Quaternary Alluvium Research Articles

Estimation of S-wave velocity structures of Tainan area, Taiwan, using array records of microtremors

In this study, the shallow S-wave velocity structures beneath the Tainan area, Taiwan are investigated using microtremor array measurements at 18 sites. An F-K spectrum method was used to calculate the dispersion curves for these sites, and surface-wave inversion was used to estimate the S-wave velocity structures beneath the Tainan area. The results indicated that, at frequencies between 0.2 and 1.1 Hz, propagation is concentrated between the northwest and south quadrants, corresponding to the coast of the Taiwan Strait. CHM, a hard central site on the Tainan tableland, was found to have higher phase velocities than the soft sites do, such as site SIM, on the Anping Plain, particularly at frequencies of 0.3–5.0 Hz. Given that the tertiary basement exhibits an S-wave velocity of 1500 m/s, the depth of the Quaternary alluvium in the Tainan area ranges from 400 m at site CHM to 1350 m at site FUP on the Anping Plain. In addition, the depth of the alluvium gradually increases radially from the central CHM site (on the Tainan tableland) to the surrounding areas. These results are consistent with the geolpogy of the Tainan area. Because our shallow S-wave velocity structures are comparable to those proposed in three other studies, our inversion results are concluded to be reasonable and valid. According to the horizontal/vertical (H/V) ratios of our microtremor array data from 18 sites, the predominant frequencies range from 1.0 to 3.8 Hz. Compared with the eastern part (i.e., Dawan lowland), the central part (i.e., Tainan tableland) has higher predominant frequencies.

Characterization of Heavy Minerals and Their Possible Sources in Quaternary Alluvial and Beach Sediments by an Integration of Microanalytical Data and Spectroscopy (FTIR, Raman and UV-Vis)

Quaternary stream sediments and beach black sand in north-western Saudi Arabia (namely Wadi Thalbah, Wadi Haramil and Wadi Al Miyah) are characterized by the enrichment of heavy minerals. Concentrates of the heavy minerals in two size fractions (63–125 μm and 125–250 μm) are considered as potential sources of “strategic” accessory minerals. A combination of mineralogical, geochemical and spectroscopic data of opaque and non-opaque minerals is utilized as clues for provenance. ThO2 (up to 17.46 wt%) is correlated with UO2 (up to 7.18 wt%), indicating a possible uranothorite solid solution in zircon. Hafnoan zircon (3.6–5.75 wt% HfO2) is a provenance indicator that indicates a granitic source, mostly highly fractionated granite. In addition, monazite characterizes the same felsic provenance with rare-earth element oxides (La, Ce, Nd and Sm amounting) up to 67.88 wt%. These contents of radionuclides and rare-earth elements assigned the investigated zircon and monazite as “strategic” minerals. In the bulk black sand, V2O5 (up to 0.36 wt%) and ZrO2 (0.57 wt%) are correlated with percentages of magnetite and zircon. Skeletal or star-shaped Ti-magnetite is derived from the basaltic flows. Mn-bearing ilmenite, with up to 5.5 wt% MnO, is derived from the metasediments. The Fourier-transform infrared transmittance (FTIR) spectra indicate lattice vibrational modes of non-opaque silicate heavy minerals, e.g., amphiboles. In addition, the FTIR spectra show O-H vibrational stretching that is related to magnetite and Fe-oxyhydroxides, particularly in the magnetic fraction. Raman data indicate a Verwey transition in the spectrum of magnetite, which is partially replaced by possible ferrite/wüstite during the measurements. The Raman shifts at 223 cm−1 and 460 cm−1 indicate O-Ti-O symmetric stretching vibration and asymmetric stretching vibration of Fe-O bonding in the FeO6 octahedra, respectively. The ultraviolet-visible-near infrared (UV-Vis-NIR) spectra confirm the dominance of ferric iron (Fe3+) as well as some Si4+ transitions of magnetite (226 and 280 nm) in the opaque-rich fractions. Non-opaque heavy silicates such as hornblende and ferrohornblende are responsible for the 192 nm intensity band.

