Muhammad A. El Hameedy, Walid M. Mabrouk, Ahmed M. Metwally
Abstract Accurate characterization of shaley-sand reservoirs remains a significant challenge in petroleum geophysics, where complex clay mineralogy often renders traditional evaluation methods unreliable. This study introduces an integrated, data-driven framework that synergizes numerical optimization and machine learning (ML) to accurately estimate formation water resistivity (R w ) and predict water saturation (S w ), overcoming the limitations of data scarcity. The workflow begins with rigorous preprocessing of well log data from 11 wells across the Norwegian North Sea and Egyptian Western Desert. First, we establish a robust, physically-constrained R w by evaluating four optimization algorithms. The Powell and Nelder-Mead algorithms emerged as superior, demonstrating the ability to recover the true Rw from log data with low error (1×10-4 RMSE) against measured samples rapidly. This optimized R w then serves as a high-quality "pseudo-core" label to generate a continuous S w log for training a comprehensive suite of ML models, including ensemble methods (Random Forest, CatBoost, XGBoost) and neural networks (ANNs, LSTM), to predict S w . The models demonstrated predictive accuracy, validated by a robust 5-fold cross-validation protocol. On the blind test wells, the top-performing models (LSTM, CatBoost , and XGBoost) achieved a coefficient of determination (R2) up to 0.944 with Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE) as low as 0.03 and 0.050 respectively. The automated fusion of optimization-derived physics with ML-driven prediction marks a transformative step toward more reliable, data-centric petrophysical workflows. This integrated framework offers a significant enhancement in reservoir characterization, providing a cost-effective and scalable methodology that reduces reliance on expensive core analyses and improves the accuracy of hydrocarbon-in-place estimations.
<p>The most abundant mineral in the upper mantle, olivine, is described as nominally anhydrous, while its high-pressure polymorph, wadsleyite, can contain up to 3 % H<span class="inline-formula"><sub>2</sub></span>O by weight. Here we focus on the quantification of total H<span class="inline-formula"><sub>2</sub></span>O content, dissolved as hydroxyl (OH), as well as hydrogen isotopic composition, i.e. <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">D</mi><mo>/</mo><mi mathvariant="normal">H</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="930dd7e3de32880de8db3a2da0740eed"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-37-305-2025-ie00004.svg" width="24pt" height="14pt" src="ejm-37-305-2025-ie00004.png"/></svg:svg></span></span> ratios, in olivine and wadsleyite using a multi-instrument approach. Our aim is to establish a calibration procedure that allows accurate quantification of the hydrogen content and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">D</mi><mo>/</mo><mi mathvariant="normal">H</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="e4022fe1fd207c62e15fbadd87aa382d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-37-305-2025-ie00005.svg" width="24pt" height="14pt" src="ejm-37-305-2025-ie00005.png"/></svg:svg></span></span> ratios of D-doped experimental samples using Raman spectroscopy, as confirmed by secondary-ion mass spectrometry (SIMS). Olivine and wadsleyite samples were synthesized under hydrothermal conditions at high pressure and doped with deuterium. Olivine and wadsleyite reference materials that were previously characterized by both Fourier-transform infrared (FTIR) spectroscopy and elastic recoil detection analysis (ERDA) were used to calibrate the measurement of water concentrations in the samples using both Raman spectroscopy and SIMS. D-doped olivine reference materials were characterized by ERDA (which is a point beam technique with the advantage of being an absolute quantification method) to find their <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">D</mi><mo>/</mo><mi mathvariant="normal">H</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="1a8248039cc78c598c0e30bf487dec86"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-37-305-2025-ie00006.svg" width="24pt" height="14pt" src="ejm-37-305-2025-ie00006.png"/></svg:svg></span></span> ratio and used to determine the instrument mass fractionation of H isotopes with the ion probe. Then we compared the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">D</mi><mo>/</mo><mi mathvariant="normal">H</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="c78995d3f67856633c35697a267d9112"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-37-305-2025-ie00007.svg" width="24pt" height="14pt" src="ejm-37-305-2025-ie00007.png"/></svg:svg></span></span> ratios determined by SIMS to the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">OD</mi><mo>/</mo><mi