New Data on Phase Composition and Geochemistry of the Muschelkalk Carbonate Rocks of the Upper Silesian Province in Poland

Abstract

Detailed description of phase composition and geochemistry of the Muschelkalk carbonate rocks of the Upper Silesian Province in Poland were presented in this article. The tests were carried out to determine mineralogical features and geochemical properties. The samples were collected from the formations of the Lower Muschelkalk (Gogolin Unit), Middle Muschelkalk (Diplopore Dolomite Unit) and Upper Muschelkalk (Tarnowice Unit, Boruszowice Unit). The following research methods were used: macroscopic description, X-Ray Diffraction, Fourier transform infrared spectroscopy, X-Ray Fluorescence and Atomic spectrometry with plasma intensification. The following carbonate phases were identified: a low-Mg calcite, a high-Mg calcite, a proto-dolomite, an ordered dolomite and a huntite. The results of XRD analysis allowed the determination of the chemical formulas of the mineral phases. XRF and ICP AES analyses allowed to establish the content of following trace elements: Sr, Ba, Al, Si, Fe, Mn, K, Na, S, Cl, Ti, Cr, Ni, Zn, Rb, Zr, Pb, As, V, Be, B, Co, Cu, Br, Mo and Cd. Apart from Sr and Ba, they are not fundamental components of carbonate rocks. They indicate the presence of minerals such as silicates, aluminosilicates, oxides and sulfides.

1. Introduction

The Upper Silesia region, which includes the areas of Tarnowskie Góry, Bytom (Lazarówka Quarry), Piekary Śląskie, Radzionków, Twardowice, Toporowice, Świerklaniec, Niezdara and Wojkowice, contains Triassic carbonate rocks, including the Lower, Middle and Upper Muschelkalk formations [1,2,3]. While the rocks of the Tarnowice and Boruszowice Units were studied in a previous project [4,5,6,7], the rocks of the Gogolin and Diplopora Units were only examined in areas with Muschelkalk deposits in the Opole Silesia region [4,5,6,8,9,10,11,12,13,14,15,16,17,18,19], and Szulc [20,21,22,23,24]. However, the presence of carbonate phases with varying magnesium content and trace elements in these formations in Upper Silesia has not yet been studied in detail.

Five carbonate phases characterized by varying magnesium (Mg) content have been identified in the limestones of Opole Silesia: low-magnesium calcite, high-magnesium calcite, protodolomite, ordered dolomite and huntite. The Upper Muschelkalk formations, including the Wilkowice and Boruszowice Units, have not yet been the subject of detailed research into identifying carbonate phases with varying magnesium content and trace elements [2,3,22]. As part of previous projects [6,7,20], individual rock samples from the Tarnowice and Boruszowice Units were studied. These rocks were mostly dolomites, with only the Radzionków sample being limestone. Due to the likelihood of carbonate phases with varying Mg content being present, including high-magnesium calcite, protodolomite, ordered dolomite and huntite, as well as trace elements, studies were undertaken on samples of the Lower, Middle and Upper Muschelkalk formations in the Upper Silesian Province using new research methods, including X-ray, FTIR, XRF and ICP-AES analysis. The results of this research project will supplement the data on the phase composition and type of trace elements in shell limestone rocks in the Upper Silesian Province.

The aim of the research is to determine the phase composition and geochemistry of rocks taken from the Lower, Middle and Upper Muschelkalk Formations (Middle Triassic). The results of the research enabled a theory to be formed regarding the conditions of rock sedimentation and the diagenetic processes to which these rocks were subjected, including the origin of trace elements and their potential impact on the practical application of the carbonate rocks under study. The article includes the results of macroscopic descriptions and analyses using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray fluorescence (XRF), as well as atomic spectrometry with plasma excitat (ICP-AES) to determine the presence of trace elements.

2. Materials and Methods

This project focuses on carbonate rocks of the Muschelkalk formation (Middle Triassic) in selected areas of the Upper Silesian Province (see Figure 1), including the following locations: Twardowice (Wolności Street, TW—Lower Gogolin Unit), Niezdara-Krzyżowa (Krzyżowa Street, (NK—Lower Gogolin Unit), Toporowice (Urocza Street, TO—Upper Gogolin Unit), Świerklaniec (Mroćko Street, (S—Upper Gogolin Unit) and Wojkowice (Sobieski Street, W—Diplopore dolomites, Jemielnica Unit). Piekary Śląskie (PSK3, Karłowicz Street and PSZ3, Zawisza Czarny Street, in the Tarnowice Unit), Bytom—Lazarówka Quarry (Lz3, in the Tarnowice Unit), Radzionków (Wilcza Street, R, in the Tarnowice Unit), and Tarnowskie Góry (TGO5—area of Długa Street, in the Tarnowice Unit and TGO4 (Tarnowskie Góry, Urokliwa Street), in the Boruszowice Unit). The names of the sample abbreviations are related to the place where the sample was taken: TW—sample from Twardowice City, NK—sample from Niezdara-Krzyżowa, TO—from Toporowice City, S—from Świerklaniec City, W—from Wojkowice City, PSK—from Piekary Śląskie City, area of Karłowicz Street, PSZ—sample from Piekary Śląskie City, Lz3—sample from Lazarówka Quarry, R—sample from Radzionków City, TGO—samples from different areas of Tarnowskie Góry City.

The Figure 2 illustrates connection of regional stratigraphic units with the International Chronostratigraphic Chart according to the lithostratigraphy of the Germanic Basin of Europe presented by Szulc [22]. The symbols of samples taken for laboratory testing have been marked on the profile. Samples were collected from formations whose deposits are exposed in the Upper Silesia region.

The test samples were collected according to the sample classification according to EN ISO 22475-1 [26]. Depending on the type of soil properties being tested, three categories of sampling methods were distinguished according to the above standard: A, B, and C. Category A methods collect completely undisturbed samples, in which the moisture content and voids index are the same as in situ conditions, and there are no changes in the soil’s components or chemical composition. Category B methods collect samples with a disturbed structure, containing all the soil components in situ while maintaining their natural moisture content. Category C methods collect samples with a disturbed structure and moisture content. The samples were collected according to category B. The samples themselves were collected during standard geotechnical drilling using a mechanical drilling rig. Point-by-point test holes were drilled with a WSG-P mechanical drill mounted on an off-road vehicle using a 90 mm diameter auger drill, with 1 m long runs. After drilling the hole and removing the cuttings, larger specimens were collected for testing. Samples were also collected from exposed surfaces, if any existed. The collected test samples were packed in plastic bags with access to natural ventilation and then transported to the target site (research laboratory).

In the first stage, all the collected rocks were described macroscopically, with textural and structural features taken into account. A study of their reaction to hydrochloric acid was also carried out. The mineral phases of the studied rocks were identified using two research methods: X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The elemental composition was determined using two test methods: X-ray fluorescence analysis (XRF) and atomic spectrometry with plasma excitation (ICP-AES).

Phase identification by X-ray diffraction (XRD) was performed in the Department of Applied Geology laboratory at the Faculty of Mining, Safety Engineering and Industrial Automation at the Silesian University of Technology in Gliwice. A Phaser 2 diffractometer from Bruker (Bruker AXS GmbH, Karlsruhe, Germany) was used with a copper lamp, a voltage of 30 kV and a current of 10 mA. X-ray diffraction enabled the identification of mineral phases with a content of at least 1%. This is the detection limit for the research equipment used. Minerals were identified using Bruker’s DIFFRAC.EVA software, which works with the Bruker’s X-ray diffractometer. This programme made it possible to determine the percentage share of mineral phases and their chemical formulas specifying the Ca and Mg content in carbonates.

