Thin Section Samples Research Articles

EARLY METAL AGE POTTERY FROM FATU AKI ANIK KNUA, TIMOR-LESTE AND THE APPEARANCE OF CERAMICS IN THE WALLACEAN ISLANDS SUPPLEMENTARY FILE 5: FAAK THIN SECTIONS CATALOGUE

This catalogue presents a record of the preliminary petrographic analysis of 21 thin section samples from the Faak Cave and Faak Open Site. It also includes an unpublished report by Dickinson (2011) that has been referred to in the main text: Summary Petrographic Evaluation of Temper Sands in Protohistoric Sherds from East Timor.

Comparison of digital image analysis methods for morphometric characterization of soil aggregates in thin sections

The purpose of this study was to investigate the applicability of semiautomatic segmentation methods for obtaining and evaluating morphometric parameters of soil aggregates in artificially prepared loose samples in soil thin sections. The object of the research is typical arable Chernozem. The aggregates were separated by wet sieving method from loose sample of upper 10 cm of the plowing horizon after erosion by a model shallow water flow on a large erosion tray. The aggregates, loosely scattered on the glass and fixed with polyester resin, were used to produce the thin sections. Images of the thin sections were taken under a polarizing microscope and then were processed using two methods compared: Adobe Photoshop + CTan and Thixomet Pro. Data on morphometric parameters of aggregates were obtained: the shape factor, the degree of roundness and the coefficient of aggregate surface roughness. The convergence of the results obtained using Photoshop + CTan by three researchers was evaluated by comparing samples using the Student's test and the Mann-Whitney test. The convergence of the averaged results obtained using Photoshop + CTan and the results obtained using Thixomet Pro was evaluated using the Mann - Whitney test. No significant differences were found between the parameters of the same aggregates obtained using a combination of Adobe Photoshop and CTan programs by different researchers. No significant differences were found between the parameters of the same aggregates obtained by the compared methods. So, one can conclude that the reliability of determining the morphometric parameters of soil aggregates using Thixomet Pro is comparable to the reliability of results when working with images of sectionsin CTan after binarization in Adobe Photoshop. The method of obtaining data on morphometric parameters of soil aggregates using Thixomet Pro completely eliminates the possibility of subjective error, shows a high degree of automation, reproducibility and reliability of the results obtained, and is faster.

Quantitative determination of the shock stage of L6 ordinary chondrites using X-ray diffraction

Abstract The shock stages of 14 L6 ordinary chondrites are estimated using the random X-ray diffraction patterns of polished thin section samples and the in-plane rotation method. The mean lattice strains and grain size factors for olivine and orthopyroxene are determined from the analyses based on the Williamson–Hall plots, which depict the tangent Bragg angle and integral breadth β. The lattice strain in olivine, eOl, is distributed from ~0.05% to ~0.25%, while that in orthopyroxene, eOpx, is distributed from ~0.1 to ~0.4%, where we selected the isolated peaks of olivine and orthopyroxene. The olivine peaks have Miller indices of (130), (211), (222), and (322), while the orthopyroxene peaks have Miller indices of (610), (511), (421), (631), and (12.1.2). The intercept for integral breadth β0O1 and β0Opx for the Williamson–Hall plots correlates with the grain size of the constituent minerals. The grain size is proportional to the inverse of β0 since the β intercept increases with the shock stage. Introducing a new parameter, –ε/log β0 for olivine (0.04–0.16) and orthopyroxene (0.07–0.32) reveals a clear relationship between them: –εOpx/log β0Opx = –0.01+ 2.0 (–εOl/log β0O1) (R > 0.9). In addition, the isolated peak of plagioclase (201) systematically changes as the shock stage increases, suggesting the progress of amorphization (maskelynitization). Another parameter, (I/FWHM)Pl(201) reveals additional relationships: –εOl/log β0O1 = 0.14(±0.01) − 5.2 × 10−5 (±5.7 × 10−6) × (I/FWHM)Pl(201), and –εOpx/log β0Opx = 0.25(±0.04) − 8.9 × 10−5 (±2.6 × 10−5) × 10–5 × (I/FWHM)Pl(201). These three parameters systematically change with the shock stage, suggesting that they are suitable shock barometers. The present method is useful to evaluate the shock stage of L6 chondrites and potentially enables quantitative shock stage classification for stony meteorites.

