Sedimentary Geochemistry

The Kamisimbi sector consists of Kibarian Precambrian and Phanerozoic formations with quartzite, sandstone, schist, phyllade, trachyte, etc. as characteristic lithology. Structurally, several structural elements have been listed including veins with a preferential orientation of NE-SW, schistosities with two preferential orientations of NE-SW and NNW-SSE; NE-SW for diaclases and joints with a preferential direction orientation E-W. There are two preferential orientations of the lamination surfaces, one of NE-SW and the other of NNE-SSW. The analysis of the constraints that have affected our field of study shows the presence of compressive forces and those of distensions. The constraints σ1, σ2 and σ3 are respectively N61°E/ 36°E NE, N251°E/ 53°WSW and N155°E/ 5°SSE. We noticed the presence of dexter setback and sinistral strike-slip. RESUME : Le secteur de Kamisimbi est constitué des formations précambriennes Kibariennes et phanérozoïques avec comme lithologie caractéristique, le quartzite, le grès, le schiste, le phyllade, le trachyte, etc. Sur le plan structural, plusieurs éléments structuraux ont été répertoriés dont les filons ayant une orientation préférentielle de NE-SW, les schistosités avec deux orientations préférentielles de NE-SW et NNW-SSE, les diaclases NE-SW, les joints avec une orientation de direction préférentielle E-W. Il se remarque deux orientations préférentielles des surfaces de stratification dont une de NE-SW et l'autre de NNE-SSW.L'analyse des contraintes ayant affecté notre secteur d'étude montre la présence des forces compressives et celles de distensions. Les contraintes σ1, σ2 et σ3 valent respectivement N61°E/ 36°E NE, N251°E/ 53°WSW et N155°E/ 5°SSE. Nous avons remarqué la présence de décrochement dextre et senestre. Mots-clefs : Sud-Kivu, Kamisimbi, Kibarien, rift, schistosité, décrochement, contrainte .

Three stratigraphic sections were sampled to demystify the geochemical properties of the shallow marine Govanda Formation, located in the Arabia-Eurasia suture zone at ~ 1500 m above sea level. This study examined the geochemistry of major, trace, rare earth elements (REE) and the petrography of carbonate rocks of the lower-middle Miocene Govanda Formation. Microfacies analysis shows that packstone and wackestone dominate the ticker western section, whereas the eastern sections contain grainstone and clastic units. The carbonates were deposited in shallow marine reef-fore-reef environments unaffected by diagenetic alterations. The limestone beds have a consistent seawater-like REE pattern, slightly negative Ce anomalies (Ce/Ce* = 0.79 in massive limestone-MSL and = 0.89 in marly limestone-ML), relatively positive Eu anomalies (Eu/Eu* = 1.18 in MSL and = 1.14 in ML), and moderately high Y/Ho ratios (37.69 n = 29). The REE + Y pattern of samples mainly retains its original characters, but the variations in the total rare earth element (ΣREE) content are detected, which could reflect minor detrital material inputs. Authigenic U, negative Ce anomalies, and trace element ratio indices such as V/ Cr, U/Th, Ni/Co, and V/(V + Ni) indicate suboxic-anoxic deposition condition. A positive correlation of Al 2 O 3 % contents with Fe 2 O 3 % links the carbonate units of the Govanda Formation to marine limestones. The Rb-Sr-Ba ternary diagram, and Sr/Ba vs. Sr/Rb, Al 2 O 3 % vs. Fe 2 O 3 %, and Ce/Ce* vs. Sm/Yb bivariate analyses imply that the studied limestones originated in a passive margin tectonic setting.

Point-bar deposits are sand-prone units of meandering fluvial stratigraphy and can form important hydrocarbon reservoirs or carbon capture sites. Large-scale (>10 km wide) point-bar deposits are typically deposited over >1000 years and show greater complexity than those in smaller-scale systems (10 2 to 10 3 m wide). False River is an oxbow lake adjacent to the Lower Mississippi River, which encloses a large Upper Holocene point-bar deposit (12.5 9 8.5 km and 20 to 20-30 m thick). In this study, we assess the planform evolution of the point-bar deposit and identify nine phases of meander growth, with the ninth being meander abandonment. The point-bar deposit grew by phases of extension, downstream accretion, expansion, and then lastly rotation. The predicted planform lithological heterogeneity was mapped, and tested using a combination of coring, natural gamma ray (NGR), electrical conductivity (EC) and hydraulic pressure tool (HPT) logging. EC logging shows the best alignment with lithology showing mud-prone sediments commonly near the top of the point-bar deposit, sand-prone sediments in the lower part and a greater prevalence of mud-prone sediment towards the terminal apex. Complexities include docked mid-channel bar deposits in the upstream limb of the point-bar deposit and the lithological detail caused by micro-adjustments of scroll bar growth. Also, the meander plug that formed during the meander abandonment phase shows both laterally and vertically accreted sediment deposits. The laterally accreted sediment tends to fine upwards as they were deposited in a waning flow, and the vertically accreted sediment tends to coarsen upwards having formed by deltaic processes. The geophysical findings are added to the lower-resolution predictive models and though we find broad correlations, there is missing detail and complexity. As such, this study presents insights that improve the global understanding of how the planform of the point-bar deposit connects to the underlying sedimentology and refines predictive techniques for better interpreting the subsurface.