This method was used to test all samples. Fourier transform infrared (FTIR) spectrometry was performed at the Materials Research Laboratory of the Faculty of Mechanical Engineering at the Silesian University of Technology in Gliwice. FTIR spectra were recorded for each material at room temperature using a Nicolet 6700/8700 FTIR spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA). The samples were measured in transmission mode in the mid-infrared range of 4000–400 cm⁻¹. Five samples were tested using this method: TW, TO, W, Lz3 and TGO4.

X-ray fluorescence (XRF) analysis was carried out in the Department of Applied Geology’s laboratory at the Faculty of Mining, Safety Engineering and Industrial Automation of the Silesian University of Technology in Gliwice. The study used a Bruker PUMA X-ray fluorescence spectrometer (Bruker AXS GmbH, Karlsruhe, Germany), which allows the determination of a wide range of elements. All samples were tested using this method.

Atomic spectrometry with plasma intensification (ICP-AES) was performed in the same department’s laboratory using an ICP-AES JY 2000 spectrometer (HORIBA Scientific, Longjumeau, France). All samples were tested using this method. The table presenting the measurement results shows the detection limit for each element.

3. Results

3.1. Macroscopic Description

As part of this project, two types of rock were examined: limestone and dolomite. Photographs of the samples are shown in Figure 3 below.

The rocks of the Lower Gogolin Unit (Figure 3a,b—TW and NK samples) are beige in color with a sparite texture and compact, disordered structure. The yellow color observed in some areas of the rock is associated with the presence of iron compounds. These compounds react strongly with hydrochloric acid. This indicates the predominance of calcite in the rocks. Therefore, these rocks can be preliminarily classified as limestone. The rocks of the Upper Gogolin Unit (Figure 3c,d—TO and NK samples) are grey-beige (Figure 3c—TO sample) or beige (Figure 3d—S sample). The yellow color observed in some areas of the rock is associated with the presence of iron compounds. Their texture is sparite and their structure is compact and disordered. They also react strongly with hydrochloric acid. Similar to the rocks of the Lower Gogolin Unit, these rocks can also be preliminarily classified as limestone.

The Diplopore dolomites of the Jemielnica Unit (Figure 3e, W sample) are dark beige in color. They have a sparite texture and a compact, disordered structure. They react slightly with hydrochloric acid. Therefore, they can be classified as limestone, which is composed mainly of calcite with a small amount of dolomite.

The rocks of the Tarnowice Unit (Figure 3f–j) vary in color, texture and structure. Those from Piekary Śląskie are characterized by a grey (Figure 3f) or brown (Figure 3g) color, with weathered parts appearing yellowish or brownish due to the presence of iron (Fe) compounds in sample PSZ3 (Figure 3g). Sample PSK3 has a compact, directional texture (Figure 3f), while sample PSZ3 is compact and disordered (Figure 3g). The directionality of sample PSK3 is related to separateness. Rocks collected from the Piekary Śląskie area react with hydrochloric acid after pulverisation, indicating the dominance of dolomite. The Radzionków rock is light brown, beige and grey in color, with a sparitic structure and a compact, directional texture associated with the presence of separation layers (Figure 3h).

A fairly strong reaction with HCl indicates the dominance of calcite in the rock. In addition, the mineral composition includes mixtures of brownish iron compounds and dark grey or black manganese minerals, forming dendrites or concentrations of fine-grained particles. Samples taken from the Lazarówka quarry (see Figure 3i, sample Lz3) are characterized by a dark brown color and reduced compactness, particularly sample Lz3. Macroscopically, the rocks exhibit a sparitic texture and a disordered, compact structure that is porous in places. Reaction with hydrochloric acid is weak or occurs after pulverisation, clearly indicating the dominance of dolomite. Therefore, it can be concluded that these are most likely dolomitic limestones or calcareous dolomites, or were once dolomitic limestones.

Samples collected from Tarnowskie Góry are yellowish-beige in color (see Figure 3j for sample TGO5). This color is associated with the presence of iron compounds. The rocks exhibit a macroscopic sparite texture and a disordered, compact structure. Sample TGO5 only reacts with HCl after pulverisation, indicating that dolomite is the dominant mineral in this rock. In addition to carbonate phases, the studied rocks contain iron compound admixtures, as evidenced by their yellowish color.

The rocks of the Boruszowice Unit (Figure 3k, sample TGO4) are yellow-beige in color. They have a sparitic texture and a compact, disordered structure. The weak or post-pulverisation reaction with hydrochloric acid clearly indicates the dominance of dolomite. Therefore, it can be concluded that these are most likely dolomitic limestones or calcareous dolomites.

3.2. Results of X-Ray Diffraction (XRD)

The XRD results for the limestones showed that the dolomite phase dominates the rocks of the Tarnowice and Boruszowice Units (samples PSK3, PSZ3, Lz3, TGO5 and TGO4;

Table 1. Results of X-Ray Diffraction.

Mineral Phase	Sample Symbol
	TW	NK	TO	S	W	PSK3	PSZ3	R	Lz3	TGO5	TGO4
	Content in [%]
Low-Mg calcite CaCO3	80	87	81	85	73	0	1	69	3	3	1
High-Mg Calcite 1 Ca0.94Mg0.06CO3	13	9	1	1	20	0	0	24	1	1	1
High-Mg Calcite 2 Ca0.9Mg0.1CO3 3	0	2	0	7	4	0	0	3	0	0	0
Ordered Dolomite 1 Ca,Mg(CO3)2	1	1	1	1	1	32	32	1	33	57	31
Ordered Dolomite 2 Ca0.50,Mg0.50(CO3)2	0	0	0	0	0	41	0	0	32	0	20
Protodolomite 1 Ca0.501,Mg0.499(CO3)2	0	0	0	0	0	22	44	0	0	0	9
Protodolomite 2 Ca1.07,Mg0.93(CO3)2	0	0	0	0	0	0	0	0	0	0	30
Fe Dolomite CaMg0.67Fe0.33(CO3)2	0	0	0	0	0	0	21	0	28	32	8
Huntite CaMg3(CO3)4	1	0	1	1	0	2	2	1	2	4	0
Quartz SiO2	3	1	14	3	0	3	0	0	1	3	0
Kaolinite Al2(H2O)2Si2O7	2	0	2	2	2	0	0	2	0	0	0
total	100	100	100	100	100	100	100	100	100	100	100