Green Glauconitic Marl Bed As A Sequence Stratigraphical Key For Interpretation Of Contact Between Qamchuqa And Bekhme Formations In Bekhal Area, Kurdistan Region, NE Iraq

This study incorporates a study of stratigraphy and sedimentology of the green glauconitic marl bed between Qamchuqa and Bekhme Formations in selected section of the Iraqi Kurdistan region. The studied area is located in Gali Garukaju near Rwanduz in Erbil Governorate, northeastern Iraq. Instead of Basal Conglomerate bed, the thin beds of green glauconitic marl occurs along the contact between Qamchuqa and Bekhme Formations in the studied section. Six samples were collected from this section, two samples for XRD and four samples for petrography analysis. Samples for XRD and petrographic analysis were taken from green glauconitic marl beds at the contact between two formations and from upper contact of Qamchuqa Formation and lower contact of Bekhme Formation. XRD analysis data proved the presence of glauconite in green marl bed. General petrographic observations of other remaining four samples in thin sections reveal that the upper contact of Qamchuqa Formation and lower contact of Bekhme Formation are dolomite and dolomitic limestone. The dolomite bed represents type 1 or type 2 depending on the thickness and extension of dolomite bed. Color, morphology, maturity and abundance of glauconite grain were the dominant factors used in the determination of the surface between the two formations. The result emphasizes that the surface was not a gradational surface consisting of low stand and condensed system tract (LST/CS). Two factors, color and morphology, of glauconite grains were analyzed by binocular microscope under reflected light. The morphology of most glauconite grains in this section is ovoidal and tabular with green to dark green in color. Based on these two factors the glauconite grains were within stages 3 and 4 of McCracken et al. (1996) classification and can be interpreted as evolved and high evolved in view of maturity. The presence, increase in concentration and mature grains of glauconite (evolved and high evolved) in marl beds at lower part of Bekhme Formation indicate transgressive or maximum flooding surfaces.

The Implication of Petrographic Characteristics on the Mechanical Behavior of Middle Eocene Limestone, 15th May City, Egypt

The construction purposes of carbonate rocks are considered a major aspect of using these bedrocks based on their mechanical behavior. Accordingly, the physical and mechanical characterization of Middle Eocene Limestone bedrock in the new urban area at the 15th May City, Egypt was studied to assess the suitability of the carbonate rocks for construction. This study has been carried out to investigate the effect of petrographic characteristics on mechanical properties. To achieve this objective, the intact 30 rock core samples from 15 boreholes were selected at different depths. Based on study of the selected samples in thin sections, the limestone in the area was classified as lime-mudstone, wackestone, and grainstone. Additionally, the uniaxial compressive strength (UCS) and Schmidt Rebound Hammer (Rn) were determined to detect the mechanical properties of the limestone bedrock. The measured parameters (UCS and Rn) demonstrated a high direct relationship with mudstone and a poor direct relationship with dolomite and high negative correlation with wackestone and grainstone. Therefore, the Middle Eocene Limestone bedrock is more durable and has medium-strength, which made it suitable for constructions. Regression analysis was performed to find out some linear relationship between mechanical properties (UCS) with petrographic characteristics. The study reveals significant positive correlation between UCS and Rn with mudstone in accordance higher values of regression coefficient (R2 = 0.91 and R2 = 0.036), and an inverse relationship of Rn with dolomite % (R2 = 0.89 and R2 = 0.02), respectively. Consequently, the strong confidence on the mechanical parameters opens the way for engineers to predict the mechanical parameters that are required for engineering properties of limestone for the urban expansion.

