Skip to Content

Instrukcja korzystania z Biblioteki

Serwisy:

Ukryty Internet | Wyszukiwarki specjalistyczne tekstów i źródeł naukowych | Translatory online | Encyklopedie i słowniki online

Translator:

Kosmos
Astronomia Astrofizyka
Inne

Kultura
Sztuka dawna i współczesna, muzea i kolekcje

Metoda
Metodologia nauk, Matematyka, Filozofia, Miary i wagi, Pomiary

Materia
Substancje, reakcje, energia
Fizyka, chemia i inżynieria materiałowa

Człowiek
Antropologia kulturowa Socjologia Psychologia Zdrowie i medycyna

Wizje
Przewidywania Kosmologia Religie Ideologia Polityka

Ziemia
Geologia, geofizyka, geochemia, środowisko przyrodnicze

Życie
Biologia, biologia molekularna i genetyka

Cyberprzestrzeń
Technologia cyberprzestrzeni, cyberkultura, media i komunikacja

Działalność
Wiadomości | Gospodarka, biznes, zarządzanie, ekonomia

Technologie
Budownictwo, energetyka, transport, wytwarzanie, technologie informacyjne

Asian Journal of Earth Sciences

A phytosociological study of river sand mine near Palri Bhoptan village, tehsil-Kisangarh, district Ajmer, Rajasthan has been undertaken to evaluate the impact of restorative interventions on floristic structure and composition. The study was aimed at enumeration of the available plant resources and obtaining a broad representation of the existing floristic variations in the mine lease area and surrounding mine buffer areas. The mine lease area is located near villages Bhanwata, Narwar, Manpura, Beer, Oontra, tehsil-Ajmer, district-Ajmer, Rajasthan. One protected forest lies within the project affected village i.e., in Palri Bhoptan while one protected forest and one open scrub lies in buffer zone of the project area. Mining is a major source of economy in Rajasthan but is also a major cause of ecological disturbance due to the land degradation and related changes in the structural and functional characteristics of the native vegetation. This study describes the floristic composition and phytodiversity assessment of mining and mining surrounding area.

http://scialert.net/abstract/?doi=ajes.2014.51.59 2014/07/11 - 10:41

Succession of tertiary strata in the Hormozgan province of southern Iran consists
of predominantly carbonate deposits and characterized by marked changes in facies
and thickness. These changes relate to sediment deposition in a foreland basin
along the NE margin of the Arabian plate. In this study, stratigraphic evolution,
microfacies are used to constrain the depositional evolution of the Tertiary
sediments. The succession was measured at four outcrop and wells sections in
the East Khamir, West Khamir, Namak and West Namak anticlines. The age of the
base of the succession is Paleocene and its upper part is probably late Oligocene.
The lower of the succession consists of interbedded wackestone to packstones
of the Pabdeh formation. These strata are overlain by up to intrashelf deposit
altered packston to grainstone (Jahrum formation) that may represent much of
late Paleocene-Eocene time. The upper part of the Jahrum formation overlain
by carbonate platform deposit (Asmari and Razak formations). We argue that the
lithofacies and sediment- accumulation history of this succession based on these
regional profiles, the tertiary depositional history of the Bandar Abbas area
was reconstructed and can be divided into two tectono-sedimentary phases suggesting
a transition from an active to a passive margin. The active phase (late Paleocene)
dominated by pelagic marls, gravity flow deposits and lateral thickness variations.
During passive phase dominated by Shallow-water facies consist mainly of packstones
to grainstone with abundant benthic foraminifera. Rapid variations in thickness,
Sequence stratigraphy and facies document the evolution of depositional processes
in the foreland basin. In the study area, the foreland basin is characterized
by a considerable SW to NE increase in stratigraphic thickness.

http://scialert.net/abstract/?doi=ajes.2014.27.39 2014/05/23 - 18:18

Trace fossils from the outcrop section of the Enugu Formation in Anambra Basin,
southeastern Nigeria, have been studied based on the varieties, types, mode
of occurrence, orientation of the burrows, wall structures and fills. Five ichnogenera
identified belong to the Skolithos and Cruziana ichnofacies and include; Skolithos
isp. Thalassinoides isp., Planolites isp., Teichichnus isp. and Chondrites isp.
The assemblage is suggestive of deposition in a nearshore setting influenced
by stressed environmental conditions due to the mixture of marine and fresh
water inflows. The lithologic characteristics, physical sedimentary structures,
the distribution and the style of the bioturbation from the base to the top
of the sequence, as well as the general absence of deeper marine ichnofacies
suggest moderate to high energy conditions in a prograding shoreline and shallow
marine environments.