Many coastal marshes dominated by the invasive species, for example, Spartina alterniflora, had been cleared to create aquaculture ponds for shrimp farming. Efforts were made in recent years to revert aquaculture ponds to wetlands using the native species Phragmites australis and Cyperus malaccensis. This study quantified the impact of this restoration effort on sediment methane production potential (PCH4) and methane emission (FT-CH4) in southeastern China. The results showed that restoration decreased PCH4 from 30.3 to 23.9 ng CH4 g􀀀 1 d􀀀 1 and
decreased FT-CH4 from 13.9 to 2.8 mg m􀀀 2 h􀀀 1. The abundance of mcrA gene decreased by 58.6 %, whereas pmoA gene abundance increased by 103.1 % in restored wetlands. Structural equation modeling (SEM) showed that decrease in PCH4 was primarily caused by changes in sediment labile organic carbon and SO42- contents, which led to a decrease in mcrA gene and an increase in pmoA gene. Reconnecting the aquaculture ponds to adjacent coastal area improved seawater exchange and oxygenation. Compared to the original Spartina-dominated marshes, the restored wetlands had lower methane contribution, above-ground vegetation biomass and organic deposition. Overall, this study showed that active restoration using native vegetation is preferred over passive restoration for
coastal wetlands.

In order to determining the timing and impact of the Deccan Trap massive flood basalt volcanism on the concomitant ecosystem, mercury (Hg) and tellurium (Te) concentrations from sediment repository of Western Tethys Sea (present day Haymana basin, Turkey) have been assessed. The Hg concentration across the sediment profile is erratic (perhaps from secondary diagenesis) and therefore, less reliable whereas the magnitude of Te enrichment in both phases of the DT LIP eruptions is in harmony with the estimated eruption rate of the Deccan lava flow and other established proxies of the K/Pg boundary crisis. Hg and Te enrichment peaks imply that the second phase eruption of the Deccan Trap large igneous province (LIP) began in the latest Maastrichtian and ended at the P0 zone into the Danian whereas the subsequent eruption pulses continued until at i least the Danian P1b zone. The redox element tracers (like U, Mo, V, As, and Cr) reflect a brief post-K/Pg recovery of the oxygen stress and the nutrient-type elements (like Ni, Zn, Cd, and Cu) suggests continuation of productivity possibly by the stress-tolerant primary producers. However, the paleo-redox conditions and paleoproductivity apparently had no significant influence on Te/Th ratios. Furthermore, it has been assumed that microalgal (dinoflagellate) primary production and anoxia-mediated microbial metabolism could modify the Te enrichment in the Haymana sediment and thus Te could also signify the oceanic paleoproductivity in times of severe environmental stress.

Ammacio kaolin deposit is found in Gibe Woreda, the Hadiya Zone, southwest of the Central Main Ethiopian Rift. A combination of geological, mineralogical, physical, and geochemical methods was employed to investigate the origins of the Ammacio kaolin occurrence. The main lithological units revealed in the study area are basalt, moderately welded tuff, and unconsolidated sediment. Results from geology, mineralogy, and geochemistry indicate that a moderately welded tuff of the study area is the principal parent rock of the Ammacio kaolin deposit. The petrographic study of the parent rock showed plagioclase (2 %), alkali feldspar (10 %), quartz (4 %), and lithic fragments (1 %) in the matrix of a fine-glassy groundmass (83 %). According to SEM, ATR-FTIR, and XRD investigations, the kaolinite of the Ammacio area possesses moderate to good crystalline characteristics. Geological, mineralogical, and geochemical signatures, with a higher chemical alteration index (CIA = 84.4 %) and chemical index of weathering (CIW = 92.4 %), indicate that the kaolinite was formed by moderate to intense supergene chemical weathering process of the moderately welded tuff. Furthermore, the origin of the Ammacio kaolin was influenced by the supergene process, as evidenced by the thick soil coverage (av. ~5 m), less than 2 g/ cm 3 bulk density, and lines with Al 2 O 3 /SiO 2 < 0.5, TiO 2 > 1 wt%, Cr + Nb < 1000 ppm, Ba + Sr > 100 ppm, and Fe 2 O 3 + TiO 2 > 1 wt% of the kaolin. Overall, the results of geological, mineralogical, geochemical, and physical examinations showed that the genesis of the Ammacio kaolin deposit is supergene.

in upstream dam catchments are the primary drivers of escalating reservoir sedimentation rates. Human encroachments into the previously undisturbed areas, localized restoration efforts, and shifting hydro-climatic regimes under global climate change have significant potential to alter the current rate of reservoir sedimentation. This underscores the need to estimate sediment yield, export and retention capacity in reservoir catchments, under future land-use and land-cover (LULC) change and climate uncertainties, to effectively manage water resource structures. Water erosion of soils constitutes a pressing environmental concern worldwide (FAO, 2015) and most academic discourses on revolves around two dominant drivers: Land-Use and Land-Cover Transformation (LULCT) and climate Krishna Gopal Ghosh