Modeling the Depositional Environment of the Sandstone Reservoir in the Middle Miocene Sidri Member, Badri Field, Gulf of Suez Basin, Egypt: Integration of Gamma-Ray Log Patterns and Petrographic Characteristics of Lithology

Understanding the depositional setting of siliciclastics reservoir is fundamental process to exploration and development of hydrocarbon reservoirs and to the multi-phase cycle of the oil and gas industry. Typically, core samples from existing or potential reservoirs can be used for interpretation of depositional environment. However, the lack of core samples in certain reservoirs represents a challenge for reservoir development plans and further exploration. To overcome the absence of core samples in the middle Miocene Sidri Member in the Badri field, Gulf of Suez, this study aimed to reconstruct its depositional settings by coupling well logging patterns and petrographic characterization of ditch cuttings. Consequently, 30 thin section samples representing the reservoir section of four wells were described in detail and standard petrographic characteristics were determined. Then, gamma-ray (GR) log patterns of the studied reservoir wells were used for interpretation of depositional environment. Petrographic analysis indicates that the sandstone reservoir is fine- to medium-grained arkose with dominant siliceous cement and composed mainly of quartz, feldspars, and lithic fragments. Pores reflecting primary and secondary porosity as well as inter-granular pores are dominant. The facies analysis indicates that the studied member has a heterogeneous nature and rapid facies change; its main lithofacies are blocky sandstones, intercalated sandstones and shales, and shales. Three electrofacies were interpreted in the studied section: (1) electrofacies-A (blocky sandstones), which is characterized by a cylindrical-shaped (right boxcar) GR trend; (2) electrofacies-B (intercalated sandstones and shales), which is characterized by an irregular log trend with serrated shape; and (3) electrofacies-C (shales), which is characterized by irregular GR trend and has no character. The interpreted results indicate a tidal channel depositional setting for electrofacies-A, mixed tidal flat depositional setting for electrofacies-B, and low relief offshore mudstone depositional setting for electrofacies-C. Finally, the results illustrate how the coupling of GR patterns with the analysis of petrographic characteristics can be used to understand the depositional setting of a hydrocarbon reservoir that lacks core samples. This work could be useful for assessment of reservoir distribution and quality, for reduction of uncertainty during field development, as well as for providing useful insight to similar hydrocarbon reservoirs elsewhere.

Wettability alteration and enhanced gas condensate recovery by treatment of carbonate reservoir rock using supercritical R134A and R404A gases

The pressure drop around the well in the production from a gas condensate reservoir causes the formation of condensate in the area before it reaches the well and surface space. This condensate and occasionally water in the porous medium can block the well and create an additional pressure drop. Studies show that the chemical treatment of this area eliminates the problem by altering the reservoir rock wettability toward a moderate and strong gasphilicity. For this purpose, fluoropolymers-, fluorosurfactants-, and fluorochemicals-coated nanoparticles can be used. In this work, we have studied two types of fluoride gas namely R134A and R404A, which are widely used in refrigeration industry as refrigerant gases, perfumery, and industrial detergents. The basis of this study was the aging of rock samples in thin sections and plugs in these two gases at different pressures above the critical pressures of them at 70 °C at different times and then conducting the contact angle experiments by placing the drop of water and condensate on the cross sections and then performing imbibition tests using plugs. The results show that in addition to the efficiency of both gases in wettability alteration to gasphilic, the gasphilic intensity obtained at constant temperature depends on the pressure and the aging time of the samples.

Dynamics in Ceramic Production: Petrographic Analysis of Ceramics from Godin Tepe III:6 and III:5

ABSTRACT Petrographic analysis was conducted on pottery from Early Bronze Age archaeological levels at Godin Tepe (western Iran), for the purpose of defining traditions of raw material procurement and ceramic production methods in the context of a local abandonment and resettlement of an agricultural town within the excavation area. Thin-section samples of ceramics representing various ware types from each phase were analysed with a polarising light microscope. The results reveal that there was some continuity in raw material procurement strategies between these phases, especially with buff common wares. The high degree of petrofabric homogeneity within buff common wares strongly suggests the presence of workshops producing them, while more variation among buff coarse and grey-black wares indicates possible household production. A distinct petrofabric of mostly metamorphosing red shale inclusions appeared in III:5, closely associated with red-slipped wares which proliferated in that archaeological phase, suggests the appearance of a novel ceramic tradition at the summit of the town mound, alongside the persistence of existing ceramic traditions and raw material procurement strategies.

