine hunting from boats and fishing on the hook. There are no scenes with traps, snares, trapping pits, which were undoubtedly used. The image of economic activity is limited to the pictures of active production of the following animals: elk, reindeer, bear, beavers, waterfowl, cetacean (dolphin), halibut, pike. Weapons and means of equipment: a spear, a bow and arrows, a harpoon, fishing hooks on a line, boats, skis and snowshoes. In general, this set corresponds to those materials that originate from excavations. [ABSTRACT FROM AUTHOR]

• OSL age of petroglyph at Daraki Chattan gave a terminus post quem of 13th millennium • Surface patina and weathering intrusion investigation by multianalytical techniques • impact on the weathering on quartz coating affects dosimetry for OSL dating The cave of Daraki-Chattan (in Rewa river, India) bears important palaeolithic rock art (petroglyphs), while the environs is exceptionally rich in stone tools, mostly of the Acheulian. The field survey and excavations in the area found cupule panel fragments almost down to bedrock; Acheulian industry to Oldowan-like industry including several hammerstones. Early work demonstrated that at least some of the petroglyphs were of the earliest documented occupation of the region. Exfoliated pieces and boulders from the rock surface were found in the sediments, some bearing cupules and grooves. Here a detailed methodological procedure is enacted consisting of luminescence dating reinforced by mineralogical issues, where the latter secures credibility of the former. The optically stimulated luminescence (OSL), of the luminescence versus depth profiles, following blue LED and Single Aliquot Regeneration (SAR) technique of quartz, was applied following the surface luminescence dating versions to date this fallen rock. The two dose profiles from the sandstone studies provided an average date for the fallen boulder in the 13th millennium, providing a constrained terminus post quem. Surface patina and intrusion of (Fe, Mn) aluminosilicate weathering solution was examined in both luminescence profiles, properly dealt with issues of X-Ray Diffraction (XRD), Scanning Electron Microscopy- Energy Dispersive Spectroscopy (SEM-EDS), X-Ray Florescence-Energy Dispersive mode (XRF/ED), Cathodoluminescence, stereomicroscope, thin sections optical microscopy (OM) and microdosimetry. Analytical petrographic results aided interpretation of luminescence data obtained. From the above rationale the two ages obtained from the two profiles can be considered close within errors, that coincide with the drastic change from last glaciation transition to the milder climate of the Holocene and the sudden end of colder Younger Dryas in ~13th Ka BP, having an impact on the weathering, erosion and exfoliation of rock surfaces caused by the significant temperature change and the resulted thermal differential expansion of rocks (onset of the Holocene). [ABSTRACT FROM AUTHOR]

Highlights • An average-face-based inpainting method is proposed in this paper. • It is utilized for two extremely challenging inpainting tasks: face reconstruction for the Willow Avalokitesvara (head was stolen) in Shimenshan No. 6 and the outermost two Avalokitesvaras (heads were broken) in Beishan No. 180. The result is valuable for art historians and conservators. • The comparative experiments illustrate the advantages of our method for the exemplar-based inpainting of images with large-scale and irregularly damaged regions. Abstract Numerous image inpainting algorithms are guided by a basic assumption that the known region in the original image itself can provide sufficient prior information for the guess recovery of the unknown part, which is not often the case in actual art image inpainting. In order to solve the challenging inpainting case that there is little image prior in the remainder of the original image, we propose an average-face-based inpainting method based on a sample database with 3 steps: reference images selection, average image generation and exemplar-based image inpainting. In which, average image generation is crucial. In the inpainting framework, the average image can be directly viewed as an inpainting proposal for the severely damaged or absolutely lost image. Moreover, the average image can be applied to exemplar-based inpainting algorithm as a sample image to extend the searching region for match patch, so as to perform the restoration for images with large-scale or irregularly damaged holes. The inpainting experiments over some facial images of Dazu Rock Carvings demonstrate the validity and effectiveness of our method. It is first utilized for two extremely challenging inpainting tasks: reconstruction for the stolen head of Willow Avalokitesvara in Shimenshan No. 6 and the absolutely broken heads of two Avalokitesvaras in Beishan No. 180. Compared to the failure of the exemplar-based inpainting algorithm within the original image and the directly duplication of a similar image, the generated average image can be as a more reliable inpainting proposal. The comparative experiments also show the efficiency and advantage of the average face applied to exemplar-based inpainting framework. Compared with some related inpainting algorithms, our method is more competitive when there is little prior information in the original image. The efficient virtual inpainting results are valuable references for both cave art historians and conservators. [ABSTRACT FROM AUTHOR]

Some of Austria's most important petroglyphs are located in the alpine region of Dachstein, carved in the local limestone. Favored by the humid and shady environment, most of the engravings are covered by extensive biological colonization. In order to assess whether and to what extent the biopatinas present on the stone cause biodeterioration, we investigated their interactions with the rock substrate by microscopy methods (and PAS-staining), in combination with a metagenomic analysis to identify the biofilms' composition. The microscopy methods highlighted a general biodeterioration state of the stone and the great boring ability of the biofilms, especially of those with filamentous cyanobacteria (e.g., Nostocales and Oscillatoriales), and showed that a thick moss biofilm (with high abundance of Bacteroidota taxa) was the most harmful for the stone support, causing severe disruption of the underlying rock. Interestingly, the analysis of stone without visible biofilm revealed a microbiome dominated by ammonia-oxidizing archaea (AOAs), probably indicating the presence of a previous degraded biofilm (source of ammonia), and a current state of deterioration (dissolution of calcium carbonate). Removal of the biopatinas, or their alteration, would expose an already altered surface, potentially giving rise to a new colonization and new cycles of biodeterioration. • Biofilms on petroglyphs were analyzed by optical microscopy, SEM and metagenomics. • PAS staining method was very useful in the visualization of biofilms in the stone. • Thick biofilms with moss seem to be related to a more severe disruption of the rock. • Biofilms penetrate deep into the stone, especially filamentous cyanobacteria. • Stone with no visible biofilm has high abundance of ammonia-oxidizing archaea (AOA). [ABSTRACT FROM AUTHOR]

