Clay mineral compositions in the surface sediment of the Chanthaburi coast(northeastern Gulf of Thailand)and their implications on sediment provenance

Clay mineral composition represents an important tracer of sediment source area,migration processes,and paleoclimatic conditions.Clay mineral analysis was performed on 15 surface sediment samples collected from the coast of Chanthaburi,Thailand.Results show that the composition of clay minerals in the study area differs substantially from that in surrounding regions of the Gulf of Thailand.The clay minerals of the Chanthaburi coast are dominated by kaolinite(~56%),followed by smectite(~21%),illite(~14%),and low concentrations of chlorite(~8%).The average illite chemistry index and crystallinity are 0.93 and 0.32,respectively.Comparative analysis of the clay mineral composition of surface sediments in several typical areas around the Gulf of Thailand indicated that the clays of the Chanthaburi coast are mainly derived from parent rock weathering in the small watersheds of the Chanthaburi and Welu rivers and the surrounding islands.Terrestrial input from the northern coast of the Gulf of Thailand(excluding the Mekong River)was previously considered negligible;however,the present results indicate that such input has impact on the eastern Gulf of Thailand.The warm humid climatic conditions in Southeast Asia are the primary factors that affect the strong chemical weathering in the study area,followed by the nature of the parent rock.

Opaque Mineralogy as a Tracer of Magmatic History of Volcanic Rocks: an Example from the Neogene-Quaternary Harrat Rahat Intercontinental Volcanic Field, North Western Saudi Arabia

The Neogene-Quaternary Harrat Rahat volcanic field is part of the major intercontinental Harrat fields in western Saudi Arabia. It comprises lava flows of olivine basalt and hawaiite, in addition to mugearite, benmorite, and trachyte that occur mainly as domes, tuff cones and lava flows. Based on opaque mineralogy and mineral chemistry, the Harrat Rahat volcanic varieties are distinguished into Group I （olivine basalt and hawaiite） and Group II （mugearite, benmorite and trachyte）. The maximum forsterite content （-85） is encountered in zoned forsteritic olivine of Group I, whereas olivine of Group II is characterized by intermediate （Fo=50）, fayalitic （Fo=25） and pure fayalite in the mugearite, benmorite and trachyte, respectively. The more evolved varieties of Group II contain minerals that show enrichment of Fe2＋, Mn2~ and Na~ that indicates normal fractional crystallization. The common occurrence of indicates that pS＋ becomes saturated in this coarse apatite with titanomagnetite in the benmorite rock variety and drops again in trachyte. Cr-spinel is recorded in Group I varieties only and the Cr# （0.5） suggests lherzolite as a possible restite of the Harrat Rahat volcanics. The plots of Cr# vs. the forsterite content （Fo） suggest two distinct trends, which are typical of mixing of two basaltic magmas of different sources and different degrees of partial melting. The bimodality of Harrat Rahat Cr-spinel suggests possible derivation from recycled MORB slab in the mantle as indicated by the presence of high-Al spinel. It is believed that the subcontinental lithospheric mantle was modified by pervious subduction process and played the leading role in the genesis of the Harrat Rahat intraplate volcanics. The trachytes of the Harrat Rahat volcanic field were formed most probably by melting of a lower crust at the mantle-crust boundary. The increase in fo2 causes a decrease in Cr203, and A1203, and a strong increase in the proportion of Fe3＋ and Mg# of spinel crystallizing from the basaltic melt at T -1200~C. The olivine-pyroxene and olivine-spinel geothermometers yielded equilibrium temperature in the range of 935-1025~C, whereas the range of 〈500-850~C from single-pyroxene thermometry indicates either post crystallization re- equilibrium of the clinopyroxene, or the mineral is xenocrystic and re-equilibrated in a cooling basaltic magma.

