Earth Science Malaysia (ESMY)

We invert Love surface waves and electrical resistivities to cooperatively examine the physical properties of the depth range shallower than 50-m. To analyze this depth range is essential for earthquake mitigation efforts. The shear-wave velocity (VS30) is particularly important to describe the dynamic characteristics of shallow Earth. The Love surface waves are treated in terms of both phase and group velocities. The phase velocities are obtained from the slant stacking while for the group velocities the multiple filter technique is utilized. A typical shot-gather is assumed to simulate the field collection of the surface wave data. The phase velocity curve represents the average structure beneath the geophone spread. The group velocity curve represents the average structure from the source to the geophone. In a single-station fashion, for each geophone location one group velocity curve is obtained. A linear system is set up to convert these single-station group velocity curves into local group velocity curves at grid points. The latter group velocities are inverted to attain the shear-wave velocity cross section. A similar approach is adopted to study the electrical resistivity structure of the underground. We simulate the field application using a theoretical model. Multiple electrode Pole-Pole array is assumed for the field collection of the resistivity data. The apparent (measured) resistivity values are inverted to attain the true resistivity structure in terms of a cross section. The inverted structures are one-dimensional reflecting depth dependent shear-wave velocities and electrical resistivities underneath the studied region.

In the present work, we deal with the petrographic and provenance of the sandstone of the Rawalpindi group in the lesser Himalayas. The formations present in the project area are Murree and Kamlial Formations of the Rawalpindi group. The petrological studies of Murree and Kamlial Formations determine the minerals composition prospect, which minerals have high proportion and which one is less proportion. Which aim to determine the petrological characteristic of these rock formations for the use of scientific studies or in engineering projects. Both of these two formations are Siwalik molasse deposits, the same orogeny correlation, same age from the same group. Determine the difference in such kind of similar rock formations are very important and also challenge in the field of geology. With highly advance petrographically analysis, it shows that Kamlial formation consists of heavy minerals such as garnet, tourmaline, etc., as compared with Murree formation consists of light minerals such as quartzite, Felice and feldspar, etc. And the provenance analysis of the sandstone of the Rawalpindi group is performed by the QFL ternary diagrams method. All the plots in the QFL diagram plot on recycled orogeny provenance field.

Morphometric analysis is the best method to understand and determine the shape, size, and dimension of a watershed. Conducting this analysis required a wide variety of quantitative measurements and mathematical analysis presenting valuable data related to hydrological characteristics of the watershed. Using GIS technique and Digital Elevation Models (SRTM-DEM) images were extremely facilitated the method and precisely boosted the results. Morphometric parameters were utilized of the Abbasan watershed determining hydrological properties and runoff assessment. The watershed area, of Abbasan covers (878.34) km2, the calculations of dimension, shape, and compactness coefficient are done which indicated elongated shape, low runoff intensity and low erosion rates. Most of the morphometric parameters were computed and analyzed such as relief properties, stream network, and drainage pattern characteristics which is referring to (2555) m elevation, low-moderate relief, six stream orders, and three types of drainage patterns respectively. Rectangular drainage patterns occupied a large area followed by Dendritic and Trellis patterns in terms of area. This study has given a comprehensive insight into the whole morphometric aspects of the Abbasan watershed.

Three Ajali sandstone ridges (L1, L2 and L3) at Uturu being quarried for construction sands were studied for soft-sediment deformation structures (SSDS) and granulometric properties distributions. SSDS that includes recumbents foresets, sands dykes, flame structures and fluid escape tubes were identified only in ridge L3. The geometry of the SSDS indicates sediment loading/density contrast, fluidization and liquefaction as the mechanisms for their formation but with liquefaction as the most dominant mechanism. Gran size analysis and granulometric curves properties calculations show that: Mean grain size ranged from fine (1.18 ɸ) to medium (2.57 ɸ); Sorting ranged from rarely poorly sorted (1.13ɸ) to well sorted (0.37ɸ) but with mean values in each ridge as moderate sorted; Skewness ranged from strongly fine skewed (1.0) to strongly coarse skewed (-1.57); and Kurtosis ranged from very platykurtic (0.27) to very leptokurtic (2.0) but with sands of ridge L3 mainly very platykurtic. Granulometric curves and bivariate plot of properties indicate fluvial deposition with rare marine influence. Results show that there is no significant variation in sediment properties and depositional environments across the three ridges. The localization of SSDS and non-proximity to any fault suggest that liquefaction, as the dominant mechanism for soft-sediment deformation, was not triggered by an earthquake. Possible mechanisms include rapid sediment loading, localised sudden subsidence induced by loading of localised oxidized compressible peats and coal; and increased in sediments’ water saturation via localised groundwater seepage. Fine grains, well sorting, fine to strongly skewed very platykurtic characteristics of sediments made it more susceptible to liquefaction.

Activities of illegal small-scale miners promote continual introduction of wide pollutants into the Aboabo stream. Their toxicity poses health threats to the inhabitants of Krapoo village in the Ahafo Region, Ghana. The study assesses the impacts of illegal small-scale mining activities on the water quality of the stream. Levels of physico-chemical and microbiological parameters were determined using standard methods. Samples of sediment, water and plant were acid-digested with aqua-regia. Total Arsenic and Total Cadmium were analysed using Flame Atomic Absorption Spectrophotometer (FLAAS) whiles Total Mercury was analysed using Cold Vapour Atomic Absorption Spectrophotometer (CV-AAS). Turbidity, faecal coliforms and E-coli readings exceeded permissible limit of 5NTU and 0MPN/100ml respectively by Ghana’s Environmental Protection Agency (GS 1212) and World Health Organisation (WHO). Temperature, Electrical Conductivity and pH values were within the limit of <30oC, 1500μs/cm and 6.5-85 respectively at both seasons. Total suspended solids readings at the midstream were higher than the permissible limit. However, levels of total dissolved solutes and dissolved oxygen recorded, were below the limit. The sediments were also heavily polluted with Mercury, Arsenic and Cadmium. Alchornea cordifolia, Chromolaena odorata and Spigella anthelmia growing within the stream were taken to assess their efficiency in removing the heavy metals from the stream. It was observed that the plants species had bioaccumulation factor (BF) greater than 1 for cadmium. Alchornea cordifolia was the only plant with BF greater than 1 for mercury. The plants species are potential hyper accumulators for mercury and cadmium hence are suitable for phytoremediation.

