Mineralogical Characterization of Early Bronze Age Pottery from the Svilengrad-Brantiite Site, Southeastern Bulgaria

Several pottery sherds from the Svilengrad-Brantiite site, Bulgaria, were mineralogically and petrographically analyzed. The aim was to add information to the very scarce material data available for Early Bronze Age pottery in the southeastern Thrace plain, Bulgaria, in order to examine a possible raw-material source of the pottery. The characterization techniques applied were optical microscopy (OM), petrographic microscopy (PM), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), X-ray fluorescence (XRF) spectroscopy, and X-ray diffraction (XRD). The pottery samples consisted of two typological groups: a local-made type and a cord-impressed decoration type influenced by foreign cultures. All of the samples were produced from fine clay pastes that had a quite similar composition, with abundant mineral grains of similar mineral composition and fragments of metamorphic and granitic rocks. The chemical compositions of each mineral in the grains and fragments were almost identical, and consistent with those from metamorphic and granitic rocks from the Sakar-Strandja Mountains near the study site. The clay paste compositions corresponded to those of illite/smectite mixed-layer clay minerals or mixtures of illite and smectite, and the clay-mineral species were consistent with those in Miocene–Pleistocene or Holocene sediments surrounding the site.

GENESIS, DEVELOPMENT, AND CLASSIFICATION FOR SOME SELECTED SOILS AT KURDISTAN REGION, NORTH OF IRAQ

The study area was located in the North of Iraq. Five sites were selected that have formed from the limestone parent material. One pedon dug in each site and was divided into a number of horizons. Thirty-five soil samples were collected for physical and chemical analyses. The climate of study sites were similar to the Mediterranean Sea climate which is hot dry in summer and cool humid in winter. The mean of annual precipitation, varies from one site to another. Studied soils classified as Mollisols, Inceptisols, Vertisols, and Aridisols. Study soils were relatively high clay content and its content at the surface horizons is lower than it at subsurface horizons, and soil texture was ranged between clayey to loamy, the high value for clay content indicates to soil development. Fine clay/Coarse clay ratio showed that the pathway of fine clay similar to the pathway of total clay. CEC values increased with increasing clay. Organic matter was high in the surface horizons and decrease with depth. The following pedogenic processes occurred in study soils loss, gain, leaching, illuviation, eluviation, alkalization, humification, lessivage, desalinization, calcification, decomposition, and synthesis.

Late Pleistocene Climate and Dust Source From the Mobarakabad Loess–Paleosol Sequence, Northern Foothills of the Alborz Mountains, Northern Iran

Paleoclimatic investigation of loess-paleosol sequences from northern Iran is important for understanding past changes in a region highly sensitive to shifts in precipitation, and along potential routes of past human migration. Here, we present carbon and oxygen isotopic compositions of bulk carbonate (δ13Cbc and δ18Obc, respectively) coupled with particle size distributions of samples from the Mobarakabad section, northern Iran, to study past wind dynamics and hydroclimate. We also present new initial clay-sized Hf-Nd isotope results from key horizons in order to assess general dust sources. Variations of δ13Cbc and δ18Obc values of modern soils compared to paleosols allow reconstruction of late Pleistocene–Holocene climate change in the area. Our results show severe drought during a major eolian deposition phase (EDP) after 34 ka. The thickness and PSD of the C horizon of unit 5 suggest significant shifts in loess sources and depositional environments during this EDP after 34 ka. Indeed, based on our new clay-sized Hf-Nd data, we hypothesize that the loess unit 5 might originate from the young crustal source of the Alborz and Kopet Dagh mountains. In general, the PSD of C horizons in the section is bimodal in the silt fraction and the very small, very fine clay fraction, with a mode at c. 1 μm in the modern soil and paleosols possibly produced by weathering and pedogenic processes. There also appears to be a good correlation between δ13Cbc and δ18Obc values, differentiating phases of loess accumulation and paleosol formation and hence providing quantitative data for reconstructing paleoclimatic conditions in the study area.

Study on Microstructure Characteristics of Clay Rock of Xigeda Formation in Xichang City Based on Softening Test and Image Recognition

Based on the Xigeda clay rock exposed in the back mountain of Nanshan Villa in Xichang City, the microstructure changes of Xigeda clay rock before and after water softening were studied by scanning electron microscope and image recognition of PCAS software. The results show that: (1) the clay rock of Xigeda group has flake and layered micro structural characteristics, and the surface of aggregates in natural state has honeycomb characteristics. After water softening, the aggregate particles decompose, the average size of particles becomes smaller, the honeycomb characteristics disappear, and the surface contours of particles become smooth and round. (2) With the increase of water saturation time, the number of aggregate particles and pores increases, the porosity decreases in advance and increases in the later stage. (3) Micro structural changes of the clay rock in Xigeda formation have two stages, in the first stage, the aggregates decompose and the produced fine granular clays fill the original pores, resulting in the decrease of porosity.In the second stage, the fine clay particles further soften, decompose and lose in the water, the porosity increases suddenly.

