Pub Date : 2021-04-23DOI: 10.7494/GEOL.2021.47.1.21
Chris Barnes, J. Majka, M. Bukała, E. Nääs, S. Rousku
The Tsäkkok Lens of the Seve Nappe Complex in the Scandinavian Caledonides comprises eclogite bodies hosted within metasedimentary rocks. These rocks are thought to be derived from the outermost margin of Baltica along the periphery of the Iapetus Ocean, but detrital records from the sedimentary rocks are lacking.Many metasedimentary outcrops within the lens expose both well-foliated metapelitic rocks and massive calc-silicates. The contacts between these two lithologies are irregular and are observed to trend at all angles to the high-pressure foliation in the metapelites. Where folding is present in the metapelites, the calc-silicate rocks are also locally folded. These relationships suggest metasomatism of the metapelites during the Caledonian orogenesis. Zircon U-Pb geochronology was conducted on sixty-one zircon grains from a calc-silicate sample to investigate if they recorded the metasomatic event and to assess the detrital zircon populations. Zircon grains predominantly show oscillatory zoning, sometimes with thin, homogeneous rims that have embayed contacts with the oscillatory-zoned cores. The zircon cores yielded prominent early Stenian, Calymmian, and Statherian populations with a subordinate number of Tonian grains. The zircon rims exhibit dissolution-reprecipitation of the cores or new growth and provide ages that span similar time frames, indicating overprinting of successive tectonic events. Altogether, the zircon record of the calc-silicate suggests that the Tsäkkok Lens may be correlated to Neoproterozoic basins that are preserved in allochthonous positions within the northern extents of the Caledonian Orogen.
{"title":"Detrital zircon U-Pb geochronology of a metasomatic calc-silicate in the Tsäkkok Lens, Scandinavian Caledonides","authors":"Chris Barnes, J. Majka, M. Bukała, E. Nääs, S. Rousku","doi":"10.7494/GEOL.2021.47.1.21","DOIUrl":"https://doi.org/10.7494/GEOL.2021.47.1.21","url":null,"abstract":"The Tsäkkok Lens of the Seve Nappe Complex in the Scandinavian Caledonides comprises eclogite bodies hosted within metasedimentary rocks. These rocks are thought to be derived from the outermost margin of Baltica along the periphery of the Iapetus Ocean, but detrital records from the sedimentary rocks are lacking.Many metasedimentary outcrops within the lens expose both well-foliated metapelitic rocks and massive calc-silicates. The contacts between these two lithologies are irregular and are observed to trend at all angles to the high-pressure foliation in the metapelites. Where folding is present in the metapelites, the calc-silicate rocks are also locally folded. These relationships suggest metasomatism of the metapelites during the Caledonian orogenesis. Zircon U-Pb geochronology was conducted on sixty-one zircon grains from a calc-silicate sample to investigate if they recorded the metasomatic event and to assess the detrital zircon populations. Zircon grains predominantly show oscillatory zoning, sometimes with thin, homogeneous rims that have embayed contacts with the oscillatory-zoned cores. The zircon cores yielded prominent early Stenian, Calymmian, and Statherian populations with a subordinate number of Tonian grains. The zircon rims exhibit dissolution-reprecipitation of the cores or new growth and provide ages that span similar time frames, indicating overprinting of successive tectonic events. Altogether, the zircon record of the calc-silicate suggests that the Tsäkkok Lens may be correlated to Neoproterozoic basins that are preserved in allochthonous positions within the northern extents of the Caledonian Orogen.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"177 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79884472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-29DOI: 10.7494/GEOL.2020.46.4.315
R. Skupio
Portable EDXRF (Energy Dispersive X-Ray Fluorescence) spectrometer with the ability to perform rock tests in a helium atmosphere was applied to prepare unique calibration coefficients and mineralogical models. These data could be used for the chemical profiling, chemostratigraphy, gamma-ray, TOC and lithological interpretation of borehole geological profile. The measurements were conducted on 19 samples of sandstones and compared to the XRF data without helium flow. The acquired dataset was calibrated to the chemical laboratory tests (ICP-MS), gamma-ray spectrometry measurements (RT-50) and combined with the mineralogical data (XRD). The new methodology enables the measurement of sodium and enhances the possibility of detecting magnesium, thorium and uranium, compared to standard handheld XRF spectrometers. The applied method is dedicated to whole cores (without sample preparation) or cuttings which must be cleaned, dried, milled and pressed.