Well logs data from four wells were analysed for determining the petrophysical and geomechanical properties of two reservoirs in the study area. The parameters derived from these properties were used to predict the likelihood of the occurrence of sanding in the reservoirs of interest. Five sand production methods were used in predicting sanding in the reservoirs of interest. The results obtained from these sand prediction methods all showed that the reservoirs were not likely to produce sanding during drilling exploration and production. Reservoir geomechanical study has a significant role that cannot be neglected in the development of various hydrocarbon exploitation procedures, such as in the exploration and production, drilling and field development phase. The role of geomechanical properties have great impact on the drill bit selection, optimization of well trajectory placement, casing design, wellbore stability analysis, safe mud weight window (SMWW) prediction and sand production. Sand production is a serious problem widely existing in oil/gas production. The problems resulting from sand influx include abrasion of downhole tubular/casing, subsurface safety valve and surface equipment, casing/tubing buckling, failure of casing or liners from removal of surrounding formation, compaction and erosion; and loss of production caused by sand bridging in tubing and/or flow lines.

This work seeks to assess the acid mine drainage (AMD) potential of stockpiled sulphidic gold bearing ore that was left untreated for a period of four (4) years. The mineralogical composition of the stockpiled sulphidic gold ore was determined using X-Ray Diffractometry (XRD) and Reflected Light Microscope. The AMD potential and kinetic studies on the ore sample were determined using Acid Base Accounting (ABA) and Humidity Cell (ASTMD 5744). The XRD and microscope analyses showed that the gold ore contain arsenopyrite and pyrite as the major sulphide minerals. The ABA confirmed that the gold sulphide ore could be a potential source of AMD with respect to AMD marginal of safety if the ore is left untreated for a very long period. Humidity Cell kinetic analysis showed a possibility of mobilizing Arsenic (As) into the geo-environment when there is a long period of oxidation of abandoned sulphide run-of-mine (ROM) ore.

A project was undertaken to create an inventory and generate relevant baseline information on household ponds in the Halda river watershed. This research is mostly belongs to Mapping and GIS analysis. At first all ponds are divided into two groups, large ponds (above 1000 m2 area) and small ponds (below 1000 m2 area). Then some important geometric and geographic parameters of large ponds are calculated. They are area, elevation and elevation wise distribution, neighbourhood distances, length, width, aspect ratio. Descriptive statistics are generated on these parameters and their mean, median, mode, sum, standard deviation, count, minimum, maximum etc. were calculated. Some informative charts are included in the result showing the findings. To calculate the area and total number of small ponds, intentional sampling is used. The average area of large ponds is about 2670 m2. The average elevation of these ponds is found 11.75 m. The mean neighbouring distance among these ponds is about 237 m and these ponds are rectangular shape in average because their average aspect ratio is 1.46 where aspect ratio 1.00 means the perfect square shape. The total area occupied by all ponds (both large and small) is estimated as 44.2 km2 and it is 2.63% of whole watershed area and 7.38 % of the valley area (here <20 m elevation and relatively plain). The total number of pond is estimated 43745 (large pond 6730 and small pond 37015) and almost all of them are in the valley area of Halda river watershed.

Lithofacies, bounding surfaces and sedimentary architectural elements exposed in two ridges at Uturu being quarried for construction sands were analysed to determine the paleoenvironment of deposition and the factors that control the deposition of sand units. Mainly outcropped is Ajali Formation overlying locally exposed Mamu Formation in Western Afikpo basin. Lithofacies identified include: Trough cross bedded medium- to coarse-grained (St), Planar cross bedded fine- to coarse-grained sandstone (Sp), Small scale planar cross bedded sandstone (SSp), Lenticular mudstone (Fm), Heterolithic sandstone/mudstone (Fsm), Horizontal stratified sandstone (Sh), Cross ripple laminated sandstone (Sr), Reddish muddy sand (Fl), Siltstone (SSm) and Shale (Fsh). The associations of lithofacies and bounding surfaces gave four fluvial and one marine architectural element. The fluvial elements which mainly characterized the Ajali Formation include: Channel-fill (CH), Macroforms Accretion (MA). Flood-Plain Fines (FF) and Channel Abandonment Fines (CAF). Offshore-shoreface fines (OSF) element defined marine Mamu Formation. The profiles of the ridges show dominance of MA followed by CH while FF is limited in occurrence and in some zones pinch-out to lenticular inter-bar mudstone. The MA is characterized by planar cross beddings, reactivation surfaces, internal grading, steep dipping ferruginized accretion surfaces and abrupt flat top which indicate mid-channel bars deposition in typical sandy braided fluvial depositional system. Generally, there is vertical aggradation/ amalgamation of channel deposits and dominance of sheet alluvial architecture. Low rate of channel avulsion, moderate rate of lateral migration and aggradation, variable discharge rate and high rate of sediment supply and subsidence were considered as factors that controlled the deposition and preservations of sand units. This study provided an understanding of mesoscopic heterogeneities and compartmentalization style inherent in hydrocarbon bearing sandy braided reservoirs which can be used as analog model for its development.