We analyzed physical properties, diatoms, and geochemistry in
a 1500-year sediment profile from a small, mid-elevation lake in
west central Costa Rica formed by a landslide. Laguna Arancibia
occupies an area long affected by landslides, including large debris
avalanches; in 2000 CE one of the largest debris avalanches
recorded in Costa Rica passed within 300 m of the lake.
A systematic archaeological survey provides context for the paleolimnological
study, showing sparse human settlement during the
Pavas archaeological phase (2250–1650 cal yr BP), a hiatus during
the Curridabat phase (1650–950 cal yr BP), and repopulation during
the Cartago phase (950–400 cal yr BP). Our record begins during the
hiatus, when diatoms indicate a shallow lake. A major shift in
diatoms followed by increased inorganic sedimentation suggests
humans returned about 880 cal yr BP. Peaks in inorganic sediment
influx during the Cartago phase document erosion from agricultural
fields or landslides possibly triggered by forest clearance. However,
stable carbon isotopes in n-alkanes of terrestrial leaf waxes indicate
extensive C3 forest since reoccupation, suggesting only moderate
deforestation for agriculture by a small population. The Spanish
Conquest may have further reduced, or completely destroyed, this
population, but evidence in the sediment record is inconclusive.

This article discussed on the status of heavy metals (As, Cr, Cu, Mn, Ni, Pb and Zn) pollution in coastal sediment cores and assess the sediment quality from Usukan Beach, Kota Belud. Several geochemical parameter analyses such as pH, moisture content (MC), organic matter (OM) and granulometric size were performed to identify the physico-chemical properties of sediments that affect the assessment of metal pollution. Heavy metals in the sediment samples were extracted using aqua regia methods and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) were employed for determination of heavy metals in extracted sediment solutions. The results show that the coastal sediment changes from acidic to alkaline when heading from inland to seaward direction, with an average pH of 5.6-8.5. The moisture content and organic matter fluctuate from low to moderately high, within the range of 4.9-21.9% and 0.30-6.73%, respectively. The coastal sediments are dominated by a sandy texture near the marine environment and change to sandy loam and sandy clay loam when heading toward the inland. The hierarchical average metal concentration shows Fe>Mn>Ni>Cr>Zn>Cu>Pb>As. Sediment quality assessment is evaluated based on the sediment quality guidelines (SQGs) and from the pollution indices such as geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (CF), modified degree of contamination (mCd) and pollution load index (PLI). The results indicated the sediment has only low degree of contamination by anthropogenic sources and the current status of the study area is safe from pollution.

Archaeological floors, on which life and diverse activities were carried out on in the past, are invaluable sources of knowledge in understanding past human and non-human activities of their respective period. These surfaces, preserving traces of past lives have witnessed a myriad of practices, from the production of tools and personal adornments to the preparation, sharing, and consumption of food, and from the processing of cereals to the controlling of animals. However, despite their importance, in-depth studies remain rare. This thesis zeroes in on archaeological earthen floors to perceive the built environment at the Pre-Pottery Neolithic site of Aşıklı Höyük in the Cappadocian volcanic highlands of modern Türkiye (cal. 8350 BCE). This research aims to uncover human-animal-plant interactions via sediments by employing phytoliths, spherulites, and sediment geochemical analysis. Utilizing this multi-proxy approach also reveals insights into anthropogenic, geological, taphonomic, and biological processes. The micro- contextual data indicate a clear compartmentalization of space for distinct activities and underscore an increasingly intricate network of interdependencies among humans and non-humans (caprines, plants, dung, and architectural features) from the lowermost phase of the settlement. Among the studied spaces, evidence of possible animal enclosures, nuanced storage practices, and indoor cereal processing suggests the fluid and dynamic nature of spatial arrangements. Overall, the application of distinct proxies enabled a robust methodological framework for future research, allowing for the reconstruction of prehistoric spaces with remarkable clarity. Geçmişte yaşamın ve çeşitli faaliyetlerin sürdürüldüğü arkeolojik tabanlar, ilgili dönemdeki insan ve insan dışı canlıların faaliyetlerini anlamada paha biçilmez bilgi kaynaklarıdır. Geçmiş yaşamın izlerini koruyan bu yüzeyler, alet ve kişisel süs eşyalarının üretiminden yiyeceklerin hazırlanması, paylaşılması ve tüketilmesine, tahılların işlenmesinden hayvanların kontrol altına alınmasına kadar uzanan sayısız uygulamaya tanıklık etmiştir. Buna karşın, önemlerine rağmen derinlemesine ele alındıkları çalışmalar nadirdir. Bu tez, günümüz Türkiye’sinin Kapadokya volkanik yüksek platosundaki Çanak Çömleksiz Neolitik yerleşimi Aşıklı Höyük’te (kal. MÖ 8350) inşa edilmiş ortamları kavramak adına arkeolojik toprak tabanlara odaklanmaktadır. Araştırma, fitolit, sferülit ve sediman jeokimyasal analizlerini kullanarak, sedimanlar aracılığıyla insan-hayvan-bitki etkileşimlerini ortaya çıkarmayı hedeflemektedir. Bu çok-göstergeli yaklaşımın uygulanması, antropojenik, jeolojik, tafonomik ve biyolojik süreçlere ilişkin önemli verilerin de açığa çıkarılmasını sağlamaktadır. Mikro-bağlamsal veriler, farklı faaliyetler için mekanın net bir şekilde bölümlendiğini göstermekte ve yerleşimin en erken seviyelerinden itibaren insanlar ve insan dışı varlıklar (koyun/keçiler, bitkiler, gübre ve mimari öğeler) arasındaki giderek karmaşıklaşan karşılıklı bağımlılık ağını vurgulamaktadır. Çalışılan mekanlar arasında, olası hayvan barınaklarına, incelikli depolama uygulamalarına ve iç mekanda tahıl işlemeye dair kanıtlar, mekânsal düzenlemelerin akışkan ve dinamik doğasını göstermektedir. Sonuçta, farklı göstergelerin uygulanması, gelecekteki araştırmalar için sağlam bir metodolojik çerçeve sunarak tarihöncesi mekanların dikkate değer bir açıklık düzeyiyle yeniden kurgulanmasına olanak tanımıştır.