Development of Sugarcane Bagasse Reinforced Onibode Clay Composite for Engineering Applications

The quest to address the environmental pollution effect posed by agro-waste by way of turning them into useful materials for engineering applications is the motivation for this research work. In this study, sugarcane bagasse (SCB) reinforced Onibode clay composite was developed via slip casting technique. Clay samples from Onibode, Ogun state, Nigeria was collected at depth of 5 meters beneath the earth surface. Sugarcane bagasse was collected from a local market in Alaba-rago, Nigeria. Onibode clay–sugarcane bagasse composite samples were developed from a mixture of fine clay particles (<150 µm) and SCB reinforcement particles (fine - <150 µm; coarse – 300 µm) of 0 – 6 %wt with a constant 53 %wt moisture and five drops of sodium silicate. The samples were fired at a temperature of 1150 oC and held for 1 hour. Mechanical properties such as thermal conductivity, linear shrinkage, bulk density and apparent porosity of the samples were evaluated. The results show that 2 wt% sugarcane bagasse (SCB) reinforcement improved the mechanical properties of the developed composite.Keywords- Sugarcane bagasse, clay, refractory properties, insulator.

Effect of Bentonite on the Coefficient of Consolidation of Soil

Bentonite is a fine clay, usually occurring as a byproduct of atmospheric weathering of volcanic ash. It is widely known for its capabilities of high absorption of moisture, and swelling, as a result of moisture contact. Bentonite has a crystalline structure with the main constituent as montmorillonite which has a dual-layered structure. It is the main ingredient responsible for imparting valuable properties to bentonite. In this study, several samples were tested from different regions of district Mardan, Pakistan, to analyze the collective effect of bentonite on the region’s soil. An analysis was conducted based on the performed tests on the samples, to predict the consolidation behavior when samples were replaced with 0%, 5%, 10%, and 15% of bentonite by mass. Thecoefficient of consolidation gives the rate of increase of settlement or consolidation when the sample is subjected to externally applied pressure. This study observed a decrease in the coefficient of consolidation of soil with the percentage increase of bentonite reaching a minimum value of 0.005 in2/min showing about four times decrease in the coefficient of consolidation with 15% replacement of soil with bentonite. This behavior of bentonite is attributed to the fact that; being a fine clay, its addition to the soil reduces its pores and fills the open spaces, hence reducing the chances of fluid to penetrate or flow through the soil, resulting in the reduction ofthe coefficient of consolidation Cv.

Geochemical alterations of forest soils in post-mining area (the Moscow brown coal basin, Russia)

&lt;p&gt;Long-term coal mining in the Moscow basin has a complex negative impact on soils of natural ecosystems. Due to underground mining operations at coal deposits in the Moscow basin spoil heaps with a high content of iron sulfides and aluminosilicates were formed. Active oxidation of sulfides in waste dumps results in the producing of toxic sulfuric acid and iron sulfates (Nordstrom and Alpers 1999). Acid mine drainage (AMD) of sulfuric acid, Al and Fe sulfates as well as pyritized material, entering from eroded spoil heaps, results in physico-chemical and morphological changes in soil properties. On foreslopes around spoil heaps technogenically transformed soils are common. Our study aimed at evaluation of post-mining geochemical transformation of soil properties, which is adjacent to spoil heaps.&lt;/p&gt;&lt;p&gt;We observed two key sites within abandoned coal mines in the western part of Moscow basin (the Tula region, Russia). Prevailing natural soils are Umbric Albeluvisols and Umbric Podzols (sod-podzolic soils and sod-podzols in Russian classification). Soils with transformed water regime are formed in mine subsidence.&lt;/p&gt;&lt;p&gt;Soil samples and displaced soil solutions (by ethanol) were analysed for acid-base properties, content and composition of readily soluble salts, content of Fe&lt;sup&gt;2+&lt;/sup&gt; and Fe&lt;sup&gt;3+&lt;/sup&gt;, H&lt;sup&gt;+&lt;/sup&gt; and Al&lt;sup&gt;3+&lt;/sup&gt;, composition of exchangeable cations, total content of S, Al, Fe, heavy metals (HM) and organic carbon).&lt;/p&gt;&lt;p&gt;Properties of newly formed soils differ significantly from natural soils. We identified the transformation of the composition of soil solutions. The basic geochemical processes in contaminated soils are as follows: the acidification and changes in the composition of ions in soil solutions from bicarbonate-sulfate-calcium to sulfate-iron-aluminum-calcium; cation exchange, leading to the replacement of C&amp;#1072;&lt;sup&gt;2+ &lt;/sup&gt;and Mg&lt;sup&gt;2+&lt;/sup&gt; ions by Al&lt;sup&gt;3+&lt;/sup&gt; and H&lt;sup&gt;+&lt;/sup&gt; ions, and, probably, by Fe&lt;sup&gt;2+&lt;/sup&gt; and Fe&lt;sup&gt;3+&lt;/sup&gt; in soil ion-exchange complex. Transformed soils were characterized by a very low degree of base saturation (less than 20%). Estimation of the saturation degree of liquid phases of transformed soils with poorly soluble compounds revealed a high oversaturation of soil solutions with Fe&lt;sup&gt;3+&lt;/sup&gt; and Al&lt;sup&gt;3+&lt;/sup&gt; hydroxides. The total content of HM in transformed soil profiles were lower than background values due to the removal of soil reserves of elements in highly acidic conditions (pH&lt;4.5). Among the morphological features of transformed forest soils intensification of podzolization process (acid hydrolysis of fine clay fractions of aluminosilicates) as well as; ferrugination (segregation of ferric iron, mainly in amorphous or poorly crystallized forms) and carbon enrichment of coal origin can be noted. Due to AMD impact that had destroyed fine clay minerals, numerous clarified areas were formed, composed of quartz and feldspar. Semi-hydromorphic soils with signs of gleying and peat accumulation were formed in subsidence areas.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;