Geology, Geophysics & Environment
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ISSN 2299-8004
e-ISSN: 2353-0790
Issue Date
2022
Volume
Vol. 48
Number
No 2
Description
Journal Volume
Geology, Geophysics & Environment
Vol. 48 (2022)
Projects
Pages
Articles
Crustal deformation of the Central Indian Ocean, south of Sri Lanka as inferred from gravity and magnetic data
(Wydawnictwa AGH, 2022) Kumar, Sistla Ravi
Bathymetry, gravity, and magnetic data across the Central Indian Ocean Basin (CIOB) along a WE track between 5°N to 1°N latitudes and 77°E to 90°E longitudes are used to identify crustal deformation due to tectonic features such as the Comorin Ridge, 85°E ridge, Ninety East Ridge, and major fracture zones. The tectonic features were interpreted along the North Central Indian Ocean using 2D gravity modelling to understand the origin and tectonic activity of the subsurface features. The Comorin Ridge is coupled with gravity anomalies with small amplitude varying 25-30 mGal in comparison with the ridge relief which suggests that the ridge is compensated at deeper depths. The focus of the present study is to prepare a reasonable crustal model of the Central Indian Ocean using gravity and magnetic data. The crustal depths of the Central Indian Ocean Basin (CIOB) determined from gravity data using the spectral method are compared with the 2D gravity modelling results. It has been observed that the crustal depths obtained from the Spectral method are in good correlation with results obtained from 2D gravity modelling. The average basement depths for the profiles were obtained as ~5 km and perhaps deviated approximately 1-2 km from the mean. In the case of curie isotherm, the crustal depths vary 9-12 km for all magnetic profiles which may indicate deformation.
Attribute analysis as a tool for determining the areas of the late diagenetic Main Dolomite deposits and assessing the stability of the seismic signal parameters
(Wydawnictwa AGH, 2022) Smalera, Norbert
The results of the lithofacial analysis of data from the Moracz 3D seismic survey were among the main premises leading to the positioning of the new petroleum exploration well in that area. Unfortunately, the reservoir properties of the drilled part of the Main Dolomite carbonates differed significantly from those anticipated by the analysis of the amplitudes of the seismic signal recorded. Such surprisingly negative results impelled the reinterpretation of 3D seismic data. Hence, a number of analyses of the amplitudes, the frequencies, and the variability of phase shift were carried out in order to determine the influence of these parameters on the lithofacial interpretation of seismic data. The results revealed a fundamental error of amplitude with the extraction maps. It appeared that the distribution of amplitudes is not essentially controlled by the reservoir properties of the Main Dolomite carbonates but by the fault shadow effect coming from Mesozoic graben in the overburden. In addition, a large diversity of frequency spectra was found, which, combined with the small thickness of the exploration level, could have contributed to incorrect identification of seismic reflections. There was also a change in seismic signatures from the same reflection in different parts of the survey, raising doubts about the distribution of the phase rotation. In order to recognize phase rotation diversity, a new seismic data analysis was based upon the selected Triassic sediments of high impedance. The obtained maps demonstrated significant variability within the data volume due to attenuation. The reinterpreted data from the Moracz 3D seismic survey proved the uneven and unstable distribution of amplitudes, frequencies, and phase which resulted in erroneous conclusions of petroleum exploration. After modeling with the use of different frequency ranges, an analysis of the amplitude extraction of the horizons related to the Main Dolomite was performed. Then the amplitude ratio attribute was selected which eliminated the influence of the regional amplitude and frequency distribution and showed the distribution. of dolomite properties more reliably than the amplitude extraction maps.