http://scialert.net/abstract/?doi=ajes.2014.40.50 2014/05/23 - 18:18

Microscopic and field studies on the Lar formation in south west of Azarshahr
in Haft-Cheshme anticline section is due to separate of three part of marl,
marly carbonate and carbonate in this formation. According to microfacies and
macroscopic fossils in carbonate section, open marine environment were identified
from a carbonate ramp. XRD test samples related to clay marl in the low and
middle part indicated existence of clay mineral such as illite and cholorite
from clastic origin in the part of upper and middle marl and illite and smectite
are diagenetic origin in the lower marl. The simultaneous presence of the minerals
in the middle marl and the lack of smectite in this section represent of temperate
climate conditions are during deposition of the middle marl. The semi-quantitative
analysis of the XRD is indicating of smectitec increasing and illite decreasing
in the lower marl part which it may represent of a warming climate and depth
sea relative increase and it was consistent with sea level change global. Important
digenetic process of identified in these formations are include: Cementation,
primary and secondary porosity and chert nodules formations (constituents) which
the secondary porosity is more than a fracture and channel types. The existence
of these fractures has created suitable underground water aquifers in this area.

http://scialert.net/abstract/?doi=ajes.2014.17.26 2014/04/14 - 23:12

Soil pile structure interaction under seismically loadings is a very complex
phenomenon involving of kinematic and inertial interaction among soil, pile
and superstructure. Piles experience kinematic bending moments caused by the
soil deformations due to the passage of the seismic waves through the surrounding
layered soil. These moments are increased at each the levels of the soil deposit
with the different modulus. A model of the soil pile interaction 2D is developed
in this paper. The main results of parametrical study on single piles obtained
by this model are compared with the exiting design methods for evaluating the
kinematic interaction between soil-pile subjected to the seismic excitations.
The shear strain and the shear stress are evaluated by the linear equivalent
method of the free field site response analyses. The results show that the kinematic
bending moment at the interface is changed by the soil nonlinearity behavior
and the frequency content of the seismic motion even in absence superstructure.

http://scialert.net/abstract/?doi=ajes.2014.1.9 2014/04/11 - 19:09

Study presents a novel algorithm to improve the frequency bandwidth of the
seismic data through removal of non-stationary wavelet in cepstrum domain. Algorithm
incorporates useful properties of both homomorphic deconvolution and spectral
decomposition by this way it estimates and filters the wavelet at each translation
of spectral decomposing Gaussian window which improve the resolution and tolerates
the non-stationary properties of seismic wavelet. This study describes the comprehensive
mathematical formulation of the algorithm and its testing on 1D, 2D synthetic
and real seismic section to confirm its applicability. Comparative testing shows
that the algorithm effectively removed the smearing effect of wavelet which
led to broader frequency spectrum and improved seismic resolution.

http://scialert.net/abstract/?doi=ajes.2014.10.16 2014/04/11 - 19:09

Okigwe district is in the complex geological environment of Imo State and lies
between latitude 5°30-5°57/N and longitude 7°04-7°26/E. It covers
a land area of about 1,824 km2. Water is becoming scarce in the area
owing to increasing demand and deteriorating quality due to pollution. This
is compounded by the gradual increase in the rate of industrial and commercial
activities and the cases of borehole failure in some parts of the area. This
study therefore aimed at delineating sites for productive boreholes. To achieve
this, 120 Vertical Electrical Soundings (VES) were sited within the study area.
The ABEM terrameter was used to acquire data using the Schlumberger electrode
array and a maximum current electrode spread of 900 m. Twelve of the VES Stations
were sited near existing boreholes to enhance interpretation. The resistivity
of the aquiferous zones varied from 33.1 Ωm obtained in the Northern part
to 32600 Ωm recorded in the Southern area. The aquifer thickness is low
in the Northern part but high in the Southern part reaching a maximum of 104.4
m recorded at Otoko. Using an average transmissivity of 1032.0848 m2
day-1 determined from pumping test, a mean conductance value of 91.222
m day-1 was obtained for the area. Hydraulic conductivity varied
from 9.8854-115.9646 m day-1 while transmissivity ranged from 992.04-10263.65
m3 day-1. With these results and the distribution of storativity
and specific capacity values, the Southern and Northeastern parts of the district
are promising for sitting boreholes with high yield expectation.

http://scialert.net/abstract/?doi=ajes.2013.1.15 2013/06/20 - 16:39

Characterizing the ground thermal regime and estimation of water balance and
mass exchange processes occurring across porous media often require knowledge
of heat flux through the surface layers. Accurate measurement of the parameter
has therefore continued to receive increasing attention by Scientists and Engineers.
Improved determination of heat flux density in porous media using the modified
Block method was thus investigated in this study with a view to addressing the
hitherto associated accuracy concerns. Heat flux densities of granular and solid
geologic materials represented by Granite and Clay samples were evaluated using
Arctic Silver® Thermal Interface Material (TIM), to measure impacts
on thermal resistance errors. Results showed heat flux density of the clay sample
increasing from 9.99 to 64.02 W m-2 with TIM while that of the granite
sample increased from 26.28 to 48.95 W m-2 with TIM. Hence, accuracy
concern was therefore largely addressed with regards to contact measurements
and the correction of the underestimation problem was validated with TIM. Modified
block method thus yielded improved results of heat flux density in clay and
granite with thermal interface material.

