Geochemistry and tectonic signifi cance of the ophiolitic rocks of the Yarpuz-Kaypak (Amanoslar, Osmaniye) area

The Bracco chromitites are hosted in the Mesozoic Ligurian Ophiolites (Italy) and provide key insights into the magmatic and post-magmatic (i.e. metamorphic and hydrothermal) evolution of gabbro-hosted chromitites in an oceanic mantle. Petrographic and mineralogical analyses reveal that the Bracco chromitites comprise cumulitic, massive to disseminated, layered chromitites overprinted by multi-stage alteration within altered olivine–clinopyroxene–anorthite cumulates. Detailed Cr–Al– Fe³+ systematics indicates that primary Cr- to Al-rich chromite, affected by metamorphic-hydrothermal processes under sub-greenschist facies conditions, locally escaped recrystallization and metasomatic modification. Consequently, chromite cores preserve their primary magmatic compositions consistent with crystallization from aluminous melts produced by low-degree partial mantle melting at a midocean ridge (MOR) setting. Metamorphic-hydrothermal alteration is marked by multi-stage ferrian chromite rims, whereas based on their Mg content the associated chlorite is classified as clinochlore. Chlorite geothermometry indicates alteration temperatures in the range of ~100-300 °C, consistent with oceanic serpentinization under prehnite-pumpellyite facies conditions. The hydrothermal fluids were oxidizing, enriched in SiO2 and MnO, and circulated through fracture networks in the shallow oceanic lithosphere. Elevated MnO amounts in alteration rims suggest widespread Mn-enrichment in these fluids, potentially linking them to seafloor Mn deposits in the Ligurian Ophiolites. Together, these findings indicate that the Bracco chromitites, their gabbroic hosts, and associated lherzolitic mantle rocks were at least partially exposed at the Tethyan seafloor prior to their final emplacement during the Alpine orogenetic phase, where serpentinization promoted complex chromite alteration.

This study aims to investigate geochemical and petrological characteristics, chemical weathering indices and provenance of the beach sands collected from 11 different sites along the coastlines of Bartın, Samsun and Ordu districts adjacent to mafic and intermediate volcanic rocks on the Pontides. Petrological findings show that the abundance of detrital quartz, feldspar and sedimentary lithic fragments increase in beach sands of the Bartın region where the SiO2 values fall in a wide range (47 to 87 wt.%). The Samsun and Ordu beach sands have moderately low SiO2 (50 to 61 wt. % and 48 to 62 wt. %, respectively) and relatively high Fe2O3 contents. LREE concentrations of investigated beach sands show enrichment patterns. Mafic minerals, especially pyroxene and magnetite grains are represented by eroded or abraded morphologies due to dissolution and erosion processes, while opaque heavy minerals show signs of recycling from basic adjacent rocks with etched to subrounded grain surface textures. The low chemical index of alteration (CIA) estimated for the beach sand samples implies the presence of fresh rock erosion along the coasts. We used magnetite to gain better understanding of the formation and origin of Fe-rich beach sands. The mineral chemistry data indicate that studied magnetites have quite similar composition and the mobility of trace elements exerts a great control on their distribution in magnetite.

Şile Neogene Basin (ŞNB) is one of the world’s crucial sedimentary clay-sand-coal basins, where approximately 3 million tons of clay and 20 million tons of sand are produced annually. The ŞNB, with a thickness of

As a result of complex studies - geological-structural, morphostructural analytical, mineralogical mapping of quartz formations, detailed geochemical work and analysis of geochemical fields – forecasting prospecting features of gold ore taxon’s: ore zone; ore field; deposit and ore body. They are characterized by groups of criteria: morphostructural, stratigraphic-lithological, structural-tectonic, magmatic, geophysical, metasomatic, mineralogical, geochemical factors and attributes, and a geological-genetic model of the gold-bearing ore-forming system in the collapse zone. Favorable geological and structural conditions for the localization of gold mineralization in the mountains of Karakchatau are associated with the areas of long-term tectonic-magmatic activation in metalliferous sediments of Є-О contrast lithological composition. The coincidence of manifestations of gold mineralization to the blocks formed by transverse faults at the sites where they intersected the Karakchatau crush zone was noted. To the channel-localizing parts inside are blocky and unextended interblock tectonic structures with positions in favorable “structural traps” in their azimuthal curvatures of executed productive types of hydrothermal, sulfidizing quartz. The results of mineralogical mapping of quartz formations along the Karakchatau crush zone (Western Uzbekistan) are considered. Five genetic types of quartz are distinguished. The most productive of them is hydrothermal quartz of types 3 and 4 associated with pyrite,arsenopyrite and gold, which forms vein fields in areas of kinks and expansion of the zone of crushing. Identification of any goods and services that can be used for commercial purposes, including in the geological structure, other regions of Western Uzbekistan. https://doi.org/10.19111/bulletinofmre.432046  

In this study, the genus Alveolina D’ Orbigny, 1826 and its Alveolina (Alveolina) D’ Orbigny, 1826 and Alveolina (Glomalveolina) Hottinger, 1960 subgenera were re-examined and identified. Systematics of the subgenera Alveolina (Alveolina)=Alv. (Alv.) and Alveolina (Glomalveolina)=Alv.(Glomalv.) have also been reviewed and revised. Alv. (Glomalv.) is considered as a subgenus, not a genus (?). Because, all the generic features of microspheric generations (fB) of these two subgenera are identical. Thus, Alveolina D’ Orbigny, 1826 and Glomalveolina Hottinger, 1960 cannot be used as if they were two different genera (?). Otherwise Glomalveolina would be the synonym of Alveolina in “Systematic Paleontology” chapter. Therefore, Alv. (Alv.) and Alv. (Glomalv.) are both subgenusses, and the structural difference between these subgenera is observed seen in their megalospheric generations (fA). Besides, description of the genus (?) Glomalveolina has never been made in any of the studies in which Glomalveolina is referred as genus (?). However, the subgenus Alv. (Glomalv.) has incorrectly been used by many authors as “genus (?) Glomalveolina Hottinger, 1960 or 1962”. https://doi.org/10.19111/bulletinofmre.501688

The toxicity risks of being over exposed to ionizing radiation in the environments are of great concern to environmental and health scientists. The distribution of radioactivity concentrations of thorium, uranium and potassium were studied in randomly selected soil samples from ten (10) farm locations in Odo Oba, southwestern Nigeria in order to determine the radiological risks of farmers’ exposure to radionuclides. The mean estimation of thorium and potassium are greater than the global average by factors of 1,5 and 2,7, while that of uranium fall below the global average. The estimation of radioactivity ratios showed a depletion of uranium and enrichment of thorium in the study area. Further analysis on the radioelements (that is, thorium, uranium and potassium) showed that 83% of the estimated radiological risks are above the global average. The multivariate analyses involving Pearson’s correlation, Factor Analysis, Hierarchical Cluster Analysis were also used to explain the correlations among the data sets. It was affirmed from the multivariate analysis that the radiological hazards occur as a result of contributions from the three naturally occurring radionuclides. The values obtained in this study revealed that the sampled locations are contaminated zones for farmers. https://doi.org/10.19111/bulletinofmre.495321