Semi-humid Climate Conditions Research Articles

Provenance of the lower Cretaceous Lumshiwal Formation, Surghar Range, northwestern Indian Plate, Pakistan: Insights from new petrographical and geochemical analysis

This paper documents the provenance and palaeoclimatic conditions of the Cretaceous Lumshiwal Formation near the western margin of the Indian plate in the Surghar Range, northwest Pakistan. The combined techniques of petrography, X-ray diffraction (XRD), and bulk rock geochemistry were utilized to reveal the source and mineral-geochemical composition and sandstone type. The petrographic analysis of the sandstones confirms the dominance of quartz, feldspar, and rock fragments, with subordinate occurrences of muscovite, magnetite, and hematite. Heavy minerals consist of tourmaline, titanite (sphene), rutile, cassiterite, monazite, and zircon. The cementing material includes ferruginous clays, jarosite, glauconite, calcite, minor dolomite, gypsum, and silica. The modal composition plot of the sandstones falls into arkose to sub-arkose, with a few lithic arkose varieties. Lithic fragments mainly include granite, with a minor occurrence of granitic gneiss, chert, phyllite, and quartz mica schist. The discriminatory provenance diagram of the sandstones suggests a transitional continental provenance. The bulk rock geochemistry of the sandstones reveals the presence of SiO2, TiO2, Al2O3, Fe2O3, FeO, MnO, CaO, MgO, Na2O, K2O and P2O5. The petrographical mineral findings were corroborated with XRD, SEM, and bulk rock geochemistry analysis (major element concentrations and their ratios), which collectively all confirm a felsic igneous source. The tectonic discrimination diagram (SiO2-log K2O/Na2O wt %) implies a dominant influx of sediment sourced from the passive continental margin of the uplifted Gondwana Indian plate. Terrigenous sediments found in the Lumshiwal Formation are interpreted to have been derived from granites and granitic gneisses of the Indian Shield. The palaeo-weathering index, including the chemical index of alteration (CIA) and the chemical index of weathering (CIW) of the Lumshiwal Formation confirms a low to moderately weathered source area. The climate discrimination plot (SiO2 versus Al2O3 + Na2O + K2O) shows that humid to semi-humid climatic conditions during the deposition of the Lumshiwal Formation.

Determination of Combined Effects of Organic and Mineral Fertilizer on Forage Yield and Quality of Annual Ryegrass

The widespread practice of using high doses of nitrogen to increase unit area yield in annual ryegrass introduces ecological and economic problems. This research was carried out over two years and aimed to determine the potential forage yield and quality of annual ryegrass by applying manure, humic acid, and low doses of nitrogen fertilizer, within the framework of sustainable forage crop cultivation. The study was carried out from 2020 to 2022 with three replications according to the randomized block split plots experimental design. According to the study results, the highest values were achieved with combinations that included manure application, and even higher values were observed when manure was applied along with low doses of humic acid and nitrogen. The M20 + H20 + N100 treatment yielded the highest fresh yield, dry matter, and crude protein. The treatments with manure, humic acid, and nitrogen fertilizer had varying effects on the ADF and NDF content of annual ryegrass, resulting in fluctuating values. In conclusion, 20 t manure, 20 L humic acid, and 100 kg ha−1 N application can be suggested for sustainable and higher dry matter production with good quality for annual ryegrass cultivation under semi-humid climatic conditions. The results obtained from this research hold promise for sustainable agricultural practices.

Petrography and geochemistry of sandstones of the Ash Shumaysi Formation in the Jeddah-Makkah region, Saudi Arabia: Implications for provenance, tectonic setting, paleoweathering, paleoclimate and paleogeography