An examination of the deeply incised Ediacaran Wonoka canyons in the Adelaide Geosyncline (most recently interpreted as subaerial valleys) demonstrates their submarine origin, and confirms them as some of the best examples of ancient outcropping submarine canyons in the world. The entire canyon-fill succession is interpreted to be of deep-water (below wave base) origin, consisting of calcareous shale and siltstone together with a variety of mass-flow deposits including turbidites, grain flows and debris flows. The canyon fill lacks definitive shallowwater structures (e.g. mud cracks, fenestral fabrics or wave ripples) at all stratigraphic levels. Canyon-lining carbonate crusts that have previously been interpreted as non-marine calcretes or tufas (and used to suggest a non-marine origin for the canyons) are argued to be of deep-water, marine, microbial origin. Extremely negative carbon isotope values from the canyon-fill and canyon-lining crusts have a primary marine origin. Previously interpreted deepening upward trends in the canyon fill (used as evidence of a subaerial erosion episode followed by drowning) are suggested to be fining upward trends, caused by the transition from canyon cutting to canyon filling, with the majority of the fill being of deep-water slope origin. The basal conglomeratic canyon-fill sediments represent the last vestiges of the high-energy, deep-water, canyon-erosion environment in which the incisions formed. A deep-water origin for the canyons is consistent with all previous stratigraphic observations of the Wonoka canyons, including the conspicuous lack of regional unconformities in the lower Wonoka Formation, and their emanation from the deep-water facies of the Wonoka Formation. A submarine canyon origin also removes the need for extreme (~1 km) relative sea level fluctuation and associated problems (i.e. an enclosed basin with Messinian-style evaporative drawdown or thermal uplift above a migrating mantle plume) required by the subaerial valley hypotheses.

An examination of the deeply incised Ediacaran Wonoka canyons in the Adelaide Geosyncline (most recently interpreted as subaerial valleys) demonstrates their submarine origin, and confirms them as some of the best examples of ancient outcropping submarine canyons in the world. The entire canyon-fill succession is interpreted to be of deep-water (below wave base) origin, consisting of calcareous shale and siltstone together with a variety of mass-flow deposits including turbidites, grain flows and debris flows. The canyon fill lacks definitive shallowwater structures (e.g. mud cracks, fenestral fabrics or wave ripples) at all stratigraphic levels. Canyon-lining carbonate crusts that have previously been interpreted as non-marine calcretes or tufas (and used to suggest a non-marine origin for the canyons) are argued to be of deep-water, marine, microbial origin. Extremely negative carbon isotope values from the canyon-fill and canyon-lining crusts have a primary marine origin. Previously interpreted deepening upward trends in the canyon fill (used as evidence of a subaerial erosion episode followed by drowning) are suggested to be fining upward trends, caused by the transition from canyon cutting to canyon filling, with the majority of the fill being of deep-water slope origin. The basal conglomeratic canyon-fill sediments represent the last vestiges of the high-energy, deep-water, canyon-erosion environment in which the incisions formed. A deep-water origin for the canyons is consistent with all previous stratigraphic observations of the Wonoka canyons, including the conspicuous lack of regional unconformities in the lower Wonoka Formation, and their emanation from the deep-water facies of the Wonoka Formation. A submarine canyon origin also removes the need for extreme (~1 km) relative sea level fluctuation and associated problems (i.e. an enclosed basin with Messinian-style evaporative drawdown or thermal uplift above a migrating mantle plume) required by the subaerial valley hypotheses.

An examination of the deeply incised Ediacaran Wonoka canyons in the Adelaide Geosyncline (most recently interpreted as subaerial valleys) demonstrates their submarine origin, and confirms them as some of the best examples of ancient outcropping submarine canyons in the world. The entire canyon-fill succession is interpreted to be of deep-water (below wave base) origin, consisting of calcareous shale and siltstone together with a variety of mass-flow deposits including turbidites, grain flows and debris flows. The canyon fill lacks definitive shallow-water structures (e.g. mud cracks, fenestral fabrics or wave ripples) at all stratigraphic levels. Canyon-lining carbonate crusts that have previously been interpreted as non-marine calcretes or tufas (and used to suggest a non-marine origin for the canyons) are argued to be of deep-water, marine, microbial origin. Extremely negative carbon isotope values from the canyon-fill and canyon-lining crusts have a primary marine origin. Previo...