Geochemical and Radiogenic Sr‐Nd Isotope Characterization of Widespread Sandy Surface Sediments in the Great Indian Desert, Thar: Implications for Provenance Studies

AbstractUnderstanding large desert formation/evolution contributing to regional‐to‐global dust cycles remains a challenge. This study presents the geochemical and Sr‐Nd isotope compositions of 51 surface sediment samples collected from the widespread hyper‐arid Thar Desert in northwestern India. The major objective is to determine sediment provenance for a better understanding of the formation/evolution mechanism of this Great Indian Desert as well as downwind dust contributions toward the Himalayas. The compositionally immature sandy Thar sediments (CIA ∼50 ± 4, WIP ∼49 ± 12, and EuN/Eu* ∼0.80 ± 0.13) are recycled materials derived from the Himalayan orogen and later modified by quartz addition and heavy mineral depletion/sorting processes. The 87Sr/86Sr (0.7259 ± 0.0012 and εNd (−12.5 ± 2.7) in the bulk of these Thar sediments are different from the earlier published compositions of the eolian sand deposits in northwestern India. The subcategories of Thar materials collected from different dune types exposed over different lithologies (Quaternary alluvium vs. Tertiary and Mesozoic sedimentary formations) are geochemically and isotopically indistinguishable, which indicates their cogenetic sources and/or sediment reworking. Thar sediments collected in this study have a predominant Indus origin along with significant contributions from the upwind Ghaggar‐Hakra paleochannels. The Indus sediments are most likely wind‐eroded from the shelf region exposed during the low sea stand of LGM and afterward deglaciation. Considering the new and published data sets, the Sr‐Nd isotope budget of dust deposited in the Himalayan frontal glaciers indicates that atmospheric mineral dust contribution from the upwind Indo‐Gangetic Plain proximal to the Himalayas is at par with dust parcels from distant natural deserts.

Human-made small reservoirs alter dryland hydrological connectivity

Our research shed light on the distribution, number, and impact of small reservoirs (SRs) on rural dryland water availability and hydrology. We measured the storage capacity, relationship to environmental variables, and effects on the hydrology of all SRs (1225) found within a Sonoran Desert basin. SRs were predominantly associated with Tertiary conglomerates and Quaternary alluvium and were less common in extrusive rocks. A higher concentration of reservoirs was observed in woodlands and thornscrub, with fewer SRs in desertscrub than anticipated by chance. The average size of these small reservoirs was 5205 m2. All SRs reached full storage capacity during the rainy season, but only 20 % retained water throughout the year. Furthermore, our analysis revealed a significant impact on basin connectivity, with only 41 % of superficial drainage being connected. Notably, two large dams were found to disconnect 26 % of the basin. Despite their relatively small watershed footprint, SRs were found to be responsible for disconnecting 33 % of the total basin area. The magnitude of rainfall events played a crucial role in connectivity dynamics. Low-magnitude rainfall events led to sediment retention in SRs, reducing connectivity, while moderate events increased connectivity by repeatedly filling SRs. High-magnitude events reshaped channels, transported sediments, and enhanced overall connectivity. The concentration of SRs in the upper reaches of the basin coincides with higher stocking rates. SRs, are relatively recent additions to desert landscapes, impacting ecological dynamics. Their construction and use fragment an already disjointed basin, thereby restricting water retention by larger dams. These findings emphasize the intricate relationship between SRs, rainfall occurrences, and the overall connectivity of the basin. We underline that documenting the cumulative effects of SRs yields valuable insights for managing water resources in arid ecosystems.