This study aims to evaluate the provenance of sandstones of the Ash Shumaysi Formation (Early Eocene to Oligo-Miocene) exposed in the Jeddah-Makkah region (an intra-continental cratonic region in the west of the central part of the Arabian Shield), in addition to re-establish the tectonic setting, paleoclimate and paleo-weathering of their source rocks. This aim has been achieved by petrographic investigation and geochemical (major, trace and rare earth elements) analysis of the sandstones. Integration of both petrographic and geochemical data reflects a derivation of the sandstones from intensively-weathered and multi-recycled felsic igneous (granites) rocks, with a minor contribution of intermediate (granodiorite), mafic igneous (andesite), metamorphic (mainly gneisses) and recycled sedimentary rocks, which correspond to the Precambrian rock units of the west of the central part of the Arabian Shield. The latter was developed under semi-humid climatic conditions in the source area. Tectonically, the source rocks are of a cratonic interior in a passive continental margin of the Upper Continental Crust. This passive continental margin was later affected by rifting as revealed from the discrimination function diagrams of high-silica samples of sandstones. In general, the Ash Shumaysi sandstones may represent erosional products of the nearby high-topographic crystalline rocks of the Western Arabian Shield that were located in a tectonically stable passive margin subjected to a subsequent continental rift. Results of this study could add to the knowledge about paleoweathering, paleoclimate and tectonic setting in the Arabian Shield which is a part of the southern margin of the broad stable continental shelf of the northern margin of the Gondwana supercontinent.

Provenance, weathering, climate and tectonic setting of Padma River sediments, Bangladesh: A geochemical approach

The major, trace, and rare earth element (REE) compositions of sediments from the Padma River, Bangladesh have been examined using XRF and INAA analysis to determine their geochemical compositions, provenance, climate, weathering intensity and tectonic setting. The Padma River sediments from the region were remarkably comparable, demonstrating elemental depletion and pointing to a low geochemical maturation. Sediment samples are classified as arkose which are considered as chemically immature sediments, deposited under semi-arid to semi-humid climatic conditions due to the weakening of Indian summer monsoon. The low CIA values (48.6–58.8), PIA (48.1–63.4) and Rb/Sr ratios of the river sediments suggest low intensity of chemical weathering in the source area. The Padma River is originated from the Higher Himalaya and the sediments derived from metasediments (Higher Himalayan Crystalline Series) as are evident by major, trace elements discriminate diagram and REE pattern. Most of the sand samples were derived from felsic source rock (granite) whereas some samples are plotted in the intermediate rock types (granodiorite) in the A-CNK-FM and discriminant function diagrams. High LREE enrichment and relatively flat HREE fractionation in chondrite-normalized REE patterns (LaN/YbN = 7.50–13.20) demonstrated felsic source origin. TiO2 versus Zr plot shows that Padma River sediments have felsic to intermediate provenance. According to Log (K2O/Na2O) vs. SiO2 discriminant diagram and La–Th–Sc, Th–Sc–Zr/10 ternary plot, the Padma River sediments were deposited in passive continental margin. The Padma River sediments have been compared with Yarlung Zangbo River (YZR), Brahmaputra-Jamuna River (BJR), Ganges River (GR) and Upper Meghna River (UMR), which results suggest that there is contrast among the sediments of different Himalayan Rivers in relation to provenance, weathering intensity and tectonic setting.

Development of an analytical permeable pavement model for vehicular access areas

Permeable pavements (PPs) are widely used for stormwater control in urbanized areas as they provide absorption and retention of surface runoff. Previous studies on PP systems mainly focus on non-vehicular access areas with light traffic loads where the base usually connects to native soils which allow exfiltration from the bottom. The runoff reduction performance of the PPs in vehicular access areas (PPs-VAA) featured by more complex structure with underdrain outflow control still needs in-depth investigation. In this study, an analytical probabilistic model was developed to quantify the runoff control performance of PPs-VAA taking into account the effects of climate conditions, layer configurations and varying underdrain outflows. The calibration and verification of the proposed analytical permeable pavement model for vehicular access areas (APPM-VAA) were performed by comparing the analytical results with SWMM simulation results. The model was tested in case studies in Guangzhou and Jinan, China, with humid and semi-humid climate conditions, respectively. Close agreement between the results obtained from the proposed analytical model and those from continuous simulation outputs was observed. The proposed analytical model is proved to be capable of rapidly assessing the runoff control performance of PPs-VAA; it can thus be used in the hydrologic design and analysis of permeable pavement systems in engineering practices.