Trace Element and Sulfur Isotope Compositions of Gold-bearing Pyrite from the Zhangjiawa Iron Skarn Deposit,Laiwu District:Implications for Sources of Early Cretaceous Gold Mineralization in the North China Craton

Objective The Zhangjiawa iron deposit is the largest-tonnage and representative iron skarn deposit,with proven reserves of 290 Mt at an average of 46%Fe(up to>65%),in the Laiwu district,eastern North China Craton(NCC)(Figs.1 a,b;Duan and Li,2017).Iron mineralization at Zhangjiawa is mainly hosted along a northern contact zone between the Kuangshan dioritic intrusion and Middle Ordovician carbonate rocks that host numerous evaporite intercalations(Figs.1b,c).

Application of sequence stratigraphy to Triassic terrestrial strata in Tahe area of Tarim Basin

Based on a synthetic geological study of drilling,well logging and seismic data,core observations and geochemical analysis,it is recognized that Triassic sedimentary facies in the Tahe area of Tarim Basin include braided river deposits filling erosional valleys,and sublacustrine fan,canyon and delta facies.Braided river deposits filling erosional valleys are dominated by coarse-grained lithic quartz sandstone with oblique bedding,and represent the most important sedimentation type of sandstone in the study area.Sublacustrine fan and canyon facies are mainly distributed in the Middle Oil Member.Most delta sediments are deposited in highstand system tract(HST),Because of frequent changes in base level,delta sediments are commonly eroded and rarely preserved.Sedimentary cycles are clearly reflected by lithology,sedimentary structures and well logging data,and are closely related to the changes in lacustrine level.In accordance with the basic principle of sequence subdivision,seven type-I boundaries can be recognized in Triassic strata and six type-I sequences are subdivided correspondingly.In general,lowstand system tract(LST) is well developed within stratigraphic sequences and forms the main body of reservoir sandstone in this area;highstand system tract(HST) and transgressive system tract(TST) are often eroded by upper sequences or missed,Although various factors have different influences on terrestrial sequence stratigraphy,the classical sequence stratigraphy theory proposed by VAIL can be applied to terrestrial strata.

Effect of pyrite content of feed and configuration of locked particles on rougher flotation of copper in low and high pyritic ore types

Misreported pyrite into copper concentrates dramatically declines copper grade and recovery. Copper flotation can be also more complicated if flotation feed comes from an elevated-pyritic copper ore. In this investigation, the effect of two different ore types(high pyritic and low pyritic feeds) was studied on rougher stage of industrial copper flotation circuit. Samples were taken from different streams and the structure of chalcopyrite within the pyrite and non-sulfide gangue minerals was examined in various size fractions for mentioned ore types. Results indicated that 72% and 56% of the total floated pyrite was transferred to concentrate in first four cells in the low and high pyritic feeds, respectively. Whereas, this proportion for floated SiO_2 in last ten cells was detected as 72% and 71%, respectively. A detailed interpretation of the effect of locked particles in different size fractions on rougher flotation cells is studied from industrial point of view.

New insights into the flotation responses of brucite and serpentine for different conditioning times: Surface dissolution behavior

The inadvertent dissolution of gangue minerals is frequently detrimental to the flotation of valuable minerals.We investigated the effect of conditioning time on the separation of brucite and serpentine by flotation.By analyzing the Mg2+concentration,relative element content,and pulp viscosity,we studied the effect of mineral dissolution on brucite flotation.The results of artificially mixed mineral flotation tests(with-10μm serpentine)showed that by extending the conditioning time from 60 to 360 s,a large amount of Mg2+on the mineral surface gradually dissolved into the pulp,resulting in a decreased brucite recovery(from 83.83%to 76.79%)and an increased recovery of serpentine from 52.12%to 64.03%.To analyze the agglomeration behavior of brucite and serpentine,we used scanning electron microscopy,which clearly showed the different adhesion behaviors of different conditioning times.Lastly,the total interaction energy,as determined based on the extended DLVO(Derjaguin-Landau-Verwey-Overbeek)theory,also supports the conclusion that the gravitational force between brucite and serpentine increases significantly with increased conditioning time.