Implications of active Gavilgarh/Salbardi fault on the evolution of the late Quaternary landscape in Central India

The morphometric indices (MI) have been calculated along the Gavilgarh/Salbardi Fault (G/SF) to investigate active deformation, tectonic uplift, and basin tilt to find out its impact on the late Quaternary landscape. To explore the tectonic intensity, we computed MI such as stream-length gradient index (SL), hypsometric integral (HI), transverse topographic symmetry factor (T), asymmetry factor (Af), basin elongation ratio (Re), mountain front sinuosity (Smf) and valley floor width to valley height ratio (Vf). The necessary field investigations were carried out on the evolution of the Quaternary landscape to ascertain the various morphometric indices. The evaluated values of SL, HI, Re, Smf, and Vf show the high uplift of the northern block exists as opposed to the southern block, and the tilt and asymmetric character of the basins are shown by T and Af values. The presence of sedimentary landscapes like Quaternary alluvium, triangular facets, natural levees, and boulder-pebbly beds, indicates that the area has recently experienced tectonic activity. The assessed values of MI with supporting field evidence proposed that the northern block is uplifted and the basins are tilted because of the effect of G/SF.

Tectonic, Topographic, Geologic, and Hydroclimatic Influence on Crack Formation During the 2021 Haiti Earthquake

AbstractThe 14 August 2021 Haiti earthquake mainly portrayed reverse motion to the east near L’Asile town and left‐lateral strike‐slip motion to the west near Camp‐Perrin town. To map the rupture and infer its segmentation, we conducted the first post‐seismic field reconnaissance along the left‐lateral strike‐slip Enriquillo fault from L’Asile to Macaya mountain. We identified 98 linear, minor cracks that are not representative of primary fault surface rupture. Analyzing the topographic slope distribution, we detected that the cracks were often located in areas that are prone to topographic instability. About 60% of the cracks are located in Quaternary alluvium and Middle‐Miocene continental marls, indicating a preference for soft sediments. The rivers also have an impact, as crack lengths and openings negatively correlate with their distance to neighboring rivers. In addition, the earthquake occurred in a rainy region with up to 2,479.34 mm of rainfall in 2021, increasing soil instability. Above all, we found a contrast and asymmetry between the eastern and the western parts of the rupture. By dividing the 60‐km long rupture into two equal parts, we observed 57 cracks to the west against 41 to the east. The longest and the widest cracks are to the west. Analyzing their orientation, the cracks mainly oriented as left‐lateral strike‐slip faults to the west and mainly thrusts to the east. This configuration appears to be influenced by the slip pattern of the 2021 Haiti earthquake and consistent with the regional stress field.

Quantitative assessment of relative tectonic activity in the eastern Bandung Basin, Indonesia

ABSTRACT The Eastern Bandung Basin is composed of predominantly Quaternary volcanic rocks and is influenced by tectonic activity. This research aims to determine and evaluate the morphotectonic characteristics and its implication to the potential geological disaster in the Eastern Bandung Basin. The morphotectonic indices used in this research consist of Stream Length Gradient Index (SL), Asymmetric Factor (Af), Hypsometric Integral (Hi), Ratio of the Valley Floor to the Height of the Valley (Vf), Basin Shape (Bs), and Sinousity of the Mountain Front (Smf). The research area consists of subwatersheds, namely Upper Citarik, Cijalupang, Ciwirama, Ciburial, Cikeruh, and Cimande. The research area is mostly located on hilly to mountainous area with flat to very steep slopes (0–56°). The research area is composed of Quaternary volcanic rocks in the north, east, and south as well as Quaternary alluvium in the central part of the research area. Based on the quantitative assessment, the research area has IRTA values of classes 3 and 4, indicating low to moderately active tectonics. It can be related to active faults and Quaternary volcanic rocks. Class 3 of IRTA corresponding to moderately active tectonics occurs mainly in the Upper Citarik and Cimande subwatershed. Class 4 of IRTA mainly takes place in the Cijalupang. Ciwirama, Ciburial, and Cikeruh subwatershed.