Mineralogical and geochemical characterization of lacustrine calcareous shale in Dongying Depression, Bohai Bay Basin: Implications for paleosalinity, paleoclimate, and paleoredox conditions

Shale is an important self-sourced reservoir rock in many sedimentary basins worldwide. In this research work, a geochemical history of variations in the sedimentary environment of the lacustrine basin is analyzed based on extensive shale samples collected from the lower 3rd member (Es3L) and upper 4th member (Es4U) of the Paleogene Shahejie Formation in the Boxing Sag (Dongying Depression, East Coast of China). The representative shale samples were analyzed for total organic carbon (TOC) contents, mineralogical composition, the concentration of different elements (major, minor, and trace), kerogen types and vitrinite reflectance (Ro), and different sedimentary structures to understand the evolution of the depositional settings and their effect on the distribution of shale lithofacies in this basin. The TOC content in this shale ranges from 0.08 % to 13.6 %. Ro values range from 0.55 to 1.19 % with type-I to type-II kerogens. The studied shale is composed of calcite (average 37.83 wt%), dolomite (avg. 10.47 wt%), quartz (avg. 23.8 wt%), plagioclase (avg. 3.91 wt%), clay (avg. 20.84 wt%), and pyrite (avg. 2.85 wt%). Seven lithofacies have been established including mixed shale, calcareous shale, laminated limestone, argillaceous shale, dolomitic shale, siliceous shale, and siliceous dolomite based on mineral composition, TOC contents, and sedimentary structures. Different geochemical proxies including Sr/Ba, Ca/Ca + Fe, C-values, CIA values, Ti/Al, Al/Al + Fe, Al/Ti, V/V + Ni, Ni/Co, and Fe/Ca + Mg were used to interpret salinity, paleoclimate, detrital influx, provenance, paleoredox and water depth of the depositional environment in the studied shale. The detailed interpretation of the sedimentary environment suggested that during the deposition of Es3L shale, the terrigenous influx was high in shallow to a deep open lacustrine system with higher primary biogenic productivity. Semi-humid climatic conditions with higher precipitation rates prevailed during the deposition of this shale. On the other hand, relatively limited terrigenous input with low bioproductivity prevailed during the deposition of Es4U shale in the study area. Semiarid to humid climatic conditions with strong evaporation prevailed during the deposition of this shale. In this research work, a detailed depositional model of the Es3L–Es4U shale in Boxing Sag is established. The interpretations deduced from the current research work are likely to expand the knowledge of shale lithofacies and the genesis of lacustrine fine-grained sedimentary rocks, as well as can offer a theoretical foundation for lacustrine shale oil exploration and development.

Paleoenvironmental changes during the early Toarcian Oceanic Anoxic Event: Insights into organic carbon distribution and controlling mechanisms in the eastern Tethys

• Unlike N Europe, TOC contents are significantly varied in lower Toarcian sediments of the eastern Tethys . • Anoxic, but non-sulfidic conditions prevailing during the T-OAE. • Humid climates promoted moderate continental weathering during the T-OAE. • Marine productivity was commonly high during the T-OAE in the eastern Tethyssouthern Qiangtang Basin. • Organic carbon burial and oil shale accumulation sustained by increased primary productivity. The Toarcian Oceanic Anoxic Event (T-OAE; Early Jurassic, ca. 183 Ma) represents an intense Mesozoic organic carbon burial event that was associated with the formation of oxygen-deficient conditions at paleo-shelf seas, as well as in lacustrine settings. Global scale increase in organic carbon accumulation occurred in connection with profound changes in climate conditions and perturbations of biogeochemical cycles. This study presents geochemical data for lower Toarcian and Bajocian-Bathonian sediments exposed in the Bilong Co section, located in the southern Qiangtang Basin of central Tibet. During Early and Middle Jurassic times, the study site was located in the north-eastern marine of the Tethys Ocean. A total of 83 rock samples, spanning the Quse (lower Toarcian) and Sewa formations (upper Bajocian-Bathonian), were analyzed for their total organic carbon (TOC) content, carbon isotopes of bulk carbonate and kerogen, as well as major and trace elements. Data allowed to assess changes in the environmental conditions in the eastern Tethys Ocean and further allowed to reconstruct changes in paleo-weathering conditions, marine primary productivity, and redox regimes that occurred in association with the T-OAE. In addition, factors that controlled the accumulation of organic material in the sediment are discussed. Enrichment factors (EF) of redox-sensitive trace elements, their relationship with TOC, and C org /P total molar ratio attest to predominantly anoxic pore and bottom waters in southern Qiangtang Basin during the T-OAE. On the contrary, oxic conditions prevailed during pre- and post-T-OAE times. During the T-OAE, the development of anoxic conditions were most likely linked to an increase in marine primary productivity, as revealed by C org /P total molar ratio, as well as Al-normalized Ba, and Zn concentrations, and their relationship with TOC. Data further attest to a moderate to low marine primary productivity during pre- and post-TOAE times. During the T-OAE, an increase in the marine primary productivity was linked to intensified continental weathering, facilitated by semi-humid climate conditions. Compilation of TOC data from various depositional settings in the eastern Tethys Ocean revealed a high spatial variability, highlighting the importance of local intrabasinal processes on organic matter accumulation.