Origin of Phosphorite Nodules of Lebedinsky Iron Deposit in Kursk Magnetic Anomaly (KMA) of the Russian Platform

Phosphorite has become increasingly important as the raw material for phosphatic fertilizer. Phosphorite nodules are widespread in the Kursk complex deposit (Russian platform). Genesis of these nodules has long been a matter of debate, and this has hampered understanding of the mechanism and controls in the formation of the nodules. In this paper, we report the petrographical, mineralogical, and geochemical data of the Lebedinsky phosphorite nodules. Petrographic study reveals complex phosphatic cement resulting in the replacement of apatite minerals around quartz grains. The main mineral composition consists of quartz, phosphate minerals (apatite, francolite mainly), feldspar, iron hydroxides and carbonate minerals. These results, when combined with available data, are used to address the origin of the phosphorite nodules. The nodules are characterized by the universal presence of biogenic and chemical signatures which is phosphorus crown around crystal grains. The structure of the nodules is massive. Their texture is depicted by basaltic cement and concretion, which consists mainly of apatite and its varieties, with general formula: Ca_10 (PO_4, CO_3) 6(F,OH,Cl). Variation of mineralogy appears dependent on geological setting. Microscopic observations of biogenic fossils in Lebedinsky phosphorite favor a chemical and biogenic origin of phosphorites. Weathering has been suggested to be capable of liberating as much as 20 %-35 % P_2O_5 from sedimentary rocks. Previous investigations demonstrate that weathering of the Proterozoic substratum was the main cause in the formation of Fe, Mo, Mn, Pb, Zn, and P in the Russian platform. We therefore suggest that both weathering and biochemical processes have been positive in the formation of the Lebedinsky phosporite nodules. However, whether continental weathering or oceanic bio-chemical processes are more relevant in the phosphorite accumulation remains undetermined.

The characteristics, formation and exploration progress of the potash deposits on the Khorat Plateau, Thailand and Laos, Southeast Asia

The giant potash deposit on the Khorat Plateau is one of the most promising targets for exploitation of potassium salts.So far,many researches and geologic survey have been conducted on the giant potash deposits.Hence,it is necessary to make an overall review on the potash deposits.The potash deposit on the Khorat Plateau was formed during the Middle to Late Cretaceous,during which seawater was enriched in Ca2+and depleted in SO42-compared with those of modern seawater.In addition to seawater,continental water and hydrothermal fluids could have affected the evaporite basins.The seawater was probably derived from Tethys ocean,and the brine should have evaporated to some extent before entering into the basin systems based on the evidence of absence of carbonates and unproportionate sulphate compared with chloride salts.The paleo-climate during Middle to Late Cretaceous was characterized as high temperature and extremely arid environment,which is favourable for deposition of potassium-magnesium saline minerals.The major saline minerals are of anhydrite,halite,carnallite,sylvite and,tachyhydrite,with trace amounts of borates.The resources of the potash deposit on the Khorat Plateau could be approximately as much as 400×109 t of carnallite and 7×109 t of sylvite.The evaporite sequences have been deformed and altered by postdepositinal processes,including tectonic movements and chemical alteration.Salt domes were formed in the postdepositional processes.Based on the analyses of geophysical surveys and drilling projects,high-quality sylvinite ores are commonly found at the flanks of those salt domes due to incongruent dissolution of carnallite.The furure potential prospecting areas for the highquality sylvinite ores would be on the edges of the Khorat Plateau.

Equilibrium, thermodynamic, and kinetic of Cr(VI) adsorption using a modified and unmodified bentonite clay

The capacities of natural and modified Brazilian bentonite samples as adsorbents to remove hexavalent metal chromium were investigated under several conditions in batch and column methods. The raw material, Ca-bentonite, was modified by anchorament of 3-aminopropyltrietoxisilane （APS） and 3,2- aminoethylaminopropyltrimetoxisilane （AEAPS） in the surface of bentonite sample： This type of new occurrence of bentonite is suitable as a raw material for adsorption process. Adsorption behavior of three bentonite types was strongly depending on pH of adsorbate solution, contact time adsorbent/adsorbate, and initial concentration of Cr（VI）. The results were confirmed by column method and reveals that the adsorption process of materials accorded by the Redlich-Peterson, Sips, Dubinin-Radushkevich, and tang- muir isotherm models. The exothermic entbalpic values reflected a favorable energetic process for chro- mium ions anchored in the material surfaces. The negative Gibbs free energy results supported the spontaneity of three adsorption reactions with Cr（VI） ions.