, Figure 4b), while the calcite phase dominates the rocks of the Gogolin and Diplopore Dolomite Units (samples TW, NK, TO, S, W and R; Table 1, Figure 4a). Huntite was also identified in some samples from the Gogolin Unit (TW, TO and S—see Table 1 and Figure 3a) and the Tarnowice Unit (PSK3, PSZ3, R, Lz3 and TGO5—see Table 1) and the Boruszowice Unit (TG4—see Table 1, Figure 4b). The following non-carbonate phases were identified: quartz (in PSK3, PSZ3, Lz3, TGO5 and TGO4) (see Table 1), and kaolinite (in samples TW, TO, S, W, PSK3 and R) (Table 1, Figure 4a). High-magnesium calcite in samples from Twardowice (Table 1), Toporowice (Table 1), Wojkowice (Table 1), Radzionków (Table 1), the Lazarówka Quarry (Table 1) and the Tarnowskie Góry region (Table 1) has the formula Ca_0.94Mg_0.06CO₃. Samples from Niezdara-Krzyżowa (NK, Table 1) and Świerklaniec (S, Table 1, Figure 4a) contained two types of high-magnesium calcite: one with the formula Ca_0.94Mg_0.06CO₃ and the other with the formula Ca_0.9Mg_0.1CO₃. Dolomite phases were identified in all samples. Dolomite with the formula CaMg(CO₃)₂—ordered dolomite—was found in all the examined rocks. Dolomite with the formula (Ca_0.5Mg_0.5)₂(CO₃)₂ (samples PSK3, PSZ3, Lz3, TGO5 and TGO4—see Table 1, Figure 4b) can also be considered ordered dolomite. In samples PSK3, PSZ3, Lz3, TGO5 and TGO4 (Table 1, Figure 4b), dolomite phases with a lower magnesium content were also identified, characterized by the following formulas: Ca_0.501Mg_0.449(CO₃)₂ and Ca_1.07Mg_0.93(CO₃)₂, which can be considered protodolomite, as well as a dolomite phase with iron substitution, CaMg_0.67Fe_0.33(CO₃)₂. Huntite, with the formula CaMg₃(CO₃)₄, was identified in the samples of the Gogolin Unit (Table 1), the TO sample (Table 1), the S sample (Table 1, Figure 3a), the Tarnowice Unit samples (PSK3, PSZ3, Lz3, R, TGO5, Table 1) and the Boruszowice Unit sample (TGO4, Table 1, Figure 4b). This is a calcium carbonate phase with a higher magnesium content than ordered dolomite, but lower than magnesite.

When analyzing the X-ray diffraction (XRD) results, it should be noted that in the rocks of the Tarnowice Unit (PSK3, PSZ3, Lz3 and TGO5; (Table 1) and the Boruszowice Unit (TGO4; Table 1, Figure 4b), the carbonate phases enriched in magnesium dominate. Mainly, dolomite phases, high-magnesium calcite and huntite dominate. In contrast, in the rocks of the Gogolin Unit (TW, NK, TO and S, Table 1, Figure 4a), the Diplopore Dolomite Unit (W, Table 1) and the sample of the Tarnowice Unit (R, Table 1), the calcite phases dominate, with low-magnesium calcite prevailing. Dolomite and huntite phases are also present in these rocks. However, these minerals occur in small quantities of 1–3%.From the non-carbonate phases in samples TW, NK, TO, S, PSK3, PSZ3, Lz3, TGO5, TGO4, (Table 1, Figure 4a,b), quartz, with the formula SiO₂, was identified, and in samples: TW, TO, S, W, PSK3, R (Table 1, Figure 4a)—kaolinite M2, with the formula Al₂(H₂O)₂Si₂O₇.

The results of X-ray diffraction (XRD) analysis indicate that the carbonate phases with elevated magnesium content (dolomite, high-magnesium calcite and huntite) predominate in samples of the Tarnowice Unit (PSK3, PSZ3, Lz3 and TGO5; Table 1) and the Boruszowice Unit (TGO4; Table 1, Figure 4b). Therefore, these rocks can be classified as dolomites. In the Gogolin Unit samples (TW, NK, TO and S, Table 1, Figure 4a), the Diplopore Dolomite Unit sample (W, Table 1) and one Tarnowice Unit sample (R, Table 1), calcite phases dominate, primarily low-magnesium calcite. These limestones are slightly enriched in carbonate phases with elevated Mg content.

The low quartz content of up to approximately 4% (in samples TW, NK, TO, S, PSK3, PSZ3, Lz3 and TGO5 and TGO4—see Table 1, Figure 4a,b) and the low kaolinite content of up to approximately 3% (in samples TW, TO, S, W, PSK3 and R—see Table 1, Figure 4a) indicate the purity of these rocks, as determined using the XRD method.

3.3. Fourier Transform Infrared Spectroscopy (FTIR) Results

Based on the absorption spectra obtained from Fourier infrared analysis (

Table 2. Values of minerals spectra bonds in the analyzed carbonate rocks in cm⁻¹ [7].

Sample Symbol	Low-Mg Calcite CaCO3	High-Mg Calcite (Ca,Mg)CO3	Dolomite Ca,Mg(CO3)2	Huntite CaMg3(CO3)4	Quartz SiO2	Feldspars	Clay Minerals
TW (Figure 5a)	v3 = 1422 v4 = 712 v2 = 874 v1 + v3 = 2513 v1 + v4 = 1799 other bonds—2599, 2875, 2983, 2984, 3446	–	–	v3 = 1530 v1 = 1110 v2 = 869	1097 799 515 469	–	kaolinite Al2Si2O5(OH)4 604
TO (Figure 5b)	v3 = 1422 v4 = 712 v2 = 874 v1 + v3 = 2513 v1 + v4 = 1789 other bonds—2599, 2875, 2983, 2984, 3446	–	–	v3 = 1530 v1 = 1110 v2 = 869	1097 799 515 469	–	kaolinite Al2Si2O5(OH)4 605
W (Figure 5c)	v3 = 1422 v4 = 712 v2 = 874 v1 + v3 = 2513 v1 + v4 = 1799 other bonds—2599, 2875, 2983, 2984, 3446	–	–	v3 = 1530 v1 = 1110 v2 = 869	1097 799 515 469	–	–
Lz3 (Figure 5d)	v4 = 712 v2 = 874 other bonds–2984	v3 = 1428 v2 = 876 v1 + v4 = 1802 other bonds—2984, 3470	v1 = 1100 v1 + v4 = 1819 other bonds—2525, 2605	v3 = 1572 v1 = 1109	799 515 467	1034	kaolinite Al2Si2O5(OH)4 604
TGO4 (Figure 5e)	v3 = 1422 v4 = 712 v2 = 874 v1 + v3 = 2513 v1 + v4 = 1797 other bonds–2875, 2983, 3446	–	v4 = 728 v2 = 880 v1 = 1101 v1 + v4 = 1819 other bonds–2605	v3 = 1530 v1 = 1113	1097 799 515 469	–	–

, Figure 5), the minerals comprising the tested limestones, particularly the carbonate phases, were identified [7]. Among the carbonate minerals present in the examined samples, in addition to low-magnesium calcite, the following were identified: high-magnesium calcite (Table 2, Figure 5d), dolomite (Table 2, Figure 5d,e) and huntite (Table 2, Figure 5a–e). The non-carbonate phases identified were quartz (Table 2, Figure 5), feldspar (Table 2, Figure 5d) and kaolinite (Table 2, Figure 5a,b,d).

Low-magnesium calcite was identified in the rocks based on the following bands: v₃ = 1422 cm⁻¹ (Table 2, Figure 5); v₂ = 874 cm⁻¹ (Table 2, Figure 5a–e); v₄ = 712 cm⁻¹ (Table 2, Figure 5a–e); v₁ + v4 = 1799 cm⁻¹ (Table 2, Figure 5a–c,e); and v₁ + v₃ = 2513 cm⁻¹ (Table 2, Figure 5a–c,e) and, in some samples, based on additional infrared bands (Table 2, Figure 5a–c,e) [26,27]. ‘Pure’ calcite (low magnesium) is usually characterized by a v₃ band with lower values ranging from 1400 to 1422 cm⁻¹. Magnesium substitutions in magnesium calcite crystals cause a shift of the v₃ band towards higher values. High-magnesium calcite, which was identified only in the Tarnowice Unit rock (sample Lz3—see Table 2 and Figure 5d), was determined based on the following bands: v₃ = 1428 cm⁻¹, v₂ = 876 cm⁻¹, v₁ + v₄ = 1802 cm⁻¹, and far-infrared bands at 2984 cm⁻¹, 3470 cm⁻¹, and 1435 cm⁻¹ [26,27].