Numerical investigation and modelling of controllable parameters on the photovoltaic thermal collector efficiency in semi-humid climatic conditions

ABSTRACT Hybrid Photovoltaic Thermal (PV/T) systems are energy-generation systems that transform thermal irradiance into both electrical and thermal energy at the same time. Hybrid photovoltaic thermal systems consist of a photovoltaic panel connected to a thermal collector. The main objective of this paper is to find the optimal operating conditions that can be controlled to decrease the photovoltaic panel temperature in order to improve the electrical and thermal performance of PV/T systems. In this work, we proposed the 3D numerical model that is implemented within the COMSOL Multiphysics program to study the PV/T system. The experimental input data being used in this research study reflects a typical Algerian area with semi-humid climate conditions. We study the effect of water velocity, pipe length, diameter, thickness and inlet fluid temperature on the electrical and thermal performance using the design of experiments (DOE) method. Further, the analysis of variance (ANOVA) is used to identify which of these effects impact the most the photovoltaic thermal and electrical efficiencies, the response surface methodology (RSM) is employed to describe how these effects are interacting. Based on ANOVA analysis, the following factors are reported to be important: water velocity, pipe diameter, pipe length and the inlet fluid temperature. Further, there is a significant interactions between water velocity, pipe length and pipe diameter. Among the operating conditions being calculated using the RSM, the optimal one is found when water velocity, pipe length, pipe diameter, pipe thickness and inlet water temperature have the following values, 0.05 m/s, 7.27 m, 0.01 m, 0.0008 m and 10°C, respectively. The corresponding thermal, electrical and overall efficiency were found around 80.73%, 12.87% and 93.60%, respectively. The proposed simulation model provides a reliable framework to study, improve and predict PV/T systems performance whilst ensuring low computational time.

The spatial pattern of agricultural ecosystem services from the production-living-ecology perspective: A case study of the Huaihai Economic Zone, China

Clarifying the spatial pattern of multiple ecosystem services and the production-living-ecology is crucial for promoting the sustainable development of regional agricultural ecosystems. In this paper, taking the Huaihai Economic Zone (HEZ) as a case study area, we used a series of geospatial models and multisource data to construct a framework for assessing the production-living-ecology of agricultural ecosystem services. Then, the ecosystem services and comprehensive production-living-ecology index of the cropland in the entire study area were evaluated and analyzed. Finally, we used a method of regionalization with dynamically constrained agglomerative clustering and partitioning to identify the subclusters of agricultural ecosystems in the study area and proposed the concept of regional management. We found that (1) for the single service of agricultural ecosystems, based on warm temperate semihumid climatic conditions and topographic factors, water conservation, carbon sequestration and oxygen release and grain production services in the HEZ showed spatial consistency in 2017; the distribution characteristics of these factors were high in the south and low in the north; the distribution of soil maintenance services was the opposite, and the high value of culture and recreation services was scattered and distributed in areas with good ecological background conditions and convenient transportation. (2) The production-living-ecology index in the HEZ generally showed a distribution pattern of high in the south and low in the north. (3) Through zoning, the 1884 grids, 12 partitions, and 6 subclusters provide references for the management of different types of agricultural ecosystem services. Our results can provide scientific guidance for the development of effective agricultural ecosystem management programs and the optimization of cropland development.