mathvariant="normal">OH</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="41pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="2cc1e29e7cbb5e6250616346ce803788"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-37-305-2025-ie00008.svg" width="41pt" height="14pt" src="ejm-37-305-2025-ie00008.png"/></svg:svg></span></span> intensity ratio determined by Raman spectroscopy for three wadsleyite samples, finding a conversion factor of 0.85 (error of <span class="inline-formula">∼2</span> %). After correction of the instrument response, we find that the Raman scattering cross-section (<span class="inline-formula"><i>K</i></span>) of OH is slightly lower than that of OD; still <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M12" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>K</mi><mi mathvariant="normal">OH</mi></msub><mo>/</mo><msub><mi>K</mi><mi mathvariant="normal">OD</mi></msub><mo>=</mo><mn mathvariant="normal">0.95</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="81pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="c3bf3845ff844d5d2ce2456a7fe38c05"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-37-305-2025-ie00009.svg" width="81pt" height="14pt" src="ejm-37-305-2025-ie00009.png"/></svg:svg></span></span> is in agreement with previous studies. <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">D</mi><mo>/</mo><mi mathvariant="normal">H</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="1da8140e20db6bd42f7b603d40e61948"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-37-305-2025-ie00010.svg" width="24pt" height="14pt" src="ejm-37-305-2025-ie00010.png"/></svg:svg></span></span> ratios in doped samples can therefore be determined using Raman spectroscopy, which is a more accessible technique than SIMS, with a detection limit of <span class="inline-formula">90±10</span> ppm wt for both D<span class="inline-formula"><sub>2</sub></span>O and H<span class="inline-formula"><sub>2</sub></span>O.</p>
María Gabriela Fernández-Manteca, Borja García García, Celia Gómez-Galdós
et al.
<i>Patella vulgata</i> shells preserve geochemical and structural variations that can provide insights into past environmental conditions. Their composition, primarily calcium carbonate with organic residues from the biomineralization process, is influenced by external factors, such as sea surface temperature. Raman spectroscopy has emerged as a rapid, non-destructive tool for studying biogenic carbonates, enabling the identification of crystalline phases, organic components, and ion distribution. In this study, Raman imaging was applied to six shell sections of <i>P. vulgata</i> live-collected from Langre Beach in Cantabria, Spain. Spectral data were acquired using a Raman probe with a 532 nm excitation laser, providing high-resolution mapping of structural and compositional features. The analysis revealed spatial variations in mineralogy, organic matrix distribution, and ion incorporation in the calcium carbonate lattice, suggesting patterns originating during shell formation. Notably, the results suggest a consistent relationship between the organic and mineral components of the shells, with carotenoid distribution and carbonate ion substitution in the calcium carbonate lattice following similar growth patterns. These findings highlight the potential of Raman spectroscopy for studying biomineralization processes and the environmental records preserved in marine mollusk shells.
Co and Ni minerals are described in ores of the Mikheevskoe porphyry copper deposit (South Urals, Russia). Minerals of the cobaltite–gersdorfte series (CoAsS–NiAsS), violarite (FeNi2S4), millerite (NiS), pentlandite (Ni5.5Fe3.4)8.9S8.0 and melonite (NiTe2) are identifed. They overgrow pyrite, chalcopyrite and bornite and belong to late low-temperature assemblages. Cobalt and Ni are also incorporated in pyrite. The latter, being the most widespread mineral of the deposit, is a major carrier of these metals. The variability of Co and Ni minerals is determined by the presence of serpentinites, which replaced ultramafc rocks.
R. I. Shaibekov, A. M. Shmakova, E. M. Tropnikov
et al.
The rock composition and ore mineralization of the Malenkiy site located within the Khengur gabbro-dolerite complex of the Pay-Khoy were examined. Petrogeochemical analysis revealed two varieties of the studied rocks: fine-crystalline quartz and medium- and coarse-crystalline quartz containing metagabbro-dolerite. The Y, Zr, and Nb contents suggest that metagabbro-dolerites formed in an intraplate setting from enriched mantle sources during the melting of garnet peridotite, with a small contribution from the melt source of ancient continental crust. Two types of ore mineralization were distinguished: nest- and veinlet-disseminated sphalerite-chalcopyrite-pyrrhotite (type I) and veinlet-disseminated cobaltite-pentlandite-chalcopyrite-pyrrhotite (type II). The most efficient ore mineralization was type II, which is characterized by the presence of both high-temperature cobalt- and nickel-bearing sulfide minerals, as well as low-temperature tellurides of palladium (kotulskite) and silver (hessite).