{"title":"Portable XRF spectrometer with helium flow as a tool for lithological interpretation","authors":"R. Skupio","doi":"10.7494/GEOL.2020.46.4.315","DOIUrl":"https://doi.org/10.7494/GEOL.2020.46.4.315","url":null,"abstract":"Portable EDXRF (Energy Dispersive X-Ray Fluorescence) spectrometer with the ability to perform rock tests in a helium atmosphere was applied to prepare unique calibration coefficients and mineralogical models. These data could be used for the chemical profiling, chemostratigraphy, gamma-ray, TOC and lithological interpretation of borehole geological profile. The measurements were conducted on 19 samples of sandstones and compared to the XRF data without helium flow. The acquired dataset was calibrated to the chemical laboratory tests (ICP-MS), gamma-ray spectrometry measurements (RT-50) and combined with the mineralogical data (XRD). The new methodology enables the measurement of sodium and enhances the possibility of detecting magnesium, thorium and uranium, compared to standard handheld XRF spectrometers. The applied method is dedicated to whole cores (without sample preparation) or cuttings which must be cleaned, dried, milled and pressed.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"34 1","pages":"315-320"},"PeriodicalIF":0.8,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88032348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-26DOI: 10.7494/GEOL.2020.46.4.301
M. Łukaszewski
There are numerous conventional fields of natural gas in the Carpathian Foredeep, and there is also evidence to suggest that unconventional gas accumulations may occur in this region. The different seismic signatures of these geological forms, the small scale of amplitude variation, and the large amount of data make the process of geological interpretation extremely time consuming. Moreover, the dispersed nature of information in a large block of seismic data increasingly requires automatic, self-learning cognitive processes. Recent developments with Machine Learning have added new capabilities to seismic interpretation, especially to multi-attribute seismic analysis. Each case requires a proper selection of attributes. In this paper, the Grey Level Co-occurrence Matrix method is presented and its two texture attributes: Energy and Entropy. Haralick’s two texture parameters were applied to an advanced interpretation of the interval of Miocene deposits in order to discover the subtle geological features hidden between the seismic traces. As a result, a submarine-slope channel system was delineated leading to the discovery of unknown earlier relationships between gas boreholes and the geological environment. The Miocene deposits filling the Carpathian Foredeep, due to their lithological and facies diversity, provide excellent conditions for testing and implementing Machine Learning techniques. The presented texture attributes are the desired input components for self-learning systems for seismic facies classification.