Geochemical Partitioning of Heavy Metals and Metalloids in the Ecosystems of Abandoned Mine Sites: A Case Study within the Moscow Brown Coal Basin

Significant environmental impacts of mining activities connected with high-sulfur materials result from the production of acid mine drainage and potentially toxic elements, which easily migrate to adjacent ecosystems due to the typical absence of vegetation on spoil heaps and toeslope talus mantle. In this paper, we present the results of the first comprehensive study of the ecosystems affected by acidic and metal-enriched (Al, Ca, Co, Cu, Fe, Mg, Mn, Ni, and Zn) mine drainage conducted at spoil heaps and adjacent talus mantle under semihumid climate conditions within the Moscow Brown Coal Basin (Central Russian Upland, Tula Region, Russia). A total of 162 samples were collected, including 98 soil samples, 42 surface water samples, and 22 plant samples (aerial tissues of birch). Coal talus mantle materials of Regosols were characterized by the increased concentration of water-soluble Ca, K, Mg, and S, and all mobile fractions of Al, Co, S, and Zn. The chemical composition of birch samples within the zones affected by acid mine drainage differed insignificantly from those in the unpolluted ecosystems with black soils, due to the high tolerance of birch to such conditions. Differences between the affected and undisturbed sites in terms of the chemical composition decreased in the following order: waters > soils > plants. The geochemical characterization of plants and soils in coal mining areas is essential for the mitigation of negative consequences of mining activities.

Provenance and depositional characteristics of Lathi Formation in southern part of Jaisalmer Basin: Implications for exploration of sandstone type uranium mineralization

The lower Jurassic Lathi Formation covers about 900 sq. km area and forms the lowermost unit of Jaisalmer Basin of western Rajasthan. Lithologically the Lathi Formation comprises of conglomerate, sandstone, siltstone, shale and mudstone. The sandstones are generally medium- to coarse-grained, moderately sorted and show variation in colour, grain-size and texture. Petrographic studies indicate a mixed provenance for the Lathi sandstone. On the basis of geochemical data, theses sandstones are classified into sub-arkose, litharenite and sub-litharenite. Palaeo-weathering indices such as CIA (80.45), CIW (85.23) and PIA (84.23) suggest moderate to high degree of chemical weathering of the source area, intermediate and felsic igneous provenance, under humid to semi-humid climatic conditions. Further, the geochemical data indicate the sedimentation in a passive continental margin setting. The Bouguer gravity image clearly depicts the north westward slope of the basement. Modelling studies of the gravity data revealed average depth to the basement as 800m, 400m and 250m respectively in northwest, central and southeastern parts of the surveyed area. Exploration activities by Atomic Minerals Directorate for Exploration and Research have resulted in location of several uranium anomalies in the Lathi Formation. Lathi Formation is characterised by many favourable parameters such as fertile provenance, arkosic sandstones intercalated with shale/mudstone, reduced sedimentary facies with carbonaceous matter, lignite and pyrite deposited in continental to marginal marine environment. Malani Igneous Suit and metamorphic rocks constitute the basement for Jaisalmer Basin. Malani rhyolites and granites are fertile source of uranium, containing 6.7 ppm and 9.2 ppm average and intrinsic uranium respectively. Presence of carbonaceous matter and pyrite bearing sandstones, indicative of reducing environment at depth below water table (R.L. 150 m), was reported during subsurface exploration in Lathi sandstone which is a favourable condition for Lathi sediments to host uranium mineralization.

Geochemical Characteristics of Quartzite in Parts of Paleoproterozoic Dhanjori Group, Singhbhum Craton, Eastern India: Implications for Provenance and Paleoweathering