Research-oriented Geoscientist with a Master's degree in Geology and advanced technical training from the Geological Survey of India (GSI). Published author in peer-reviewed international journals with expertise in environmental geochemistry, heavy metal contamination, microplastic pollution, sediment risk assessment, hydrogeology, and GIS applications. Experienced in university-level teaching, research mentoring, and peer review. Strong leadership background through NCC training and state-level sports participation.

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Clay minerals are exceptionally well preserved in marine black shale of the ca. 2.1 Ga Francevillian Group in southeastern Gabon. The FB Formation of the Francevillian Group is characterized by smectite-rich clay minerals including randomly ordered (R0-type) and ordered (R1-type) mixed layer illite/smectite (I/S). The preservation of R0-type clay minerals suggests unexpectedly slow mineral transformation and a moderate degree of diagenesis, which is unique, considering the Paleoproterozoic age of the sedimentary rocks. R0-and R1-type, smectiterich particles occur in stratigraphic intervals with high organic carbon content and are associated with carbonaceous filamentous structures, suggesting formation of clay-organic matter complexes. Our data suggests that clay minerals may have enhanced organic matter preservation, providing the oldest example where a link between clay minerals and organic matter sequestration can be established. Our findings are consistent with the hypothesis that clay minerals enhanced organic carbon burial and aided in atmospheric oxygen accumulation through time.

Clay minerals are exceptionally well preserved in marine black shale of the ca. 2.1 Ga Francevillian Group in southeastern Gabon. The FB Formation of the Francevillian Group is characterized by smectite-rich clay minerals including randomly ordered (R0-type) and ordered (R1-type) mixed layer illite/smectite (I/S). The preservation of R0-type clay minerals suggests unexpectedly slow mineral transformation and a moderate degree of diagenesis, which is unique, considering the Paleoproterozoic age of the sedimentary rocks. R0-and R1-type, smectiterich particles occur in stratigraphic intervals with high organic carbon content and are associated with carbonaceous filamentous structures, suggesting formation of clay-organic matter complexes. Our data suggests that clay minerals may have enhanced organic matter preservation, providing the oldest example where a link between clay minerals and organic matter sequestration can be established. Our findings are consistent with the hypothesis that clay minerals enhanced organic carbon burial and aided in atmospheric oxygen accumulation through time.

The Beach sand, Obedoluogbeyi and Idogbo communities along Sapele bypass in Benin Region, Nigeria were studied for environmental and maturity indices. Forty (40) samples were collected and experimentally analysed for textural characteristics heavy minerals composition, pebble morphology and petrographic thin section. The examination of heavy minerals showed that the major deposit of heavy minerals was opaque. The graphic mean (average 1.542) revealed that medium to coarse sand size sediments predominated which are moderately to well sorted (average 1.141), typical of Continental paleo-environment. The graphic skewedness (average 3.445) typifies a period of a balance between erosion and deposition of the sediments with the majority of the sediments being substantially coarsely skewed and a small amount of strongly finely skewed sediments. In the graphic kurtosis (3.64), are consistent with mesokurtic to leptokurtic sand grains, characteristic of an intermediate to high energy ancient fluvial depositional environment. The sand was compositionally mature (Qtz >90%), mineralogical mature (MMI average = 18.66) and chemically immature sub-mature (ZTR = 70.10). The ancient environment of the deposition from the average of the sorting value is typical of a continental origin. This finding is authenticated by the environmental discrimination plots which also confirm a continental environment of deposition for the coastal plain sand. The fluvial or continental origin indicates past river processes, which helps to reconstruct regional paleoenvironment. Textural and compositional maturity suggests significant transport and sorting by water. The mineralogical maturity provides insights to source rock weathering or recycling. Overall, understanding the origin and maturity, guides exploration strategies.

ABSRTACT Marine sedimentary phosphorites of Late Cretaceous, Paleocene and Eocene age are wide spread in the Western Desert of Iraq. The Paleocene deposits (Akashat Formation) are the most extensive in thickness and distribution, and are industrially exploited. They are granular phosphorites composed mostly of ooids and peloids, with accessory amounts of coprolites and fish scales. The cementing material is calcite. The phosphate mineralogy is carbonate fluorapatite (francolite). Rare earth elements, phosphorus and yttrium were analyzed in ten concentrated carbonate fluorapatite samples from the Paleocene phosphorite of Iraq. The concentrated apatites included coprolites, peloids – ooids, bones and teeth. The results show lower REE content relative to average world phosphorites, and the coprolites contained the highest concentrations among the three types of phosphate grains studied, whereas the bioclasts contained the lowest concentrations. The data were normalized relative to aver...

Se realizaron analisis de arcillas minerales, elementos mayores, traza y tierras raras (ETR) para interpretar los cambios paleoclimaticos, el paleointemperismo y las condiciones de paleo-reduccion-oxidacion en las capas de lutita de la seccion Tuape de la Caliza Mural de Sonora. La asociacion mineralogica de arcillas (ilita-clorita-caolinita-esmectita) de la seccion Tuape proporciono informacion sobre las condiciones climaticas y ambientes de deposito que predominaron durante el Aptiano tardio-Albiano temprano. Los patrones de tierras raras normalizados con condrita estan caracterizados por el enriquecimiento de tierras raras ligeras (ETRL) y la disminucion de tierras raras pesadas (ETRP) con anomalia negativa de Eu. Los valores del indice de alteracion quimica (CIA por sus siglas en ingles) y del indice de alteracion de plagioclasas (PIA por sus siglas en ingles) para estas lutitas asi como el diagrama A-CN-K, indican que su intemperismo quimico es de una intensidad moderada. Los b...