As the magnesium content of high-magnesium calcite crystals increases, the v₃ band shifts towards higher values of up to 1439 cm⁻¹, which may be characteristic of dolomite (the v₃ band for dolomite typically ranges from 1440 to 1443 cm⁻¹) [26,28,29,30]. The dolomite phase was identified in the rocks of the Tarnowice (sample Lz3, Table 2, Figure 5d) and Boruszowice (sample TGO4, Table 2, Figure 5e) units based on the following bands: v1 = 1100 cm⁻¹ (Table 2, Figure 5d) and 1101 cm⁻¹ (Table 2, Figure 5e); v₂ = 880 cm⁻¹ (Table 2, Figure 5e); v₁ + v₄ = 1819 cm⁻¹ (Table 2, Figure 5d,e); v₁ + v₃ = 2525 cm⁻¹; and further infrared bands at 2525 cm⁻¹ (Table 2, Figure 5d) and 2605 cm⁻¹ (Table 2, Figure 5d,e) [26,27]. The results show a gradual shift in the bands towards higher values, ranging from the lowest for low-magnesium calcite to the highest for dolomite. The following bands appeared in all the samples tested (Table 2, Figure 5a–e): v₃ = 1530 cm⁻¹ (Table 2, Figure 5a–c,e) or 1572 cm⁻¹ (Table 2, Figure 5d); v₁ = 1110 cm⁻¹ (Table 2, Figure 5a–c); 1109 cm⁻¹ (Table 2, Figure 5d); or 1113 cm⁻¹ (Table 2, Figure 5), v₂ = 869 cm⁻¹ (Table 2, Figure 5a–c), indicating the presence of huntite (CaMg₃[CO₃]₄), a carbonate phase with a higher magnesium content than dolomite [26,31,32,33]. This mineral occurs in sedimentary rocks in vadose zone formations [31,32,33]. The huntite phase can form as a result of hydrothermal processes, dolomite weathering, or the transformation of magnesium calcite at high temperatures.

Other bands occurring in the analyzed spectra of Triassic carbonate rocks indicate the presence of quartz admixtures (469–467 cm⁻¹, 515 cm⁻¹, 799 cm⁻¹—see Table 2 and Figure 5a–e, and 1097 cm⁻¹—see Table 2 and Figure 5a–c,e, feldspar (1034 cm⁻¹) (see Table 2 and Figure 5d) and kaolinite (604–605 cm⁻¹) (see Table 2 and Figure 5a,b,d).

The results indicate that low-magnesium calcite is dominant in the rocks of the Gogolin and Diplopore dolomite units. Additionally, huntite is present in the carbonate rocks of these formations. High-Mg calcite was only identified in rocks of the Tarnowice Unit, while dolomite was identified in rocks of the Tarnowice and Boruszowice Units. Huntite was also identified in the rocks of these formations. Of the non-carbonate minerals, quartz was identified in all the rocks, feldspar in the Tarnowice Unit sample, and kaolinite in the Gogolin and Tarnowice Unit samples [7].

3.4. Results of X-Ray Fluorescence Analysis (XRF)

The elements present in the tested carbonate rocks were determined as part of the XRF analysis. The limestone test results are presented in

Table 3. Composition of main elements in samples.

Element	Sample Symbol [%Mass]
	TG4	TG5	Lz3	PSK3	PSZ3	R	TO	TW	NK	S	W
Na	0.04	0.04	0.00	0.00	0.15	0.00	0.00	0.00	0.00	0.00	0.00
Mg	21.00	20.00	22.00	27.00	28.00	0.59	0.57	0.59	0.87	0.51	0.33
Al	3.90	2.90	1.70	2.80	0.42	1.90	1.80	0.84	0.66	0.58	0.33
Si	8.50	6.60	3.80	6.70	0.58	4.20	6.10	2.30	1.50	1.60	0.88
K	1.30	0.73	0.12	0.80	0.00	0.85	1.70	0.54	0.40	0.41	0.19
Ca	59.00	66.00	57.00	60.00	66.00	66.00	88.00	95.00	96.00	96.00	97.00
Mn	0.32	0.15	1.20	0.18	0.28	0.04	0.06	0.04	0.04	0.03	0.02
Fe	5.10	3.40	13.00	2.00	3.20	1.40	1.20	0.60	0.81	0.58	0.50

,

Table 4. Trace element composition in samples.

Element	Sample Symbol [%Mass]
	TG4	TG5	Lz3	PSK3	PSZ3	R	TO	TW	NK	S	W
S	0.00	0.10	0.00	0.14	0.02	0.02	0.02	0.03	0.01	0.03	0.14
Cl	0.08	0.06	0.08	0.13	0.13	0.08	0.00	0.00	0.00	0.00	0.00
Ti	0.16	0.13	0.06	0.15	0.00	0.13	0.14	0.06	0.00	0.00	0.00
Cr	0.00	0.01	0.00	0.01	0.00	0.03	0.00	0.00	0.03	0.00	0.00
Ni	0.00	0.02	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Zn	0.18	0.06	0.74	0.22	0.52	0.05	0.07	0.03	0.02	0.02	0.02
Rb	0.01	0.00	0.00	0.01	0.00	0.00	0.01	0.00	0.00	0.00	0.00
Sr	0.01	0.04	0.02	0.04	0.03	0.11	0.14	0.06	0.04	0.07	0.08
Zr	0.01	0.01	0.02	0.01	0.00	0.00	0.03	0.00	0.00	0.00	0.00
Ba	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.86
Pb	0.05	0.01	0.17	0.03	0.03	0.00	0.02	0.01	0.01	0.01	0.02
As	0.00	0.00	0.00	0.00	0.01	0.00	0.00	0.00	0.00	0.00	0.00
V	0.00	0.01	0.02	0.00	0.00	0.01	0.00	0.00	0.00	0.00	0.01

and

Table 5. Composition of main oxides and LOI in samples.

Oxide	Sample Symbol [%Mass]
	TG4	TG5	Lz3	PSK3	PSZ3	R	TO	TW	NK	S	W
Na2O	0.02	0.02	0.00	0.00	0.08	0.00	0.00	0.00	0.00	0.00	0.00
MgO	13.25	12.72	14.20	16.77	17.26	0.54	0.41	0.40	0.59	0.35	0.22
Al2O3	2.80	2.10	1.25	1.98	0.29	1.98	1.49	0.65	0.51	0.45	0.25
SiO2	6.92	5.41	3.16	5.37	0.46	4.96	5.71	2.03	1.31	1.41	0.77
K2O	0.60	0.34	0.06	0.36	0.00	0.56	0.90	0.27	0.20	0.20	0.09
CaO	31.41	35.42	31.05	31.44	34.33	50.95	53.87	54.77	54.89	55.22	55.43
MnO	0.16	0.07	0.60	0.09	0.13	0.03	0.03	0.02	0.02	0.02	0.01
Fe2O3	2.50	1.68	6.51	0.96	1.53	0.99	0.68	0.32	0.43	0.31	0.26
LOI	42.34	42.24	43.17	43.03	45.92	39.98	36.91	41.54	42.06	42.05	42.96
Total	100.00	100.00	100.00	100.00	100.00	100.00	100.00	100.00	100.00	100.00	100.00

.