Geomorphic evolution of a tropical river basin in the Deccan Volcanic Province: a critical water supply source to Mumbai metropolitan region (MMR), India

ABSTRACT Reservoir siltation lowers a dam’s effective storage capacity, which is mostly determined by the sediment discharge from soil erosion in the watersheds. The morphometric parameters are significant in determining erosional susceptibility of watersheds. In the present study, morpho-hypsometric aspects of the Surya sub-basin, a major tributary of Vaitarna river, has been considered. This river system and associated dams provide the major source of drinking water supply to the Mumbai Metropolitan Region (MMR). A major part of the river flows through the Deccan Volcanic Province (comprising basalts) and Quaternary alluvial deposits. The seven sub-watersheds (SWs) of Surya sub-basin were analysed using the morphological parameters (linear, areal, and basin shape aspects), along with ratio factors and hypsometric integral (HI) values. The HI values for the SWs range from 0.11 (SW-1) to 0.51 (SW-6) with a HI value of 0.21 for the whole Surya sub-basin. The relatively high HI values of SW-6 (0.51) and SW-7 (0.31) indicate that these SWs are relatively prone to high erosion and sediment discharge resulting in dam siltation, and will be a great threat to livelihood of millions of people in the MMR. Therefore, prioritizing these SWs for proper engineering measures could reduce erosion and improve recharge.

Lithotectonic setting, paleoweathering, maturity, sediment recycling and paleoredox conditions of quaternary alluvium from Mayo Sina (Tchad). A geochemical approach

The alluvial material in the two PITs of the Mayo Sina in the southern part of Chad, were subjected to a geochemical analysis in order to determine the source rock lithological composition, tectonic context, degree of weathering, type of climate at the period of weathering, and cycles of sedimentation and maturity. Plotting source lithology charts with values of La/Sc, Th/Sc, La/Co, and Cr/Th indicated that the sediments originated from a felsic source rock composition. The Enrichment of LREE/HREE and a negative chondrite Eu anomaly confirm the felsic source rock composition. A passive tectonic context for the source rock of the sediments is revealed by binary charts (SiO2 versus K2O/Na2O) in conjunction with innovative discrimination plots (DF 1 and DF 2 (Arc-Rift-Col)M1, DF (A-P)M, and DF (A-P)MT). The exceptional degree of plagioclase removal and weathering is demonstrated by the results of the Plagioclase Index of Alteration (PIX) and Chemical Index of Alteration (CIX). The proportion of SiO2/Al2O3 and the new index of compositional variation (ICVnew), which exclude iron and calcium oxides from the formula, indicate that the sediments are immature to mature. Schematic representations of K2O/Na2O ratio indicate that the sediments have undergone both primary to secondary phases of sedimentation.

A new insight for geophysical and geospatial mapping quaternary alluvium of Indo-Gangetic plains for exploration and assessment of groundwater in Haryana, India

A comprehensive study on groundwater exploration and assessment was conducted, integrating geophysical, geological, lithological, and resistivity logging techniques for a holistic evaluation of groundwater resources in Haryana, India. The primary research objective was to gain insight into the geological composition of alluvial sand and its implications for groundwater occurrence in Haryana's semi-arid region. The study showcases high-resolution electrical resistivity tomography results alongside conceptual cross-sectional models and 3D lithological models, revealing buried channels that serve as groundwater sources and saturated sand as well as recharge conduits within the alluvial region of Haryana. Moreover, borehole drilling at two sites and resistivity logging data demonstrate a strong correlation between various lithologies and resistivity logs. Overall, groundwater prospect zones are delineated at depths ranging from 18 m to over 100 m based on resistivity values of aquifer zones inferred from electrical resistivity tomography models, as well as mapped thick sand layers with significant hydrogeological importance in the study area. This emphasizes the stress on the aquifer system, where groundwater is being extracted from deeper depths. The conceptual litho-sectional model reveals a thick sand signature at intermediate depths, indicating the presence of buried paleochannels extending from Galedwa (Kurukshetra) to Jubbal (Yamunanagar). Additionally, the 3D lithological models, along with the electrical resistivity tomography results, facilitate strategic planning for shallow and deep boreholes for groundwater exploration and prospecting, aiming at sustainable groundwater development and management of resources in both the present and future.

Epidemiology of cutaneous leishmaniasis in children of Khyber Pakhtunkhwa, Pakistan.