Singhbhum craton preserves the records of sedimentation, magmatism, and tectono-thermal events from Mesoarchaean to Neoproterozoic. The Dhanjori Group (DG), located on the northeast margin of the Singhbhum craton, comprises of a variety of rocks including quartz pebble conglomerate, quartzite, schist, inter-layered with mafic to intermediate and rarely acidic lava flows, tuff and agglomerate. Petrography and geochemical characteristics of the Dhanjori quartzite have been undertaken to interpret paleoweathering and provenance characteristics. Studied quartzites are made up of abundant quartz, feldspar, mica, and lithic fragments. With the help of geochemical data, the studied quartzites are classified as quartz-arenites and sub-arkoses. In addition to the A-CN-K plot, various chemical indices such as the chemical index of weathering (CIW), chemical index of alteration (CIA), and plagioclase index of alteration (PIA) indicate moderate to intense chemical weathering of the provenance under semi-humid climatic conditions. Rare earth element (REE) chondrite normalized patterns of the studied samples illustrate enriched light rare earth elements (LREEs) (LaN/SmN = 3.11–6.19), depleted heavy rare earth elements (HREEs) (GdN/YbN = 0.35–3.12) and negative Eu anomaly (Eu/Eu* = 0.55–0.87, ∼ 0.68). Such patterns are similar to that of the upper continental crust (UCC). In the discrimination function diagram, studied samples of the Dhanjori Group fall in quartzose sedimentary field. In addition, La/Sc vs. Th/Co and La-Th-Sc diagrams, various ratios like Th/Sc (∼0.61), La/Sc (∼4.42), Th/Co (∼0.03), La/Co (∼0.11), and Cr/Th (∼141.62) imply a mixed provenance for the studied samples. Hence, it has been inferred that the meta-sediments and ortho-amphibolites of the older metamorphic group, Singhbhum granitoid complex, as well as associated Archaean metavolcanic suites, would have acted as the probable source rocks for the studied Dhanjori quartzites.

Geochemical analysis for evaluating the paleoweathering, paleoclimate, and depositional environments of the siliciclastic Miocene-Pliocene sequence at Al-Rehaili area, Northern Jeddah, Saudi Arabia

Geochemical data and their various approaches are useful to evaluate the climatic control on the depositional environments. This study aims to evaluate the paleoweathering and plaeoclimate condition that have controls on the depositional environments of the Miocene to Pliocene siliciclastic sequence at Al-Rehaili area, north of Jeddah. To achieve this aim, selected sandstone samples were geochemically (major and trace elements analysis) and petrographically examined. The results of these analyses reveal that the examined sandstones were deposited in non-marine (fluvial/alluvial-lacustrine) environments and suffered from weak to intermediate chemical weathering and intense physical induration under semi-arid to semi-humid climatic conditions.

Sedimentological and Geochemical Charectesization of Manaveli and Cuddalore Formations, Puducherry Basin, India

Sedimentological and Geochemical Charectesization of Manaveli and Cuddalore Formations, Puducherry Basin, India 
 
 Shyam N. Mude, Shyam Yawale and Vishal Choudhari 
 
 Department of Geology, Fergusson College (Autonomous), Pune- 411004, India
 Email: shyam.mude@fergusson.edu; shyammude25@yahoo.co.in
 
 Abstract: The lithostratigraphically rocks of Puducherry basin (Sub-basin of Cauvery Basin) have been classified as Valudavur, Mettuveli, Karasur, Manaveli, Cuddalore formations in ascending order of deposition. The sedimentological and geochemical studies of sediments from Manavali (Paleocene) and Cuddalore (Mio-Pliocene) formations were carried out to understand grain size variation and distribution of major oxides and trace elements. 
 The sieve analysis was used to study grain size variation and on the basis of grain sizes various geo-statistical parameters were calculated to understand depositional environment. The discriminant function analysis of the sediments from the Cuddalore Formation infers that mostly the sedimentation was occurred in fluvio-deltaic environment with incursions of shallow marine environment whereas bivariate plots suggests that the deposition was occurred in riverine to deltaic environment.
 The major element geochemistry of the Manaveli and Cuddalore formations have been carried out to understand the provenance, paleoclimate and source area weathering conditions. The values of CIA (Chemical Index of Alteration), CIW (Chemical Index of Weathering), ICV (Index of Compositional Variability) and PIA (Plagioclase Index of Alteration) of the sediments infer high weathering was occurred in source area of sediments for Manaveli and Cuddalore formations. The ratio (Al2O3+K2O+Na2O)/SiO2 indicate semi-humid climatic conditions during deposition of Cuddalore Formation whereas Manaveli Formation was deposited in semi-arid climatic conditions. The discriminant function diagram (A-CN-K Plot), suggest Quartzose sedimentary provenance for Cuddalore and Mafic igneous provenance for Manaveli Formation. 
 