The success of today’s calcifying organisms in tomorrow’s oceans depends, in part, on the resilience of their skeletons to ocean acidification. To the extent this statement is true there is reason to have hope. Many marine calcifiers demonstrate resilience when exposed to environments that mimic near-term ocean acidification. The fossil record similarly suggests that resilience in skeletons has increased dramatically over geologic time. This “deep resilience” is seen in the long-term stability of skeletal chemistry, as well as a decreasing correlation between skeletal mineralogy and extinction risk over time. Such resilience over geologic timescales is often attributed to genetic canalization—the hardening of genetic pathways due to the evolution of increasingly complex regulatory systems. But paradoxically, our current knowledge on biomineralization genetics suggests an opposing trend, where genes are co-opted and shuffled at an evolutionarily rapid pace. In this paper we consider two possible mechanisms driving deep resilience in skeletons that fall outside of genetic canalization: microbial co-regulation and macroevolutionary trends in skeleton structure. The mechanisms driving deep resilience should be considered when creating risk assessments for marine organisms facing ocean acidification and provide a wealth of research avenues to explore.
Abstract A significant deposition of black shales occurred during the Mesoproterozoic Oxygenation Event (MOE). In order to investigate the hydrocarbon generation potential and organic matter enrichment mechanism of these shale deposits, we studied the Xiamaling Formation shale in the North China region as a representative sample of the Mesoproterozoic shale. The research involved organic petrology, organic geochemistry, mineralogy, and elemental geochemistry. The following observations were made: (1) The depositional environment of the Xiamaling Formation shale can be categorized as either oxic or anoxic, with the former having shallow depositional waters and high deposition rates, while the latter has deeper depositional waters and slower deposition rates. (2) Anoxic shales exhibited significantly better hydrocarbon generation potential compared to shales deposited in oxic environments, although the latter still demonstrated high hydrocarbon generation potential. (3) Shales deposited in anoxic environments displayed higher paleoproductivity compared to those deposited in oxic environments. The high deposition rate in oxic environments slowed the decomposition and mineralization of organic matter, leading to the formation of high-quality shales. In contrast, the strong paleoproductivity, along with favorable preservation conditions, accounted for the high hydrocarbon potential of anoxic shales.
Kalateh Pialeh prospect area is located in the Kopeh Dagh zone, approximately 15 km northeastern of Esfarayen city. The area is composed of sedimentary rocks deposited during the Jurassic, Cretaceous, and Tertiary periods, which include microconglomerate, dolomitic limestone, sandy limestone, limestone, conglomerate, and marl. Mineralization occurs as epigenetic deposits hosted by dolomitic limestone and limestone. Two mineralization stages were identified. The first stage consists of a pyrite-galena-sphalerite assemblage with replacement and breccia textures, and the second stage comprising a galena-sphalerite assemblage with vein-veinlet, open space filling, and replacement textures. Dolomite and calcite are the most abundant gangue minerals associated with lesser amount of quartz and barite. Main alterations consist of calcitization and dolomitization. Galena mineral exhibits maximum geochemical anomalies of 1843 ppm for zinc, 7 ppm for arsenic, and 11 ppm for copper. Microthermometric studies on primary fluid inclusions (LV) reveal homogenization temperatures ranging from 180°C to 265°C for stage 1, and from 167°C to 214°C for stage 2. Salinities for these stages were found to be between 7.8 wt.% to 14.5 wt.% NaCl equiv., and 11.7 wt.% to 12.2 wt.% NaCl equiv., respectively. Based on evidence such as structurally controlled mineralization, the type of alterations and their linear expansion, simple mineralogy of ore, geochemistry, and fluid inclusion data, Kalateh Pialeh prospect area is similar to lead-zinc epithermal deposits.