In Pakistan, cutaneous leishmaniasis is an emerging tropical disease and a very high number (>70%) of children are afflicted by this marring infection. This study aimed to scrutinise the prevalence, spatial distribution and socio-demographic and behavioural risk factors associated with cutaneous leishmaniasis in children aged <5-15 years in Khyber Pakhtunkhwa. A total of 1, 559 clinically confirmed records of children diagnosed with cutaneous leishmaniasis (January-December) from 2020 and 2022 were obtained from selected district hospitals. In addition, a risk factors-related questionnaire was administered to 1, 011 households (400 in 2020 and 611 in 2022) in nine districts during a household survey. The maximum number of cutaneous leishmaniasis cases was recorded in 2022 (n = 877, 56.25%) as compared to 2020 (n = 682, 43.75%). The hospital records showed a greater number of male patients in the 2022 cohort (n = 603, 68.76%). The highest number of cases were observed in children aged 5-9 years in 2022 (n = 282, 32.16%) and 2020 (n = 255, 37.39%). In 2020 and 2022, cutaneous leishmaniasis cases showed peak aggregation in March (n = 118, 17.3%) and January (n = 322, 36.72%). From a spatial analysis, the maximum number of cutaneous leishmaniasis cases was recorded at 59-1700 m elevation in various land-use/land-cover and climatic regions with quaternary alluvium rock formations. A multivariate logistic regression model analysis of risk factors from the households survey suggested that age group, socio-economic status, construction materials of the house, use of insect repellents, Afghan refugee camps in the village/district, knowledge and biting times of sand flies, frequent use of mosquito bed nets, presence of domestic animals in the house, knowledge of the transmission period and peak month of leishmaniasis infection increased the risk of acquiring cutaneous leishmaniasis (p value < 0.05). Our analysis demonstrated that cutaneous leishmaniasis in children is influenced by a variety of environmental, socio-demographic and behavioural risk factors in Khyber Pakhtunkhwa. The increase in recorded cases of cutaneous leishmaniasis in children in 2022 compared to 2020 suggests that the infection likely extended to new foci in the province.

Soil quality assessment in low human activity disturbance zones: a study on the Qinghai-Tibet Plateau.

The Qinghai-Tibet Plateau, located at the Third Pole and known as the "Asian water tower," serves as a crucial ecological barrier for China. Grasping the soil quality on the Qinghai-Tibet Plateau holds paramount importance for the rational and scientific exploitation of soil resources within the region and is essential for vegetation restoration and ecological reconstruction. This study, conducted in Maqin County, Qinghai Province, collected 1647 soil samples (0-20cm) within a study area of 6300km2. Sixteen soil indicators were selected that were split into beneficial (N, P, S, and B), harmful (Cr, Hg, As, Pb, Ni, and Cd), and essential (Cu, Zn, Se, Ga, K, and Ca) elements. The Soil Quality Index (SQI) was computed to assess soil quality across diverse geological contexts, land cover classifications, and soil profiles. The results indicate that the overall SQI in the study area was comparatively high, with most regions having an SQI between 0.4 and 0.6, categorized as moderately to highly satisfactory. Among the different geological backgrounds, the highest SQI was found in the Quaternary alluvium (0.555) and the lowest in the Precambrian Jinshuikou Formation (0.481). Regarding different land-use types, the highest SQI was observed in glacier- and snow-covered areas (0.582) and the lowest in other types of grassland (0.461). The highest SQI was recorded in typical alpine meadow soil (0.521) and the lowest in leached brown soil (0.460). The evaluation results have significant reference value for the sustainable utilization and management of soil in Maqin County, Qinghai Province, China.

Prediction of void ratio and shear wave velocity for soil in quaternary alluvium using cone penetration tests

Prediction of void ratio and shear wave velocity for soil in quaternary alluvium using cone penetration tests

Cretaceous–eocene flysch of the sochi synclinorium (western caucasus): sources of clastic material based on the results of U–Th–Pb isotope dating of detrital zircons