Ongoing work in Daraki-Chattan cave, India, has revealed important Paleolithic rock art (petroglyphs) in the form of cupules. The site is rich in stone tools of Acheulian industry to Oldowan-like industry including several hammerstones. The present investigation concerns a further detailed methodological and complementary approach for dating a quartz-arenite sandstone clast from just above the lowest exfoliated cupule, combining surface luminescence chronology with petrography. The optically stimulated luminescence equivalent dose profiles versus depth from quartz were studied to date this clast. Two different dose-depth profiles were measured spanning to 28 mm depth, one natural depth profile and one for a sample following exposure to daylight for nine months. Equivalent dose versus depth profiles indicate bleaching in several millimeters. Varied spatial luminescence response, its effect on the luminescence-depth profiles and interpretation to circumvent minor anomalies are fully discussed in terms of non-luminescent/dull faint minerals, coating, and inhomogeneous distribution of feldspars. Thin section analysis was performed using both optical and cathodoluminescence microscopy. The former indicates mineral origin, distribution and size with dominance of monocrystalline quartz grains that makes rock type classified to a typical quartz sandstone (arenite); the latter identifies blue- and dull cyan-luminescent quartz crystals and recognizes luminescent minerals centers. Three additional micro-samplings were performed for X-ray and scanning electron microscopy analysis on specific points of the profile for minerals and chemical elements. The method followed and dose profiles from the present buried sandstone, suitably discussed, provided an average date for at least two burial sun exposure histories of the fallen stone piece of around 46 ka and 71 ka before current era, providing a constrained terminus post quem for the exfoliated clast from the cave wall with petroglyphs. [ABSTRACT FROM AUTHOR]

Abstract The petroglyphs of Gobustan are an important historical source that allows us to get an idea about the material and spiritual culture of the population inhabiting the region in various historical periods. The analysis of the specific features of the creative process let us imagine how the ancient artists of Gobustan conveyed some aspects of their creative perception and specifics of their world view. In this respect, the "Firuz 2" shelter on Kichikdash Mountain in Gobustan is of special interest. "Firuz 2" lies at the foot of a vertically standing boulder oriented N-S. (stone №19). The archaeological site is located at the western side of this stone covered with petroglyphs. On this surface numerous female figures, images of hunters, animals and boats are fixed. Visual domination of images of female figures and boats make a uniform semantic plot. It should be noted that from Mesolithic and Neolithic occupation layers of Gobustan separate stones on which female figures near boats are also represented are found. It is quite possible that this composition is characteristic to this period. Images of female figures on stone №19 stylistically differ from each other and some of them are executed in profile with prominent bellies. Besides these, images of animals (aurochs, wild boars, onagers, gazelles, bezoar goats) were depicted on stone №19. Under the stone and on the north side, there is a strip of rocky blocks lying deep in the soil. On one of these rocks (stone 19-a), split in two parts, images of boats were recorded. The stone was found in the Neolithic layer. Images of boats of this kind are also registered on stone №19. On three of them the symbol of the sun is represented on the bow. In the Caucasian region, images of boats are only met in Gobustan rock art. Considering attentively these images of boats, can be supposed that they belong to the Neolithic period of Gobustan culture and existed throughout millennia. In order to get some chronological control, various methods were combined: analogies with stones found in cultural layers and bearing similar images, study of the stylistic features and the stratigraphic method. AMS dating of the cultural layers of the "Firuz 2" site allowed to understand the variability in the form and meaning of the petroglyphs of various periods. Previously, artifacts from the cultural layer of "Firuz 2" site had been dated to the end of Mesolithic and beginning of Neolithic period. The last AMS dating provided the result: 7850 ± 30 BP, which led to suppose that Gobustan was the earliest center in which navigation emerged in the Caucasian region. [ABSTRACT FROM AUTHOR]

Marking petroglyphs with chalk is a common practice to enhance them for documentation and reproduction. Although this procedure has started to be less frequently used, there is no knowledge about the interaction between the rock engravings nor about the effectiveness achieved by the common cleaning procedures of such markers considering the chalk extraction and the induced damage to the rock. This study evaluates the interaction between two chalks of different composition (calcite and gypsum) and a granite on which the majority of NW Iberian Peninsula-petroglyphs are carved. Granitic samples marked with these chalks were subjected to artificial rain events and high temperatures (700 °C) related to fires. After each aging test, chemical and physical modifications on the rock were analysed by means of stereomicroscopy, x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and colour spectrophotometry. Moreover, the evaluation of the effectiveness and harmfulness of several mechanical and chemical cleaning procedures commonly used in the field of cultural heritage conservation was carried out. Both chalks remained at different extent on the surface after the artificial rain events. Water would promote a different penetration-depth of the chalks into the stone, depending on their solubility. High temperatures led to mineral phase transformations of the chalks influencing the interaction with the rock. Regarding cleaning effectiveness, despite a few chalk remains were found in all the cleanings, chemical methods showed higher effectiveness than mechanical procedures even though some of them leave chemical contamination. Benzalkonium chloride can be considered as the cleaner with the best results to extract both types of chalk on granite. [ABSTRACT FROM AUTHOR]

• Digitalized JRC profiles ＆ engraving technology were used to prepare the same NRRSs. • Shear strength of the rock-CTB interface does not increase with surface roughness. • Damage evolution of the sheared rough rock-CTB interface were analyzed. • A new shear strength criterion of the rough rock-CTB interface was established. The shear behavior of the interface between rock and cemented tailings backfill (CTB) is extremely critical to the backfill design and stability of the backfilled underground mined-out areas. The corresponding shear behavior and surface damage can be significantly affected by the roughness of the rock surfaces. In our study, sandstone with the same rough surface were prepared using rock engraving technology. The direct shear tests on the rough rock-CTB interfaces were carried out under four different normal stresses and six different roughness of the rock surfaces. The interfacial shear strength and corresponding surface damage were analyzed. A new shear strength criterion of the rough rock-CTB interface was then proposed and verified. Our study shows that the compressive deformation of the combined specimen is much larger than that of dilatancy under a higher normal stress. The residual shear strength is less affected by the rock surface roughness under lower normal stress. The corresponding shear strength of the rough rock-CTB interface does not necessarily increase with the rock surface roughness due to the large strength difference between the sandstone and CTB. The interfacial damaged zones, which increase with the normal stress, are roughly concentrated in the larger concave section of the corresponding 2D profiles. The established shear strength criterion of the rock-CTB interface consists of basic mechanical and morphology parameters which can be easily estimated by the general laboratory tests. The findings obtained from this study can be used to quantify the effect of the rough rock-CTB interface on the stability of CTB. [ABSTRACT FROM AUTHOR]