http://scialert.net/abstract/?doi=ajes.2013.16.23 2013/06/20 - 16:39

Study of attenuation characteristics of electromagnetic signals passing through
porous media is becoming increasingly relevant in providing important insights
into the physical properties of the medium and objects that are buried therein.
Laboratory experiments have been carried out in this work to determine the relationship
between Q-factor of the electromagnetic signal passing through buried metals
and the porosity of the surrounding sediments. Sediments were obtained from
Erinle River in Ilobu, Southwestern Nigeria and Iron, Silver and Copper plates
of similar dimensions were buried inside box-filled sediment in succession.
Electromagnetic signal was passed through metals, sediments and sediments with
buried metals while lissajous figures generated at different frequencies were
analyzed to assess the impacts of buried objects. Results showed that Q-factor
decreased as the porosity of riverbed sediments increased. Of the metals buried
inside the sediments, Iron had the most attenuating effect while Silver plates
had the least, except at frequency 400 Hz where Copper had the least and at
600 Hz where there were some overlaps between Silver and Copper. Q-factor increased,
for all metals and at all signal frequencies, up to a maximum value at the porosity
of 0.24 and thereafter decreased. Knowledge of Q-factor from attenuated signals
is therefore, a useful way to characterize and identify buried materials.

http://scialert.net/abstract/?doi=ajes.2013.24.31 2013/06/20 - 16:39

This study presents the result of spectral analysis of aeromagnetic data of Abeokuta area, a basement complex of South-western Nigeria. Aeromagnetic survey is a powerful tool in delineating the regional geology of buried basement terrain. The purpose of magnetic surveying is to investigate the subsurface based on the variation in the observed magnetic field result from the differences in the magnetic properties of the underlying rocks, or in some cases cultural sources. In order to achieve the aim of this study, matched pass filtering operation was performed on digitised aeromagnetic data of the area under consideration to separate magnetic anomalies produce by shallow features and cultural features separated from anomalies produced by deeper geologic unit. Two-dimensional spectral analysis revealed that the magnetic sources are mainly distributed at two levels. The shallow source is depth 0.467 km below ground level is inferred to be due to the intrusions within the region. The deeper sources depth, which is 2.797 km below ground, is attributed to the underlying basement. The mean shallow depth and deeper depth are 0.467 km and 2.797 km, respectively. The shallow depth of 0.467 km might probably due to intrusive within the sediment while deeper depth of 2.797 km is attributed to underlying basement. Variation in magnetic depth values reveals the general trends in the magnetic basement surface.

http://scialert.net/abstract/?doi=ajes.2012.70.78 2013/03/20 - 02:18

This study was carried to characterize the basement rocks and groundwater potentials
by delineating the resistivity and overburden thickness of subsurface lithology
of Odeda quarry, south-western, Nigeria. Vertical electrical soundings were
carried out at fifteen locations using Schlumberger electrode arrangement. The
maximum current electrode spread and potential electrode separation were 200
and 5 m, respectively. Data acquired were interpreted using the manual partial
curve matching method and a fast computer iteration technique to generate the
geoelectric layer of various resistivity values and thicknesses. The geoelectric
sections revealed the lithological sequence as: topsoil, weathered layer and
fresh bedrock. The overburden coefficient of anisotropy also revealed that,
the underlying basement rock is suspected be granite gneiss/granite-schist.
The overburden coefficient of anisotropy was calculated for each sounding location
and this ranges from 1.00 to 2.30. This was used in delineating the study area
into region underlain by granite gneiss (λ between 1.00 and 1.03) and those
regions with granite-schist (λ between 1.30 and 2.30) as the underlying
basement rocks. At locations where current terminated at the fresh bedrock region,
the thicknesses were undetermined. Groundwater potential is presumed to be very
low within the study area as outcrops of gneissic rocks dominate the area. Locations
where the regolith is of appreciable thickness, the resistivity of the layer
suggests a material medium likely composed of clay/sandy clay or clayey sand
which are not good aquiferous media from which groundwater could be extracted.