{"title":"The application of volume texture extraction to three-dimensional seismic data – lithofacies structures exploration within the Miocene deposits of the Carpathian Foredeep","authors":"M. Łukaszewski","doi":"10.7494/GEOL.2020.46.4.301","DOIUrl":"https://doi.org/10.7494/GEOL.2020.46.4.301","url":null,"abstract":"There are numerous conventional fields of natural gas in the Carpathian Foredeep, and there is also evidence to suggest that unconventional gas accumulations may occur in this region. The different seismic signatures of these geological forms, the small scale of amplitude variation, and the large amount of data make the process of geological interpretation extremely time consuming. Moreover, the dispersed nature of information in a large block of seismic data increasingly requires automatic, self-learning cognitive processes. Recent developments with Machine Learning have added new capabilities to seismic interpretation, especially to multi-attribute seismic analysis. Each case requires a proper selection of attributes. In this paper, the Grey Level Co-occurrence Matrix method is presented and its two texture attributes: Energy and Entropy. Haralick’s two texture parameters were applied to an advanced interpretation of the interval of Miocene deposits in order to discover the subtle geological features hidden between the seismic traces. As a result, a submarine-slope channel system was delineated leading to the discovery of unknown earlier relationships between gas boreholes and the geological environment. The Miocene deposits filling the Carpathian Foredeep, due to their lithological and facies diversity, provide excellent conditions for testing and implementing Machine Learning techniques. The presented texture attributes are the desired input components for self-learning systems for seismic facies classification.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"28 1","pages":"301-313"},"PeriodicalIF":0.8,"publicationDate":"2021-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89678369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-19DOI: 10.7494/GEOL.2020.46.3.223
B. Yaman, M. Ertuğrul
Studies associated with climate change and variability are of great importance at both the global and local scale in the global climate crisis. In this study, change-point detection and trend analysis were carried out on mean, maximum, minimum air temperatures and total precipitation based on monthly, seasonal and annual scale in Bartin province located in the western Black Sea Region of Turkey. For this aim, 4-different homogenei - ty tests (von Neumann test, Pettitt test, Buishand range test and standard normal homogeneity test) for change- point detection, Modified Mann–Kendall test and Şen’s innovative trend test for trend analysis, and Sen’s slope test for the magnitude estimation of trends were used. According to the test results, the summer temperatures in particular show increasing trends at the 0.001 significance level. Mean maximum temperature in August, mean minimum temperature in June and August, and mean temperature in July and August are in increasing trend at the 0.001 significance level. Over a 51 year period (1965–2015) in Bartin province, the highest rate of change per decade in air temperatures is in August (0.55°C for T max , 0.46°C for T min and 0.43°C for T mean ) based on Sen’s slope. However, the study showed that apart from October precipitation, there is no significant trend in monthly, seasonal and annual precipitation in Bartin. Increasing trends in mentioned climate variables are also visually very clear and strong in Şen’s innovative trend method, and they comply with the statistical results. As a result, the study revealed some evidence that temperatures will increase in the future in Bartin and its environs.
{"title":"Change-point detection and trend analysis in monthly, seasonal and annual air temperature and precipitation series in Bartın province in the western Black Sea region of Turkey","authors":"B. Yaman, M. Ertuğrul","doi":"10.7494/GEOL.2020.46.3.223","DOIUrl":"https://doi.org/10.7494/GEOL.2020.46.3.223","url":null,"abstract":"Studies associated with climate change and variability are of great importance at both the global and local scale in the global climate crisis. In this study, change-point detection and trend analysis were carried out on mean, maximum, minimum air temperatures and total precipitation based on monthly, seasonal and annual scale in Bartin province located in the western Black Sea Region of Turkey. For this aim, 4-different homogenei - ty tests (von Neumann test, Pettitt test, Buishand range test and standard normal homogeneity test) for change- point detection, Modified Mann–Kendall test and Şen’s innovative trend test for trend analysis, and Sen’s slope test for the magnitude estimation of trends were used. According to the test results, the summer temperatures in particular show increasing trends at the 0.001 significance level. Mean maximum temperature in August, mean minimum temperature in June and August, and mean temperature in July and August are in increasing trend at the 0.001 significance level. Over a 51 year period (1965–2015) in Bartin province, the highest rate of change per decade in air temperatures is in August (0.55°C for T max , 0.46°C for T min and 0.43°C for T mean ) based on Sen’s slope. However, the study showed that apart from October precipitation, there is no significant trend in monthly, seasonal and annual precipitation in Bartin. Increasing trends in mentioned climate variables are also visually very clear and strong in Şen’s innovative trend method, and they comply with the statistical results. As a result, the study revealed some evidence that temperatures will increase in the future in Bartin and its environs.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"5 1","pages":"223-223"},"PeriodicalIF":0.8,"publicationDate":"2021-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78312451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-19DOI: 10.7494/GEOL.2020.46.3.238
