by Edwin Ayuk Ndip, Christopher M. Agyingi, Matthew E. Nton and Michael A. Oladunjoye
Original Research
The Mamfe Basin is an intra-continental basin in southwestern Cameroon. Shale from Cretaceous strata in the Mamfe Formation has been poorly characterized in terms of their palaeo-environmental conditions and origin of the organic matter. Also, the thermal maturity of the shale has not been well established. The aim of this study is to determine the origin of the organic matter, evaluate the thermal maturity, palaeo-environmental conditions, and thereby deduce their hydrocarbon generative potential. Biomarker geochemical analyses was carried out on the organic matter extracts of some selected shale samples from Mamfe Formation having total organic carbon content ranging from 0.69 and 4.50 wt. % (av. =1.82 wt. %). Base on the total organic carbon content, the shales are described to have good hydrocarbon generative potentials. Thermal maturity parameters base on 20S/(20S +20R), and ββ/(ββ + αα) C29 sterane ratios along with CPI and OED indicate that the analysed samples from Mamfe Formation sit at mature oil window generation. The origin of the organic matter have been deduced to be mainly of terrestrial plant source with minor lacustrine and marine influences. Palaeo-environmental conditions were decipher to be of sub-oxic to anoxic conditions that have preserved the organic matter. This study have highlight valuable insight based on the biomarker geochemistry of the shales of the Mamfe Basin thereby reducing petroleum exploration risk.
Journal of Geosciences and Geomatics. 2021, 9(1), 28-44. DOI: 10.12691/jgg-9-1-4
Pub. Date: May 14, 2021
3844 Views5 Downloads
by Ononeme O.E, Lucas F.A and Fregene T.J
Original Research
Paleoenvironmental recontruction of tertiary sediments in F- field, greater Ughellidepobelt Niger delta basin was carried out using Fifty (50) Ditch Cutting samples at different intervals between 2,010ft and 10,170ft, prepared using palynological sample processing technique and analyzed under the microscope. A total of 4,243 palynomorphs were recovered, the presence of diagnostic palynomorphs such as Zonocostites ramonae, Monoporites annulatus, Verrucatosporites usmensis and dinocysts such as spiniferites sp, sumatradinium hispidicum, Lingulodinium machaerophorum aided in the establishment of two varying paleoenvironments which are Continental – Transitional Environment and Paralic (Inner Neritic) Environments. The Continental – Transitional settings is suggested from depths (15ft to 7,800ft) based on the abundance of miospore (pollen and spore) such as Zonocostites ramonae, Monoporites annulatus and Verrucatosporites usmensis and the absence of dinocysts. The Paralic (Inner Neritic) Environment was defined at depths (7,830ft – 10,185ft). This environment was suggested due to the presence of dinocysts such as spiniferites sp, sumatradinium hispidicum and Lingulodinium machaerophorum.
Journal of Geosciences and Geomatics. 2021, 9(1), 24-27. DOI: 10.12691/jgg-9-1-3
Pub. Date: May 07, 2021
2140 Views6 Downloads
by Dodo J. D., Nwodo G. O. and Ojo P. E.
Original Research
The total zenith tropospheric delay (ZTD) is an important parameter of the atmosphere which directly or indirectly give reflection of the atmospheric condition in a local GPS network. The use of the global tropospheric models such as the Saastamoinen model, Hopfield model, Neil model etc in estimating the tropospheric effects at the local level leaves much to be desired. These models are derived using data from available radiosonde obtained from Europe and North America continents. The global atmospheric condition used as constants in these models provides a broad approximation of the tropospheric conditions, but ignores the actual atmospheric conditions on a given location i.e. do not take into account the latitudinal and seasonal variations in the atmosphere. It is necessary to assess the effects of the troposphere on geodetic measurements based on ground meteorological measurements including temperature, pressure, and relative humidity. Daily RINEX GPS data from eight (8) Malaysian Real Time Kinematic GPS Network (MyRTKnet) stations in Southern Malaysia from year 2006 to June 2008 thus; covering 2½ years were processed. A computer program for modelling 2½ years of local meteorology within the network was developed and called MetMOD, similarly a program, call SaastroMOD was developed to estimate the local zenith hydrostatic delay. The results showed that, the estimated local tropospheric delay considered the temporal and spatial variation of the network thus; giving true reflection of the tropospheric delay in a local GPS network as against the standard atmosphere which ignores the actual local condition with a standard deviation of 0.18 m having a maximum zenith tropospheric delay (ZTD) of about 2.6 m. The best zenith hydrostatic delay (ZHD) comes from station JHJY with a standard deviation of 0.353 cm, while the best zenith wet delay (ZWD) comes from station TGRH with a standard deviation of 5.943 cm. The models show that, while parameters evolved for ZHD are constant at different locations, however, those parameters evolved for ZWD show significant variations from one location to the other. Hence then use of the local meteorological parameter in modelling tropospheric delay improves GPS positional accuracy.
Journal of Geosciences and Geomatics. 2021, 9(1), 10-23. DOI: 10.12691/jgg-9-1-2
Pub. Date: April 16, 2021
5454 Views8 Downloads
by Lucas Boakye and Tekleab Gala
Original Research
The central Ethiopian highlands, which are attracting massive population influx from the surrounding areas, are being subjected to myriad environmental changes and impacts thereof. Hence, an in-depth understanding of the statuses, and trends of the environmental resources on the highland is critical. This study used archived remotely sensed Landsat data to produced Land Use and Land Cover maps of the highlands and changes over 32 years (1985 – 2017). The Hybrid Maximum Likelihood Algorithm and image segmentation techniques; and Land Change Modeler were deployed. Accordingly, Agricultural lands, Grass/Bare lands, Lakes/Ponds, Scrublands, Settlement/Urban areas, Vegetation areas, and Wetlands were detected and mapped. Overall mapping accuracies and kappa statistics ranged between 84% - 87.6% and 95.7% - 94.4%, respectively. Agriculture is the dominant Land Use and Land Cover type throughout, though the compositions of the remaining Land Use and Land Cover types have changed since 1985; except for Lakes/Ponds, and Wetlands. Settlement/Urban areas have grown by 546%, at the expense of agricultural lands and vegetation areas, a condition that is exposing farmers to the loss of massive cropland and woodlands. Additionally, Agricultural lands have changed into Grass/Bare lands and Scrublands, as shreds of evidence of the environmental impacts of the rapid urbanization. Therefore, with an anticipated growing population and urban expansion on the highland, it is essential to promote practices of sustainable land resource management and development in the region.
Journal of Geosciences and Geomatics. 2021, 9(1), 1-9. DOI: 10.12691/jgg-9-1-1
Pub. Date: April 12, 2021
3425 Views5 Downloads