Introduction
Sediment-hosted Pb–Zn deposits are typically found in clastic-carbonate (Sedex type deposits) and carbonate (Irish type and Mississippi Valley-type (MVT) deposits) rocks (e.g., Goodfellow & Lydon, 2007). In Iran, the wide distribution of clastic and carbonate rocks has led to the formation of various types of sedimentary-hosted lead and zinc deposits.These deposits occur in Cretaceous carbonate units, including Malayer-Esfahan, Tabas- Poshte-Badam, Yazd-Anarak, and Central Alborz metallogenic belts (Rajabi et al., 2012). Kalateh Pialeh prospect area, located in Kopeh Dagh zone, about 15 km northeastern of Esfarayen city, is the first report of lead and zinc mineralization in this zone. Kopeh Dagh zone is characterized by the absence of magmatic activity, the presence of limestone formations, and abundant hydrocarbon reserves (such as Khangiran Gas Field). This study summarizes the alteration, mineralogy, geochemistry, and fluid inclusion studies, and then discuss the ore genesis of Kalateh Pialeh prospect area.
Material and methods
Following field work, thin sections and polished slabs from the host rocks, veins and veinlets were studied using optical microscope. Red alizarin was also used to differentiate between calcite and dolomite. Galena minerals were seperated from host rock by using standard techniques involving crushing and handpicking under a binocular microscope at Ferdowsi University of Mashhad. Minor and rare element metal concentrations from galena were analyzed using ICP-OES techniques on five samples at Zarazma laboratory in Iran, while XRD analysis of the samples was done at the same laboratory. Microthermometric analysis of fluid inclusions was carried out on seven samples using a Linkam THM 600 heating-freezing stage combined with an Olympus TH4–200 microscope stage at Ferdowsi University of Mashhad, Mashhad, Iran.
Results and Discussion
The area comprises sedimentary units of microconglomerate, dolomitic limestone, sandy limestone, limestone, conglomerate, and marl. Vein-type epigenetic mineralization occurs along fault zones with trending NW–SE/vertical dip in dolomitic limestone and limestone. Mineralization can be divided into two stages: Pyrite-galena-sphalerite assemblage (with replacement and breccia textures), and galena-sphalerite assemblage (with vein-veinlet, open space filling, and replacement textures). The main alterations consist of calcitization and dolomitization. The oxidation and weathering processes have resulted in the formation of hemimorphite, smithsonite, cerussite, goethite, and hematite in the ore zones. Gangue minerals consist of calcite and dolomite with lesser amounts of barite and quartz. Geochemical analyses of the galena mineral reveal maximum anomalies for zinc (1843 ppm), arsenic (7 ppm), and copper (11 ppm). Microthermometric studies on primary fluid inclusions (LV) show homogenization temperatures ranging from 180 to 265°C and from 167 to 214°C for stages 1 and 2, respectively. The fluid salinities for these stages range from 7.8 to 14.5 wt.% NaCl and from 11.7 to 12.2 wt.% NaCl, indicating a wide range of salinities.The temperature of ore-forming fluids in MVT deposits varies from 50 to 250°C, with the majority falling within the 70 to 170°C range , and their salinity is between 10 and 30 wt. % NaCl (Leach et al., 2010). In Kalateh Pialeh sam ples, primary fluid inclusions hosted in quartz crystals homogenize to the liquid phase at temperatures ranging from 167°C to 265°C, (mostly in the range of 80 to 200°C) and the average salinity of 11 wt. % NaCl.
The salinity of the hydrothermal fluids at studied area varies from 7.8 to 14.5 wt. % NaCl. This wide range can be attributed to the mixing of two fluids with different salinities. These salinities can be divided into two groups with low salinity (7.8 to 10 wt. % NaCl) and high salinity (13.9 to 14.5 wt. % NaCl). The presence of two types of primary inclusions with different salinity but similar homogenization temperature is a sign of isothermal mixing of two fluids.
Moussa Ouedraogo, Moustapha Sawadogo, Issiaka Sanou
et al.