http://scialert.net/abstract/?doi=ajes.2012.79.87 2013/03/20 - 02:18

The cycle of El Niño-Southern Oscillation (ENSO) is very crucial to
affect the natural climate variability in a particular region. Direct measurement
of ENSO cycle and to understand their comprehensive physical mechanism are still
difficult for sustainable development. For that purpose, a Precipitable Water
Vapor (PWV) derived from a ground-based Global Positioning System (GPS) receiver
is proposed. The PWV for the year 2011 gathered from Universiti Malaysia Sabah
located in Kota Kinabalu, Malaysia (UMSK) together with two other selected GPS
stations centered the Borneo region in pathways of Niño 4 region, named
Nanyang Technological University (NTUS) in the Singapore and Manila Observatory
(PIMO) in Philippines were analyzed. The GPS PWV was also compared with PWV
taken from Radiosonde (RS). The results found a good agreement between GPS PWV
and RS PWV with correlation coefficients ranging from 0.6 to 0.8, significantly
at the 99% confidence level. PWV at Philippine's station demonstrated a drop
about 7.8 mm before the first monsoon and PWV in the whole station look like
a bimodal pattern throughout the year. An investigation of ENSO episode in September
with weak-to-moderate intensity between PWV and the sea-surface temperature
anomaly demonstrated an inverse correlation due to La Niña events. This
promising result indicates that during the La Niña event, the PWV is
increased when the sea-surface temperatures getting cold and thereby slow down
the GPS signals.

http://scialert.net/abstract/?doi=ajes.2012.88.95 2013/03/20 - 02:18

Peat’s stratigraphic sequence
contains information related to humification, hydrology, nutrient content and
formation history of the bog. These are vital information needed for effective
assessment of the deposit’s economic
potentialities and environmental impact. This research is aimed at developing
a model for delineating stratigraphic sequences of Pontian Peatland with ground
penetrating radar. The study involves imaging of prominent reflection layers
within the subsurface of the deposit and laboratory determination of organic
content of the soil samples collected at various depth intervals on the study
area. Four Ground Penetrating Radar (GPR) transects were scanned at regular
interval spacing. Comparison of the processed radar image with the experimental
data leads to the identification of three prominent stratigraphic layers: Top
soil fabric with high ash content (low organic content), hemic layer of low
ash content (high organic content) and kaolinitic clay with moderate organic
content. The study could therefore serve as a means of assessing and monitoring
fertility level and hydrological pattern of the deposit.

http://scialert.net/abstract/?doi=ajes.2012.36.49 2012/10/10 - 20:28

A detailed understanding of the biostratigraphy of the Dahomey Basin in southwestern
Nigeria will broaden our knowledge of the Basin which traversed different West
African countries especially as Nigeria is working towards increasing her petroleum
output. The palynological investigation of eight surface outcrops from Ifon
town of the Upper Araromi Formation processed using conventional methods of
disaggregation and removal of carbonates and silicates with hydrochloric acid
and hydrofluoric acid and further treatment with hot hydrochloric acid (HCl),
wet-sieving over a 5-micron sieve and the Branson Sonifier 250 used for the
complete removal of silt and clay particles. Each residue was prepared for study
as strewn mounts using Loctite. The samples yielded a rich assemblage of Maastrichtian-Paleocene
palynomorphs among which were common Ariadnaesporites spinosa, A.
nigeriensis, Ariadnaesporites sp., Foveotriletes margaritae,
Rugulatisporites caperatus, Distaverrusporites simplex, Cingulatisporites
ornatus, Zlivisporis blanensis, with dinoflagellate cysts, diatom
frustules and abundant palm pollen Longapertites marginatus, L. vaneendenburgi,
L. microfoveolatus, Proxapertites operculatus, Monocolpopollenites
sphaeroidites, Spinizonocolpites echinatus, S. baculatus,
S. kostinensis, Retidiporites magdalenensis, Mauritidites lehmanii,
Tubistephanocolpites cylindricus, Echitriporites trianguliformis,
E. longispinosus, Monocolpites marginatus, Retimonocolpites nigeriensis,
Racemonocolpites racematus and Arecipites sp. The palynological age
assigned to the samples were based on already published ranges of the palynostratigraphically
important taxa. The preponderance of these palm pollen, together with diatom
frustules and a dinoflagellate cyst suite dominated by Gonyaulaceleans, indicates
sediment deposition in a highly productive shallow marine environment.

http://scialert.net/abstract/?doi=ajes.2012.50.62 2012/10/10 - 20:28

Sole use of chemical fertilizers as a nutrient source for intensive paddy rice production has likely caused a decline in soil fertility and rice yields. This study examined the effects of poultry manure and sewage sludge application on nitrogen (N) uptake, dynamics and efficiency of usage. A 15N isotope dilution method was used to estimate the amount of N in rice plants derived from the poultry manure and sewage sludge. The results showed that the percentage of 15N recovered from sewage sludge and poultry manure was 19 and 36%, respectively. Most of the N uptake by rice was from the soil and varied from 54-64%. The relative efficiency of poultry manure and sewage sludge was 80 and 85%, respectively. No significant difference was observed in the N loss rate and the N residual into soil post harvesting between the poultry manure and sewage sludge.