Isotope Dating of the Potash and Rock Salt Deposit at Bamnet Narong, NE-Thailand

Bamnet Narong is located in northeastern Thailand (Chaiyaphum Province). It is the largest salt mine in the country and has been mined for decades. The landscape in this part of Thailand is characterised by a low plateau, which is called the Khorat Plateau. The plateau is divided into two basins by the Phu Phan Range, the Sakhon Nakhon Basin in the north and the Khorat Basin in the south. The analysed potashes and rock salts are deposited in the Maha Sarakham Formation, which represents the salt-bearing strata of the Khorat Basin. The stratigraphic age of this deposit has been debated since the late 1960’s. The assigned ages range from Mid-Cretaceous to Late Cretaceous and up to the Eocene. In this study different isotopic dating systems (Rb-Sr, Sr-Sr, K-Ar and K-Ca) were applied. The stratigraphic age for the time of deposition was confirmed to be Mid Cretaceous (Cenomanian). Furthermore, the homogeneity of the carnallites was investigated in order to trace a possible redistribution of rubidium.

Gold grade variation and stream sediment geochemistry of the Vaimba-Lidi drainage system, northern Cameroon (West Africa)

Stream sediment geochemistry remains a versatile tool in exploration especially in regions where knowledge of the primary mineralization is lacking and the exploration activities are still at reconnaissance stage. In this study, we investigate the concentrations of gold and associated elements in stream sediment samples from the Vaimba-Lidi drainage system in northern Cameroon;a relatively remote area where alluvial gold is worked locally, and exploration activities are at early stage. The main river and its principal first and second order tributaries were sampled, panned for gold grain recovery and the 100 μm size fraction analyzed for Au by fire assay with Ni finish. A suite of other elements were analyzed for by inductively coupled plasma mass spectrometry (ICP-MS). Gold grades estimated by the panning and weighing technique rarely exceed1 g/t while the Au concentrations from chemical analysis range from 3.0 to 354.0 ppm. The spatial distribution of gold and all the other elements are presented as point symbol maps and the data analyzed using multivariate statistics. From the principal component analysis (PCA), the As-Mo-W-Ag as well as the Au-Zn factors point to the presence of primary hydrothermal gold-sulphide mineralization in the area and this can be further investigated. These results highlight the importance of multielement analysis and multivariate statistical interpretation of sediment geochemical data in inferring the nature of the underlying primary mineralization in any region.

New Evidence of Sauropod Dinosaurs from the Early Jurassic Period of Thailand

The oldest dinosaur assemblages of Thailand deposit in continental sedimentary rocks of the Nam Phong Formation. Not only Isanosaurus attavipatchi was discovered but at least two more species of basal sauropods were found. A partial skeleton from Phu Hin Tan locality refers to sauropod taxon A. It is different from Isanosaurus and shares some characteristics with basal sauropods in the Early Jurassic. The sauropod taxon B was found in Non Sra Ard locality. Base on postcranial skeleton, sauropod taxon B shares some characteristics of the family Vnlcanodontidae. Moreover, several fragments of the sauropods specimen are also found in Pha Khok Wang Yang and Phu Noi localities. All of the evidences above indicate that there are a highly diversity of sauropods in the Nam Phong Formation. At least three sauropod species （including Isanosaurus） were found in the Nam Phong formation. The issue about the age of the Nam Phong has been debated for a long time between the Triassic and Jurassic age. All of sauropodomorphs, in this study, are more likely the Early Jurassic period dinosaurs than the Triassic period dinosaurs. And they have deposited in the upper part of Nam Phong Formation.