The first results of U–Th–Pb isotope dating of detrital zircons (dZr, N = 130, n = 91) from the Middle Danian sandstones (63.9–65.3 Ma) of the Cretaceous–Eocene Novorossiysk–Anapa flysch, widely developed in the Sochi synclinorium (Southern slope of the Western Caucasus) are presented. The maximum dZr age is 2973 ± 12 Ma, the minimum dZr age is 318 ± 3 Ma; weighted average age of the 4 youngest dZr ~ 322 ± 7 Ma. There are no signs of the destruction products of the Jurassic magmatites involved in the structure of the Greater Caucasus and the Crimean Mountains into the sedimentary basin, in which the Novorossiysk-Anapa flysch was formed. A high degree of similarity between the provenance signals of the Danian sandstones from the Novorossiysk-Anapa flysch, some Paleogene-Neogene and Early Quaternary (Early Pleistocene) sandstones of the Western Caucasus and Western Cis-Caucasia, red-colored Upper Permian and Lower Triassic sandstones of the Moscow syneclise, as well as Late Quaternary alluvium of the lower reaches of the draining vast expanses of the Russian plate Don and Volga rivers has been revealed. On this basis, it was concluded that in the Middle Danian there were no eroded mountain structures of the Greater Caucasus and Crimea, and the main volume of detrital material composing the Novorossiysk-Anapa flysch was formed due to the recycling of Permian-Triassic and younger strata of the Russian Plate.

Geospatial liquefaction probability models based on sand boils occurred during the 2017 M5.5 Pohang, South Korea, earthquake

The 2017 Pohang earthquake, triggered by an enhanced geothermal system, had a moment magnitude (M) of 5.5 and caused liquefaction in Pohang City, South Korea. Notably, approximately 600 sand boils were observed only in the soft Quaternary alluvial sediments. This contrasts with most historic liquefaction cases that occurred in earthquakes with M ≥ 6.0. In addition, ground and building settlements were reported in Pohang City. To assess the liquefaction hazard for the Pohang earthquake within the city, we define a 14.4 km2 area where the majority of liquefaction was observed. Using the liquefaction data, we develop eight geospatial liquefaction probability models using logistic regression (LR) and random forest (RF) algorithms (five LR- and three RF-based models). These models consider geospatial data (peak ground acceleration, peak ground velocity, slope-derived average shear wave velocity of the upper 30 m, compound topographic index, distance to the nearest water, and roughness) and geotechnical data (averaged standard penetration test N values up to 20 m depth, depth to rock). We evaluate the performances of our eight models and existing global and regional geospatial models using four indicators: accuracy, balanced accuracy, F1 score, and area under the receiver operating characteristic curve. The three RF-based models outperform the other models, followed by the best LR-based model and the global geospatial model from Zhu et al. (2015). Finally, we apply the best RF-based model to the entire Pohang City and evaluate its applicability to other regions and earthquakes. The estimated liquefaction probabilities agree well with the observed distributions of the sand boils and settlements. These geospatial liquefaction models provide a valuable tool for continuously mapping liquefaction hazards in areas with similar geological and geotechnical conditions to Pohang.

ГЕНЕЗИС ОЗЕРА ТУГАР-САЛГАН В ЗАПАДНЫХ ПРЕДГОРЬЯХ ЮЖНОГО УРАЛА

Lake Tugar-Salgan is located on the territory of the Ishimbay Municipal District of the Republic of Bashkortostan,10 km southeast of the city of Sterlitamak, at the foot of Shikhan Toratau (Turataw). Despite the morphometric parameters of the lakeestablished a long time ago, its origin is not fully clear. The genesis of the lake is considered to be karstic, but the formation mechanismand even its belonging to the type of karst based on the composition of the karst rocks have not been established. The purpose of theresearch is to determine the conditions and factors of the formation of Lake Tugar-Salgan, which is a complex natural monument ofrepublican importance. Data from a state hydrogeologic survey, a survey of exogenous geologic processes, and the author's 2022 fieldsurvey served as source data for this article. Research methods employed in the study include morphological and morphometric surveysof the lake bed and of the nearest landforms in its vicinity. It has been established that the lake formation was connected with thedevelopment of karst process in the gypsum of the Kungurian Stage of the Early Permian and the lake is located in the rear part of the third supra-flood terrace of the Belaya River valley. The distribution of surface manifestations of sulfate karst in the lake area is directlydependent on the age of relief elements on which they have been formed and inversely dependent on the thickness of non-karst sediments covering karst gypsum. Along with these, the main factor of the lake formation is the course of relief formation in the NeogeneQuaternary time. The karst basin with the lake is located at the mouth of the modern semi-blind erosion-karst ravine, and in the EarlyPliocene its mouth opened 89 km to the west in the paleovalley of the Belaya River. After the paleovalley had been filled with Plioceneand then Pleistocene sediments, the middle and mouth parts of the ravine and the karst landforms were buried under Quaternary alluvium. It was in the rear part of the third supra-floodplain terrace of the Belaya River valley, in the karst basin only partially filled withclayey Middle Pleistocene sediments, where Lake Tugar-Salgan was formed.

