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

2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Faisal Alqahtani ◽  
Mohammed Khalil
Keyword(s):  
Chemical Weathering ◽  
Major And Trace Elements ◽  
Climatic Conditions ◽  
Depositional Environments ◽  
Geochemical Data ◽  
Geochemical Analysis ◽  
Climatic Control ◽  
Trace Elements Analysis ◽  
Area North ◽  
Semi Arid

AbstractGeochemical 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.

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

2021 ◽  
Vol 38 (1) ◽  
pp. 41-50
Author(s):  
Shijo Mathew ◽  
Pritam Karmakar ◽  
Rajeev Bidwai ◽  
S K Sharma ◽  
Navin Goyal ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Gravity Data ◽  
Source Area ◽  
Sedimentary Facies ◽  
Climatic Conditions ◽  
Uranium Mineralization ◽  
Coarse Grained ◽  
Geochemical Data ◽  
Carbonaceous Matter ◽  
Jaisalmer Basin

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.

scholarly journals Effect of Temperature on Sowing Dates of Wheat under Arid and Semi-Arid Climatic Regions and Impact Quantification of Climate Change through Mechanistic Modeling with Evidence from Field

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 927
Author(s):  
Jamshad Hussain ◽  
Tasneem Khaliq ◽  
Muhammad Habib ur Rahman ◽  
Asmat Ullah ◽  
Ishfaq Ahmed ◽  
...  
Keyword(s):  
Climate Change ◽  
Grain Yield ◽  
Arid Region ◽  
Field Experiments ◽  
Climatic Conditions ◽  
Seasonal Temperature ◽  
Sowing Dates ◽  
Rcp 8.5 ◽  
Semi Arid Region ◽  
Semi Arid

Rising temperature from climate change is the most threatening factor worldwide for crop production. Sustainable wheat production is a challenge due to climate change and variability, which is ultimately a serious threat to food security in Pakistan. A series of field experiments were conducted during seasons 2013–2014 and 2014–2015 in the semi-arid (Faisalabad) and arid (Layyah) regions of Punjab-Pakistan. Three spring wheat genotypes were evaluated under eleven sowing dates from 16 October to 16 March, with an interval of 14–16 days in the two regions. Data for the model calibration and evaluation were collected from field experiments following the standard procedures and protocols. The grain yield under future climate scenarios was simulated by using a well-calibrated CERES-wheat model included in DSSAT v4.7. Future (2051–2100) and baseline (1980–2015) climatic data were simulated using 29 global circulation models (GCMs) under representative concentration pathway (RCP) 8.5. These GCMs were distributed among five quadrants of climatic conditions (Hot/Wet, Hot/Dry, Cool/Dry, Cool/Wet, and Middle) by a stretched distribution approach based on temperature and rainfall change. A maximum of ten GCMs predicted the chances of Middle climatic conditions during the second half of the century (2051–2100). The average temperature during the wheat season in a semi-arid region and arid region would increase by 3.52 °C and 3.84 °C, respectively, under Middle climatic conditions using the RCP 8.5 scenario during the second half-century. The simulated grain yield was reduced by 23.5% in the semi-arid region and 35.45% in the arid region under Middle climatic conditions (scenario). Mean seasonal temperature (MST) of sowing dates ranged from 16 to 27.3 °C, while the mean temperature from the heading to maturity (MTHM) stage was varying between 12.9 to 30.4 °C. Coefficients of determination (R2) between wheat morphology parameters and temperature were highly significant, with a range of 0.84–0.96. Impacts of temperature on wheat sown on 15 March were found to be as severe as to exterminate the crop before heading. The spikes and spikelets were not formed under a mean seasonal temperature higher than 25.5 °C. In a nutshell, elevated temperature (3–4 °C) till the end-century can reduce grain yield by about 30% in semi-arid and arid regions of Pakistan. These findings are crucial for growers and especially for policymakers to decide on sustainable wheat production for food security in the region.