Anisotropic pore structure of shale and gas injection-induced nanopore alteration: A small-angle neutron scattering study

Gas transport in the shale matrix is controlled by pore structure, which can ultimately influence natural gas production potential and carbon sequestration in shale gas reservoirs. In this study, in situ small-angle neutron scattering (SANS) measurements under methane and CO2 injections were employed to investigate two Marcellus Shale thin section samples cut parallel and perpendicular to the bedding. Marcellus Shale nanopores show intrinsic anisotropy over the detected length scale of 5–2000 Å. Microscopic gas transport could be inhibited due to the decrease of accessible porosity with increasing gas pressure. The degree of inhibition may be higher for CO2 than for methane, and for the direction normal to the bedding than in the bedding direction. In addition, under the condition of liquid CO2, higher porosity reduction for the direction normal to the bedding may insight into nanoscale anisotropic wettability in the shale matrix.

РЕЗУЛЬТАТИ ПЕТРОГРАФІЧНОГО ДОСЛІДЖЕННЯ ЗНАХІДКИ КАМ'ЯНИХ ЛИВАРНИХ ФОРМ ДОБИ БРОНЗИ

The present article is devoted to the mineralogical and petrographic research of raw materials of the collection of casting molds of the Bronze Age, found by the expedition of Dnipropetrovsk National Historical Museum named after D.I. Yavornytskyi during the excavations of the archaeological monument of Tokivske-1, located near the village Tokivske of Apostolove Rayon, Dnipropetrovsk Oblast. The finding of casting molds is of great importance, since it can be the evidence of bronze foundry production existence in the territory of the monument, which until now was regarded only as a megalithic place of worship. Provenance determination of the raw materials of casting molds can help to identify the role of Tokivske-1 in the system of metalworking cells of the Sabatynivska culture time (XVI–XIII centuries BC) and to establish its links with the ancient centers of mining of stone raw materials. According to previous petrographic studies, it is known that stone molds were made mainly of talc-chlorite-tremolite schists, since this material was easily processed and could withstand more castings than clay molds. Because of this, stone casting molds were highly valued, as well as bronze wares and ingots, and were transported over long distances. The purpose of the study was to establish links between the archaeological monument of Tokivske-1 and known mining and metallurgical centers of the Bronze Age, on the basis of mineralogical and petrographic research of raw materials of casting molds. As a result of the study of samples in thin sections and by X-ray diffraction analysis, it was established that the stone molds were mainly made of tremolite-chlorite-anthophyllite meta-ultrabazites. The determination of the origin of the rocks from which the casting molds were made was carried out by comparing their mineralogical and petrographic features with the features of similar rocks that form natural outcrops, as described in geological survey reports and literary data, and as observed by us in rock samples from natural outcrops in the Middle Dnipro and the Azov Sea areas. It was ascertained that the rocks from which all the casting molds of the collection were made do not form natural outcrops in the Middle Dnipro area and are not characteristic of the Kryvyi Rih area, which is considered to be the main center of raw materials extraction for the stone foundry forms of the Late Bronze Age on the territory of Ukraine. It was established that such rocks are more characteristic of the Western Azov Sea area, but one can not exclude another source of raw materials of the mold collection, in particular the Southern Urals, where bronze metallurgy was significantly developed and similar stone matrices were used. The obtained results suggest revision of established ideas on sources of supply of stone raw materials during the late Bronze Age.

QTL and Transcriptomic Analyses Implicate Cuticle Transcription Factor SHINE as a Source of Natural Variation for Epidermal Traits in Cucumber Fruit.