The Ewekoro Limestone of the eastern Dahomey Basin, Southwestern Nigeria, represents
an important carbonate unit with significant industrial and economic value. This study
presents an integrated petrological and geochemical investigation of the Ewekoro
Limestone in order to determine its mineralogical composition, microfacies characteristics,
and depositional environment. Field observations and systematic sampling were carried out
at the Ewekoro Quarry, Ogun State. Petrographic analyses of thin sections were conducted
using optical microscopy, while mineralogical and geochemical compositions were
determined using X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques.
The limestone is predominantly composed of calcite with minor quartz and clay minerals.
Petrographic examination reveals abundant skeletal and non-skeletal grains including
foraminifera, gastropods, bivalves, peloids, ooids, and intraclasts set within micrite and
sparry calcite matrices. Microfacies analysis indicates that the limestone is mainly
wackestone to packstone, locally grading into grainstone. Geochemical results show high
CaO contents with low concentrations of MgO, SiO₂, Al₂O₃, and Fe₂O₃, suggesting a relatively
pure limestone.
The combined petrographic and geochemical characteristics indicate deposition in a
shallow marine shelf environment under relatively low-energy conditions, followed by
minor diagenetic modification. The results demonstrate that the Ewekoro Limestone is
suitable for cement manufacture and other industrial applications, and provide a basis for
further sedimentological and geochemical studies within the Dahomey Basin.

The Solonker suture zone is one of the most important tectonic boundaries in the southeastern part of the Central Asian Orogenic Belt (CAOB). An ~630 km-long reflection seismic profile across this suture was recently completed by the Chinese SinoProbe Project. The processed seismic data show clear crustal structures and provide new constraints on the tectonic and crustal evolution models. The Moho is delineated as a relatively flat boundary between a strongly reflective lower crust and a transparent mantle at a depth of ~40-45 km (~14.5 s two-way travel time), which is in agreement with the refraction data recorded along the same profile. In a broad view, the profile images an orogen that appears bivergent with, and approximately centered on, the Solonker suture zone. The southern portion of this profile is dominated by a crustal-scale, cratonward propagating fold-andthrust system that formed during the late Permian and Triassic through collision and subsequent convergence in a post-collisional stage. The major thrust faults are truncated by Mesozoic granitoid plutons in the upper crust and by the Moho at the base of the crust. This geometry suggests that the Moho was formed after the thrusting event. The northern portion of the profile, although partially obliterated by post-collisional magmatic bodies, shows major south-dipping folding and thrusting. Bands of layered reflectors immediately overlying the Moho are interpreted as basaltic sills derived from the mantle. Episodic mafic underplating may have occurred in this region, giving rise to post-collisional magmatic events and renewal of the Moho. A few mantle reflectors are also visible. The overall geometry of these mantle reflectors supports the tectonic models that the southern orogen (Manchurides) experienced south-directed subduction and the northern orogen (Altaids) underwent north-directed subduction prior to collision along the Solonker suture zone.

• india has a large cultural diversity and old traditions. • Jaipur (Pink city) is a city of palaces and a heritage city of india. The observatory in Jaipur has recently been included in world heritage, not far (265 km) from the international airport in new Delhi. • Jaipur is one of the cities of the tourist's "Golden Triangle" of india (new Delhi-Jaipur-agra). • a one-day mid-conference visit to the touristic highlights of the city (Palace of the Wind, city Palace, Observatory, amber Fort, Jaigarh Fort) will therefore be offered to the participants. • The city has a large and very old university, University of rajasthan, supported by the state Government of rajasthan.

The Nankai accretionary complex is the most recent addition to the accretionary complexes of southwest Japan and has preserved a record of sediment flux to the trench during its construction. In this study, we use U-Pb zircon and fission track analysis of both zircons and apatites from sediments taken from the forearc and trench of the Nankai Trough, as well as rivers from southwest Japan to examine the exhumation history of the margin since the Middle Miocene. Modern rivers show a flux dominated by erosion of the Mesozoic-Eocene Shimanto and Sanbagawa accretionary complexes. Only the Fuji River, draining the collision zone between the Izu and Honshu arcs, is unique in showing much faster exhumation. Sediment from the Izu-Honshu collision is not found 350-500 km along the margin offshore Kyushu indicating limited along-strike sediment transport. Sediment deposited since 2 Ma on the midtrench slope offshore the Muroto Peninsula of Shikoku (ODP Site 1176) and on the lower slope trenchward of the Kumano Basin (IODP Sites C0006E and C00007E) shares the dominant source in the Shimanto and Sanbagawa complexes seen in the modern rivers. Prior to 5 Ma, additional sediment was being sourced from further north in more slowly exhumed terrains, ~350 km from the trench axis. Around 9.4 Ma, U-Pb zircon ages of ~1800 Ma indicate enhanced erosion from the North China Craton, exposed in northern Honshu. In the middle Miocene, at ~15.4 Ma, the sediment was being derived from a much wider area including the Yangtze Craton (U-Pb ages ~800 Ma). We suggest that this enhanced catchment may have reflected the influence of the Yangtze River in supplying into the Shikoku Basin prior to rifting of the Okinawa Trough at 10 Ma and migration of the Palau-Kyushu Ridge to form a barrier to transport. The restriction of Nankai Trough provenance to Mesozoic source partly reflects continued uplift of the Shimanto and Sanbagawa complexes since the Middle Miocene.