The elemental composition analysis of the carbonate rocks indicates that the highest percentages are accounted for by the elements that make up carbonate minerals (i.e., Ca, Mg, C and O; see Table 3, Table 4 and Table 5). These elements are components of carbonate phases such as low-magnesium calcite, high-magnesium calcite, dolomite and huntite. Trace amounts of other elements, such as Al, Si, K, Mn and Fe, were also detected in some samples, as well as Na, P, S, Cl, K, Ti, Cr, Ni, Zn, Rb, Sr, Zr, Ba, Pb, As and V. Manganese and iron can replace calcium (Ca) and magnesium (Mg) in carbonate minerals. Strontium and barium are elements that are originally present in aragonite, an unstable form of calcium carbonate. Like high-magnesium calcite, aragonite undergoes a transformation into low-magnesium calcite during diagenesis.

Sr and Ba often appear in carbonate phases. According to the literature, strontium (Sr) occurs in the skeletons of marine organisms [12,14,34,35,36,37,38]. The presence of Sr in aragonite is associated with a larger ionic radius than that of Ca, meaning it can easily enter the aragonite structure, which is more similar to strontianite than calcite. Consequently, aragonite contains more strontium than calcite [14,39]. However, aragonite is an unstable form of calcium carbonate, similar to high-magnesium calcite, and it transforms into low-magnesium calcite during diagenesis. Consequently, the presence of strontium alone can indicate that the original calcium carbonate phase was aragonite. Like Sr, Ba occurs in the skeletons of marine organisms. It has a similar ionic radius to Sr [14,34,35,36,40], so it will more easily enter the structure of aragonite than calcite.

Silicon (Si), aluminium (Al) and potassium (K), as well as some iron (Fe) and vanadium (V), will be part of aluminosilicates, mainly feldspars and clay minerals [38]. S, Ti, Cr and some Fe, Ni, Cu, Zn, Pb and Rb will probably be bound in sulfides and oxides, and As will probably be bound in Fe sulfides. Nickel (Ni) is incorporated into the structures of clay minerals during sedimentation processes. Like Si, Al, K, Na and Fe, Ni may be part of aluminosilicates and may also form sulfides and arsenides [38]. Chlorine is bound in chlorides and phosphorus is present in organic matter.

Taking into account the main elements in the samples, the content of CaO and MgO oxides, MgCO₃ and the Ca:Mg ratio were calculated based on the test results (

Table 6. MgCO₃ content and Ca/Mg ratio.

Sample Symbol	Ca [%]	CaO [%]	Mg [%]	MgO [%]	MgCO3 [%]	Ca/Mg
TG4	59.00	38.28	21.00	13.25	27.83	2.81
TG5	66.00	35.42	20.00	12.72	26.71	3.30
Lz3	57.00	31.05	22.00	14.20	29.82	2.59
PSK3	60.00	31.44	27.00	16.77	35.22	2.22
PSZ3	66.00	34.33	28.00	17.26	36.25	2.36
R	91.00	50.95	0.59	0.54	1.13	154.24
TO	88.00	53.87	0.57	0.41	0,86	154.38
TW	95.00	54.77	0.59	0.40	0.84	161.02
NK	96.00	54.98	0.87	0.59	1.24	110.34
S	96.00	55.22	0.51	0.35	0.74	188.23
W	97.00	55.43	0.33	0.22	0.46	293.93

). These calculations were performed to classify the tested rocks according to the Chilingar (1957) [41] and Pettijohn (1975) [10] classifications (see

Table 7. Classification according to Chilingar G.V. (1957) [%] [41].

Rock Name	Ca/Mg Ratio
magnesium dolomite	1.0–1.5
dolomite	1.5–1.7
calcareous dolomite	1.7–2.0
limestone dolomite	2.0–3.5
highly dolomitic limestone	3.5–16.0
dolomitic limestone	16.0–60.0
dolomitic limestone	60.0–105.0
calcite limestone	more than 105.0

,

Table 8. Classification according to Pettijohn F.J. (1975) [10].

Rock Name	Dolomite Content [%]	MgCO3 Content [%]	MgO Content [%}
limestone	0.0–10	0.0–4.4	0.0–2.1
dolomitic limestone	10–50	4.4–22.7	2.1–10.8
calcareous dolomite	50–90	22.7–41.0	10.8–19.5
dolomite	90–100	44.0–45.4	19.5–21.6

and

Table 9. Position of the analyzed rocks in classifications based on Ca/Mg ratios and MgO and MgCO₃ [%] content.

Formation Name	Name of Variety	Sample Symbol	Ca/Mg	MgO [%]	MgCO3 [%]	Name of the Rock in the Classification of Chilingar G.V. (1957) [41]	Name of the Rock in the Classification of Pettijohn F.J. (1975) [10]
Lower Gogolin Unit	Rock from Twardowice	TW	161.02	0.40	0.84	Limestone	Calcite limestone
	Rock from the vicinity of Niezdara-Krzyżowa	NK	110.34	0.59	1.24	Limestone	Calcite limestone
Upper Gogolin Unit	Rock from Toporowice	TO	154.38	0.41	0,86	Limestone	Calcite limestone
	Rock from the vicinity of Świerklaniec	S	188.23	0.35	0.74	Limestone	Calcite limestone
Diplopore Dolomites Unit	Rock from Wojkowice	W	293.93	0.22	0.46	Limestone	Calcite limestone
Tarnowice Unit	Rocks from Piekary Śląskie	PSK3	2.22	16.77	35.22	Calcareous dolomite	Calcareous dolomite
		PSZ3	2.36	17.26	36.25	Calcareous dolomite	Calcareous dolomite
	Rock from Radzionków	Rd	154.24	0.54	1.13	Limestone	Calcite limestone
	Rock from the Lazarówka Quarry	Lz3	2.59	14.20	29.82	Calcareous dolomite	Calcareous dolomite
	Rock from the Tarnowskie Góry area	TG5	3.30	12.72	26.71	Calcareous dolomite	Calcareous dolomite
Boruszowice Unit	Rock from the Tarnowskie Góry area	TG4	2.81	13.25	27.83	Calcareous dolomite	Calcareous dolomite

).

According to Chilingar’s classification (1957) [41], the data presented in Table 7 indicate that the rocks from the Tarnowskie Góry area, the Lazarówka Quarry and Piekary Śląskie are calcareous dolomites, while the rocks from Radzionków, Toporowice, Twardowice, Niezdara-Krzyżowa, Świerklaniec and Wojkowice are limestones (Table 9). According to Pettijohn’s (1975) [10] classification (Table 8), the rocks from the Tarnowskie Góry area, the Lazarówka quarry and Piekary Śląskie are calcareous dolomites, while the rocks from Radzionków, Toporowice, Twardowice, the vicinity of Niezdara-Krzyżowa, Świerklaniec and Wojkowice are calcite limestones (Table 9). The research results confirmed the hypothesis that the rocks taken from the Tarnowskie and Piekary Ślaskie areas and the Lazarówka quarry, which are part of the Tarnowskie layers, belong to the dolomite group. Meanwhile, the rocks taken from the Gogolin layers (Twardowice, Toporowice, Świerklaniec and Niezdara-Krzyżowa), Jemielnica (Wojkowice) and some rocks from the Tarnowskie layers (Radzionków) belong to the limestone group.