In this study, the sugar cane bagasse from Burkina Faso has been calcined at temperatures ranging from 550 to 750 °C with a heating stage of 2 or 3 h to produce pozzolanic ashes as supplementary cementitious materials for eco-cement production. The ashes obtained were subsequently characterized for their chemistry, mineralogy, and pozzolanic activity. The results of the characterization have shown that the ashes are rich in amorphous silica with a high Blaine specific area and a density around 2,5 g/cm3. The ashes are siliceous pozzolan type F. The main crystalline phases identified in these ashes are quartz (SiO2), calcite (CaCO3), muscovite (KAl2AlSi3O10(OH)2), microcline (KAlSi3O8), and hematite (Fe2O3). Frattini's test has shown that all ashes own a pozzolanic activity due to the formation of CSH resulting from the reaction between the portlandite of cement and amorphous silica of ashes. The strength activity index evaluated with 25 wt% cement replacement by SCBA is greater than the minimum value of 75% required by the standard for all the ashes except those prepared at 700 °C for 3 h, 750 °C for 2 or 3 h. Thus, these ashes can be used as a partial substitute for clinker in cement production.
Materials of engineering and construction. Mechanics of materials
This study was carried out to determine the sedimentary provenance of Upper Cretaceous turbidites of Tanjero Formation. The sandstone portion of the unit has been examined based on field and laboratory studies. Seven sections were measured and described in detail on the perfectly cropped out part of the unit at the southern limb of the Sulaimaniyah Syncline. The thickness of the measured sections varies from 120 m to 192 m. The measured sections start from the top of the underlying Shiranish Formation to the syncline axis in the Tanjero Formation. For petrographic analysis sixty- nine representative rock samples were collected. Modal analysis and ternary diagrams point out that, the sandstones are calclithite (litharenite), very fine to medium grained in size consisting of chert, siltstone, mudstone, radiolarian chert and radiolarian mudstone fragments, angular to subangular in shape, very poorly to moderately sorted, transported over short distances and represent submature stage. Grain contact types and high contact index (4.7) indicate moderate to tightly packing, moderate compaction. Transported broken neritic fossil shells, moderately rounded glauconite grains, and undefinable fossils in the altered carbonate rock fragments indicate that the tectonic provenance, lithic recycle category, composed of not only the clastics as interpreted in previous studies derived from Lower Cretaceous Qulqula (radiolarian) Formation which represents deep marine, but also it revealed that a sedimentary formation must also exist in the source area, which is the Lower Cretaceous Balambo Formation.
Hussain Asghar, Muhammad Sabir Khan, Saeed Abbas
et al.
A systematic geochemical investigation of the Laki Formation from the selected regions of Southern Indus Basin Pakistan Basin has been carried out. This paper presents the characterization of hydrocarbon potential, type of kerogen, thermal maturity, the origin of organic matter, depositional environment, and bulk mineralogy of the Laki Formation shales. The total organic carbon (TOC) content of the Laki shale ranges from 0.53 to 2.66 wt. %. The values indicate that Laki shales have fair to very good hydrocarbon potential. Type III kerogen is identified in the Laki shale based on TOC and residual potential (S2) data. Maturity parameters (Tmax & Methyl phenanthrene index) suggest that Laki shales are thermally immature for the generation of hydrocarbons. Normal alkane data and stable carbon (δ13C) isotopic value (-9.67 ‰ PDB) of the Laki shale indicates the predominantly marine origin of the organic matter. Dibenzothiophene/phenanthrene (DBT/P) ratio (0.08), Phytane (Ph)/n-C18 versus Pristane (Pr)/n-C17, and Pr/Ph versus DBT/P data suggest a marine environment of the Laki shale. The marine setting of the Laki Formation shale is further evident by coralline algae and Alveolina oblonga. X-ray diffraction (XRD) data reflect that Laki shale is brittle since it is dominated by high quartz and carbonates.