Joseph Aisabokhae, M. Adeoye
The area which transcends the Precambrian basement complex onto the Sokoto sector of the Iullemme-den basin in northwestern Nigeria presents a unique prospect for geothermal exploration research in the absence of regional heat production data, despite its tectonic history and depositional characteristics. In this study, geophysical exploration employing radiometric technique was adopted to classify the petrologic units within the fringes of the Iullemmeden basin and the adjoining crystalline basement complex so as to estimate the radiogenic heat potential within the terrain that may support geothermal considerations. Airborne radiometric measurements acquired over the area were digitized and processed to obtain radioelement concentration maps and the K/Th/U ternary map. Results show that the ranges of measured concentrations of 40K, 238U and 232Th are 4.6 to 18.9%, 0.7 to 4.9 ppm and 4.6 to 18.9 ppm respectively. Radiogenic heat estimation derived from radioelement data within eight petrologic units comprising quaternary sediments, schist, carbonates, shale/clay, younger granites, older granites, gneissic rock and migmatite showed that the lowest radiogenic heat production estimates ranging from 0.27–0.66 μW∙m−3 were recorded in the sedimentary terrain within the quaternary sediments while the highest radiogenic heat production values of between 2.04 to 2.34 μW∙m−3 were recorded in the basement com-plex within gneissic rocks. The spatial distribution of radiogenic heat in the area showed an increased heat gradient within the basement complex and a diminishing heat gradient over the Iullemmeded basin.
{"title":"Spatial distribution of radiogenic heat in the Iullemmeden basin – Precambrian basement transition zone, NW Nigeria","authors":"Joseph Aisabokhae, M. Adeoye","doi":"10.7494/GEOL.2020.46.3.238","DOIUrl":"https://doi.org/10.7494/GEOL.2020.46.3.238","url":null,"abstract":"The area which transcends the Precambrian basement complex onto the Sokoto sector of the Iullemme-den basin in northwestern Nigeria presents a unique prospect for geothermal exploration research in the absence of regional heat production data, despite its tectonic history and depositional characteristics. In this study, geophysical exploration employing radiometric technique was adopted to classify the petrologic units within the fringes of the Iullemmeden basin and the adjoining crystalline basement complex so as to estimate the radiogenic heat potential within the terrain that may support geothermal considerations. Airborne radiometric measurements acquired over the area were digitized and processed to obtain radioelement concentration maps and the K/Th/U ternary map. Results show that the ranges of measured concentrations of 40K, 238U and 232Th are 4.6 to 18.9%, 0.7 to 4.9 ppm and 4.6 to 18.9 ppm respectively. Radiogenic heat estimation derived from radioelement data within eight petrologic units comprising quaternary sediments, schist, carbonates, shale/clay, younger granites, older granites, gneissic rock and migmatite showed that the lowest radiogenic heat production estimates ranging from 0.27–0.66 μW∙m−3 were recorded in the sedimentary terrain within the quaternary sediments while the highest radiogenic heat production values of between 2.04 to 2.34 μW∙m−3 were recorded in the basement com-plex within gneissic rocks. The spatial distribution of radiogenic heat in the area showed an increased heat gradient within the basement complex and a diminishing heat gradient over the Iullemmeded basin.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"86 1","pages":"238-238"},"PeriodicalIF":0.8,"publicationDate":"2021-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85520821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-19DOI: 10.7494/GEOL.2020.46.3.251
U. Woźnicka
The method of the semi-empirical calibration of a neutron well logging probe was developed by Jan Andrzej Czubek on the concept of the general neutron parameter ( GNP ) and tested positively at the neutron calibration station in Zielona Gora, Poland. The neutron probe responses in a wide range of neutron parameters (and thus lithology, porosity and saturation) were also computed using the Monte Carlo method. The obtained simulation results made it possible to determine the calibration curves using the Czubek concept in a wider range than by means of the original method. The very good compatibility of both methods confirms the applicability of the GNP as well as the Monte Carlo numerical experiments, which allow for a significant extension of the semi-empirical calibration in complex well geometries taking into account e.g., casing or invaded zones.