The Nyingchi region is the best location to investigate the nature and evolution of the deep crust beneath the Lhasa terrane, as the middle and lower crust rocks are well exposed due to the long-term uplift and erosion of the Namche Barwa syntaxis. A systematic study of whole rock geochemistry and zircon U-Pb age and Hf isotope was conducted on granitic rocks exposed in the area. These data, combined with U-Pb ages and Hf isotopes of detrital zircons from river sands, were utilized to reveal the nature of the deep crust. The granitic intrusions in the area can be divided into two main stages, i.e., the latest Cretaceous to Eocene (67–44 Ma) and the Late Oligocene (28–23 Ma). The earlier stage of granitic rocks has SiO 2 contents of 67.65–75.22 wt% and exhibits highly variable zircon ε Hf (t) values ranging from −15.5 ± 1.3 to 9.2 ± 0.8, suggesting that they were derived from a remarkably heterogeneous source. The late stage of granitic rocks, with SiO 2 of 64.37–75.86 wt%, has zircon ε Hf (t) values ranging from 1.6 ± 1.3 to 3.9 ± 0.8, indicating that they were derived from a relatively homogenous and slightly depleted source. In combination with literature data, it is proposed that the Late Oligocene magmatism may prevail in the Lhasa terrane and this extensive magmatic pulse can be attributed to coeval delamination of the subducted Indian continent. [ABSTRACT FROM AUTHOR]

Shiny grooved rock surfaces found in archaeological sites are common across west Texas and the Southwest (U.S.). In most cases they are cursorily described, with very little in terms of detailed characterization and analysis. Interpretations regarding the meaning of the grooves include fertility rituals and functional use (e.g., bone tool or axe polishing), while the formation of the shiny surface has been attributed to lichen, foot or hand traffic, and hide or plant processing. In the Lower Pecos region (Texas), such remains are common in rockshelters. In several cases, there is only one such surface at a prominent location within the site, commonly associated with bedrock features (mortars, slicks, etc.). We used Structure from Motion (SfM) to document, characterize and analyze more than 700 elongated grooves and incisions concentrated on one shiny surface, at Skiles Shelter. All were mapped, and the larger grooves were also measured and studied using macro-lens and microscope photos. The direction and sequence of engraving were reconstructed, with evidence for most grooves and incisions being earlier than the shiny cover. The incorporation of small pits with the engravings was established. Although organic residues were retrieved from several bedrock features at the site, no distinct chemical signature was identified from the shiny surface. We could not ascertain the origin of the shiny crust, and based on other works and our observations we suggest that hand or foot traffic, hide working and plant fiber processing are the most likely explanations. [ABSTRACT FROM AUTHOR]

Composition and distribution of tricyclic terpanes, tetracyclic terpanes and hopane in crude oils from Tarim, Turpan, Ordos and Qaidam basins, NW China, were investigated, and some new source dependent parameters were developed and evaluated. C 19 and C 20 tricyclic terpanes are more abundant in terrigenous oils, with C 24 tetracyclic terpane dominant. Relatively higher carbon number tricyclic terpanes, especially C 23 tricyclic terpane, are often the dominant homologues in crude oils from saline lacustrine and marine sources. On the whole, the relative content of C 23 tricyclic terpane of crude oils follow the order of saline lacustrine oils > marine oils > freshwater lacustrine oils > terrigenous oils for C 19–23 tricyclic terpane. Some new parameters based on the tricyclic/hopane and tetracyclic/tricyclic terpane as well as tetracyclic/hopane ratios, could be used to distinguish the oils and source rocks with similar maturity deposited in different sedimentary environments. [ABSTRACT FROM AUTHOR]

The Kerguelen mantle plume triggered the rift of Eastern Gondwana to open the eastern Indian Ocean, with the formation of ~ 132 Ma Comei–Bunbury large igneous province (LIP). The Comei area is located in the eastern Tethyan Himalaya, paleogeographically belonging to Greater India. The Laguila bimodal intrusive rocks from the Comei area consist of mafic (gabbro-diabase) and felsic rocks (quartz monzonite-granodiorite). This paper presents detailed LA-ICP-MS zircon U-Pb chronology, major and trace elements, and Sr-Nd-Pb isotope geochemistry of the Laguila bimodal intrusive rocks, in order to constrain the early activity of the Kerguelen mantle plume. LA-ICP-MS zircon U-Pb dating shows that the Laguila intrusive rocks were emplaced in the Early Cretaceous (~ 134–130 Ma). The Laguila mafic rocks are enriched in LREE, LILE and HFSE, similar to those of oceanic island basalts (OIB). Their 87 Sr/ 86 Sr i (0.7054 to 0.7066), 143 Νd/ 144 Nd (T) (0.512548 to 0.512619) and ( 206 Pb/ 204 Pb) t ratios (18.492 to 18.859) are comparable with those basalts derived by the Kerguelen hot spot. Elemental and isotopic data suggest that they were likely derived by partial melting of the Kerguelen plume source in the spinel–garnet transition zone (~ 60–80 km). The Laguila felsic rocks share most of the geochemical features of A-type granite and show different 87 Sr/ 86 Sr i (0.7171 to 0.7204), 143 Νd/ 144 Nd (T) (0.511874 to 0.511956) and ( 206 Pb/ 204 Pb) t ratios (19.087 to 19.274) from those of the mafic rocks. They were likely derived by partial melting of crustal rocks at a shallow depth (< 30 km) triggered by underplating of the coeval basaltic magmas. The Laguila intrusive rocks were emplaced in a rift setting during the breakup of eastern Gondwana, associated with the Kerguelen plume activity. We calculated the magmatic volume of Comei–Bunbury basalts and the result is ~ 1.1 × 10 4 km 3 . The small volume is not reconciled with those typical models for the initial magmatic eruption of mantle plume. It was possible that the thick lithosphere (> 150 km) underneath Greater India prevented the Kerguelen plume from large-scale melting because of the high pressure when the latter impinged onto the former at ~ 132 Ma. The shallow source (~ 60–80 km) of the Laguila mafic rocks indicate that they originated likely from a series of “diapirs” or “fingers” rising from the head of the Kerguelen plume, which penetrated into the thick lithospheric mantle of Eastern Gondwana at enough shallow depth for melting. [ABSTRACT FROM AUTHOR]

The Dampier Archipelago (properly known as Murujuga ) is a rich rock art province in north-western Australia which documents an arid-maritime cultural landscape. But this Archipelago of 42 islands has only existed since the mid-Holocene. When people started to engrave art here, the granophyre bedrock was part of an inland range, more than 160 km from the coast. The Pilbara archaeological record demonstrates human responses through over forty thousand years of environmental change. This paper discusses how rock art across Murujuga can give insights to changing dynamics of people in place as well as depicting major environmental change. A predictive model is developed to assist in understanding the social changes which have been wrought by sea-level rise and consequential environmental changes. [ABSTRACT FROM AUTHOR]