The fruit surface is a unique tissue with multiple roles influencing fruit development, post-harvest storage and quality, and consumer acceptability. Serving as the first line of protection against herbivores, pathogens, and abiotic stress, the surface can vary markedly among species, cultivars within species, and developmental stage. In this study we explore developmental changes and natural variation of cucumber (Cucumis sativus L.) fruit surface properties using two cucumber lines which vary greatly for these traits and for which draft genomes and a single nucleotide polymorphism (SNP) array are available: Chinese fresh market type, Chinese Long ‘9930’ (CL9930), and pickling type, ‘Gy14’. Thin-section samples were prepared from the mid-region of fruit harvested at 0, 4, 8, 12, 16, 20, 24 and 30 days post pollination (dpp), stained with Sudan IV and evaluated for cuticle thickness, depth of wax intercalation between epidermal cells, epidermal cell size and shape, and number and size of lipid droplets. ‘Gy14’ is characterized by columnar shaped epidermal cells, a 2–3 fold thicker cuticular layer than CL9930, increased cuticular intercalations between cells and a larger number and larger sized lipid droplets. In both lines maximal deposition of cuticle and increase in epidermal size coincided with exponential fruit growth and was largely completed by approximately 16 dpp. Phenotyping and quantitative trait locus mapping (QTL) of fruit sampled from an F7:F8 Gy14 × CL9930 recombinant inbred line (RIL) population identified QTL regions on chromosomes 1, 4 and 5. Strong QTL for epidermal cell height, cuticle thickness, intercalation depth, and diameter of lipid droplets co-localized on chromosome 1. SSR markers on chromosome 1 were used to screen for recombinants in an extended RIL population to refine the QTL region. Further fine mapping by KASP assay combined with gene expression profiling suggested a small number of candidate genes. Tissue specificity, developmental analysis of expression, allelic diversity and gene function implicate the regulatory factor CsSHINE1/WIN1 as a source of natural variation for cucumber fruit epidermal traits.

Mineralogy and Geochemistry Variation of Igneous Rocks from Ungaran and Muria Volcano and Its Processes related to Subduction Zone Magmatism of Sunda Arc

Sunda Arc represent Quaternary magmatism as one of the most significantly active volcanic arc in Indonesia resulted from subduction of oceanic plate beneath continental plate. Along this subduction system, there are systematic variations in subduction angle, depth, crust thickness, and composition contribute to geochemical characteristic of igneous rocks along and across the arc. This study compared mineralogy and geochemistry characteristics from two volcanoes which represent across-arc variation. Petrographic analysis have been conducted on rocks’ thin section samples from Ungaran and Muria Volcano to characterize mineralogy of rocks. Selected samples were analyzed using X-Ray Fluorescence (XRF) for geochemistry of major and trace elements. Mineralogy of Ungaran rocks are dominated by plagioclase, clinopyroxene, and hornblende phenocrysts with composition range from andesite to basaltic andesite of high-K calc alkaline series. Samples from Muria Volcano are from alkaline series characterized by feldspathoid and alkali feldspar rich rocks with calcic plagioclase and pyroxene phenocrysts. This mineral assemblages, supported by major elements data suggest fractionation process in magma. Geochemical trend is systematically consistent with other island arc setting, where there is significant increase of total alkali from Ungaran to Muria. Trace element data shows decreasing in LILE/HFSE ratio further from arc. This suggests that Ungaran has more crustal and subducted slab influence, while Muria has higher degree of partial melting from deeper Benioff Zone.

Simplified Sample Embedding and Polishing Methods for Preparing Hydrophilic, Fragile, or Solvent-Susceptible Materials for Thin Sections for Microscopic Analyses.