Jan Andrzej Czubek根据一般中子参数(GNP)的概念提出了中子测井探头的半经验校准方法，并在波兰Zielona Gora的中子校准站进行了验证。利用蒙特卡罗方法计算了各种中子参数(包括岩性、孔隙度和饱和度)下的中子探针响应。得到的仿真结果使得利用Czubek概念确定比原方法更大范围的校准曲线成为可能。两种方法的良好兼容性证实了GNP和蒙特卡罗数值实验的适用性，这使得考虑到套管或侵入层等复杂井的几何形状，可以大大扩展半经验校准。
{"title":"Progress in the development of the semi-empirical calibration of neutron probes based on Monte Carlo modeling","authors":"U. Woźnicka","doi":"10.7494/GEOL.2020.46.3.251","DOIUrl":"https://doi.org/10.7494/GEOL.2020.46.3.251","url":null,"abstract":"The method of the semi-empirical calibration of a neutron well logging probe was developed by Jan Andrzej Czubek on the concept of the general neutron parameter ( GNP ) and tested positively at the neutron calibration station in Zielona Gora, Poland. The neutron probe responses in a wide range of neutron parameters (and thus lithology, porosity and saturation) were also computed using the Monte Carlo method. The obtained simulation results made it possible to determine the calibration curves using the Czubek concept in a wider range than by means of the original method. The very good compatibility of both methods confirms the applicability of the GNP as well as the Monte Carlo numerical experiments, which allow for a significant extension of the semi-empirical calibration in complex well geometries taking into account e.g., casing or invaded zones.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"1 1","pages":"251"},"PeriodicalIF":0.8,"publicationDate":"2021-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89330202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-19DOI: 10.7494/geol.2020.46.3.205
Polina Lemenkova
This study examined the relationships between topographic structure and submarine geomorphology, sediment thickness, geophysical anomaly fields, geological settings and tectonic lineament stretching of the Arabian Sea region, Carlsberg Ridge morphology, Makran Trench depths by GMT. The study included spatial analysis of the high-resolution datasets (GEBCO, EGM96, GlobSed) and geomorphological modeling of the 300km-width cross-section profiles of the Makran Trench. The analysis shown correlation between complex geologic and tectonic structure, asymmetric geomorphology and geophysical anomaly fields. The Makran Trench is formed in the subduction zone of the Arabian and Eurasian plates at the basement of the continental margin of Pakistan. Submarine geomorphic structure of the Arabian Sea is complicated by the Carlsberg Ridge, Owen Fracture Zone, Aden-Owen- Carlsberg Triple junction, numerous faults and rifts. The geophysical fields of the marine free- air gravity correlate with distribution of these geomorphic structures. Bathymetric analysis of the trench revealed the most frequent depth (448 samples) at -3,250 to -3,500 m, following by intervals: -3,000 to -3,250 m (225 samples), -2,750 to -3,000 m (201 samples). Gently declining continental slope of the coastal elevations correlate with gradually decreasing depths, as equally distributed bins: 124 samples (-2,500 to -2,750 m), 96 (-2,250 to -2,500 m), 86 (-2,000 to -2,250 m). Makran Trench has asymmetric geomorphology with a high slope steepness on the continental slope of Pakistan and low steepness with flat valley on the oceanward side.