Cet article s'inscrit dans une série de résultats de recherche que nous avons développés dans le cadre de la préparation d'une Thèse de Doctorat en cours, sur l'occupation humaine dans la haute vallée de l'Oued Sayyad durant le Néolithique et la Protohistoire. Ces résultats consistent dans la découverte de nouveaux sites de gravures rupestres dans la région de Tainzert, sur la commune de Taghjijt, dans la région de Guelmim (Maroc). Ces sites contiennent un nombre important de gravures de divers sujets, des tumulus préhistoriques, des abris et des découvertes archéologiques notamment de l'industrie lithique. Cet ensemble de découvertes peut ajouter de nouvelles données archéologiques sur l'histoire de la région et l'histoire du Maroc en général. This article is part of a series of research results that we have developed in the context of the preparation of a PhD thesis on human occupation in the upper valley of the Oued Sayyad during the Neolithic and Protohistory. These results consist in the discovery of new rock engraving sites in the region of Tainzert, in the commune of Taghjijt, in the region of Guelmim (Morocco). These sites contain a large number of engravings of various subjects, prehistoric burial mounds, shelters and archaeological finds, notably of lithic industry. This set of discoveries can add new archaeological data on the history of the region and the history of Morocco in general. [ABSTRACT FROM AUTHOR]

Des gravures rupestres en provenance de la Tunisie centrale (Jebel Ousselat) et centro-méridionale (la région de Gafsa) montrent des ovaloïdes, de types et de morphologies divers, isolés ou associés à des animaux sauvages et domestiques, principalement des béliers ornés. Nous examinons ici, ces cas d'associations et nous proposons quelques interprétations. Rock art engravings discovered in the central (Jebel Ousselat) and centro-southern Tunisia (Gafsa region), show ovaloids of various types and morphologies associated with wild and domestic animals mainly ornate rams. We examine here these cases of associations and propose some interpretations about. [ABSTRACT FROM AUTHOR]

Abstract: While not well-known or well-studied, Grenada's (Caribbean) Carib Stones host over 100 individual petroglyphs (rock engravings) representing some of the Caribbean's best examples. Two sites were assessed for this study: Duquesne Bay along the northwest Caribbean coast and Mt. Rich in the northern tropical rainforest. Their importance notwithstanding, little has been done to manage or assess the Stones other than basic glyph recording. This study employed the Rock Art Stability Index (RASI) to assess and document each panel's overall geologic stability. Using more than three-dozen rock decay elements, RASI represents an efficient and rapid tool to assess petroglyphs and pictographs, assigning an “Excellent–Good–Problems–Urgent Danger–Great Danger–Severe Danger” ranking based on a quantitative score. Overall, 13 panels were assessed individually, with a few exhibiting “Good” status, two in “Great Danger”, and the remaining exhibiting “Problems”. Analyses show the Duquesne Bay site remains at the behest of its proximity to water, such as stagnating puddles, waves, or storm and household runoff. In contrast, the Mt. Rich site receives substantial rainfall and remains under rainforest canopy, yet is significantly more stable. This research demonstrates the need for further monitoring efforts and lays the groundwork for continued study and assessment of the Carib Stones, while at the same time raising their profile to the international stage in hopes of securing greater recognition ultimately leading to better management practices. [Copyright &y& Elsevier]

Abstract: The Burrup Peninsula and surrounding Dampier Archipelago, in Western Australia, contain the world's largest known gallery of rock art engravings (petroglyphs), estimated to number up to 1 million images. The peninsula is also the site of major industrial development and there are concerns that industrial emissions may adversely affect the stability and longevity of the rock art. We have studied the natural processes and rates of weathering and erosion, including the effects of fire, that affect the stability of rock surfaces and hence the longevity of the rock art, using cosmogenic nuclides. The concentration of 10Be in quartz yields erosion rates in the range 0.15–0.48 mm/1000 years on horizontal rock surfaces and 0.34–2.30 mm/1000 years on vertical rock faces. The former, largely caused by mm-scale surface flaking, are amongst the lowest erosion rates measured by cosmogenic nuclides anywhere in the world. The latter are inferred to represent a combination of mm-scale flaking and very rare centimetre- to metre-scale block falls, controlled by failure along joint planes. Such low erosion rates result from a combination of resistant rocks, low relief and low rainfall, favouring long-term preservation of the petroglyphs – long enough to encompass the known period of human settlement in Australia. [Copyright &y& Elsevier]

This article considers public decision involving conflicting values and interests by presenting a case (Portugal, 1990s) where the construction of a dam already under way following an Environmental Impact Assessment procedure (EIA) was abandoned in order to preserve prehistoric rock engravings. The Foz Côa case illustrates the methodologies currently adopted under European Union law in the support of public decision concerning large infrastructures with significant impact on the environment and/or the cultural heritage, highlighting their limitations when confronted with the complexity and the plurality of values commonly at stake in such circumstances. We assume that the reasonableness of a public decision is meant to emerge from a process through which the various and conflicting reasons for acting are brought together, implying the opening of ends, and not only of means, to discussion and inquiry, a deliberative perspective which is put in contrast with the monistic methodologies supporting public decision-making under the EIA procedure. Some broader lessons may be drawn from the analysis of this case, we argue, regarding the conditions under which a regulatory system should tackle the diverse and conflicting values involved in public decision that affects today's highly-prized values like the environment or the cultural heritage. [Copyright &y& Elsevier]

Abstract: A group of methyltrimethyltridecyl chromans (MTTCs) was found in core samples of Member 1 (K2n1) and Member 2 (K2n2) of the Nenjiang Formation (Upper Cretaceous) from the SK-l southern borehole (Songliao Basin, China). They are assigned for the first time in sediments older than the Tertiary in China. Their composition and distribution are indicative mainly of the redox and salinity conditions in the depositional environment. The δ-MTTC isomer is in relatively higher abundance in samples from enhanced salinity and reducing conditions, but was not detected in samples from aerobic and low salinity environments, while α-MTTC appears to be present in samples from environments with a broad range of salinity and redox conditions. The α-MTTC/γ-MTTC (α/γ) ratio has a similar indication as that of the α/δ ratio and could be used as a corroborative ratio of paleosalinity. A combination of biomarker parameters suggests that the massive lacustrine petroleum-prone source rocks associated with the K2n1 interval were likely developed under a stratified water column with enhanced salinity and an anoxic bottom water layer, associated with a much less saline (fresh to brackish) upper water layer. [Copyright &y& Elsevier]