The mineralogical and petrogeochemical features of the Neoproterozoic kimberlite rocks of the Lahtojoki and Niilonsuo pipes of the Kaavi cluster (Kaavi-Kuopio, Finland) have been studied, differences in their petrogeochemical composition, quantitative and chemical composition of oxide minerals of deep (mantle) and kimberlite genesis have been revealed. The kimberlites of the pipes are moderately titanic, but the TiO2 content in the kimberlites of Niilonsuo is higher (2.11 wt.%) than in the kimberlites from the breccia of the Lahtojoki pipe (1.07 wt.%). The kimberlites of the Niilonsuo pipe also differ in higher concentrations of Fe2 O3 , Ca, P, K, Rb, V, Nb, Ba, Th, U, Ta and REE. In the Lahtojoki kimberlite breccias the main TiO2 concentrator mineral is magnesian ilmenite (13,3—15,2 wt.% MgO; 0,5—4,4 wt.% Cr2 O3 ), (macrocrysts up to 4 mm); the fine-grained matrix of rocks contains small grains of rutile, chromespinelides, Mn-ilmenite and sometimes titanomagnetite. Macrocrystals of magnesian ilmenite have been not found in the kimberlites of the Niilonsuo pipe, perovskite acts as the main mineral of titanium, and chromespinelids and titanomagnetite are less common. Long-term crystallization of relatively large (up to 200 μm) perovskite grains proceeded according to estimates using an Nb-Fe-perovskite oxybarometer under a wide range of oxygen fugacity (fо2 ) of the kimberlite melt (NNO from -3,8 to 5,1). Chromespinelids from the groundmass of kimberlite pipe rocks differ in composition, but have the same specific zonality — enrichment of Al and Mg in the edge zones of crystals, which is possibly due to the dissolution of phlogopite phenocrysts in the rising kimberlite melt. In addition to oxide minerals, djerfisherite is widely distributed in the groundmass of kimberlites of the Niilonsuo pipe, the composition of which for the rocks of the body has been described for the first time. The combination of features of oxide mineralization indicates unfavorable conditions for the preservation of diamonds during their transportation by kimberlite melt.
ÖZ
İzmir -Dış- Körfezi’ndeki Uzun ada, Hekim adası, Çiçek
adaları ve Karantina adasında, bölgenin geç Erken Miyosen kalkalkali
asidik-ortaç volkanizmasından türeyen volkanoklastikler ile Orta Miyosen gölsel
çökelleri ve alkali volkanitler yüzeyler. En yaşlı kaya birimi, geç Erken
Miyosen döneminde esas olarak kalkalkali andezitikdasitik ürünler veren Kocadağ
volkanizmasından türemiş Kocadağ volkanoklastikleri ile simgelenir. Uzun ada
kuzeyinde yayılım gösteren volkanoklastik istif, ignimbirit ve bloklu kül akışı
fasiyeslerindeki piroklastikler ile volkanik kütle akması (lahar) fasiyesindeki
epiklastiklerden oluşur. Foça Yarımadası’nın bulunduğu çevreden türeyerek Uzun
adanın bulunduğu bölgeye ulaşan riyolitik ignimbiritlerin temsil ettiği Foça
tüfü, Kocadağ volkanoklastikleri üzerine başlıca iki patlama evresinde
yerleşmiştir. Patlama evreleri arasındaki durgun dönemde, Değirmentepe üyesi
adıyla ayırtlanan, volkanik kaba kırıntılı alüviyal çökeller depolanmıştır.
Foça Yarımadası’ndaki korelan ignimbiritlerle yanal ilişkili bir riyolit
domundan 16,0 My K/Ar yaşı alınmış ve Foça tüfünün Erken Miyosen sonlarında
bölgeye yerleştiği değerlendirilmiştir.Foça tüfü üzerinde uyumsuzlukla yer alan
egemen gölsel Orta Miyosen istifi Urla grubu kapsamında tanımlanmıştır. Urla
grubu, alttan üste, alüviyal Beşiktepe formasyonu, gölsel ortamda çökelmiş
volkanik yoğunluk akması çökelleri ile felsik ignimbirit aradüzeylerinde oluşan
Pırnallı ada volkanoklastikleri, alkali bazik volkanitlerin simgelediği Hekim
adası bazaltı ve gölsel Urla kireçtaşı’nı kapsar. Foça tüfü üzerindeki uyumsuz
konumuyla Orta Miyosen havza kenarı çökelimini yansıtan Beşiktepe formasyonu,
yalnızca Uzun adada yüzeyler. Hekim adası ve Çiçek adalarındaki yayılım alanı
içinde tabanı gözlenemeyen Pırnallı ada volkanoklastik istifi, esas olarak
sualtı çekim akması dinamikleriyle çökelmiş epiklastiklerden oluşur ve farklı
kaynaklanma derecelerinde trakitik ignimbirit ara düzeyleri kapsar. Pırnallı
ada volkanoklastiklerini oluşturan başlıca kaya türü bileşenleri, Menteş
Yarımadası’nda Orta Miyosen boyunca etkinliğini sürdüren alkali trakitik
volkanizmadan türemiştir. Urla kireçtaşı istifinin tabanına sil şeklinde
sokulan Hekim adası bazaltının çıkış merkezi, adını aldığı Hekim adasındadır.