{"title":"Relationship between geomorphology of the ocean seafloor with the tectonic structure of the Earth's crust and anomalous geophysical fields: Makran Trench, Arabian Sea","authors":"Polina Lemenkova","doi":"10.7494/geol.2020.46.3.205","DOIUrl":"https://doi.org/10.7494/geol.2020.46.3.205","url":null,"abstract":"This study examined the relationships between topographic structure and submarine geomorphology, sediment thickness, geophysical anomaly fields, geological settings and tectonic lineament stretching of the Arabian Sea region, Carlsberg Ridge morphology, Makran Trench depths by GMT. The study included spatial analysis of the high-resolution datasets (GEBCO, EGM96, GlobSed) and geomorphological modeling of the 300km-width cross-section profiles of the Makran Trench. The analysis shown correlation between complex geologic and tectonic structure, asymmetric geomorphology and geophysical anomaly fields. The Makran Trench is formed in the subduction zone of the Arabian and Eurasian plates at the basement of the continental margin of Pakistan. Submarine geomorphic structure of the Arabian Sea is complicated by the Carlsberg Ridge, Owen Fracture Zone, Aden-Owen- Carlsberg Triple junction, numerous faults and rifts. The geophysical fields of the marine free- air gravity correlate with distribution of these geomorphic structures. Bathymetric analysis of the trench revealed the most frequent depth (448 samples) at -3,250 to -3,500 m, following by intervals: -3,000 to -3,250 m (225 samples), -2,750 to -3,000 m (201 samples). Gently declining continental slope of the coastal elevations correlate with gradually decreasing depths, as equally distributed bins: 124 samples (-2,500 to -2,750 m), 96 (-2,250 to -2,500 m), 86 (-2,000 to -2,250 m). Makran Trench has asymmetric geomorphology with a high slope steepness on the continental slope of Pakistan and low steepness with flat valley on the oceanward side.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"3 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78529602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.7494/GEOL.2020.46.4.285
Pham Nhu Sang, N. Phuong, Vu Thai Linh, B. V. Sang
In Northeast Vietnam, Suoi Thau-Sang Than is considered as a high potential area of polymetallic deposits. 1,720 geochemical samples were used to investigate polymetallic mineralization; thereby polymetallic ore occurrences in this study region were discovered and the statistical and multivariate analysis helps to define geochemical anomalies in some northeastern regions, namely Suoi Thau, Sang Than, and Ban Kep. The statistical method and cluster analysis of geochemical data indicate that the Cu, Pb, and Zn elements are good indicators, and most of them comply with the lognormal or gamma distribution. Based on the third-order threshold, the geochemical anomalies of the content of the Cu, Pb, and Zn elements reflect the concentration of copper forming ore bodies in the mineralized zone, and clearly show the concentration in three distinct zones. The trend surface analysis which was employed to determine spatial variations and relationships among these good indicator elements and anomalous areas revealed relative changes in the content of the indicator elements, and they can be considered as regular. Moreover, the goodness of fit obtained trend functions of Pb and Zn, and Cu elements is a third-degree trend surface model. These results indicate that the models can be useful in studying geochemical anomalies and analyzing the tendency of the concentration of indicator elements in the Suoi Thau-Sang Than region. Additionally, it is suggested that the statistical analysis shows a remarkable potential to use the bottom river sediments in the region to investigate polymetallic mineralization. Moreover, geochemical data can help to evaluate geochemical anomalies of the pathfinder elements and potential mineral mapping of the Suoi Thau-Sang Than region in Northeast Vietnam.