Abstract: In April 2009, a new rock art site was discovered in Libya. Kaf Tahr is situated in Cyrenaica, in the Djebel Akhdar (the “green mountain”). This new site with engravings displays several interests. Firstly, it is only the third rock art site discovered – or at least published – in Cyrenaica. Secondly, this rock shelter is the only one that had shown engravings belonging to at least two different chronological periods, the first one being very probably prehistoric, and the second, post-prehistoric. Finally, the engraving of a man (with a sword and a shield) and the engraving of a horse are the first discovered in the area. These two engravings could have been realized in the protohistoric period. This period is well-known in the Libyan Fezzan (“libyco-berberian period” or “horse period”) but it has never been defined in Cyrenaica. Owing to the lack of research, the long period separating the end of Prehistory from the beginning of the greek colonization is hitherto totally unknown. If these engravings would belong to this period, they would be the first elements attesting of a metal work and a horse domestication in Cyrenaica before the historic period. [Copyright &y& Elsevier]

Abstract: Lithic microwaste (<1mm in maximum dimensions) is produced during lithic tools and rock engraving manufacture. For tools or rocks containing quartz, small particles persist as microwaste initially on the ground surface but later at least some particles are incorporated into sedimentary deposits associated with the occupation site. If microwaste is distinguished from naturally occurring sediments, then optical dating of microwaste or its surrounding sediment would provide a mechanism for establishing a terminus-ante-et-post-quem for archaeological deposits. Identification of microwaste is undertaken by comparing the shape of microwaste particles with those from surface sediments, taking particular note of angularity and irregular shapes; and by analysing quartz grain surface morphologies. On the basis of surface features identified on experimental microwaste, particles identified as microwaste are separated from the sedimentary grains. Scanning electron microscopy and light microscopy are used to determine surface differences between pedogenic grains and anthropogenic material from archaeological deposits. Single-grain OSL dating technique is then employed for age determinations for particles identified as microwaste. It has been noted in previous research that microwaste particles may lie within or close to the age boundaries of the surrounding sediments but not necessarily where larger lithic material is found. Microwaste is incorporated into sediment and is not subjected to the same degree of movement as larger lithic waste and stone tools within the deposit. The advantage of dating microwaste directly by OSL is that it removes ambiguity about archaeological association. Archaeological events can be dated directly and correlated with sediment ages from surrounding environments, regardless of post-depositional processes. Sand grains surrounding artefacts are dated, usually leaving open the question of the association of the artefact to the sedimentary level, as the artefact may have been displaced from its original depositional level. [Copyright &y& Elsevier]

Abstract: The site of Abourma, situated in the mountains of Makarrassou, is the most important site known in the Republic of Djibouti. It has yielded almost 3 km of rock carvings, which essentially comprise of wild and domesticated animals, beasts which are in common with all the rock engravings of the region. However, Abourma has revealed other much rarer scenes. This is where men appear. The hunting scenes are numerous, varied and sometimes very detailed. The most exceptional are the scenes of men fighting where the archers are facing each other and the scene where the men form a circle around a cow. The men of Abourma add some life to the rock carvings of Djibouti with scenes of significant acts. They shed some innovative light onto certain aspects of the past cultures of Djibouti, of which we have found a number of traces. [Copyright &y& Elsevier]

Abstract: Three hundred thousand rock engravings show the history of the population which lived in an Alpine valley for 10,000 years. The decoding of the pictures introduces us to the world of myths and beliefs, in the thinking of a society which evolved from the Epipalaeolithic to the Iron Age in Europe. [Copyright &y& Elsevier]

Abstract: More than 100,000 graphic signs, of which 40,000 are figurative, were carved on around 4000 rocks in the mont Bego region, in Tende, in the southern Alps, approximately 80 km north of Nice (Alpes-Maritimes). These carved rocks are dispersed at an altitude of 2000 to 2700 m in the high valleys surrounding mont Bego and are regrouped in seven different sectors: the Merveilles valley, Valaurette, val de Fontanalba, val de Sainte-Marie, Valmasque, col du Sabion and the Vei del Bouc lake. The daggers, halberds and axes represented by these carvings make it possible to attribute them to Chalcolithic cultures, like the Remedello, or to early Bronze age cultures, like the Polada or the Rhodanian, and to date them between 3300 and 1800 years BC. Among the 40.000 figurative carvings, very few iconographic themes are represented: corniculates (about 70% of all figurative carvings), harnesses (2.9%), daggers (about 5.4% of all figurative carvings), halberds (1.1%), axes (0.08%), reticulates (5.5%), rectangular or oval shaded zones (6.9%) and several rare anthropomorphous figures. The consistency of the techniques and of the iconographic themes shows that these carvings were not carried out at random. They correspond to a conception of the world, transmitted from generation to generation by way of a graphic code. These representations are in fact ideograms: by carving signs and symbols, these Chalcolithic and Bronze Age populations depicted real or imaginary objects and by combining them, they created ideas in relation to the natural or supernatural world. The rock carvings of the mont Bego region correspond to a symbolic language inscribed in stone at the end of the fourth millenium and throughout the third millennium BC., by the first metallurgic settlers in the southern Alps. The ideograms were thus inscribed on rocks polished by Quaternary glaciers in the sacred Bego mountain. These carvings, the works of agricultural and pastoral populations in the southern Alps during the Chalcolithic and the ancient Bronze age, translate not just the daily preoccupations of these populations who needed rain, sources and lakes in order to fertilise their fields, but also their cosmogonic myths. At the centre of these myths are the bull god, brandishing lightning, master of the storm and provider of fertilising rain, and the high goddess, mother goddess or goddess earth, who needs to be fertilised herself by rain from the sky in order to bring abundance to humans. [Copyright &y& Elsevier]

Abstract: San rock paintings in the Cape, South Africa, are residual but readable images that contain some intentionally ambiguous figures. Male and female figures were almost never ambiguous at the time of painting but many have become so, after much loss of detail. The boundary between animals and people, by contrast, is often ambiguous with therianthropic, animal-headed human figures quite commonly depicted. These decisions are rooted in a world view that is well documented in San folklore and ethnography. [Copyright &y& Elsevier]