In the preparation of thin sections for microscopy, embedding and polishing processes in particular can change the composition and morphologies of samples. Soils and ashes are very fragile and solvent-susceptible, and appropriate sample preparation procedures have not been well-established. To improve the existing preparation methods and make them easier and faster, we embedded freeze-dried blocks, polished, and then examined these thin-section samples using polarization microscopy, laser microscopy, and field emission scanning electron microscopy with energy-dispersive X-ray spectrometry, and electron backscattered diffraction (EBSD). Appropriate thin-section samples can be prepared by: (1) rinsing with acetone and then embedding with Spurr resin along with repeated evacuation and ventilation, rather than conventional dehydration/replacement; (2) polishing using silicon carbide paper and diamond slurries, and then wiping with a cloth and a synthetic oil; and (3) slightly rinsing with 100% ethanol to remove the oil. The preparation method minimized contamination and pores, and showed flat surfaces and sometimes EBSD patterns. Freeze-drying has been claimed to cause the development of cracks due to ice crystal formation upon freezing, however, our method not only overcomes such problems for microscopic observation but saves substantial time, taking only 2 days in total to process a specimen, and requiring less than 1 g of resin and ~1 g of sample.

Geology, Petrology and Geochemistry of Volcanic Rocks Around Arba Minch, Southern Ethiopia

The study area is subpart of the southern main Ethiopian Rift and geographically bounded between UTM (Universal Transverse Mercator) coordinates of 662000m-669000m latitude and 336000m-341000m longitude. The main aim of this study is to investigate the geological, petrographic and geochemical properties of volcanic rocks around Arba Minch, southern Ethiopia. Both field and laboratory analytical techniques are employed to characterize minerals and the rock types. Eight thin section samples are prepared to study petrographic properties of minerals and five best representative samples are analyzed for whole rock chemistry using ICP-MS (Inductively Coupled Plasma-Mass Spectrometry). Petrographically, samples from the porphyritic basalt show phenocrysts of olivine and plagioclase within the fine-grained groundmass. There are rounded to subrounded holes or vesicles that appear white under plane polarized light observations and dark under cross polarized light observations which further confirms vesicular nature of the basalt. Thin section sample from rhyolite outcrop shows phenocrysts of K-feldspar and quartz within tiny fine-grained groundmass of feldspar minerals. Aphanitic basalt, Porphyritic basalt, vesicular basalt, rhyolite and dolerite are the rock units found in the study area. The geochemical results of the analyzed samples indicate silica ranges of (48.5-60.1)%. Based geochemical classifications made, rock units are classified into rhyolite, basalt, hawaiite and mugherite rock types. Trace element analytical results show all samples lie on the within plate tectonic setting. The rare earth and trace element ratios and spider diagrams confirmed that most samples are derived from magmas of asthenospheric source with little crustal contamination.

Mineralized biosignatures in ALH-77005 Shergottite - Clues to Martian Life?

Abstract The ALH-77005 Martian meteorite was found in Allan Hills on Antarctica during the Japanese National Institute of Polar Research (1977-1978) mission. One thin section sample was studied by optical microscopy for microtexture and by FTIR-ATR microscopy for interpretation of biogenic minerals and embedded organic materials. The geochemical data (biogenic elements, δ13C) of ALH-77005 meteorite from literature implementing recent results were compared to terrestrial geological samples. The ALH-77005 has poikilitic textures with coarse pyroxenes and brown olivines, and with recrystallized melt pocket. The coarse-grained minerals do not contain any alteration along the grain boundaries. Melt pocket and vicinity of opaque minerals contain biogenic signatures as filamentous, coccoidal forms of iron-oxidizing bacteria. The biosignatures were determined by 1) coccoidal, filamentous forms, 2) presence of embedded organic material, 3) presence of biogenic minerals, like ferrihydrite, goethite, and hematite. The other signatures for biogenicity of this meteorite are strong negative δ13C, enrichment of Fe, Mn, P, Zn in shock melt support scenario. This study proposes presence of microbial mediation on Mars.