http://scialert.net/abstract/?doi=ajes.2012.63.69 2012/10/10 - 20:28

The propagation of Love waves in presence of a horizontal rigid barrier of finite length in the surface layer has been discussed. The transmitted waves have been obtained by using Wiener-Hopf technique and Fourier transform. The numerical computation has been done by assuming depth of barrier small as compared to the wavelength of the incident wave. It has been observed that the transmitted waves decrease as the distance from the barrier increases and die out after a very long time. The result of semi-infinite barrier has been obtained as a special case of this problem.

http://scialert.net/abstract/?doi=ajes.2012.1.12 2012/05/11 - 19:57

The propagation of Love waves in presence of a horizontal rigid barrier of finite length in the surface layer has been discussed. The transmitted waves have been obtained by using Wiener-Hopf technique and Fourier transform. The numerical computation has been done by assuming depth of barrier small as compared to the wavelength of the incident wave. It has been observed that the transmitted waves decrease as the distance from the barrier increases and die out after a very long time. The result of semi-infinite barrier has been obtained as a special case of this problem.

http://scialert.net/abstract/?doi=ajes.2012.1.12 2012/05/11 - 19:57

In this study, the Analytical Hierarchy Process (AHP) method was used to produce a landslide susceptibility map for an area located in the central northern part of Peninsular Malaysia. The study was carried out using remote sensing data, field surveys, historical data and Geographic Information System (GIS) tool. Eleven factors that influence the occurrence of landslide were chosen for this study: Slope gradient, slope aspect, curvature, distance from road, drainage density, lithology, foliation dip, topographic/bedding relationship, lineament density, soil and rainfall. The Landslide Susceptibility Index (LSI) was computed from the combined weighed thematic maps of factors based on the assigned weights and ratings given by the AHP method. The AHP results were verified with existing landslide locations, which yielded the accuracy rate of 80.97%. Hence the landslide susceptibility map generated with the AHP method is useful for preventing or minimizing possible landslides and could be adopted in the proper planning for land use and construction in the future.

http://scialert.net/abstract/?doi=ajes.2012.13.24 2012/05/11 - 19:57

In this study, the Analytical Hierarchy Process (AHP) method was used to produce a landslide susceptibility map for an area located in the central northern part of Peninsular Malaysia. The study was carried out using remote sensing data, field surveys, historical data and Geographic Information System (GIS) tool. Eleven factors that influence the occurrence of landslide were chosen for this study: Slope gradient, slope aspect, curvature, distance from road, drainage density, lithology, foliation dip, topographic/bedding relationship, lineament density, soil and rainfall. The Landslide Susceptibility Index (LSI) was computed from the combined weighed thematic maps of factors based on the assigned weights and ratings given by the AHP method. The AHP results were verified with existing landslide locations, which yielded the accuracy rate of 80.97%. Hence the landslide susceptibility map generated with the AHP method is useful for preventing or minimizing possible landslides and could be adopted in the proper planning for land use and construction in the future.

http://scialert.net/abstract/?doi=ajes.2012.13.24 2012/05/11 - 19:57

Pahang River flows from its upstream at Cameron highlands to its downstream at Pekan into the South China sea. The hydrodynamics of Pahang river as well as data on the long term variation of its water level, rainfall and river flow from the year 1980 to 2009 have been identified based on analysis at three gauging stations, namely the Sg. Yap, Temerloh and Lubuk Paku Gauging Stations. The highest of the total rainfall was triggered by the Northeast Monsoon which occurs from November to March yearly. The average monthly water level of the Pahang River at Sg. Yap ranged from 43.49 m (July) to 45.36 m (Dec.), at Temerloh from 24.73 m (August) to 26.71 m (Dec.) and at Lubuk Paku from 12.70 m (July) to 15.23 m (Dec.). The recorded monthly rainfall at Sg. Yap was from 106.67 to 254.01 mm, while at Temerloh it was from 93.75 to 219.83 mm and at Lubuk Paku from 79.81 to 324.57 mm. The average monthly discharge of the Pahang River at Sg. Yap was 845.78 m3 sec-1, while at Temerloh it was 1008.50 m3 sec-1. At Lubuk Paku, the recorded monthly discharge was 1184.46 m3 sec-1. At least five critical points coincided with the flood events along Pahang River from the year 1980 to 2009.