• Performance of smartphone photogrammetry (SP) for rock joints was comprehensively evaluated. • Five laboratory-sized rock joint specimens were selected and operated by 24 experimenters for SP. • SP can be applied to achieve acceptable accuracy and precision of joint roughness measurements for engraving rock and replica rock joints. • The applied SP tends to underestimate the joint roughness of rock joint specimens. The roughness of rock joint surfaces plays a vital role in the hydrological and mechanical properties of discontinuous rock masses. Applicable and reliable measurements are important for investigating the roughness characterization of rock joints. This research comprehensively evaluates the performance of smartphone photogrammetry for rock joints through a roughness characterization method. Five laboratory-sized rock joint specimens were selected and operated by 24 experimenters to assess the trueness and precision of smartphone photogrammetry based on Structure from Motion- Multi View Stereo (SfM-MVS) photogrammetry technique. Benchmark data from a structure light scanner were used to assess the usability of smartphone photogrammetry through the directional roughness metric method. The results show that it can be applied to achieve acceptable trueness and precision of joint roughness measurements for engraving rock and replica rock joints with no reflective or translucent materials. In addition, the roughness errors of the subsampled models with point intervals of 0.25 mm, 0.5 mm, and 1.0 mm are close to each other. [ABSTRACT FROM AUTHOR]

Abstract: Desert varnish of pristine sandstone and petroglyph surfaces from Takabart Kabort (Naturalistic Bubaline Art School) and Alamas (Tanzina Art School) can be well classified by their (SiO2+Al2O3):MnO2, Al2O3:SiO2, and P2O5:CaO ratios. Specific ratios are due to the occurrence of clay minerals like illite, kaolinite, smectite, and feldspar, quartz, carbonates like calcite and dolomite, manganese oxyhydroxides, and apatite. Their occurrence corresponds to the local origin and composition of the primary aeolian material. In general, the analyzed desert varnish shows lamination patterns characterized by alternating MnO2-rich and -poor layers (⩽25wt% MnO2) at rather constant iron oxyhydroxide content (6wt% Fe2O3). Varnish on non-engraved surfaces exhibits three MnO2-rich layers, whereas varnish-coated petroglyphs reveal minor lamination patterns corresponding to the dating of petroglyphs by rock art. The older Naturalistic Bubaline Art School petroglyphs (about 6–4kaBP) and the younger Tazina Art School petroglyphs (about 3.8–3kaBP) contain only two and one MnO2-rich layer, respectively. It is assumed that the occurrence of such microlaminations is caused by climate changes in North Africa. Three humid periods are discerned from the Terminal Pleistocene to Holocene in the literature. Such periods are suitable to induce manganese accumulation by biotic and abiotic processes. Accordingly, the distinct lamination patterns gained from this study verify the dating of petroglyphs by rock art. From another point of view, classification of the above petroglyphs may be provided by analyses of microlaminations independently on cultural historical aspects. [Copyright &y& Elsevier]

Abstract: Intermediate to acidic porphyries and dacites in the Awulale and Sanchakou area of the Xinjiang Tianshan region, China, conform to the definition of high-SiO2 adakite (HSA). These volcanic or subvolcanic rocks are characterized by high Na2O (Na2O>K2O), high Sr/Y (51–327), and strong depletions in HREE and HFSE (Nb, Ta, and Ti). Despite these characteristics, they are distinct from a suite of adakites in the same area that are inferred to be derived from partial melting of subducted slab. Differences between the two suites are evident mainly in their rock association, isotopic ages and compositions of Sr and Nd isotopes. The subducted slab-related adakites are associated with common island arc rocks, niobium-enriched basalt (NEB) and high-Mg andesite (HMA), formed in the late Carboniferous (320–334 Ma) and are characterized by relative high ɛ Nd(t) (+3.4−+11.6) and low (87Sr/86Sr) i ratios(0.7032–0.7063). In contrast, the Awulale and Sanchakou adakites were generated during the middle to late Permian (260–278 Ma), possess a wide range of low ɛ Nd(t) (+0.75−+5.69), a greater range of (87Sr/86Sr) i (0.7039–0.7054) and have young Nd model ages (T 2DM 472–699 Ma). In addition, their Mg# (35–56) and compatible element contents (MgO=0.93–2.22 wt.%; Cr=4.95–16.41 ppm; Ni=2.9–25.8 ppm) are relative low compared to the subducted slab-related adakites(Mg#=55–71; MgO=1.22–6.78 wt.%; Cr=24–132 ppm; Ni=2.28–45.61 ppm). Based on these characteristics, the regional association of igneous rocks, and evidence from a global geoscience transect (GGT), the Awulale and Sanchakou adakites represent a genetically distinct suite in the Xinjiang region. We proposed that the source of these adakites was basaltic rock underplated to the base of the lower crust, that partial melted at the rutile-bearing amphibole-eclogite facies (>650 °C and 1.5 Gpa minimum pressure (≥50 km)). [Copyright &y& Elsevier]

Abstract: Solubilities for a wide range of siderophile elements (SE: Ni, W, Re, Ir, Os, Pt, Rh) have been determined in a haplobasaltic melt composition (An42Di58) using the mechanically assisted equilibration (MAE) technique. Here we present a review of the data obtained and the experience gained over the past decade using this approach. In particular, the major experimental and analytical challenges encountered (and inferred to result from so-called “nanonugget” formation) are described. After a general background overview of siderophile element solubility experiments, the experimental (MAE) and analytical techniques are described. Major element composition was routinely determined by electron microprobe analyses (EMP), whereas trace elements were determined using a wide variety of analytical techniques (Ni, W: INAA, EMP, ICP-AES; Re, Ir, Pt, Rh and Os: INAA, SIMS, dissolution- (diss-ICPMS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS)). The last technique, in particular, has demonstrated its powerful capabilities for micro-analyses, supplying information on both absolute trace element concentrations and on small scale heterogeneities in run products. All investigated SEs exhibit solubilities whose systematic variation with oxygen fugacity (fO2) is consistent with their presence as stoichiometrically dissolved oxide species in the melt phase. There is no indication of zero-valence species dissolved at any fO2 condition. In the case of highly-SE (HSE: Pt, Rh, Re, Os, Ir), INAA results appear to indicate a decrease of HSE solubility with decreasing fO2 down to a fO2 limit which depends on the investigated HSE. Below this limit, bulk HSE concentrations remain either constant with large variations or increase with further fO2 decrease. Duplicate analyses of samples by LA-ICPMS reveal increasing amounts of so-called nanonuggets with decreasing fO2, which lead to high HSE concentrations in the glass samples obtained by bulk analytical methods such as INAA. The formation of HSE (and potentially some SE) nanonuggets in low fO2 samples raises the question of whether nanonuggets are formed either during the quench by precipitation from precursor species dissolved homogeneously in the melts, or are precipitated in situ at high temperature due to true thermodynamic oversaturation. The combination of the MAE technique with LA-ICPMS micro-analytical methods has enabled us to extend our knowledge of the solubility behaviour of HSE to unprecedentedly low fO2 values. Clarification of the solubility mechanism for SE as well as the nanonugget issue, however, will undoubtedly require further novel experimental designs. [Copyright &y& Elsevier]