An Experimental Study on Interactions Between Imbibed Fracturing Fluid and Organic-Rich Tight Carbonate Source Rocks

Summary Carbonate reservoirs dominate oil (70%) and gas (90%) reserves in the Middle East, and imbibition is the main mechanism for fracturing-fluid uptake during the hydraulic-fracturing stimulation process. Because of the highly heterogeneous nature of tight carbonate source rocks, it is crucial to understand the effects of imbibed fluid on the mechanical, morphological, and flow properties of carbonate rocks. Although the influence of imbibed fluids on the wettability of carbonate reservoir has been studied extensively, research regarding the effects of imbibed fluids on the texture and mineralogy of carbonate rocks is still very limited. This paper aims to provide a conceptual approach and work flow to characterize and quantify microstructure and mineralogy changes in carbonate rocks caused by imbibed fluids. A thin section of a low-permeability organic-rich carbonate-rock sample [7×7×0.3 mm (length×width×thickness)] was used in the study. The sample was submerged into 2%-KCl (pH = 7.1) fluid from one end to simulate the spontaneous-imbibition process. A scanning electron microscope (SEM) was used to capture the sample's morphological changes before and after spontaneous imbibition. Energy-dispersive-spectroscopy (EDS) maps were measured before and after fluid treatment to investigate changes in various elemental distribution. In addition, inductively coupled plasma (ICP) equipped with an optical-emission-spectrometer (OES) detector was used to quantify dissolved-ion concentration in the treatment fluid. Permeability and porosity were measured using core plugs with dimensions of 1.0×1.5 in. (diameter×length) before and after fluid treatment. During the imbibition process, approximately one-half of the sample was submerged in the treatment fluid. The SEM images for the thin-section sample showed three zones with distinct fluid-uptake characteristics. In Zone I, which was fully submerged in the testing fluid, a significant amount of mineral dissolution was observed. In Zone III, which was above the testing-fluid level, considerable mineral precipitation was detected. While in the transition zone just above the water/air interface (Zone II between the previous two zones), only a minor level of mineral dissolution was observed. Elemental-distribution changes resulting from the fluid treatment were identified by EDS analysis in all three zones. Gypsum and calcite crystals dissolved into imbibed fluids upon reaction. Gypsum was found reprecipitated on the rock surface in the zones above fluid level. The observed gypsum formation likely resulted from the dissolution of the gypsum from the rock matrix, then reprecipitation later from the imbibition experiment caused by water evaporation. Absolute-permeability and porosity measurements for core-plug samples have shown that both were increased after the imbibition process.

Geometry and kinematics of Main Frontal thrust-related fault propagation folding in the Mohand Range, northwest Himalaya

The Main Frontal thrust (MFT) shapes the ∼2500 km-long frontal Himalayan arc between two syntaxes. Surprisingly, the structural geometry and kinematics of the MFT sheet remains poorly constrained along portions of this arc even though it is a major seismogenic plate boundary hazard that affects 53 million people living in the Himalaya and roughly 600 million living in the combined Himalayan drainage basin (Apollo, 2017). Here, we integrate methods to constrain and quantify MFT deformation and its associated topographic growth in the Mohand Range at the northwestern Himalayan front. We use (a) new structural data and trishear modeling to detail the MFT-related structural geometry across a portion of the range and confirm it to be a fault propagation fold with an exposed monocline in the hanging wall as previously hypothesized (Srivastava et al., 2016), and (b) microstructural, finite strain, and grain size analysis from 11 transport-parallel thin section samples of Middle Siwalik sandstones to propose that the fold formed by near-surface (∼1–5 km), frictional-sliding and block-supported cataclastic flow. New luminescence dating of fault gouge and uplifted sand bodies indicate that MFT activity is older (∼105 ka) in the central compared to the western (∼15 ka) Mohand Range, implying that recent MFT motion has been variable and segmented. We next present Boundary Element Method-based dislocation modeling results along 3 transects to confirm that the along-strike topographic growth is variable, but consistent with the existing data and our interpretations. Balanced cross sections indicate that a maximum of 23–26 km2 area was eroded from the Mohand Range since folding began. Modern era estimates of minimum erosion from our dislocation modeling compared to existing topographic profiles suggest that ∼1 km2 erosion occurred in the range. Our integrated approach helps us to better constrain, resolve reported inconsistencies, and advance our understanding of MFT-related deformation, topographic growth and erosion within the Dehradun recess and across its outboard range front. Himalayan arc-segmentation into salients and recesses likely impacts along-strike earthquake rupture propagation, thus it is important to understand how each segment behaves, evolves, and perhaps interrelates as part of a larger perspective towards evaluating active collisional wedge fronts and their potential seismic hazards.