Groundwater from coastal aquifers plays a significant role in agriculture, but its diminishing of quality often impacts crop production and soil sustainability by leading to soil salinization and the deterioration of irrigation water standards. This study addresses the pressing issue at Mornang Plain in Tunisia utilizing an integrated approach that combines statistical analysis (principal component analysis (PCA) and cluster analysis (CA), geographic information system (GIS), and machine learning (ML) techniques to assess and predict irrigation water quality. Key parameters such as irrigation water quality index (IWQI), potential salinity (PS), sodium percentage (Na%), and sodium adsorption ratio (SAR) were evaluated to assess water quality for agricultural use. The study identified three main groundwater facies (Na-Cl, Ca-Mg-SO 4 ,

Despite the central role of fire in Pleistocene and Palaeolithic lifeways, the relationship among hominins, fire, and their environment remains unclear. Ancient combustion residues hold a wealth of molecular data that may help to resolve some of these questions, yet standardised guidelines for reconstructing past fire traces are notably lacking. In this study, we examine extensive combustion residues overlying Middle Palaeolithic deposits from the open-air site of Ormesson (France). To determine whether the combustion residues are of natural or human origin, multiproxy approaches including anthracology, lipid biomarker, and benzene polycarboxylic acid (BPCA) analyses are applied. These techniques are used to characterise organic matter and pyrogenic carbon compositions in the deposits, providing insights into surrounding vegetation, palaeoenvironmental shifts, and the production parameters involved in the formation of the char assemblage. Lipid biomarker evidence suggests that the pre-fire local environment featured abundant coniferous vegetation (e.g., Pinaceae taxa), which is supported by anthracological evidence for a predominance of Pinus cf. sylvestris/nigra complemented by Betula sp. taxa. The post-fire environment saw a contraction of coniferous vegetation, concurrent with an expansion of deciduous taxa, grasses and herbaceous material. The combustion event, which resulted in 67 % of the charcoal assemblage exhibiting vitrification, produced PyC contents of up to 362 g/kg OC in soil samples and 443 g/kg OC in charcoal samples, with aromatic condensation values of up to 34 %. BPCA-derived predictions of heat treatment temperatures yielded values of approximately 300-400 • C for charcoal samples and 400-550 • C for soil samples in the burned layer, constituting the first instance in which quantitative temperature estimations are obtained from BPCA results. Based on the integrated evidence, we accept the null hypothesis that the studied combustion residues are natural in origin. However, the similarity of archaeometric and geochemical signatures from natural and human-controlled fires underscores the need for interdisciplinary, multiproxy efforts to improve the identification of past fire regimes.

Central Myanmar Basin (CMB) lies between the two major strike-slip faults: Sagaing Fault to the east and Kabaw Fault to the west. Central Volcanic Line of Myanmar emplaced en-echelon array of P-shears along the fault zone, which was active dextral as surrounding major faults at a low angle about 15 • to the shear zone boundary. CMB was developed as strike-slip partitioned transpression model as proposed in this study. The transprsession tectonic is common with oblique convergence subduction as well as collision of India Plate to West Myanmar Block, especially effects on the CMB. Structural evidence are occurred as en-echelon folding and fracturing by satellite photos, field observation and 3D strain ellipsoid construction showing plane strain by pure shear upon ideal strike-slip with simple shear. In this study, two types of transpression distinguished as homogeneous and strikeslip partitioning which are developed within the frame of the strike-slip fault with progressive deformation. Under the condition of the strike-slip partitioned transpression, strain partitioning is distinctly occurred together with progressive deformation and reactivation of pre-existing structures such as cylindrical fold to double plunging fold, normal fault to oblique slip fault and positive flower structure. Deformation process related to the India Plate movement deduced the period of Late Miocene and Pliocene-Pleistocene based on the structural analysis in Rakhine Coastal region, western Myanmar. During the period between the Late Miocene to Pliocene-Pleistocene, pre-existing ophiolite zone in the Indo-Myanmar Ranges (IMR) was split up different zones by the Sagaing Fault displacement, accompanied to the West Myanmar Block movement with India Plate subduction. Accordance with the Sagaing Fault displacement and group of mud volcanoes shifting, the CMB moved northward about 450km with displacement rate 5-7cm per annum by the 45-50 • convergent angle of India Plate collision to Eurasia Plate. Transpression deformation of northward compression was developed in the CMB, simultaneously on the other side transtension as pull-apart basin was formed by Andaman Sea opening at the south on the Sagaing Fault. During the Miocene time, collision of India Plate to Eurasia Plate was principal and caused the deformation at northern border the India, in which India Plate moved both in northwards and rotated anti-clockwise, whereas West Myanmar Block together with Sibumasu Block rotated clockwise becoming final closure of the northeasternmost Assam and Myanmar regions. During the Oligocene time, deposition of the shallow marine Barail formation in the Bengal Basin and shallow marine to continental shelf sequences in the CMB started as twin trough. This study provides the transpression deformation in the CMB and related regions during syn-and post-collision of India Plate to West Myanmar Block with position and kinematic structural interpretation.