Abstract: Sedimentary rock samples from the Ypresian Basin, in central-northern Tunisia, were analyzed by two well-proven organic geochemical methods: Rock-Eval (RE) pyrolysis and gas chromatography–mass spectrometry (GC–MS) analysis. These techniques were uses to obtain independent parameters on organic matter composition, its thermal maturity, and environment of deposition. This study reveals a close concordance between Rock-Eval pyrolysis data and polycyclic biomarkers parameters such as hopanes and steranes. RE pyrolysis in conjunction with GC–MS analysis show that the Ypresian Basin sediments contain a variable but notable organic-rich facies during the Ypresian and prove an unequivocal evidence for Type-II organic matter, which lies dominantly prior to the peak stage of the conventional oil window (end of diagenesis-beginning of catagenesis). The case study from the Ypresian Basin shows that these methods remain undoubtedly suitable for a good assessment of the petroleum potential of source rocks and rapid geochemical characterization of sedimentary organic matter. [Copyright &y& Elsevier]

Abstract: Analyses of hundreds of rock varnish samples from latest Pleistocene and Holocene geomorphic features in the drylands of western USA reveal a regionally replicable Holocene microlamination sequence. This sequence consists of 12 approximately evenly spaced weak dark layers intercalated with 13 orange/yellow layers. Preliminary radiometric age calibration indicates that six dark layers in the upper portion of the sequence were deposited during the last 6000 yr, diagnostic of the Little Ice Age and late Holocene wet events; five dark layers in the lower portion of the sequence were deposited after the termination of the Pleistocene but slightly before 7000 YBP, indicative of the early Holocene wet events; and one dark layer in the middle portion of the sequence was deposited around 6500 YBP, suggestive of the middle Holocene wet phase. Our age calibration further indicates that the Holocene wet events represented by the dark layers largely correlate in time with the millennial-scale Holocene cooling events in the North Atlantic region. This radiometrically calibrated and climatically correlated Holocene microlamination sequence was then used as a unique correlative dating tool to determine surface exposure ages of geomorphic and geoarchaeological features in western USA deserts. The varnish microlamination (VML) dating of debris flow fan deposits in Death Valley, California, yields minimum ages of 12,500, 12,500–11,100, 11,100, 10,300, 9400, and 2800 YBP for six debris flow fan building events, suggesting that such events were more likely to have occurred during relatively wet periods of the Holocene. The VML dating of a prehistoric grinding stone from Chili of northern New Mexico yields a minimum age of 900–1100 YBP for the abandonment of this occupation site by the Anasazi Indians. The VML dating of a prehistoric flaked stone (a primary core) from Ocotillo, southern California, yields a minimum age of 12,500 YBP for the flaking of this stone artifact, suggesting at least a Paleo-Indian human occupation at Ocotillo during the terminal Pleistocene. These results indicate that, when properly applied, the VML dating technique has the great potential to yield numerical age assignments for surface stone tools, petroglyphs, and geoglyphs of prehistoric age in the drylands of western USA. [Copyright &y& Elsevier]

Abstract: The semiological study of a set of rock engravings such as the one in the Haut Atlas would consist in studying the graphic elements within their context to determine their mutual relations, because such relations are meaningful. Some details could be signs to which we could attach a conventional meaning. But, being unable to identify these conventional signs by their meaning, we must look for similarities between the figures themselves. Indeed, the repetition of some relations will provide constitutive elements of the global meaning. Unfortunately, ignoring the relative positions of the figures, I can only give some indications about what such a study should entail. So, I focus on one hand on the attributes of the figures, which are, in any case, identity marks, and on the other hand, on the context of the figures, that is the graphics around the figure, in order to outline the likely semantic field and the actions, actual or symbolic, in which they are involved. [Copyright &y& Elsevier]

Abstract: The continental carbonate deposits of the Zarand Basin were deposited within an intra-continental strike-slip basin situated in the northwestern corner of central Iran. They consist of distal alluvial mudstones to marlstones, carbonate pond deposits, carbonate and siliciclastic-infilled channels, and lacustrine carbonates deposited within a distal alluvial–lacustrine–palustrine complex. Both sedimentological and palaeontological evidence suggest that these sediments mostly formed within an open hydrological system. The common presence of root traces, greyish green mudstones, calcareous nodulisation, mottling, and desiccation breccias indicate a palustrine setting. The carbonate deposits of the Zarand Basin were formed under an overall semi-arid climate but periods of more aridity characterised by extensive calcretization can be distinguished in the stratigraphical sections. Both tectonics and climate have contributed in controlling the sedimentation of the Zarand Basin. Archaeological and geomorphological evidence provides a unique sub-recent analogue for ancient palustrine limestones developed within an intra-continental basin under a semi-arid climatic regime. The combination of geological and archaeological data and their comparison with historical documents show that the so-called historical lake of Saveh was the remnant of the more ancient wetland system which dominated the Zarand region during the late Quaternary. [Copyright &y& Elsevier]

