Geology, Geophysics and Environment

Front page

2023-06-29

Editorial page

2023-06-29

Instruction for the authors

2023-06-29

Gases in the near-surface zone of the reclaimed Barycz municipal waste landfill – a case study from southern Poland

Paulina A. Kopera — 2023-04-21

The formation of biogas at municipal landfills and the significant emission of greenhouse gases from these facilities into the environment were the main reasons for analyzing the molecular composition of soil gas in the near-surface zone at the reclaimed part of the Barycz municipal waste landfill. The relations between the studied components (methane, carbon dioxide, light hydrocarbons and non-hydrocarbon components) and impact of the magnitude of recorded concentrations of methane and carbon dioxide on their emission to the atmosphere were evaluated. Two profiles were determined, along which 41 soil and landfill gas samples were taken at 20-meter intervals. At the same time, emissions were measured at each sampling point using a static chamber with a portable fluxometer. Chromatographic analysis showed that the concentrations of methane and carbon dioxide fluctuated in the ranges: 2.1 ppm – 76 vol% and 0.04 ppm – 11 vol%, respectively. Relatively high concentrations of these gases were determined at many of the measurement points, and this was particularly evident at the A-A’ profile, indicating stronger biochemical processes in this part of the landfill, or lateral migration of methane from the neighbouring stage II of the landfill, where biogas extraction is currently taking place. In addition, significant correlations between methane, carbon dioxide, and oxygen were demonstrated, indicating ongoing methane fermentation processes. Based on the study, it can be concluded that the southern part of the A-A’ profile is an optimal place to locate a degassing well from which biogas production could be used. However, the research is only preliminary and, it will be necessary to extend the soil gas tests before the final decision on the location of the well is made. Moreover, it has been shown that the concentrations of methane and carbon dioxide measured at points located outside the landfill were low. This means that generated biogas probably does not migrate beyond the boundaries of reclaimed waste landfill, but this will need to be confirmed by performing additional soil gas tests inside and outside the landfill area. The preliminary assessment of the effectiveness of the reclamation carried out was confirmed by the negligible values of the measured methane and carbon dioxide emissions on the surface.

Integration of seismic and well data for a 3D model of the Balkassar anticline (Potwar sub-basin, Pakistan)

Muhammad Mudasir — 2023-06-02

The Potwar sub-basin is an important hydrocarbon producing zone of the Upper Indus basin and has significant oil and gas potential. The Balkassar area is the main oil field of the Potwar sub-basin and oil is mainly produced from Eocene carbonates. The Chorgali Formation is of Eocene age and is the main reservoir rock in this area. Structurally, the Potwar sub-basin is complicated, and surface features often do not reflect subsurface structures. This is due to the presence of detachments at different levels. In such cases, it is necessary to integrate seismic data with geological information for an accurate delineation of subsurface structures. Eleven seismic profiles were interpreted to understand subsurface structural style. To correlate well data with seismic data, a synthetic seismogram has been generated. Time, velocity and depth contour maps have been prepared. A 3D model for the Chorgali Formation has been prepared which confirms that this is a four-way anticlinal structure bounded by faults. It makes this structure more favorable for hydrocarbon accumulation. Moreover, a cross section has been prepared for five wells to show that the Chorgali Formation is spreading. Based on it, to show the relationship between compressional tectonics and basement slope, a 3D structural model has been prepared. In this case study, the Balkassar anticline was interpreted as a four-way closure pop-up structure which provides a structural trap for the accumulation of hydrocarbons. This study will help us understand the accumulation of hydrocarbons in the same type of structural traps in the Potwar sub-basin and in similar kinds of basins. It is also relevant to oil exploration within Pakistan.

Alunogen from the sulfate efflorescence of the Stone Town Nature Reserve in Ciężkowice (the Outer Carpathian Mountains, Poland)

Mariola Marszałek — 2023-06-07

Alunogen (Al₂(SO₄)₃∙17H₂O), a rare secondary mineral, has been found in the efflorescence on sandstones from the Stone Town Nature Reserve in Ciężkowice, southeastern Poland. This is probably the first find of this salt on such rocks in Poland. Alunogen forms in various geological environments, but mainly from the oxidation of pyrite and other metal sulfides in ore deposits and Al-rich Earth materials under low-pH conditions. Its crystallization at this particular site depends on a set of necessary physicochemical (pH, concentration), climatic (season, temperature, humidity), site-related (location and protection of efflorescence), and mineralogical (the presence of pyrite) conditions. This paper presents the mineralogical and geochemical characteristics of the alunogen from the Stone Town Nature Reserve (based on SEM-EDS, XRPD, EPMA and Raman spectroscopy methods) as well as of the efflorescence itself (based on XRPD and STA coupled with QMS and FTIR for the analysis of gas products). Crystals of alunogen take the shape of flakes, often with a hexagonal outline, clustered in aggregates forming a cellular network. Its calculated formula is (Al_1.96Fe³⁺_0.01)_Σ1.97(SO₄)₃∙17H₂O (based on 12 O and 17 H₂O). The unit-cell parameters refined for the triclinic space group P1 are: a = 7.423 (1) Å, b = 26.913 (5) Å, c = 6.056 (1) Å, a = 89.974 (23)°, b = 97.560 (25)°, g = 91.910 (22)°. The Raman spectra (SO₄) bands are: intensive 995 cm⁻¹ (ν₁); low-intensive 1069, 1093 and 1127 cm⁻¹ (ν₃); low-intensive 419 and 443; medium-intensive 470 cm⁻¹ (ν₂); and medium-intensive 616 cm⁻¹ (ν₄₎. Those at 530, 312 and at 338 cm⁻¹ are assigned to water vibrations and those at 135, 156, 180 cm⁻¹ to the lattice modes. Although the efflorescence contained an admixture of other minerals (pickeringite, gypsum and quartz), the predominant alunogen is almost chemically pure and the above parameters are consistent with the values reported in the literature for alunogen from different locations and of various origins.