Liquid-liquid extraction of phosphorus from sulfuric acid solution using benzyl dimethyl amine

This study addresses the liquid-liquid extraction behavior of phosphorus from a sulfuric acid solution using benzyl dimethyl amine(BDMA)in kerosene.The extraction equilibria investigated with varied BDMA concentrations could reveal the formation of 3[BDMA]·[H_(3)PO_(4)]^(-)complex in the organic phase.The thermodynamic properties determined at various temperatures indicated that the process was exothermic with a calculated enthalpy(△H^(Θ))of−24.0 kJ·mol^(−1).The organic-to-aqueous phase(O/A)volume ratio was varied to elucidate the quantitative extraction of phosphorus.The McCabe-Thiele diagram plotted for the extraction isotherm was validated for the requirement of three counter-current stages in the extraction at an O/A volume ratio of 2.0/3.5.The back-extraction of phosphorus from the loaded organic phase was quantitatively achieved by contacting 4.0 mol·L−1 H2SO4 solution in three stages of counter-current contact at an O/A volume ratio of 3/2.This study can be applied to remove phosphorus from the sulfuric acid leach solutions of monazite processing,and many other solutions.

Effects of Additives on Some Selected Properties of Base Sand

In this study, effects of sawdust, coal dust and iron filling additives at varied proportions on some selected properties of moulding sand were investigated. Consequently, cylindrical specimens with different percentages of additives were prepared based on standard procedures. The prepared specimens were subjected to basic moulding sand testing including moisture content, bulk density, porosity, permeability, green compression strength and green shear strength using standard methods and equipment. From the obtained test results, all the experimental additives were found to improve the selected moulding properties of the base (silica) sand. Moulding sand specimen with sawdust additive revealed a relatively better compaction as compared to moulding sand specimens with coal dust and iron filling additives respectively. The moisture absorbing strength of the moulds was also found to increase with increasing percentage of sawdust. Addition of coal dust to the moulding sand was found to improve sand porosity and permeability which results in less casting defects, and due to improved moisture absorbing strength of sawdust, moulding sand specimens that contained sawdust were equally found to exhibit good compaction with maximum green compressive strength of 108.99 kPa. Also, the combination of 25% sawdust, coal dust and iron filling in the moulding sand was found to produce mould with optimum green shear strength value of 54.49 kPa.

Sedimentology and Stratigraphy of Phu Sung Fossil Site of the Lower Cretaceous Sao Khua Formation, Sakon Nakhon Province, Northeastern Thailand

“Phu Sung”, a new fossil site in Sakon Nakhon Province was recently reported. Phu Sung fossils are very complete and in very well-preserved condition. They were found in reddish micaceous silty mudstone. The stratigraphy and sedimentology show that Phu Sung succession is a continental deposit in the fluvial system and it is in the Early Cretaceous Sao Khua Formation of the Khorat Group. According to lithology, fossils were deposited in a quiet environment, such as overbank deposit, small pond or oxbow lake margin. Sedimentary structures such as desiccation crack and calcrete indicate semi-arid to arid paleoclimate condition which probably corresponds to the taphonomy or preservation of the fossils.

Analysis on Some Physical and Chemical Properties of Oreke Dolomite Deposit

The suitability of Oreke dolomite in Kwara State, Nigeria as a raw material for the manufacturing of refractories was investigated. The Oreke dolomite samples were mingled with feldspar, clay, and quartz to form a blend. The fifteen (15) Blend samples were moulded and analyzed for their chemical, physical and mechanical properties. The characterization was carried out in accordance with American Society of Testing and Material (ASTM). The blend samples were tested for various refractory properties such as bulk density, porosity, cold crushing strength, linear shrinkage, refractoriness and others like water absorption and compressive strength. The chemical composition of the Blend was determined, using X-Ray Fluorescence Spectrometer and the result shows that Silica is 60%, Alumina is 11.5%, Iron Oxide is 0.48%, Calcium Oxide is 10%, Magnesium is 6.4%, Alkali is 10.4%, and Loss of Ignition of the sample is 15.28%. The addition of 10%-12% quart contents with dolomite of 20%-25% contents complements the percentage of silica in the blend thereby improving the properties of the blend. The strength characterization shows that the Compressive Strength (mean value) of the blend samples is 5.65 N/m2 with respect firing temperature. The strength classification varies between medium to high and was found to satisfy the allowable standard values for the production of refractory wares.