Variation in climate determines differences in the effects of abiotic variables on the phytoplankton community in tropical ecosystems

2018 ◽  
Vol 69 (3) ◽  
pp. 357
Author(s):  
F. H. Portella Corrêa de Oliveira ◽  
A. N. Moura ◽  
Ê. W. Dantas
Keyword(s):  
Phytoplankton Community ◽  
Synergistic Effects ◽  
Climatic Conditions ◽  
Cylindrospermopsis Raciborskii ◽  
Tropical Reservoirs ◽  
Physicochemical Variables ◽  
Abiotic Variables ◽  
Tropical Climates ◽  
Semi Arid ◽  
Canonical Analyses

The present study demonstrates the effects of abiotic variables on phytoplankton in two different tropical climates. Samples were taken from tropical reservoirs, including six from a tropical climate (As) and five from a semi-arid climate (BSh). Phytoplankton samples were identified, biomass was quantified and climatic and physicochemical variables were evaluated. Canonical analyses were performed in order to observe the effects of abiotic variables on phytoplankton. In both As and BSh ecosystems, the effects of the physicochemical variables were significant, but the synergistic effects between variables and climatic conditions were more pronounced in BSh. Micronutrients had a significant role in structuring the phytoplankton community in both As and BSh. In As, Cylindrospermopsis raciborskii occurred in the presence of lower concentrations of zinc and copper, whereas in BSh this species was present in the presence of higher concentrations of zinc. In the As climate, Geitlerinema amphibium, Cyclotella meneghiniana, Planktothrix agardhii and Microcystis aeruginosa were associated with higher sodium concentrations in the water, whereas in the BSh climate these species experienced lower rainfall. The findings of the present study show that climate determines the effects of abiotic variables on the phytoplankton community in both an independent and synergistic manner. In the present study, phytoplankton in tropical and semi-arid reservoirs is mostly regulated by nutrients, the effects of which vary according to climate.

Chemical weathering in semi-arid soils of the Russian plain

CATENA ◽  
2021 ◽  
Vol 206 ◽  
pp. 105554
Author(s):  
P.I. Kalinin ◽  
I.Yu. Kudrevatykh ◽  
V.V. Malyshev ◽  
L.S. Pilguy ◽  
A.V. Buhonov ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Russian Plain ◽  
Arid Soils ◽  
Semi Arid

Genetic Diversity Analysis of Salvadora Oleoides Decne: An Evergreen Dry Land Fruit Tree of Rajasthan, India

2021 ◽  
Author(s):  
Juleri M Upendra ◽  
Shari Nair ◽  
Satyawada R Rao ◽  
Harchand R Dagla
Keyword(s):  
Genetic Diversity ◽  
Random Amplified Polymorphic Dna ◽  
Splice Junction ◽  
Genetic Distances ◽  
Climatic Conditions ◽  
Fruit Tree ◽  
Group Method ◽  
Dry Land ◽  
Intron Splice ◽  
Semi Arid

Abstract Genetic diversity of Salvadora oleoides Decne is analyzed by cumulative data of 10 Random Amplified Polymorphic DNA (RAPD), 10 Inter Simple Sequence Repeats (ISSR) and 7 Intron Splice Junction (ISJ) markers. The plant is an evergreen fruit tree and well distributed in semi-arid and sub-humid climatic conditions of Rajasthan, India. RAPD, ISSR and ISJ primers accounted for 84.4%, 85.3%, 85.9% polymorphism. Average 0.23 PIC is accounted for RAPD, ISSR and ISJ primers. The genetic similarity ranged between 0.42-0.89. Analysis of molecular variance (AMOVA) revealed higher variation (73%) at intra-population than inter-population (27%) level. Genetic distances based on Un-weighted Pair Group Method with Arithmetic mean (UPGMA) dendrogram and Principal Coordinate Analysis (PCoA) is correlated with physical distances or climatic conditions of Salvadora oleoides Decne in a semi-arid and sub-humid environment of Rajasthan. The present investigation may help in the understanding of gene flow systems between physical distances and environmental heterogeneity of the populations for better management of Salvadora oleoides Decne in the region.