Tectonic strain in salt rock mass based on measurements

Zbigniew Szczerbowski — 2023-03-13

The measurement method with the application of an extensometer for the detection of the manifestation of tectonic strain is presented in this paper. The instrument is operated in underground construction for engineering purposes, and the authors applied it in a deeply placed underground old mine gallery in the Bochnia Salt Mine, just at the tectonic boundary of the Outer Carpathians which is commonly considered to be a tectonically active zone. The presented study is characterized by two basic features. The first is the placement of the measurements deep in an old mine which is an environment free of atmospheric factors disturbing the detection of a tectonic signal. The second is a combination of routine measurements carried out for engineering purposes and research measurements enabling the extension of the observation of displacements in the space outside underground workings, inside the rock mass that has been penetrated by extensometer probes. The extensometric measurements have been made using three 7-meter long sections. The results showed the differentiation in the displacement rates of points placed in the side walls: in the southern profile, the annual displacements are approximately 1.5 mm and in the northern one – approximately 1 mm. The combined result corresponds to the amount of the annual convergence value which has been determined by the classical surveys in the excavation where extensometric measurements have been made. What is more, the ongoing displacements in the southern side wall involve the entire part of the rock mass which is penetrated by an extensometric probe, but the displacements in the northern side are only observed in the first 2 m of the penetrated part of the rock mass. This differentiation is interpreted by the authors as being the result of tectonic strain acting from the south exerted by the Carpathians.

3D Block Modelling of the Sin Quyen IOCG Deposit, North Vietnam

Hao Duong Van — 2023-04-11

The IOCG Sin Quyen deposit is located in the Red River shear zone of North Vietnam. The ore bodies are known as hydrothermal veins and are hosted in Proterozoic metapelite. A block modelling approach was used to build a 3D model of the ore bodies. An analysis was carried out on Surfer^R 11 computer software using the archival data recorded from several dozen boreholes distributed within the study area, as well as data obtained from the mineral and chemical analysis of 50 samples collected recently in the deposit. The ore bodies generally trend in a NW-SE direction with an average azimuth of 107° and a dip of around 70°. Cu content in the ore bodies is inhomogeneous. In the bed extension direction, the exponential correlation of Cu concentration in ore bodies is recognized within 2,500 m, while in the direction perpendicular to the bed strike, the exponential dependence is observed at 500 m of distance. The high-grade mineralisation of copper within the ore bodies is often at the altitude interval from ∼100 m to ∼150 m above sea level (asl). These bodies are also rich in uranium and gold-bearing minerals. The total resources of Cu, U and Ag were estimated and amounted to 361,000; 12.7 and 11.87 tonnes respectively. The model indicates the downward extension of some ore bodies to below 300 m beneath the ground surface.

Recognition of the flysch substrate using the electrical resistivity tomography (ERT) method to assess the effectiveness of the injection process

Michał Ćwiklik — 2023-05-10

During the construction of a section of the S-7 Lubień – Rabka-Zdrój dual expressway, located in the area of the Carpathian flysch (Carpathian Flysch Belt, South Poland), damage to the embankment was observed, as well as cracks and depressions in the new pavement. An analysis of the geological and engineering conditions in the area of the road section under construction showed the existence of a complex tectonic structure of the flysch formations, a shallow groundwater table, and numerous landslides. In order to stabilize the road substrate, it was decided to carry out injections, and the locations of these injections were initially geotechnically tested. However, due to the high variability of the geological structure, the target method employed was electrical resistivity tomography (ERT), which performed the survey in two stages. In Stage I, the geoelectrical/geochemical structure of the near-surface zone was identified, and the probable causes of road damage were indicated. This stage was completed by performing the stabilization and sealing process of the ground with an injection mixture. In Stage II, studies were carried out to evaluate the effectiveness of the injection process. The ERT method effectively identified the shallow geological structure and, in particular, delineated the zone of strong fractures in the flysch and areas associated with faults. Using the electrical resistivity tomography method, it was also possible to determine the injection mixture’s approximate penetration depth and the loosening zone’s degree of filling.

Geology, Geophysics and Environment

Front page

Editorial page

Table of contents

Instruction for the authors

Gases in the near-surface zone of the reclaimed Barycz municipal waste landfill – a case study from southern Poland

Integration of seismic and well data for a 3D model of the Balkassar anticline (Potwar sub-basin, Pakistan)

Alunogen from the sulfate efflorescence of the Stone Town Nature Reserve in Ciężkowice (the Outer Carpathian Mountains, Poland)

Tectonic strain in salt rock mass based on measurements

3D Block Modelling of the Sin Quyen IOCG Deposit, North Vietnam

Recognition of the flysch substrate using the electrical resistivity tomography (ERT) method to assess the effectiveness of the injection process