http://scialert.net/abstract/?doi=ajes.2012.25.35 2012/05/11 - 19:57

Pahang River flows from its upstream at Cameron highlands to its downstream at Pekan into the South China sea. The hydrodynamics of Pahang river as well as data on the long term variation of its water level, rainfall and river flow from the year 1980 to 2009 have been identified based on analysis at three gauging stations, namely the Sg. Yap, Temerloh and Lubuk Paku Gauging Stations. The highest of the total rainfall was triggered by the Northeast Monsoon which occurs from November to March yearly. The average monthly water level of the Pahang River at Sg. Yap ranged from 43.49 m (July) to 45.36 m (Dec.), at Temerloh from 24.73 m (August) to 26.71 m (Dec.) and at Lubuk Paku from 12.70 m (July) to 15.23 m (Dec.). The recorded monthly rainfall at Sg. Yap was from 106.67 to 254.01 mm, while at Temerloh it was from 93.75 to 219.83 mm and at Lubuk Paku from 79.81 to 324.57 mm. The average monthly discharge of the Pahang River at Sg. Yap was 845.78 m3 sec-1, while at Temerloh it was 1008.50 m3 sec-1. At Lubuk Paku, the recorded monthly discharge was 1184.46 m3 sec-1. At least five critical points coincided with the flood events along Pahang River from the year 1980 to 2009.

http://scialert.net/abstract/?doi=ajes.2012.25.35 2012/05/11 - 19:57

Jubaila Formation is of the Upper Jurassic and covers the shallow shelf and the Central Arabian intrashelf basin. Unweathered limestone and soil samples were collected from the base of the roadcut (about 10-15 m below the surface of Jubaila Formation). XRD was applied for whole sample and clay fraction of limestone rock and soil samples. Moreover, Differential thermal and thermo gravimetric analysis (DTA, TGA) were carried out with whole sample fraction of limestone rocks and soils. Calcite was recognized as a major mineral of limestone rocks and other samples. Also, quartz and kaolinite were approved with all samples. Soil samples have low content of 2:1 clay minerals and more kaolinite. Clay fraction of samples has kaolinite, illite and illite/smectite. The content of illite and illite/smectite was more with soil samples comparison with other samples. The existence of calcite and absence of other calcium carbonates (such as aragonite, Mg-calcite and nesquehonite, etc.) indicates how old is study area (Jubaila Formation). Transformation of Mg-calcite to calcite, supply Mg ion which is necessary of smectite generated by transformation of illite. Because of, soil’s strap was stuck between limestone rocks made low leaching and drainage environment which supported generation of illite/smectite mineral.

http://scialert.net/abstract/?doi=ajes.2011.203.213 2012/02/22 - 16:36

In this study, we report the variation in foF2 (critical frequency of F2 layer) parameter by correlation method at the time of strong seismic event. Ionosonde data installed at different locations were used for analysis purpose of four cases of earthquakes. Considering two ionosonde recorders, where one ionosonde is in the earthquake preparation zone and the other is out side of it. By correlation analysis method Karl’s Pearson coefficients have been calculated. Results of the study showed the anomaly in the Karl’s Pearson coefficient related to foF2 parameter, few days before the seismic activity. This fact can be regarded as precursory phenomena. The changes in the F-layer density may be interpreted as a result of associated seismic electric field generated by internal gravity waves. It may be due to the inflow of energy from the earth and then propagated upward which perturb the F-region of ionosphere. Hence, ExB drift in the ionospheric region get changed. This study may be beneficial for prediction of earthquake.

http://scialert.net/abstract/?doi=ajes.2011.214.222 2012/02/22 - 16:36

The bearing capacities and coefficient of subgrade reaction of sand and shale lithologies of Niger Delta sedimentary basin, Nigeria have been computed from shear wave velocities using a relatively simple formula. The shear velocities were obtained from five oil exploratory wells. The computed ultimate bearing capacities of the sand ranges from 3141.755 to 5593.447 kN m-3 with an average of 4367.601 kN m-3 while, that of the shale ranges between 2487.786 and 6335.588 kN m-3 with an average of 4411.687 kN m-3. The computed allowable bearing capacity of the sand varies from 1047.252 to 1864.482 kN m-3 while that of the shale lithology is from 829.262 to 2111.863 kN m-3. Furthermore, the estimated subgrade reaction for the sand varies between 41890.07 and 74579.29 kN m-3 while that of the shale is from 33170.48 to 84474.5 kN m-3. The results show that the bearing capacities of the sand and shale lithologies are very high. This may be attributed to high consolidation and compaction of the formations in the subsurface and thereby resulting in the stability of most foundations in the area. Although, the shale lithology has a high bearing capacities and coefficient of subgrade reaction yet it is not advisable to put foundation on it whenever it is close to the earth surface because when it has the ability to swell/contract whenever it absorb or looses water it.