{"title":"Statistical evaluation of the geochemical data for prospecting polymetallic mineralization in the Suoi Thau – Sang Than region, Northeast Vietnam","authors":"Pham Nhu Sang, N. Phuong, Vu Thai Linh, B. V. Sang","doi":"10.7494/GEOL.2020.46.4.285","DOIUrl":"https://doi.org/10.7494/GEOL.2020.46.4.285","url":null,"abstract":"In Northeast Vietnam, Suoi Thau-Sang Than is considered as a high potential area of polymetallic deposits. 1,720 geochemical samples were used to investigate polymetallic mineralization; thereby polymetallic ore occurrences in this study region were discovered and the statistical and multivariate analysis helps to define geochemical anomalies in some northeastern regions, namely Suoi Thau, Sang Than, and Ban Kep. The statistical method and cluster analysis of geochemical data indicate that the Cu, Pb, and Zn elements are good indicators, and most of them comply with the lognormal or gamma distribution. Based on the third-order threshold, the geochemical anomalies of the content of the Cu, Pb, and Zn elements reflect the concentration of copper forming ore bodies in the mineralized zone, and clearly show the concentration in three distinct zones. The trend surface analysis which was employed to determine spatial variations and relationships among these good indicator elements and anomalous areas revealed relative changes in the content of the indicator elements, and they can be considered as regular. Moreover, the goodness of fit obtained trend functions of Pb and Zn, and Cu elements is a third-degree trend surface model. These results indicate that the models can be useful in studying geochemical anomalies and analyzing the tendency of the concentration of indicator elements in the Suoi Thau-Sang Than region. Additionally, it is suggested that the statistical analysis shows a remarkable potential to use the bottom river sediments in the region to investigate polymetallic mineralization. Moreover, geochemical data can help to evaluate geochemical anomalies of the pathfinder elements and potential mineral mapping of the Suoi Thau-Sang Than region in Northeast Vietnam.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"32 1","pages":"285-299"},"PeriodicalIF":0.8,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85484152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-22DOI: 10.7494/GEOL.2020.46.4.259
M. A. Adeleye, Kazeem Oladayo Yekeen, Sikiru A. Amidu
Hydrocarbon exploration analysis from a seismic stratigraphic approach was carried out within the Beta Field, Coastal Swamp Depobelt, Niger Delta, to identify system tracts and sequence boundaries that could be associated with potential hydrocarbon accumulation. 3D seismic volume and data from four wells were analyzed. Depositional sequences, system tracts, sequence boundaries, and candidate maximum flooding surfaces were picked from logs, while reflection patterns and terminations were interpreted from seismic sections. Log shapes from gamma rays in combination with seismic facies analysis were interpreted in order to delineate lithology, depositional environments and depositional sequences. Seismic attributes were extracted and were draped on gridded surfaces from the interpreted seismic horizons. These were integrated with structure maps to obtain structural and stratigraphic trends, and possible presence of reservoir sand. Five depositional sequences and nine seismic facies were identified within the field. The depositional sequences were designated Sequences S1 to S5 based on the depth of the occurrences and stacking patterns. This study reveals a progression from fluvial depositional settings to the shelf. The main reservoirs identified are the sand units of the highstand and lowstand within three depositional sequences (S1, S4 and S5) although interbedded sands within the TST of S4 and S5 are also suspected of being potential reservoirs. The channel sand deposits within the study area are suspected to be hydrocarbon bearing as they occurred within the complex fault trapping system popular in the Niger Delta. The application of seismic stratigraphy, as shown in this study, serves to encourage exploration in the Niger Delta where it could be effectively employed for reducing risk in hydrocarbon exploration.
{"title":"Seismic stratigraphic analysis for hydrocarbon exploration in the Beta Field, Coastal Swamp Depobelt, Niger Delta","authors":"M. A. Adeleye, Kazeem Oladayo Yekeen, Sikiru A. Amidu","doi":"10.7494/GEOL.2020.46.4.259","DOIUrl":"https://doi.org/10.7494/GEOL.2020.46.4.259","url":null,"abstract":"Hydrocarbon exploration analysis from a seismic stratigraphic approach was carried out within the Beta Field, Coastal Swamp Depobelt, Niger Delta, to identify system tracts and sequence boundaries that could be associated with potential hydrocarbon accumulation. 