3.5. Results of ICP-AES Spectrometry

The following elements were detected in the tested carbonate rocks using ICP-AES spectrometry: Be, B, Ti, V, Cr, Co, Ni, Cu, Zn, As, Br, Sr, Zr, Nb, Mo, Cd and Pb. The results are presented in

Table 10. Results of ICP AES analysis [ppm].

Element	Detection Limit	Sample Symbol (Measured Value for Element)/Standard Deviation—STD [Values in ppm]
		TW/STD	NK/STD	TO/ STD	S/ STD	W/ STD	PSK3/STD	PSZ3/STD	R/ STD	Lz3/ STD	TGO5/STD	TGO4/STD
Be	0.002	0/-	0/-	0/-	25/1	30/1	15/1	20/1	60/1	55/1	0/-	10/0.5
B	0.005	35/1	80/2	55/1	25/1	45/1	95/3	65/1	75/1	55/1	85/1	95/2
Ti	0.005	610/5	90/2	1355/10	95/2	80/2	1321/12	85/2	1125/10	545/7	1120/10	1250/10
V	0.007	45/1	55/1	0/-	20/1	95/2	55/2	0/-	95/3	160/7	110/6	95/2
Cr	0.001	55/1	280/5	65/1	25/1	45/1	105/5	100/1	321/4	55/1	110/6	98/1
Co	0.01	0/-	0/-	6/0.2	0/-	0/-	8/0.1	0/-	0/-	10/0.5	5/0.2	0/-
Ni	0.001	65/1	98/3	0/-	0/-	0/-	0/-	70/2	25/1	55/1	210/4	85/2
Cu	0.002	55/1	60/2	45/1	55/1	10/q	25/1	65/1	20/1	95/4	65/2	55/1
Zn	0.01	295/5	210/7	720/5	215/6	310/4	210/3	5500/15	530/7	820/8	620/8	190/5
As	0.57	0/-	15/1	0/-	25/1	35/1	21/1	115/3	60/2	55/1	35/1	25/1
Br	0.36	10/1	11/1	5/0.1	10/1	20/1	10/0.8	20/1	0/-	25/1	55/4	10/0.5
Sr	0.001	625 4	410/5	1422/9	780/5	830/5	410/3	320/5	1250/10	205/9	410/8	120/5
Zr	0.001	25/1	0/-	295/4	55/1	75/2	120/2	55/1	95/3	220/9	120/5	110/5
Nb	0.005	0/-	0/-	5/0.1	9/1	5/0.1	0/-	10/0.5	3/0.1	4/0.3	11/0.7	5/0.2
Mo	0.03	4/0.09	10/1	5/0.1	7/0.2	5/0.1	6/0.1	10/0.5	0/-	2/0.1	10/0.7	5/0.1
Cd	0.01	0.5/0.01	0.5/0.02	2/0.08	1/0.01	0.2/0.01	0.2/0.01	2/0.01	0.3/0.01	1.1/0.1	0.7/0.01	0.5/0.01
Pb	0.014	155/2	110/2	210/2	110/3	200/5	320/5	310/4	95/2	190/4	120/5	510/6

and Figure 6.

The results of the research indicate the presence of the following elements in all the rocks examined: B, Ti, Cr, Cu, Zn, Sr, Cd and Pb. Additionally, Be was detected in samples TGO4, Lz3, PSK3, PSZ3, R, S and W, and in samples TGO4, TGO5, Lz3, PSK3, R, TW, NK, S and W, V was detected. Co was detected in samples TGO5, Lz3, PSK3 and TO; Ni in samples TGO4, TGO5, Lz3, PSZ3, R, TW and NK; and As in samples TGO4, TGO5, Lz3, PSK3, PSZ3, R, TO, TW, NK, S and W. S and W—As; in samples TGO4, TGO5, Lz3, PSK3, PSZ3, R, TW, NK, S and W—Br; in samples TGO4, TGO5, Lz3, PSK3, PSZ3, R, TW, NK, S and W—Mo. S and W—Zr; and in samples TGO4, TGO5, Lz3, PSZ3, R, TO, S and W—Nb and Mo.

Measurements performed using ICP-AES spectrometry revealed the presence of the following elements in selected samples that were not detected during XRF analysis: Be, B, Co, Cu, Br, Mo and Cd. These elements occur at relatively low concentrations, probably below the XRF detection limit.

Copper (Cu) and molybdenum (Mo) can be found in the form of sulfides. Like Ni and Cr, molybdenum is bound in clay minerals. Nb may be present as an impurity in titanium and zirconium minerals or manganese concretions [4,14]. Cadmium (Cd), bromine (Br) and cobalt (Co) usually occur in aluminosilicates, sulfides or oxides [4,14]. Cd is bound in zinc sulfides. It can also occur alongside Fe, Mn, and Co in smithsonite [4,14]. Beryllium occurs in bauxites, kaolins and clayey weathering products in sedimentary rocks [38].

Within the group of sedimentary rocks, clay minerals such as hydromicas (e.g., illite and glauconite) are characterized by a notably higher boron content. Boron is also present in marine organisms [38].

4. Discussion

This project focuses on carbonate rocks in selected areas of the Silesian Province. This topic was chosen due to the likelihood of carbonate phases with varying magnesium content being present in these rocks. This was identified during previous projects in the limestones and dolomites of the upper shell limestone of the Tarnowice strata in the aforementioned areas. The research area covers Tarnowskie Góry, Bytom (Lazaróka Quarry), Piekary Śląskie, Radzionków, Toporowice, Twardowice, the Niezdara-Krzyżowa area, Świerklaniec, and Wojkowice.

4.1. Analysis of Research Results

X-ray diffraction (XRD) results showed that samples PSK3, PSZ3, Lz3, TGO5 and TGO4 (see Table 1, Figure 4b) are dominated by carbonate phases with an elevated magnesium content, such as dolomite, high-magnesium calcite and huntite. By contrast, samples TW, NK, TO, S, W and R (see Table 1, Figure 4a) are dominated by calcite phases, primarily low-magnesium calcite. Therefore, it can be assumed that samples PSK3, PSZ3, Lz3, TGO5 and TGO4 are dolomites, while samples TW, NK, TO, S and W represent limestones with only slight enrichment in carbonate phases with elevated magnesium content. The low quartz content (up to approximately 4% in samples TW, NK, TO, S, PSK3, PSZ3, Lz3, TGO5 and TGO4; see Table 1, Figure 4a,b) and kaolinite content (up to approximately 3% in samples TW, TO, S, W, PSK3 and R; Table 1, see Figure 4a)—which is at the limit of determination using the XRD method—is testament to the purity of these rocks.

Fourier transform infrared spectroscopy (FTIR) also yielded a great deal of interesting data. The results showed that the TW, NK, TO, S, W, R and TGO4 rocks are primarily made up of low-magnesium calcite. Some samples also contained magnesium-enriched carbonate phases, such as dolomite and huntite. Samples PSK3, PSZ3, Lz3 and TGO5 are dominated by high-magnesium calcite and dolomite. Huntite occurs in smaller quantities. Of the non-carbonate minerals, quartz was identified in all the rocks; feldspar was identified in samples PSK3 and Lz3; and kaolinite was identified in samples TW, TO, S and Lz3. Data obtained from FTIR analysis confirmed the XRD results, thus confirming that samples TGO5, PSK3, PSZ3, Lz3 and TGO4 belong to the dolomite group and samples TW, NK, TO, S, W and R belong to the limestone group.