Urla kireçtaşının tabanındaki kıyı gerisi çökellerine alttan sokulan bazaltın
üst dokanağında, lav-sulu sediman ilişkisini yansıtan peperitler oluşmuştur.
Ana element bileşimine göre trakibazalt ve bazaltik trakiandezit olarak
adlanabilen bazik lavlardan 14,8±0,8 My K/Ar yaşı alınmıştır. Foça
Çöküntüsü’nün ortasında yüzeyleyen Hekim adası bazaltı, Foça Yarımadası’ndaki
Ilıpınar bazaltı ile Urla havzasındaki Ovacık bazaltının zaman-kayastratigrafik
korelanıdır. Hekim adası bazaltını transgresif olarak üstleyen Urla kireçtaşı
istifi, kıyı gerisi çamurtaşlarıyla başlar, stromatolitik onkoidler ve algal
biyoklastlardan yapılı kıyı önü çökellerini izleyen çörtlü kireçtaşları ile
Orta Miyosen sonlarına kadar devam eder.
The objective of this study was to investigate the physical, chemical, and mineralogical composition of lateritic soils in order to use these soils as potential commercial products for industrial application in the future. Five lateritic soils derived from various parent materials in Taiwan, including andesite, diluvium, shale stone, basalt, and Pleistocene deposit, were collected from the Bt1 level of soil samples. Based on the analyses, the Tungwei soil is an alfisol, whereas other lateritic soils are ultisol. Higher pH value of Tungwei is attributed to the large amounts of Ca2+ and Mg2+. Loupi and Pingchen soils would be the older lateritic soils because of the lower active iron ratio. For the iron minerals, the magnetic iron oxides such as major amounts of magnetite and maghemite were found for Tamshui and Tungwei lateritic soils, respectively. Lepidocrocite was only found in Soka soil and intermediate amounts of goethite were detected for Loupi and Pingchen soils. After Mg-saturated and K-saturated processes, major amounts of mixed layer were observed in Loupi and Soka soils, whereas the montmorillonite was only detected in Tungwei soil. The investigation results revealed that the parent materials would play an important role during soil weathering process and physical, chemical, and mineralogy compositions strongly affect the formation of lateritic soils.
Bu çalışmada Gümüşhane şehir merkezinden geçen karayolu kenarındaki topraklarda ve bu topraklarda yetişmiş akasya (Robinia pseudoacacia L.) ağaçlarının 1-2 yıllık sürgünlerinde ağır metal/iz element birikimleri araştırılmıştır. Topraklardaki ağır metal içerikleri Zenginleşme Faktörü (EF) ve Jeobirikim indeksi (Igeo) parametreleri kullanılarak, bitkilerdeki ağır metal içerikleri ise Biyo Birikim Faktörü (BAF) ile incelenmiştir. Igeo verilerine göre toprağın Cr, Co, Cu, Rb, Sr bakımından kirlenmemiş, V, Ni, ve Zn bakımından kirlenmemiş-orta kirlilikte olduğu, As bakımından orta aşırıca-aşırı kirli, Pb bakımından ise orta-aşırı derecede kirlenmiş olduğu görülmüştür. EF parametrelerine göre ise Cr, Co, Sr ve Ba’ca yok-az derecesinde zenginleştiği, Ni ve Cu’ca yok-orta derecede, Zn açısından az-aşırı, As’ce aşırı-çok aşırı ve Pb’ca ise az-çok çok aşırı zenginleştiği gözlenmektedir. Akasya sürgünlerinin iz/ağır element içeriklerinin genel olarak akasya için normal değerler içinde olmakla birlikte, Cu, Fe, Mo, Ni, Sr ve Zn konsantrasyonlarının bazı örnek noktalarında normal değerlerin üst sınırlarının üstünde ve/veya bu değerleri aşmış olduğu tespit edilmiştir.