Structural and Stratigraphic Study of Hazara-Kashmir Syntaxis with the Aid of Geographic Information System and Field Data Approach

Abstract This research area is located along the Hazara-Kashmir Syntaxis in the sub-Himalaya. The Hazara-Kashmir Syntaxis runs through numerous areas within Mirpur district. One of the key characteristics of the Hazara-Kashmir Syntaxis is its antiformality. The project area is bounded to the east by the Riasi fault and to the west by the Jhelum fault, while to the south it is bounded by Salt Range Thrust. Research is being conducted in the areas of Narmah, Sahan, Pirgali, Kas Guma, Mohra Jangu, and Kalri. Fold-and-thrust belts are present in the sub-Himalayan region ofPakistan. Essentially, there are two major folds: the Sahan syncline and the Gaiyan anticline. The Sahan syncline is characterized by an open fold and a southwest orientation. In contrast, open-to-close folds in Gaiyan anticlines are oriented to the southwest. The area is characterized by five major faults: the Narmah fault, the Dhok Poran fault, the Dubal fault, the Pirgali fault, and the Jabi fault. Folds and faults in the project area are the product of NE-SW or NW-SE compaction of the Himalaya. In the research project area sedimentary rocks of Early Miocene- Recent age are located. The rocks which are exposed in the study area includes: the Early-Middle Miocene Kamlial Formation, Middle-Late Miocene Chinji Formation, Late-Miocene Nagri Formation, Late-Miocene Dhok Pathan Formation, Pliocene Soan Formation, and Quaternary Alluvium deposits. Sedimentary structures in the area consist primarily of crossed bedding and rip-ups. These structures define the facing of stratigraphic units.

Hydrochemical and isotopic studies providing a new functional model for the coastal aquifers in Douala Coastal Sedimentary Basin (DCSB)/Cameroon

A new conceptual model of the hydrogeological systems in Cameroon's Douala Coastal Sedimentary Basin (DCSB) was constructed. The model is based upon the basin's known geology, plus data from recent field campaigns that allowed the collection of rainwater and groundwater samples for analyses of stable isotopes (δ2H, δ18O, δ13C), radiogenic isotopes (3H, 14C), and water chemistry. Aquifer characteristics that were thereby deciphered include recharge, isotopic distributions, residence times, and mixing processes. Rainfall samples (mean δ18O = −2.0 ‰; mean δ2H = −6.80 ‰; weighted mean = −2.4 ‰ δ18O, −9.85 ‰ δ2H) scatter along two distinct lines, thus indicating that local rainfall events undergo processes during convective events, variability in humidity, amount effects, and seasonal variations. Stable isotope values of river water samples are close to the weighted mean of local precipitation, with some downstream enrichment. The Quaternary/Mio-Pliocene superficial aquifer system (depth < 70 m) and the intermediate Oligocene/Upper Eocene aquifer system (depth: 70 to 200 m) exhibit evidence of similar fractionation processes through an enrichment gradient of δ-values. The enrichment is more pronounced at the top of the superficial aquifer, which is very exposed to direct rainfall water infiltration, evaporation, and amount effects. The depth profiles of δ-values coupled to water chemistry and tritium contents, evidence leakage between (i) the superficial system's Quaternary alluvium sands and Mio-Pliocene sands; and (ii) the superficial and intermediate systems. Thus, the aquifers that contain modern, post nuclear groundwater are characterized by flow exchanges and direct recharge from rainfall events. In contrast, the Upper Eocene system has depleted δ-values and lower bicarbonate contents, suggesting not only that this system was recharged by rapid infiltration (with limited effect of evaporation), but that this recharge occurred during a cooler time in the past. The residence times (computed from 14C dates) indicate uncorrected ages ranging from hundreds to thousands of years.