3D seismic volume and data from four wells were analyzed. Depositional sequences, system tracts, sequence boundaries, and candidate maximum flooding surfaces were picked from logs, while reflection patterns and terminations were interpreted from seismic sections. Log shapes from gamma rays in combination with seismic facies analysis were interpreted in order to delineate lithology, depositional environments and depositional sequences. Seismic attributes were extracted and were draped on gridded surfaces from the interpreted seismic horizons. These were integrated with structure maps to obtain structural and stratigraphic trends, and possible presence of reservoir sand. Five depositional sequences and nine seismic facies were identified within the field. The depositional sequences were designated Sequences S1 to S5 based on the depth of the occurrences and stacking patterns. This study reveals a progression from fluvial depositional settings to the shelf. The main reservoirs identified are the sand units of the highstand and lowstand within three depositional sequences (S1, S4 and S5) although interbedded sands within the TST of S4 and S5 are also suspected of being potential reservoirs. The channel sand deposits within the study area are suspected to be hydrocarbon bearing as they occurred within the complex fault trapping system popular in the Niger Delta. The application of seismic stratigraphy, as shown in this study, serves to encourage exploration in the Niger Delta where it could be effectively employed for reducing risk in hydrocarbon exploration.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"283 1","pages":"259-271"},"PeriodicalIF":0.8,"publicationDate":"2020-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80191704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-06DOI: 10.7494/GEOL.2020.46.4.273
M. Polutrenko, Yevstakhiy Kryzhanivs’kyy, Ya. T. Fedorovych
A determination of soil corrosivity on three sections of a main gas pipeline in the Western region of Ukraine has been carried out. We have distinguished areas of development of biocorrosive processes with the participation of sulphate-reducing bacteria (SRB). Soil evaluation by the degree of corrosivity has been conducted. We used weight, titrimetric, gravimetric methods, pH-metry, ten-fold limit dilution method and Postgate nutrient medium B for culturing SRB. It has been established that the soil in the first area selected along the lower generatrix of the main gas pipeline has a high degree of corrosivity. It was ascertained that corrosive metal damage increases in the “ferrozone” with the growth of metal exposition time from 24 to 72 hours. The soil selected in the middle part and from above the pipeline refers to soils with a normal degree of corrosive activity. Innovative biostable insulating coatings based on bituminous-polymerous mastic MBPID-1 have been developed, modified with organic inhibitors from the class of quaternary ammonium salts and amines. Regularities of influence of nature of nitrogen-containing corrosion inhibitors of industrial production M, N, L, H and K on the corrosion rate of 17G1S steel for 180 days have been established. It was found that the corrosion rate of steel specimens remained unchanged throughout the study in variants with the presence of inhibitors H and K in the test systems, which indicated their bioresistance to the effect of SRB bacteria.
{"title":"A determination of areas of biocorrosion development on the route of a main gas pipeline in the Western region of Ukraine","authors":"M. Polutrenko, Yevstakhiy Kryzhanivs’kyy, Ya. T. Fedorovych","doi":"10.7494/GEOL.2020.46.4.273","DOIUrl":"https://doi.org/10.7494/GEOL.2020.46.4.273","url":null,"abstract":"A determination of soil corrosivity on three sections of a main gas pipeline in the Western region of Ukraine has been carried out. We have distinguished areas of development of biocorrosive processes with the participation of sulphate-reducing bacteria (SRB). Soil evaluation by the degree of corrosivity has been conducted. We used weight, titrimetric, gravimetric methods, pH-metry, ten-fold limit dilution method and Postgate nutrient medium B for culturing SRB. It has been established that the soil in the first area selected along the lower generatrix of the main gas pipeline has a high degree of corrosivity. It was ascertained that corrosive metal damage increases in the “ferrozone” with the growth of metal exposition time from 24 to 72 hours. The soil selected in the middle part and from above the pipeline refers to soils with a normal degree of corrosive activity. Innovative biostable insulating coatings based on bituminous-polymerous mastic MBPID-1 have been developed, modified with organic inhibitors from the class of quaternary ammonium salts and amines. Regularities of influence of nature of nitrogen-containing corrosion inhibitors of industrial production M, N, L, H and K on the corrosion rate of 17G1S steel for 180 days have been established. It was found that the corrosion rate of steel specimens remained unchanged throughout the study in variants with the presence of inhibitors H and K in the test systems, which indicated their bioresistance to the effect of SRB bacteria.","PeriodicalId":12724,"journal":{"name":"Geology, Geophysics and Environment","volume":"42 1","pages":"273-283"},"PeriodicalIF":0.8,"publicationDate":"2020-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89297767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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