The geoarchaelogical research on the Late Pleistocene Mousterian occupation deposits of the Abric Romaní rock shelter (Capellades Barcelona, Spain)

Changes in the focus of such research in conjunction with scientific advances have diversified the relationship between Earth sciences, Archaeology and History. Today, the core concept of geoarchaeology focuses on the study of anthropic sediments recovered from archaeological sites and landscapes. The potential results that anthropic sediments can offer were highlighted in the last third of the 20th century. Currently, the study of anthropic sediments is a dynamic field within archaeological research focusing on multi-scale analyses such as I try to present in this paper. Here, I give a sedimentary description of the living floors using sediments associated with the use of fire in the archaeological bed north of the Abric Romaní rock-shelter site. The data are the lithological descriptions of the combustion structures taken from the field record and thin section samples. The objective is to provide observations to demonstrate the physical reality of the living floors in the sedimentary record of archaeological sites and landscapes. My main conclusion highlights the importance of knowledge about historic and prehistoric human settlements in order to guide the field record and sampling of these rare sedimentary records. The aim of the research on the Romaní rock shelter is to report on the paleoecology and the autoecology of the archaic human groups through the archaeological record.

Fabric of soil derived from parna and the riddle of transported pellets

It is generally accepted that large areas of southern New South Wales (NSW) and northern Victoria are mantled by soils derived from clayey loess deposits called parna. These parna deposits are believed to have formed during arid phases of the Pleistocene and the mineral constituents are assumed to have been transported as silt- and fine sand-sized pellets of calcareous clay, with some companion quartz grains of a similar size. A common property of parna-derived soils is subplasticity, where the apparent field texture grade becomes more clayey with increasing mechanical working of the bolus. This propensity for subplastic behaviour suggests that parna-derived soils contain stable silt- and fine sand-sized pellets of clay, yet there has been little direct micromorphological evidence of these pellets ever published. In the present study, thin section samples from several parna type-sites in southern NSW were examined micromorphologically to reveal the presence of very well size-sorted quartz grain populations (companion grains) and identifiable prolate clay aggregations of a similar silt to fine sand size. These prolate pellets, comprised of quartz, illite, kaolinite and chlorite, have a very distinctive mosaic-speckled b-fabric and are more widely distributed throughout the soil than the similarly sized and shaped faunal faecal pellets. Where these pelletal aggregations are not evident, such as in the deeper parna deposits, abundant illuviation features suggest that clay particles deposited within the parna, whether as pellets or coatings on grains, have subsequently undergone considerable weathering and a range of pedogenic processes.

Layer Additive Production or Manufacturing of Thick Sections of Ti-6Al-4V by Selective Electron Beam Melting (SEBM)

Selective electron beam melting (SEBM) is an established layer additive manufacturing or production process for small-to-medium–sized components of Ti-6Al-4V. Current literature data on SEBM of Ti-6Al-4V are, however, based principally on thin-section (<1″; mostly <0.5″) samples or components. In this research, 34-mm-thick (1.34″) Ti-6Al-4V block samples were produced through use of default Arcam SEBM parameters and characterized versus section thickness. High densities (99.4–99.8%) were achieved across different thick sections, but markedly inhomogeneous microstructures also developed. Nonetheless, the tensile properties measured from 27 different thickness-width positions all clearly satisfied the minimum requirements for mill-annealed Ti-6Al-4V. SEBM produced highly dense thick sections of Ti-6Al-4V with good tensile properties. Large lack-of-fusion defects (80–250 µm) were found to be mainly responsible for variations in tensile properties.