Petrographic and geochemical properties of the ignimbrites around Hatunsaray (Konya)

The study area is located around the town of Hatunsaray, approximately 40 km away from the south-west of Konya. In this study, the petrological and geochemical characteristics of the Bulumya ignimbrite, Detse ignimbrite and Sadıklar ignimbrite observed in the region were revealed. The study area contains Upper Miocene - Lower Pliocene aged Güneydere formation and overlying Bulumya ignimbrite, Detse ignimbrite, Sadıklar ignimbrite and Quaternary alluviums. All these units were formed in the Upper Miocene - Lower Pliocene aged fluvial and lake environment and have a lateral vertical transition with carbonate, clastic units. The gray-colored Bulumya ignimbrite contains andesite-dacite rock fragments and large pumice grains. The Detse Ignimbrite is yellow in color and shows a well sorted lapilli tuff composition. The Sadıklar Ignimbrite, on the other hand, contains agglomeratic levels with yellow colored slightly fused lenses and wedge geometry. All ignimbrite samples have porphyric texture and were classified as “crystal-vitric tuff” and “crystal lithic-vitric tuff” in the glass-crystal-rock fragment classification. Petrographic investigations of ignimbrites show that major components are quartz, plagioclase, plagioclase microliths, biotite, amphibole, opaque minerals and rock fragments. Geochemical data shows that all ignimbrite samples are subalkaline, trachy-andesite, andesite-basaltic andesite and calc-alkaline in character. When the main oxide, trace and rare earth elements in ignimbrites are evaluated, fractional crystallization controlled by feldspar minerals is observed. In addition, the high K and Rb content in the spider diagrams indicate crustal contamination. The distribution of the ignimbrite samples in the Rb/Y-Nb/Y diagram suggests that the magma source forming the samples is enriched by subduction and/or crustal components.

Characterization of groundwater in Quaternary aquifer of the Yanbu Al-Nakhl Basin, Al-Madinah Al-Munawarah Province using pumping tests and hydrochemical techniques

In the Yanbu Al-Nakhl Basin, Quaternary aquifer is the main source of groundwater supply for different uses. The groundwater wells that have been drilled in this area are now not subject to local government regulation in terms ofdistances and daily pumping rates. This may lead to declines in groundwater levels and deterioration of its quality. The primary goal of this research is to characterize the Quaternary aquifer using measurements of hydraulic parameters and groundwater quality. To achieve this purpose, all aquifer parameters such as thickness, lithology, depth to water, water table, well loss, formation loss, well efficiency, transmissivity and hydraulic conductivity were measured. Moreover, chemical analysis for major ions as well as minor and trace elements of 14 samples were carried out to determine the physicochemical properties, groundwater facies, controlling mechanisms and five irrigation water quality indices (IWQIs). The results revealed that, groundwater originates mainly from highly permeable Quaternary alluvial sediments of (60 m thickness), and flows generally from north to south. The calculated hydraulic parameters indicated that, the average of well efficiency(γ) ranges from 42.21% to 72.2%, transmissivity (T) varies between 88.2 and 105.4 m2/day, and hydraulic conductivity (K in m/day) ranges from 4.41 to 9.3. In hydrochemical point of view, there are various types for groundwater in the study area including Ca - HCO3, Na - Cl, mixed Ca – Mg – Cl - SO4, and Na – Ca - HCO3. The processes of evaporation and rock – groundwater interaction were significantly influenced the groundwater quality in the Wadi. The computed IWQIs (TDS, TH, SAR, PS, MH, and RSC) had mean values of 1537.685, 678.31, 3.940625, 2.140625, 25.85687 and −10.8068 respectively, indicated that no restriction range for agriculture uses characterizes the majority of groundwater in Wadi Yanbu Al-Nakhl basin.