by Abdullahi A.M, Haruna A.I, Usman A.M and A. S. Arabi
Original Research
The Gwon-Gwon area Pegmatite is hosted by the late Pan-African Leucogranite and the Migmatites. X-ray fluorescence base investigation was conducted on the twenty four (24) representative samples from the granites, pegmatites and migmatites. Major and trace elements analysis of the samples was carried out and the results shows that the granites are fertile, silicic (quartz-rich) and peraluminous (Aluminium Saturation Index - Al/CNK >1.1) suggesting an S-type origin, resulting in the crystallization of Al-rich minerals like Muscovite. It is therefore proposed that the development of the rare-metal pegmatite of Gwon-Gwon is related to the granite magmatism which is evident from the ternary plots, deducing a genetic link between the granitoids and the pegmatites even though there exist incomplete fractionation due to incomplete partial melting or poor sourcing of materials during anatexes. Also the clustering of samples suggest that fractionation was precisely partial, and that the paucity of rare elements in the migmatites precludes it from being the origin of the pegmatites.
Journal of Geosciences and Geomatics. 2017, 5(1), 37-45. DOI: 10.12691/jgg-5-1-4
Pub. Date: February 06, 2017
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by Anam Safi Ibrahim and Thomas.G. Ngigi
Original Research
This research uses multi-temporal medium resolution satellite images and ground truthing to analyze the patterns and dynamics of Kenyan coastal mangrove forest cover changes spanning over 30 years from 1990-2015. The major aims of this study were to first analyze and assess mangrove forest cover and change over the period 1990 to 2015 together with the specific drivers. Replacement of cloudy pixels with the best available non-cloud pixels from a secondary image was followed by maximum likelihood classification from which change detection analysis was carried out. Literature reviews and interviews were then used to correlate these land use changes with their potential drivers. Metrics were extracted from the image and correlated with the ground observed biomass values to model the linear relationship between the selected variable and biomass. Independent component transformation 3 was found to show the strongest correlation with biomass with a coefficient of determination value of about 0.7. Based on the post classification change detection, during the epoch 1990-2000, mangrove area decreased by about 7.03%, forestland decreased by about 21.11%, cropland also decreased by about 0.39%. Grassland, however, increased by about 3.54% while settlement increased by a significant 74 percentage points.
Journal of Geosciences and Geomatics. 2017, 5(1), 24-36. DOI: 10.12691/jgg-5-1-3
Pub. Date: January 16, 2017
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by Arshad Amin and Shahab Fazal
Original Research
Man has been using land since the beginning of human civilization. Over the time, growing population demanded more land which expanded its use, so forests that share their borders with built-up or agricultural land use are prone to further degradation than the forests that share their borders with non-forest, natural land cover e.g., wetland, water bodies, grassland etc. The increased use led to increase in the rate of degradation and fragmentation of forest land. Deforestation is the prime cause for the forest land fragmentation and dense forests are very sensitive to this phenomenon where roads are one of the major causes of fragmentation. The present study focusses on the land use dynamics and forest landscape fragmentation of Shopian district of hill state of Jammu and Kashmir from 1995 to 2015. The study is based on remotely sensed data using landscape fragmentation model in GIS. The analysis shows that agricultural and built-up land use has continued to increase at the cost of rich forest cover which has not only significantly decreased but is in the deplorable state. Forest land fragmentation analysis revealed the increase in deforestation and the degradation of the dense forest into small and isolated patches.
Journal of Geosciences and Geomatics. 2017, 5(1), 12-23. DOI: 10.12691/jgg-5-1-2
Pub. Date: January 11, 2017
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by Wotchoko Pierre, Nkouathio David Guimollaire, Kouankap Nono Gus Djibril, Chenyi Marie-Louise Vohnyui, Guedjeo Christian Suh, Bulam Annyta Tangie, Tchokona Seuwui dieudonne and Seplong Yannick
Original Research
The Wainama West area belongs to the Cameroon volcanic Line (CVL). Three petrographic types of lavas are identified: basanites, trachytes and rhyolites. Basanites with porphyritic texture are made up of minerals: plagioclase, clinopyroxene, olivine phenocrysts and opaque minerals within a groundmass; trachytes with microlitic-porphyritic texture are composed of phenocrysts of sanidine, hornblende, plagioclases, pyroxene and opaque minerals enclosed in a fine groundmass showing a preferred orientation. Rhyolite shows a microlitic-porphyritic texture made up of quartz, sanidine and opaque minerals in the groundmass. According to their geochemical behaviour, major elements show an enrichment in SiO2 (42.7–70.7 wt.%), Al2O3 (13.7–16.6 wt.%), Na2O (2.3–6.3 wt.%), K2O (1.3–4.9 wt.%) and an impoverishment in MgO (8.3–0.02 wt.%) and CaO (10.0–0.5 wt.%) from basanite to rhyolite. Some binary diagrams indicate a good correlation with some minor elements (Cr, Ba, Zr, Sr, Rb, and Nb) against SiO2. REE patterns of the rocks are characterized by a negative anomaly in Eu (0.3Eu/Eu*0.4) in basanite and weak negative anomaly in Eu (0.1Eu/Eu*0.2) from trachytes to rhyolites, with parallel profiles. The Wainama West lavas are found to have originated from a single primary melt similar to that of OIB and the continental basalt but with slightly higher Nb/Ta content. From the Dy/Yb vs La/Yb diagrams, the major processes resulting to the generation of this primary melt is the partial melting of garnet peridotite, of the high degree (11-12%). The Wainama West alkali lavas were formed in intraplate setting of continental part of the CVL.
Journal of Geosciences and Geomatics. 2017, 5(1), 1-11. DOI: 10.12691/jgg-5-1-1
Pub. Date: January 05, 2017
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