http://scialert.net/abstract/?doi=ajes.2011.223.227 2012/02/22 - 16:36

Ground motions are highly coupled with site conditions. Dynamic soil properties such as shear modulus and damping are the most prominent factors of amplification phenomenon during earthquakes. The shear modulus degradation and damping ratio curves have been developed based on the nonlinearity soil from hysteresis loops. Effective confining pressure and plasticity index are governing factors that effect the nonlinearity soil behavior. In this study, the shear modulus degradation and damping ratio curves were derived from cases. The first case was based on only effective confining pressure, whereas, the second case was based on effective confining pressure and plasticity index. These two models adopted equivalent linear method for the site response analyses. A set of outcomes are introduced to show the influence of the two models of curves in the site response.

http://scialert.net/abstract/?doi=ajes.2011.148.156 2011/12/21 - 23:01

The source rock potential and thermal maturation of the Tertiary lignite series within the Ogwashi-Asaba Formation, Southern Nigeria was assessed by Rock-Eval pyrolysis, maceral analysis and vitrinite reflectance measurements. The Total Organic Carbon (TOC), Genetic Potential (GP) and Hydrogen Index (HI) values for the coals ranged from 44.93 to 63.54 wt.%, 104.65 to 248.13 mg HC/g rock and 157 to 402 mg HC/g TOC, respectively. These values indicate that the coals have gas and oil generating potential. Maceral analyses showed that the coals are dominated by huminite with subordinate amount of liptinite and inertinite. HI versus Oxygen Index (OI) diagram and atomic H/C ratios of 1.04-1.55 and O/C ratios of 0.27-0.33 classify the organic matter in the coals as Type II kerogen whereas plots of HI versus Tmax indicated a mixed Type II-III and Type III kerogen, respectively. Vitrinite reflectance values of 0.24 to 0.36% Ro and Tmax values between 404 and 425°C suggested that the coals are thermally immature with respect to petroleum generation.

http://scialert.net/abstract/?doi=ajes.2011.157.170 2011/12/21 - 23:01

Surface dynamics and tectonic geomorphology can indicate tectonic activity of a region. By using analytical capability of a MATrix LABoratory (MATLAB) toolbox in conjunction with Shuttle Radar Topography Mission Digital Elevation Models (SRTM DEMs) some parameters of tectonic geomorphology were extracted. Also, extracted drainage networks and sub-basins were analyzed. The aim of this study was the evaluation of surface dynamics and tectonic geomorphology conditions of the study area in southwestern Zagros mountains, Iran. In this order, some parameters such as isobase and incision maps were extracted for the generation of morphometric maps for surface dynamics and basin analysis. Also Stream-length gradient index (SL) was analyzed and hypsometric analysis performed for mapping tectonic and lithologic effect on drainages and basin hypsometry. A morphotectonic interpretation of the Behbahan Region (SW Iran) is performed and the findings indicate a high correlation between surface dynamics and basin analysis parameters with neotectonics features in the study area.

http://scialert.net/abstract/?doi=ajes.2011.171.182 2011/12/21 - 23:01

Water is a precious natural resource, without which there would be no life on Earth. Human beings body weight is also composed of two-third water. Our day to day life depends on the availability of inexpensive clean water and safe ways to dispose it after use. As a source of water, groundwater obtained beneath the earth’s surface is often cheaper, more convenient and less vulnerable to pollution than surface water. Gadilam river basin covering sedimentary part lies between Latitudes 11°25’00 to 11°45’00 N and Latitudes of 79°18’00 to 79°47’60 E. Earlier Public Works Department (Government of Tamil Nadu), 1992 has done geohydrological field data collection including geological mapping; meteorological data was collected from Public Work Division (PWD); Remote sensing study was done through Landsat TM satellite imagery. The Landsat TM and SRTM satellite images were geometrically rectified with reference to the Survey of India (SOI) topographical sheets of 1:50,000 scale using ERDAS IMAGINE 8.7 software. From SOI toposheets and later using linearly stretched False Colour Composite (FCC) of Landsat TM satellite data and by using other image processing techniques were used to interpreted to map the geomorphology of this region. Water table fluctuations map was prepared using pre and post monsoon water level data. Water level fluctuation map is prepared by using spatial analyst tool of Arc GIS software. From the fluctuation map, it was found that maximum recharge is found in the central and southern part of the study area as water table is occurring at 43 m below the ground level. North-Eastern and western part of the study area shows minimum rise in water level with less than 7 m.