 Keywords: Grain Size, Geochemistry, Manaveli, Cuddalore, Puducherry Basin

Palaeoweathering, Tectonic Setting and Climatic Condition of Sabarmati Alluvial Plain in Ahmadabad City, Gujarat, Western India

The present study emphasizes major elemental geochemical attributes-based prediction of nature, palaeoweathering intensity, provenance, tectonic setting and palaeoclimatic condition of source area of Sabarmati alluvial sediments lying in Ahmadabad locality, Gujarat, India. The sediments successions are comprised of gravel, poorly graded sand, with dominant silty and clayey sands, silt and clay with low-to-high level of plasticity. The sediments exhibit increasing concentration of MnO followed by P2O5, TiO2, K2O, MgO, Na2O, CaO, Fe2O3, Al2O3 and SiO2 which supports quartz dominating sand layers in comparison with silty and clayey sequences. The values of SiO2/Al2O3, Na2O/Al2O3 and K2O/Al2O3 and higher values of ICV indicate immature sediments with low dilution of ‘Na’ and ‘K’. Lithologically, the majority of sediments belong to shale and Fe-shale varieties. The values of ICV, CIA, CIW and PIA and various bivarient and discrimination diagrams reveal the mechanical fragmentation, abrasion and low to moderate degree of chemical palaeoweathering of fragments of felsic and intermediate igneous rocks of rift basin located at island arch and active continental margin under arid/semi-arid conditions sporadically interfered by short-term humid and semi-humid climatic conditions were responsible for formation of sediments sequences of the area.

Using data on soil ECa, soil water properties, and response of tree root system for spatial water balancing in an apple orchard

The study aims at spatial analysis of water deficit of fruit trees under semi-humid climate conditions. Differences of soil, root, and their relation with the spatial variability of crop evapotranspiration (ETa) were analyzed. Measurements took place in a six hectare apple orchard (Malus x domestica ‘Gala’) located in fruit production area of Brandenburg (latitude: 52.606°N, longitude: 13.817°E). Data of apparent soil electrical conductivity (ECa) in 25 cm were used for guided sampling of soil texture, bulk density, rooting depth, root water potential, and volumetric water content. Soil ECa showed high correlation with root depth. The readily available soil water content (RAW) was calculated considering three cases utilizing (i) uniform root depth of 1 m, (ii) measured values of root depth, and (iii) root water potential measured during full bloom, fruit cell division stage, at harvest. The RAW set the thresholds for irrigation. The ETa was calculated based on data from a weather station in the field and RAW cases in high, medium and low ECa conditions. ETa values obtained were utilized to quantify how fruit trees cope with spatial soil variability. The RAW-based irrigation thresholds for locations of low and high ECa value differed. The implementation of plant parameters (rooting depth, root water potential) in the water balance provided a more representative figure of water needs of fruit trees Consequently, the precise adjustment of irrigation including plant data can optimize the water use.

Phosphatase enzyme activity in different soils formed on bazaltic parent material under semi humid climate conditions

Soil enzymes have an important role in determining the function of microorganism in soil ecosystem. In addition, the enzyme activities give much knowledge on the biochemical processes occurring in soil. Therefore, soil enzymes such as dehydrogenase, phosphatase and urease are indicators of soil biological productivity and activity. This study was carried out to determine phosphatase activity in different land use of Bafra-Engiz Basin, Samsun and to investigate the relations between soil pedogenetic processes, land use, elevation and phosphatase activities. For this purpose, soil samples taken from the four soil profiles classified as Typic Haplustert and Lithic Ustorthent. The analysis results related to phosphatase activity of soils in the study area changed between 8.1-177.3 μg p-nitrophenol. Moreover, according to statistical analysis results different profiles and different elevation were found to be important at 1% level of effect on phosphatase enzyme activity in the soils. Finally, it was also determined that the effect of different land use type on the activity of phosphatase enzyme activity in the soil was insignificant as statistically.