Geochemistry and Petrography of Alkaline rocks from Monte Santo Alkaline Intrusive Suite, Western Araguaia Belt, Tocantins State, Brazil

The Monte Santo Alkaline Intrusive Suite (MSAIS) is an association syenite foid, nepheline syenite and syenite. The MSAIS rocks are intruded in metapelites of the Rio do Coco meta-volcanic-sedi- mentary Sequence and are abundant pegmathoid veins cutting all of them. The mineral paragenesis is represented by aegirina, arfvedsonite, albite and nepheline, crystallized during the initial phase of crystallization. A late magmatic phase show nepheline, perthite, calcite and biotite, and a hydrothermal phase allowed for the formation of cancrinite, sodalite, analcime and natrolita associated with altered nepheline. The geochemical analyses showed metaluminous and medium to high potassium characteristics, being classified as miaskitic rocks, according to agpaicity and the Na + K > 1/6Si indexes. However, the mineralogical assemblage suggests a low to medium agpaitic composition, which can be related to a transition from miaskitic to agpaitic crystallization regime. The rare earth elements showed depletion in heavy rare earth and a strong negative Eu anomaly and enrichments in the some lithophile elements, suggesting a differentiated pattern later, which can be associated to metasomatic alterations.

Lithostratigraphy of the Late Cretaceous Khao Ya Puk Formation in Nakhon Thai Region, Thailand: Implication for Depositional Environment

The Khao Ya Puk Formation (>400 m thick) is well exposed in the Nakhon Thai Region, and is subdivided into three members. The Khao Ya Puk Formation overlies conformably on top of the anhydrite layer of the upper rock salt Maha Sarakham Formation. In turn, it is overlain unconformably by the Phu Khat Formation. The Khao Ya Puk Formation is interpreted to have been deposited by freshwater lake area in arid climate inland subkha in the Late Cretaceous. Lithostatigraphically, Khao Ya Puk Formation can be correlated with the Phu Tok Formation that has been deposited in the Khorat-Ubon basin and Udon-Sakon basin of the Khorat Plateau.

Effect of Heat Treatments on Corrosion of Welded Low-Carbon Steel in Acid and Salt Environments

Effect of heat treatment on the corrosion of welded low-carbon steel in 0.3 M and 0.5 M of hydrochloric acid and sodium chloride environments at ambient temperature (25oC) has been investigated. Arc welded low-carbon steel sample of known composition were subjected to the corrosion reagents for 21 days (504 hours). pH and weight loss values were taken at interval of 3 days. Thereafter, weight loss method was used to measure therate of corrosion attack on the heat treated samples at ambient temperature. Results obtained showed that at low concentration, the annealed sample exhibits better corrosion characteristic as compared to the normalized and quenched samples. However, at higher concentration the normalized sample exercised better service performance over the annealed and quenched samples. Thequenched sample was found to have relatively low corrosion performance over the annealed and normalized samples at both low and high concentrations of the media.

Liberation Size and Beneficiation of Enyigba Lead Ore, Ebonyi State, South-East Nigeria

This research work centered on the determination of Liberation Size and Enrichment of Enyigba Lead Ore in Ebonyi state, Nigeria. The study reviews the fundamental operations in mineral processing i.e. the comminution process for the release and liberation of the valuable minerals particles from the ore association, and the eventual separation and concentration of the valuables from the gangue. The ore was pulverized, sieved to liberation size and beneficiated. The mesh of grind was found to be 189 μm, and the liberation size was established to be 63 μm sieve size having the highest percentage of lead of 15.1% then enriched to 69.8% by froth flotation method and was assessed by using x-ray fluorescence (XRF). The lead concentrate by weight was obtained to be 81.80%, confirmed being of high economic grade having surpassed 60% wt Pb element in an ore. It is hoped that this will enhance its development to meet both local and international demand for potential investment opportunities.