Abstract: Many rocks are representative of inclusion–matrix systems where rigid inclusions float on a ductile matrix. The geological analogues of such inclusion–matrix systems are theoretically modelled with the help of Jeffery''s (1922) theory. In recent years, there have been a number of reinvestigations on the rotational motion of rigid inclusions to account for some geological observations that are not yet predicted in models based on Jeffery''s theory. Adding to this effort, this paper investigates the effects of (1) inclusion concentration and (2) the degree of coherence at the inclusion–matrix interface on the rotation behaviour of rigid inclusions in a multiple inclusion system during simple shear deformation. Shear-box experiments were run on models containing multiple, identical elliptic cylinders of wax mimicking rigid inclusion embedded within putty representing ductile matrix. Two sets of experiments were performed, with and without lubrication at the inclusion–matrix interfaces. Each model had an isolated inclusion to reveal the variation of rotations of single and multiple inclusions. Increase in inclusion concentration (α) results in contrasting rotation behaviour of isolated and multiple inclusions initially oriented parallel to the shear direction. When the interfaces were not lubricated, inclusions in multiple association rotated antithetically, whereas the isolated one almost remained stationary. In models wherein the inclusion–matrix interfaces were lubricated with liquid soap, both isolated and multiple inclusions rotated antithetically, but the isolated inclusion rotated at a lower rate. With increasing inclusion concentration, the difference in the rates of antithetic rotation between isolated and multiple inclusions tended to be larger in both lubricated and non-lubricated conditions. The sense of rotation of isolated as well as multiple inclusions, initially oriented perpendicular to the shear direction, was always synthetic irrespective of the nature of the interface (lubricated or non-lubricated); however, the instantaneous rotation rates of inclusions in multiple association were higher than that of the isolated inclusions disposed in the same orientation. Rotation of inclusion in an inclusion–matrix system is basically induced by the traction exerted by the flowing matrix on the surface of the inclusion during deformation. Employing a hydrodynamic model it is shown that mutual mechanical interaction among inclusions, which is a function of inclusion concentration (α), modifies the stresses at the inclusion–matrix interface to a large extent. Moment calculations reveal that inclusions oriented parallel to the shear direction experience an antithetic moment in response to the normal stress components, the magnitude of which increases with increasing inclusion concentration. This implies that rotation of shear-parallel inclusions in antithetic sense is favoured by higher inclusion concentration. On the other hand, inclusions oriented perpendicular to shear direction experience a moment that induces synthetic rotation. The magnitude of the synthetic moment is larger for larger inclusion concentration leading to increase in the rate of synthetic rotation. Using the theoretical model, the moments are calculated as a function of the aspect ratio of inclusions and the inferences based on this moment calculation are complemented with experimental findings. [Copyright &y& Elsevier]

About 30 years ago a rock shelter with engravings by early settlers was found at Montalvaˆnia, northern end of state of Minas Gerais, Brazil. Lower part of engravings was covered with thin deposit of calcite mixed with quartz grains, due to occasional flood. This mixture of two minerals was dated by thermoluminescence and electron paramagnetic resonance using in both cases, additive method. The accumulated dose DAC, that is, natural radioactivity and cosmic rays radiation dose that induces TL and EPR signal intensity has been found to be around 50 Gy both by TL and EPR methods. The annual radiation dose rate was estimated to be about 1.027 mGy/a from knowledge of uranium, thorium and potassium content determined by inductively coupled plasma-mass spectrometer system.The age of this calcite plus quartz deposits was estimated to be about 50 ka. [Copyright &y& Elsevier]

The Gemigaya petroglyphs, in the area of Nakhichevan, are very important historical monuments. They are the only known ones of the ancient periods, dated from the IVth to the Ist millennium, and they constitute the main source for the scientific study of the creation and evolution of art in that area. The Noah’s myth attests the development of close relations with the civilization centers of the Near East at that time. [Copyright &y& Elsevier]

The devitalization of lithobionts prior to their removal from engraved rocks is a common conservation practice periodically undertaken in rock art sites. In this study, we assessed in situ the efficacy of three traditional biocides and of an innovative microwave heating system, and compared different application protocols to devitalize foliose and crustose lichens and a cyanobacteria-dominated biofilm on the rock engravings of Valle Camonica (UNESCO site n.94, Italy). The analysis of their vitality and stress responses by monitoring chlorophyll a fluorescence parameters (F v /F m , F 0 , OJIP transient) showed that the common application of biocides by brush is rather ineffective, particularly in the case of the resistant crustose lichens. The heating of rock surfaces to 70 °C for a few minutes by the microwave system caused devitalization of lithobionts to a similar extent as the biocide application with cellulose poultice, which, however, introduced high amounts of chemicals in the environment. The microwave irradiation overcame any lithobiontic stress resistance and avoided useless or excessive spread of biocides, appearing a promising sustainable approach for the parallel conservation of rock art and its surrounding natural environment. • The efficacy of three biocides and a microwave (MW) heating system was assessed. • Poultice application of biocides devitalized lichens and a cyanobacterial biofilm. • MW heating to 70 °C accomplished the same effect avoiding the use of chemicals. • The application of biocides by brush was ineffective against lichens. [ABSTRACT FROM AUTHOR]

Historical relics of Jurassic sandstones in southwest China have been subjected to weathering damage. Exfoliation, characterized by the detachment of multiple thin stone layers sub-parallel to the stone surface, is common in sandstone heritage sites. However, its mechanism of action remains poorly understood. In this study, a conceptual model of exfoliation is drawn from the literature and field investigations. To quantitatively determine the exfoliation mechanism, a range of non-destructive field-based methods (surface hardness, water absorption test, roughness, and amplitude of residual spalling layers) and laboratory analyses (scanning electron microscopy (SEM) and X-ray diffraction (XRD)) are adopted as weathering agents for separated detachments. In addition, the grain and pore sizes of weathering products are analyzed using digital image techniques. The results show that the roughness, water absorption coefficient, and pore size in sandstone surfaces increase from the inner layer to the outer layer, and their hardness and grain size decrease, respectively. The proportions of quartz, dolomite, and illite increases from the interior to the exterior, whereas the proportion of feldspar decreases correspondingly. The residual column strip structure derived from feldspar alteration and a mixed montmorillonite-illite mineral layer can be observed in the SEM images. It can be inferred from surviving environmental analysis that comprehensive actions from solar radiation, acid rain attack and capillary rise lead to sandstone exfoliation. In addition, the alteration of feldspar plays an important role during sandstone exfoliation. The results of this study enhance our understanding of the exfoliation of the Jurassic sandstone of the Chongqing Danzishi rock carvings in China. • Exfoliation was comprehensive studied and its mechanism was quantitatively revealed. • Roughness, water absorption coefficient and pore size increase from the inner layer to the outer layer, and hardness, grain size and propotion of feldspar decrease correspondingly. • Comprehensive actions from solar radiation, acid rain attack and capillary rise lead to sandstone exfoliation. [ABSTRACT FROM AUTHOR]

The recently explored sites, Kandhanthi and Mekala benchi are situated in the western part of the Kurnool district of Andhra Pradesh, South India. This is considered to be one of the richest archaeological hubs in the world of the primitive man activities. Substantial Rock Art in the form of petroglyphs, stone tools, and potsherd discovered in these sites dates back to Neolithic, Megalithic and Historical periods indicating the cultural continuity of the human race. However, the main aim of the present investigation is to record the socio-cultural profile and communicative activities of the early man. It also attempts to study the Geo-Archaeological implications of the area. The primitive man and his palaeo-art activities can well be established by knowing the geological and environmental history of the archaeological sites. This work also assayed to inter-relate the socio-cultural conditions of the primitive man activities to the present human activities at and around the investigated sites. Hence, this paper attempts to document the historicity of the newly explored sites in archaeological, ethno-archeological, and geological perspective. [ABSTRACT FROM AUTHOR]