Dendrochronological record of soil creep and landslide activity - the comparison of tree-ring eccentricity and compression wood (examples from the Kamienne Mts., Poland)
(Wydawnictwa AGH, 2022) Sitko, Katarzyna; Wistuba, Małgorzata; Malik, Ireneusz; Krąpiec, Marek; Yu, Ruide; Zhang, Haiyan
Forested mountain slopes can be simultaneously affected by soil creep and landslide activity, both of which cause the tilting of tree stems, with the result that their dendrochronological record of tree-ring eccentricity and compression wood is potentially similar. There is a need to identify similarities and differences in these records and thus our research aimed to compare patterns of eccentricity and compression wood developed by trees under the impact of soil creep and landslides. We sampled trees growing on a landslide and creeping slopes in the Kamienne Mts., with 21 Norway spruce trees were sampled on each site. We found several main differences between the dendrochronological record of landslide activity and soil creep. On the landslide we found larger number of dendrochronological events, stronger and more variable eccentricity and a similar number of upslope and downslope events. On creeping slopes, upslope eccentricity events predominate, and the number of eccentricity events dated in all trees increases in time. We also compared the utility of eccentricity and compression wood for dating mass movements. They differ in their sensitivity to stem tilting. Thus, in analyses of landslide activity and soil creep activity, it is recommended to include both wood anatomy features.
The potential to improve air quality by increasing the use of deep geothermal energy
(Wydawnictwa AGH, 2022) Hajto, Marek; Kaczmarczyk, Michał
Increasing the use of geothermal energy may be one of the tools bringing us closer to achieving the European Commission’s objective of reducing greenhouse gas emissions by 55% by 2030. Air quality improvement plays a strategic role in achieving sustainable energy development. Both European and national legislation in this field is particularly comprehensive and effective, establishing rules for monitoring and preventing air pollution in order to avoid adverse effects on human health and the environment. Unfortunately, the effective air pollutions monitoring network currently in place in Poland, with 156 monitoring stations, mainly concerns agglomerations and cities with over 100,000 inhabitants. The lack of information on the state of pollution in smaller towns is a significant limitation in terms of research aimed at assessing the effects of corrective measures taken, such as the possible transformation of district heating systems based on RES, including the use of deep geothermal energy. This paper proposes some solutions which allow the effective estimation of air conditions in locations not covered by environmental monitoring, in the context of the potential to develop geothermal resources in the rich geothermal province of Central Poland.
Geophysical assessment for gold mineralization potential over the southern part of Kebbi State using aeromagnetic data
(Wydawnictwa AGH, 2022) Augie, Abdulrahaman Idris; Salako, Kazeem Adeyinka; Rafiu, Adewuyi Abdulwaheed; Jimoh, Mufutau Owolabi
The magnetic signatures over the southern part of Kebbi State and its environs were analyzed together with the geological settings of the area to delineate the structures that may host gold mineralization. The aeromagnetic data used was the survey carried out by Fugro airborne surveys between 2005 and 2010 on behalf of the Federal Government of Nigeria. The reduction to equator (RTE), first and second vertical derivatives (FVD and SVD), Centre for Exploration Targeting (CET), analytic signal (AS), source parameter imaging (SPI) and tilt derivative (TDR) techniques were applied to the magnetic data covering the area. The results of the AS technique revealed that the study area is characterized with high amplitudes of magnetic anomalies (above 0.048 nT/m) and these could be of ferromagnetic minerals such as gold. The FVD, SVD, CET and TDR techniques also helped in delineating the lineaments (such as faults, fractures or shears zones) believed to be associated with alteration zones which play an important role in determining gold mineralized zones. The direction of the orientation of these features/lineaments trended in the NE-SW direction. The faults, fractures or shears zones delineated represent veins of possible mineralization. The depth of occurrence to the causative bodies using SPI algorithms was found to be below 137 m. Structures delineated within the area, when compared with the geological setting of the area, correspond to: quartz-mica schist, granite, biotite, gneiss, diorite, medium coarse-grained and biotite hornblende granite. Results from these techniques revealed alteration zones that may host gold. These regions correspond to the following areas: SE parts of Yauri and Shanga, Fakai, Ngaski, Zuru, Magama, Rijau, and the eastern part of Wasagu/Danko and Bukkuyum.