This study is focused on the sedimentary environments, facies distribution and sequence stratigraphy of the Santonian intervals (Ilam Formation of Bangestan Group) that host enormous hydrocarbon reserves in five giant and supergiant oilfields in the central and southern parts of the Dezful Embayment (SW Iran). This reservoir formation is investigated using detailed petrographic analysis assisted by microscopic image analyses to explain its depositional facies and sedimentary environment in the subsurface sections of this embayment. Petrographic studies led to the recognition of 18 microfacies that formed in four facies belts: inner ramp (including shoal facies and open to restricted lagoons), mid-ramp (including channels and patch reef talus facies), outer ramp and basin. To locate the approximate position of the studied wells in the conceptual depositional model, frequency analyses for facies associations are carried out. The studied intervals consist of two, thick shallowing-upward 3rd-order sequences. Facies variations of the Ilam Formation investigated throughout the studied oilfields using correlation in a sequence stratigraphic framework.

The paper presents the results of an interdisciplinary and integrated study aimed at reconstructing the long-term dynamics of activity and exploitation in the river-port area of Aquileia. By combining geological corings and stratigraphic excavation with geological, geochemical, palaeoenvironmental, archaeological, archaeozoological, and material-culture analyses, the research reconstructs the full life sequence of Aquileia’s ancient port channel. The study highlights the continuous interplay between natural events and human interventions, showing how the environment and human activities shaped one another over the centuries.

The swelling potential of fine-grained soils is a critical factor influencing the engineering and agricultural design of foundations, as it can cause significant expansion-related issues. This study investigates the swelling potential of clayey soils in the southern region of Urmia Lake, located in East Azerbaijan Province, NW Iran. A comprehensive set of laboratory tests was conducted on 125 soil samples collected from 25 distinct locations. The analyses included assessments of physicochemical properties, soil classification according to the USDA system, and clay mineralogical composition. Regression analysis was employed to develop predictive formulas for swelling potential based on laboratory indices, including water absorption, porosity, density, specific gravity (G), sulfate (SO 4) and chloride (Cl-) s concentrations, pH, Casagrande limits, unconfined compressive strength (UCS), X-ray diffraction (XRD) patterns, and clay content. The results revealed that the studied soils, classified as clay, clay loam, and silty clay, exhibit swelling potentials ranging from moderate to high. This research provides valuable insights for designing stable structures and optimizing land use in the region.

The provenance of the Upper Miocene sandstones from the Sava and Drava depressions of the North Croatian Basin was investigated using petrographic, geochemical, and heavy mineral analyses, including Raman spectroscopy. The study of these sandstones, which represent important oil and gas reservoirs in Croatia, allowed reconstruction of the Late Miocene source-to-sink model of the Lake Pannon drainage system and the evolution of the southwestern Pannonian Basin. The studied feldspatho-litho-quartzose sandstones consist of a mixture of sedimentary, metamorphic, and igneous detritus. Heavy-mineral assemblages are dominated by almandine-rich garnet with apatite, epidote, tourmaline, rutile, zircon, staurolite, and zoisite, indicative of low to medium-grade metamorphic source rocks. Higher concentrations of Ca and Mg than in the Upper Continental Crust standard (UCC) additionally reflect the abundance of limestone and dolostone rock fragments as well as carbonate cement. Geochemical compositional variations between sandstone samples from the Sava and Drava depressions primarily stem from diagenetic processes. CIX and alpha values indicate only minor weathering. Compositional features indicate an orogenic source located in the Eastern Alps and primarily represented by Austroalpine and Penninic nappes. This research offers a novel perspective to distinguish the Upper Miocene reservoirs from other sedimentary units within the basin, contributing to a more comprehensive understanding of the regional geological dynamics and supporting future exploration projects also related to energy transition.

LE 8 TIPOLOGIE CROSTALI TERRESTRI 1 crosta continentale 2 crosta oceanica 3 dorsali medio oceaniche 4 subduzione di crosta oceanica sotto crosta continentale 5 subduzione di crosta oceanica sotto crosta oceanica 6 collisione tra croste continentali 7 apertura di fosse tettoniche 8 punti caldi

The Archean granitoids of the South Gabon, dated from 3.0-to-2.5 Ga, were examined along the Archean-Proterozoic unconformity. The petrography was based on mineralogical identification using electron microscopy, X-ray diffraction, and the electron microprobe. The geochemistry was based on chemical analyses of major and trace elements, and on isotopic dating. Results of this work show that the granitoids have been affected by superimposed chloritization and illitization events that were dated by monazite U-Th-Pd isotopic data. The granitic basement shows three superimposed alteration events: 3.0-2.9 Ga primary magmatic event, 2.6 Ga propylitic, and a late oxic 1.9 Ga diagenetic event.