The X-ray fluorescence analysis (XRF) also yielded a wealth of interesting data. Based on these results, we calculated the basic oxide composition of the rocks, their Ca/Mg ratio and their MgCO₃ content. We then presented the position of the studied carbonate rocks according to the Chilingar (1957) [41] and Pettijohn (1975) [10] classifications, based on the obtained data. According to the Chilingar (1957) [41] classification, the data indicate that the rocks from the Lazarówka Quarry (Lz3), Piekary Śląskie (PSK3, PSZ3) and Tarnowskie Góry (TGO5, TGO4) area represent calcareous dolomites, while those from the Twardowice (TW), Niezdara-Krzyżowa (NK), Toporowice (TO), Świerklaniec (S), Wojkowice (W) and Radzionków (R) areas represent limestones.

According to Pettijohn’s (1975) [10] classification, the rocks from the Lazarówka Quarry (Lz3), Piekary Śląskie (PSK3, PSZ3) and Tarnowskie Góry (TGO4, TGO5) are calcareous dolomites. Meanwhile, the rocks from Twardowice (TW), the Niezdara-Krzyżowa (NK) area, Toporowice (TO), Świerklaniec (S), Wojkowice (W) and Radzionków (R) are calcite limestones. Data obtained confirmed the results of XRD and FTIR analyses, supporting the thesis that rocks from the Piekary Śląskie (PSK3 and PSZ3) and Lazarówka (Lz3) areas, as well as those from the Tarnowskie Góry (TGO5) area and the Tarnowice (TGO4) and Boruszowice (TGO4) units, belong to the dolomite group. Meanwhile, rocks collected from the Gogolin Unit (Twardowice, Niezdara-Krzyżowa, Toporowice and Świerklaniec), the Jemielnica Unit (Wojkowice) and some rocks from the Tarnowice Unit (Radzionków) belong to the limestone group.

4.2. Carbonate Phases with Magnesium

The data obtained from the research showed the presence of carbonate phases with different magnesium content in the analyzed rocks. Two varieties of high-magnesium calcite were identified, one with the formula Ca_0.94Mg_0.06CO₃ and the other with the formula Ca_0.9Mg_0.1CO₃. Dolomite phases with different magnesium content were also identified, including two ordered dolomite varieties with the formulas CaMg(CO₃)₂ and (Ca_0.5Mg_0.5)₂(CO₃)₂. Two types of protodolomite were also identified: Ca_0.501,Mg_0.449(CO₃)₂ and Ca_1.07,Mg_0.93(CO₃)₂, as well as a dolomite phase with iron substitution: CaMg_0.67,Fe_0.33(CO₃)₂. In addition to low-magnesium calcite, high-magnesium calcite, protodolomite and ordered dolomite, huntite (CaMg₃(CO₃)₄) was identified in the examined rocks.

The presence of two varieties of high-magnesium calcite indicates the complexity of the processes involved in forming carbonate phases with magnesium. This process occurred during the formation of these carbonate phases in carbonate mud at the compaction stage (an early stage of diagenesis, or the eogenetic stage), in a shallow, stagnant, epikontinental, warm, hypersaline marine basin with the participation of meteoric waters. Some of the magnesium was supplied to the seawater by the release of magnesium from the skeletons of organisms after they died [12]. The presence of three dolomite phases in the studied rocks suggests that they were originally calcium carbonate phases that underwent dolomitization during syngenetic diagenesis. According to Książkiewicz (1968) [42] and Śliwiński [43], this corresponds to Migaszewski’s [44,45] model of dolomite formation during sediment compaction [11,44,45]. During diagenesis, the Silesian-Cracow region’s dolomites were also enriched with zinc and lead ores. In the Tarnowskie Góry area, there are dolomites containing zinc and lead sulfides with silver. The formation of dolomite phases with varying Mg content, as well as enrichment, may be the result of metasomatic processes. Huntite is a specific carbonate phase with a higher Mg content than dolomite. It typically forms through hydrothermal processes, dolomite weathering, or the transformation of magnesian calcite under high-temperature conditions. It occurs in sedimentary rocks in the aeration (vadose) zone [4,11,12,13,14,20,22].

4.3. Trace Elements

The results of the XRF and ICP AES analyses showed a high content of elements such as Ca, Mg, C and O, as well as the presence of trace amounts of elements characteristic of minerals such as silicates, aluminosilicates, oxides and sulfides. These elements, apart from Sr and Ba, are not basic components of carbonate rocks. These include: Al, Si, Fe, Mn, K, Na, S, Cl, Ti, Cr, Ni, Zn, Rb, Zr, Pb, As and V. These elements are most often brought from outside into the reservoir. This is where carbonate sedimentation takes place. Some of them may be present in minerals that form during diagenesis. Manganese and iron can replace calcium (Ca) and magnesium (Mg) in carbonate minerals. Strontium and barium are elements that are originally found in aragonite, an unstable form of calcium carbonate. Like high-magnesium calcite, aragonite undergoes a transformation into low-magnesium calcite during diagenesis. Sr and Ba often appear in carbonate phases. According to literature data, strontium occurs in the skeletons of marine organisms [12,14,34,35,36,37,39]. The presence of strontium in aragonite is related to its larger ionic radius compared to calcium, which is why it easily enters the aragonite structure, which is more similar to the strontianite structure than the calcite structure. Consequently, aragonite contains more strontium (Sr) than calcite [14,39]. However, aragonite is an unstable form of calcium carbonate, akin to high-magnesium calcite. During diagenesis, it transforms into low-magnesium calcite. Consequently, the presence of strontium alone can indicate that the original calcium carbonate phase was aragonite. Like Sr, Ba occurs in the skeletons of marine organisms. As Ba has a similar ionic radius to Sr [14,34,35,36,37,38,39], it will more easily enter the structure of aragonite than that of calcite. Nickel (Ni), potassium (K), silicon (Si), aluminium (Al), as well as some iron (Fe) and vanadium (V), will be part of aluminosilicates, primarily feldspars and clay minerals. S, Ti, Cr and part of Fe, Ni, Zn and Pb will probably be bound in sulfides and oxides. Zinc (Zn) and lead (Pb) could have become bound in sulfides during metasomatism and hydrothermal activity. This led to the dolomitization of limestones in the Tarnowskie Góry region, as well as the mineralization of Zn and Pb sulfides containing silver. Fe and Mn may also be present in smithsonite. Nickel (Ni) is incorporated into clay mineral structures during sedimentation processes. Nickel can also form sulfides and arsenides. This is similar to what occurs in iron sulfides. Chlorine is bound in chlorides, while phosphorus occurs in organic matter. A Pb content in samples ranging from 0.01% to 0.17% (100 to 1700 ppm) may indicate the presence of trace amounts of calcium carbonate substituted with Pb in the rock, a mineral known as tarnowicite [46,47]. Tarnowicite is a variety of aragonite that contains an isomorphous admixture of lead carbonate (cerussite), with a PbCO₃ content in the aragonite ranging from 9 to 15% [46,47]. However, this mineral was not identified during XRD and FTIR studies. If it were present, it would be below the detection limit. It is therefore likely that Pb is bound in sulfides or oxides, or occurs as a substitution in carbonates. The ICP-AES analysis revealed the presence of the following additional elements: Be, B, Co, Cu, Br, Mo and Cd. Copper (Cu) and molybdenum (Mo) may be bound in the form of sulfides. Manganese (Nb) is bound in minerals, titanium and zircon, and manganese concretions (Stanienda, 2014; Stanienda-Pilecki et al., 2024) [6,14]. Cadmium (Cd), bromine (Br) and cobalt (Co) are found in aluminosilicates, sulfides or oxides [4]. Furthermore, Cd may be present in zinc sulfides or with Fe, Mn, and Co in smithsonite [4]. Be is found in bauxites and kaolins, as well as in clay products resulting from weathering. B, on the other hand, is found in hydromics such as illite and glauconite. Boron is also present in marine organisms [38].