Petrography and tectonic provenance of the Miocene Surma Group in parts of the Naga-Manipur hills, in and around Nungba, Northeast India

The Miocene molassic Surma sandstones in parts of the Naga-Manipur hills, in and around Nungba, Northeast India have been studied for their tectonic provenance using petrography and heavy mineral contents. The poorly-to-moderately-sorted sub-litharenite to lithic-arkose type Surma sandstones display predominance of monocrystalline quartz (av. 61%) and include undulose and non-undulose varieties and almost equal amounts of feldspars (av. 22%) and rock fragments (av. 17%). The heavy mineral suite of Surma sandstones is dominated by transparent varieties (96%) that include garnet, zircon, tourmaline, rutile, staurolite, scapolite, phlogopite, chondrodite, humite, wollastonite, hedenbergite. sphene, chlorite, sillimanite, glauconite, glaucophane, and chloritoid. These heavy minerals characterize the granitic and silicic metamorphic complexes (GM) as well as the basic metamorphic rocks (MT) like greenstones, green schist, and amphibolites relating to passive continental margin set-up. The opaque grains constitute nearly 4% of the total heavy minerals. The presence of euhedral, as well as abraded heavy mineral grains, further supports a mixed provenance having substantial contribution from sedimentary and metamorphic rocks. A ZTR index of approximately 45% indicates mineralogically sub-mature nature of Surma sandstones. Based on the light and heavy mineral suites coupled with the type of terrain available in the vicinity of the study area, it may be visualized that the sediment supply was largely made by the Himalaya, the IMR, the Shillong plateau, and the Mikir Hills under the influence of semi-arid to semi-humid climatic conditions. An overall supply from a recycled orogen provenance has been envisaged.

Biophysical effect of conversion from croplands to grasslands in water-limited temperate regions of China

The biophysical effect of land use and land cover change (LUCC) on regional climatic regulation is currently of growing interest. However, in water-limited temperate regions, the net biophysical effect of conversion from croplands to grasslands on regional climatic regulation remains poorly understood to date. To answer this concern, a modified land surface model (mEASS) and two different land use scenarios in a typical study area of the Loess Plateau of China were used in this study. We first validated the performances of mEASS model by using observations from six flux tower sites with different land cover and three metrics of the coefficient of determination (R2), the root mean square error (RMSE) and the difference between the simulated and observed data (bias). Subsequently, the biophysical effect of conversion from croplands to grasslands was investigated. Results indicated that mEASS model could well capture the seasonal dynamics of net radiation and latent heat with high R2 and lower RMSE and bias at grassland, forest and cropland sites. In the context of semi-arid and semi-humid climatic conditions, conversion from croplands to grasslands caused the cooling effect (−0.3 W/m2) at the annual scale. Similar cooling effects were found in spring (−0.4 W/m2), autumn (−0.8 ± 0.1 W/m2) and winter (−0.9 ± 0.1 W/m2). The decreased latent heat (inducing warming effects) were completely offset by decreased net radiation (inducing cooling effects), which were responsible for the net cooling effects. However, a warming effect with 1.0 ± 0.1 W/m2 was observed in summer. This is because that magnitude of decreased latent heat is greater than that of decreased net radiation in summer. These findings will enrich our understanding for the biophysical effect of conversion from croplands to grasslands in water-limited temperate regions.

VARIATION OF DEHIDROGENASE ENZYME AKTIVITY AND DIFFERENT PEDOGENETIC DEVELOPMENT ON WEATHERED BASALTIC TOPOSEQUENCES

Enzymes play the most important role in the decomposition and deterioration of organic matter inthe soil. Most of the microbial activity in the soil is determined by measuring the activities of theenzymes. The aim of this study is to examine the changes in dehydrogenase enzyme activity indifferent pedological development soils formed on the same parent material, but with differentslopes, land cover and land use under semihumid climatic conditions. It was carried out on the soilformed on the basaltic parent material in different topographical positions within the Dağköy area ofEngiz district, which is located at the south of the Samsun-Bafra Highway. In this study,dehydrogenase enzyme activity was assessed in order to reveal the biological properties of the soilof the study area and it was investigated the dehydrogenase enzyme activity in terms of soilbiological property. For this aim, six soil profiles formed on weathered basaltic parent material andlocated on toposequence of north-south transect were described according to genetic horizon andclassified as Lithic Ustorthent, Vertic Haplustept, Typic Haplustept and Typic Haplustert. I