Concentration and Nitrogen Stocks in the Soils of Semi-Arid Landscapes of Kizlyar Pastures

2020 ◽  
pp. 66-74
Author(s):  
Tatiana A. Asvarova ◽  
Gasan N. Gasanov ◽  
Kabirat B. Gimbatova ◽  
Kamil M. Hajiev ◽  
Rashid R. Bashirov ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Humus Horizon ◽  
Control Area ◽  
Climatic Conditions ◽  
Chestnut Soils ◽  
Number Of Species ◽  
Current State ◽  
Low Degree ◽  
Arid Landscapes ◽  
Semi Arid

The results of research on the current state of the nitrogen fund (reserve regime) the Kizlyar pastures. It was found that the total nitrogen ranges from 0.15-0.2 %, nitrogen easily hydrolyzed from 2.4-5.3 mg/100g in light-chestnut, meadow-chestnut soils and saline typical, and has a medium and low degree of security. The humus horizon is more enriched with nitrogen on soils of meadow-chestnut and light-chestnut compared to typical saline. N and C reserves in the soil in spring are 5.0 and 13.4 t/ha, respectively, and in autumn N and C reserves are 1.5 times lower, due to decrease the number of species and projected coverage up to 40-50% of phytocenoses in autumn, and also depends on the climatic conditions of the annual seasonality. In the control area with intensive grazing, nitrogen and carbon reserves in the soil are 1.6-1.8 times lower.

scholarly journals The influence of the climatology of the semi-arid from Alagoas-Brazil on the raw milk microbiota

2017 ◽  
Vol 3 (1) ◽  
pp. 27
Author(s):  
Ticiano Gomes do Nascimento ◽  
Euridice Farias Falcão ◽  
Maria Cristina Delgado da Silva ◽  
Josicleide Nascimento Oliveira Silvino ◽  
Pierre Barnabé Escodro ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Thermal Comfort ◽  
Vegetation Index ◽  
Raw Milk ◽  
Climatic Conditions ◽  
The State ◽  
Maximum Temperature ◽  
Climatic Data ◽  
Microbiological Analysis ◽  
Semi Arid

This study aimed to evaluate the influence of the climatology of the semi-arid from Alagoas-Brazil on the raw milk microbiota in semi-arid area of the 07 micro-regions of the State of Alagoas of Alagoas, Brazil. The climatic data were extracted from National Institute of Meteorology from the Brazilian government. The raw milk was collected after the dairy cow milking process in 12 small rural associations of the semi-arid from the State of Alagoas, during the 4 seasons and the raw milk was carried out procedures of sampling, transportation and microbiological analysis. A total of 58 samples were counted coliforms at 45°C, <em>Escherichia coli</em> and coagulase-positive <em>Staphylococcus</em>. Only 02 rural associations presented low levels of microbiological contamination, which were located in areas of climatic conditions and parameters of thermal comfort index and vegetation index favorable, but 10 rural associations presented high counting of coliforms at 45°C, <em>Escherichia coli</em>. The climatologic parameters (maximum temperature, atmospheric pressure), bovine comfort thermal index and vegetation index have showed to influence the growth of the coliforms at 45°C and <em>Escherichia coli</em> with high incidence during the summer weather. The precipitation parameter, bovine thermal comfort and vegetation index have displayed to influence coagulase-positive<em> Staphylococcus</em> counting especially during the period between the summer end and the autumn beginning seasons. New Actions, and Rural Education and Health Programs should be implemented as politics of Food Safety. New strategies and programs for dissemination more effective on the risks of transmission of pathogens and Foodborne Diseases are necessary as the part of emergence politics of the health and education areas. Regulatory Actions should be encouraged within the processes that improve the quality control of raw milk as well its bioproducts, with professional assistance relevant in agriculture area.

Sign in / Sign up

Export Citation Format

Share Document