http://scialert.net/abstract/?doi=ajes.2011.183.192 2011/12/21 - 23:01

A shallow subsurface survey was conducted along a 20 m long profile on a test site with the aim of mapping and assessing ground water resource of the area. The profile was scanned with ground penetrating radar using common offset geometric configuration. Velocity information obtained from the processed radar image were used to estimate and mapped the spatial distribution of the ground water within the shallow depth based on Topp’s empirical relation between the water content and the dielectric constant of the soil medium. Due to the absence of scattering objects within the deeper high water content region, borehole log data were used to correlate the radar reflection signatures with the observed stratigraphic sequences. Layer picking was used to delineate the water table which correlates well with the log data. Significant lateral variation in both the shallow water content and the level of water table were observed with the water table found to be within a depth range of 0.5 to 1.4 m. These were attributed to the nature of the soil identified as till with variable grain size distribution. The soil is therefore, considered to have great variation in hydraulic conductivity which implies significant variability in water retention capacity. Region of maximum water content within the shallow level was found to coincide with the region of higher level of the water table. The study therefore, appraised the effectiveness of GPR as a tool for precision agricultural practice and environmental studies.

http://scialert.net/abstract/?doi=ajes.2011.193.202 2011/12/21 - 23:01

Geoelectric investigation is carried out in the Sagar Island region to assess the prevailing groundwater condition. The Vertical Electrical Soundings (VES) are carried out in thirty-eight locations of South, Central and Northern parts of Sagar Island region to determine the subsurface hydrological conditions. Maximum current electrodes spacing (AB) of 1200 m are used. Four soundings were carried out near existing boreholes. A combination of curve matching techniques and computer iterative software are used for processing the data. VES results show mostly six layers and constitutes of topsoil layer, saline water, brackish water, impermeable clay layer, fresh water and bottommost clay with silt and fine sand lenses. The results of VES studies significantly correspond with the borehole data and a litho-resistivity relationship is established for this area. The diagnostic constant (A) calculated from the product of hydraulic conductivity and electrical conductance obtained from prescribed known value is used to find the aquifer conductivity and Transmissivity parameters in other locations under the similar hydrodynamic condition of the same region where no pumping test results of boreholes are available. Hydraulic conductivity values vary between 9.92 m day-1 at R8 to 13.56 m day-1 at R24. Transmissivity values also vary between 1687 m2 day-1 at R11 to 2868 m2 day-1 at R24.

http://scialert.net/abstract/?doi=ajes.2011.60.74 2011/07/29 - 06:40

A total of 20 topsoil (0-20 cm) and 36 subsoil (0-50 cm) samples were collected from four soil series namely the Malacca, Rasau, Bungor and Gong Chenak. The Physico-chemical properties such as particle size distribution, texture, Organic Matter content (OM), density, porosity, pH, Cation Exchange Capacity (CEC), Electrical Conductivity (EC), available nutrients and the presence of selected heavy metals were analyzed by the standard methods. The analysis showed that the subsoil and topsoil of the Rasau soil series consisted mainly of sandy loam, whereas the Bungor, Malacca and Gong Chenak soil series were mainly of clayey texture. The organic matter content of the Rasau soil series was very low; for the Malacca and Bungor series the organic matter content was low. The Gong Chenak soil series contained comparatively high OM content. Soil physical properties showed higher bulk density values in the disturbed soil horizons than in the undisturbed forest soils. All the soils studied had low pH and low electrical conductivity. The cation exchange capacity of all the soil series was low with values of less than 13.34 meq/100 g soil. The available phosphorus (P) and magnesium (Mg) values of all the soil series were low and very low, while available potassium (K) values were acceptable. Result of heavy metals analysis indicated that some heavy metals such as Pb, Zn, Cu, Co, Ni, Cr and Cd were present in all the soil series but occurred in low concentrations below the critical level.

http://scialert.net/abstract/?doi=ajes.2011.75.84 2011/07/29 - 06:40

The aim of this study was to simulate the radioactivity of the crustal rocks of the Niger delta sedimentary basin using analytic solutions of the heat conduction equation and the method of least squares regression analysis for an earth model with radiogenic heat generation. The radiogenic heat generation capacity of the rocks was estimated using data from twenty six exploratory wells in the basin with assumption of a homogeneous earth. Radiogenic heat production per unit thermal conductivity ranged from as low as 0.0000014 to 0.004 μ°C m-2 with mean radiogenic heat production per unit thermal conductivity of 0.0006 μ°Cm-2. Percentage radiogenic heat production calculations revealed that radiogenic heat contribution is between 0.0002 and 0.6% of the overall surface heat flow density for the Niger Delta. Mean percentage radiogenic heat production of about 0.1% was obtained. Fraction of surface heat flow contributed by radiogenic heat generation per unit thermal conductivity was in the range of 0.0001 to 0.144 m°C m-1. Radiogenic heat production in the region was observed to be too small to have any significant effect on the thermal parameters of the region and as a result may not be included in thermal models of the basin. The low radiogenic heat generation obtained in this study agrees with the low mean heat generation values for amphibolites rocks.

http://scialert.net/abstract/?doi=ajes.2011.85.93 2011/07/29 - 06:40