Geology, Geophysics & Environment
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ISSN 2299-8004
e-ISSN: 2353-0790
Issue Date
2021
Volume
Vol. 47
Number
No 4
Description
Journal Volume
Geology, Geophysics & Environment
Vol. 47 (2021)
Projects
Pages
Articles
An analysis of the spatial and temporal changes on the Jakobshavn Glacier (Greenland) using remote sensing data
(Wydawnictwa AGH, 2021) Olszewska, Katarzyna; Borowiec, Natalia
This article presents the problem of climate warming and the effect of melting ice caps. The problem of climate warming is discussed in two stages. In the first stage, the factors affecting global warming are discussed in detail and the effects and risks of ablation extensively described. Analyses were conducted on data available online from NASA and Carbon Dioxide Information Analysis Center. The Greenland area (Jakobshavn Glacier) was selected to visualize glacier calving front changes. The analysis of changes was performed on the selected satellite images covering the summer period (June to September) provided by the Landsat program. Then, the changes in the position of the calving front of the Jakobshavn Glacier were visualized for the period 1985–2020, with a repeatability of every 5 years. Thus, our results addressed the challenges of environmental changes to remote sensing data processing. In addition to the visualization, a surface summary of these changes was presented in the study. The results were discussed in the context of climate change data processed by means of the GIS method. Furthermore, an analysis of the effects of greenhouse gases on glacier surface changes was performed. In summary, the results reveal that satellite imagery is an excellent source of data on which to visualize glacier calving rates, comparing individual layers showing the position of the glacier calving front and calculating the area of calved ice.
X-ray diffraction studies of onshore mud volcanoes in parts of the Upper Benue Trough, northeastern Nigeria
(Wydawnictwa AGH, 2021) Musa, Ojochenemi K.; Kurowska, Ewa E.; Krzykawski, Tomasz; Onimisi, Jimoh A.
The mineralogical studies of clay from the onshore mud volcanoes discovered in parts of the Upper Benue Trough of Nigeria provide a clue about the geological formation from which the extruded mud originates. The study area is a part of the Cretaceous Upper Benue Trough filled with Early Cretaceous continental deposits and Late Cretaceous marine deposits, having a history of magmatism dating from the Albian to the Pleistocene. The study approach involves integrated inorganic geochemical analysis of the samples to reveal their composition and origin. The results of XRD analysis of the fresh clays from the mud volcano revealed the presence of quartz, kaolinite, and other clay minerals (illite-smectite), feldspars, and in a much lower quantities, other accessory minerals including muscovite, evaporites, calcite and dolomite, trona, barite, goethite. The saprolite samples are composed mainly of quartz, kaolinite, smectite-illite associations, and feldspars, traces of goethite, calcite, and evaporate minerals (sylvite, halite). The presence of calcite, dolomite, sylvite, and halite suggests the marine origin of the rocks, while trona mineral is a non-marine evaporate. The coexistence of these minerals in some of the analyzed samples suggests the deposition of sediments in a transitional environment of deposition. Traces of marine minerals are present in some of the samples but completely absent in others collected from another site. This suggests that the source rock formations from which the material originated are within the Upper Bima Sandstone interpreted as being deposited in a non-marine environment or the Yolde Formation, which is known as a transitional unit (transitional between the outcropping continental Upper Bima Sandstone and marine Pindiga Formation).
Frequency domain electromagnetic and electrical resistivity geophysical investigation of tar sands deposits in the Ijebu Waterside area, Eastern Dahomey Basin, southwestern Nigeria
(Wydawnictwa AGH, 2021) Osinowo, Olawale Olakunle; Okechukwu, Ifeayinchukwu
The use of electromagnetic conductivity and electrical resistivity geophysical techniques has been employed in this study to investigate the occurrence, thickness, and spatial distribution of bitumen deposit around Makun-Omi in the Ijebu Waterside area of southwestern Nigeria. Subsurface apparent conductivity distribution data obtained using Geonic 34-3 equipment along fifteen traverses which sounded from different depths of 7.5, 15, 30 and 60 m at inter-coil separation of 10, 20 and 40 m in vertical and horizontal coupling modes and ground resistivity distribution measurements, obtained using Geopulse Tiger Allied resistivity meter at fourteen Vertical Electrical Sounding (VES) stations, were processed and employed to characterize the subsurface in terms of tar sands distribution. The conductivity and resistivity distribution in the form of a 3D earth model, iso-depth maps, 2D sections generated from the processed conductivity and resistivity data indicate relatively low conductivity <20 mS/m and high resistivity >1300 $\Omega$ m values around tar/bitumen impregnated sands which mostly occurred in the southern part of the study area. Clearly defined conductivity and resistivity anomalies which delineate the lateral and vertical occurrence of tar impregnated sands underscore the efficacy of integrating electromagnetic and electrical resistivity geophysical techniques to identify occurrence of economic deposits of tar sands in parts of southwestern Nigeria.