4.4. Genesis of Studied Rocks Formation

Based on the research results, a theory was formulated regarding the formation of the studied rocks, which represent the following units: Gogolin Unit (Lower Muschelkalk): samples TW, NK, TO and S, Diplopore Dolomite Unit (Middle Muschelkalk: sample W, the Tarnowice Unit (Upper Muschelkalk, lower part of the profile) comprises samples PSK3, PSZ3, Lz3, R and TGO5 and the Boruszowice Unit (Upper Muschelkalk, upper part of the profile) comprises sample TGO4 and diagenetic processes influenced the final structure of these rocks.

The Middle Triassic (Muschelkalk) comprises two stages: the lower Anisian and the upper Ladinian [48,49]. The epikontinental limestone deposit, also known as the Germanic Basin, was bordered to the south by the Windelvic-Bohemian Massif, the Rhine Massif, and the Brabant Massif. These features separated the basin from the Tethys Ocean. The only connections between the two basins were the Eastern Carpathian Gate and the Silesian-Moravian Gate [1,20,22]. On average, the thickness of the shell limestone in Poland is 150–220 m, which is a small percentage of the total Triassic thickness. In some areas of the Polish Lowland, however, it exceeds 3000 m, indicating weak subsidence.

According to the classification of Lower Muschelkalk in Opole Silesia, carried out by Assmann P. [20,21,22,50,51], the lowest layers in the profile consist of limestones, marls and dolomites of the Błotnica and Gogolin formations [20,21,22]. The following units have been distinguished within the Gogolin Unit: Limestones with Pecten and Dadocrinus, Clay marl level, Cellular limestone (lower Gogolin Unit, Intraformational conglomerate, Coarse-grained limestone level, Marl limestone level and Main undulating level (upper Gogolin Unit) [3]. The Gogolin layers are followed by the Górażdże formations, the Terebratula layers and, at the top, the Karchowice layers [12,20,21,22]. Based on the research results and the environment in which diagenetic processes occur [40] and the classification of Boggs (2010), it can be assumed that the formation and diagenetic processes of the Gogolin limestones (Lower Muschelkalk) probably took place in the following zones: the deep-sea zone and the marine phreatic zone, and the shallow-sea bottom and shallow-subsurface areas (eogenetic stage of diagenesis). In some areas, these processes occurred with the participation of meteoric waters under conditions of initial marine transgression [5,6,12].

The Middle Muschelkalk deposits in Upper Silesia consist of diplopore dolomites, which are estimated to be from the transition between the Anisian and Ladinian stages. The presence of abundant algae may suggest a direct connection with the Briançon-Vercheval zone of the Alpine-Carpathian Sea during this period. This is also supported by the discovery of Alpine foraminifera [50]. Dolomites and limestones poor in fauna formed during the marine transgression that occurred in the Anisian stage [22]. The formation and diagenesis of the limestones of the Diplopore Dolomite formation and that of Tarnowice formation probably occurred under conditions of marine regression similar to those that formed the Karchowice layers, which are found in the upper part of the lower shell limestone profile.

During the Upper Muschelkalk period, fauna developed again after being suspended during the Middle Muschelkalk period. This development was the result of extensive connections with the Alpine Sea due to another transgression. The Eastern Carpathian Gate and, further west, the Rhine and Burgundy Gates were probably active at that time. At the start of the transgression, the seabed was colonized by crinoids, whose fragments formed the lower part of the Upper Muschelkalk in the form of trochite layers. The layers of Myophoria transversa Bornemann and Pecten discites (Schlotheim) are also characteristic of this area [2,3,50,51]. Limestones containing glauconite are also present. The fauna found here distinguishes these sediments from those of the Middle Muschelkalk. The Tarnowice layers lie above the Diplopore Dolomites. They are also known as plate dolomites [2,3]. They were formed during the marine transgression of the Upper Muschelkalk period, when a further limestone deposit complex was created [24]. This was primarily caused by uplift movements, which led to the Silesian-Krakow area becoming shallower and then emerging. As a result, mixed carbonate-clastic sediments of the finest-grained limestone were formed. Older sediments were also eroded, a process that continued until the beginning of the Late Triassic (i.e., the Carnian) [24]. Thus, the Boruszowice layers are a typical example of a formation resulting from a drying sea [52]. It is likely that the Tarnowice layers were originally limestone, similar to the lower and middle shell limestone sediments, and were dolomitized during diagenesis. In the Silesian-Cracow region, dolomites were mineralized with zinc and lead ores during diagenesis, and these ores were mined. In the Tarnowskie Góry area, ore-bearing dolomites containing zinc and lead sulfides with silver were mined. The Tarnowskie Góry dolomites may therefore have formed as a result of metasomatic processes, probably in a similar way to ore-bearing dolomites. This is indicated by the presence of carbonate phases with varying magnesium content, among other things.

5. Conclusions

Based on the research results obtained and their interpretation, the following conclusions were formulated:

• It is confirmed that the rocks of the Gogolin Unit (Lower Muschelkalk), the Diplopore Dolomite Unit (Middle Muschelkalk), the Tarnowice Unit (Upper Muschelkalk—lower part of the profile) and the Boruszowice Unit (Upper Muschelkalk—upper part of the profile) have diverse mineral compositions and carbonate phases. These results corroborate data obtained from previous studies involving selected rock samples from the Tarnowice and Boruszowice Units, as well as the Gogolin unit in Opole Silesia.
• The following mineral phases: low-magnesium calcite (CaCO₃); two varieties of high-magnesium calcite: (Ca_0.94Mg_0.06CO₃ and Ca_0.9Mg_0.1CO₃, two varieties of ordered dolomite with the formulas: CaMg(CO₃)₂ and (Ca_0.5Mg_0.5)₂(CO₃)₂, two types of protodolomite: Ca_0.501Mg_0.449)₂(CO₃)₂ and Ca_1.07Mg_0.93(CO₃)₂, a dolomite phase with iron substitution (CaMg_0.67Fe_0.33)(CO₃)₂ and a huntite with the formula CaMg₃(CO₃)₄ were identified.
• The following rocks were found to be limestones: the rocks of the Gogolin Unit (Twardowice, Toporowice, Świerklaniec and Niezdara-Krzyżowa), the rock from the Diplopore Dolomite Unit (Wojkowice), and one rock from the Tarnowice Unit (R). The remaining rocks of the Tarnowice Unit (Piekary Śląskie, the vicinity of the Lazarówka Quarry in Bytom and Tarnowskie Góry) and the Boruszowice Unit (TGO4, from Tarnowskie Góry) are dolomites.
• The following trace elements were identified: Al, Si, Fe, Mn, K, Na, S, Cl, Ti, Cr, Ni, Zn, Rb, Zr, Pb, As, V, Be, B, Co, Cu, Br, Mo i Cd, which indicate minerals such as silicates, aluminosilicates, oxides and sulfides. Apart from strontium (Sr) and barium (Ba), these elements are not primary components of carbonate rocks.
• Based on the data, it was concluded that calcite phases (low- and high-magnesium) were formed in carbonate mud during its compaction (the early stage of diagenesis, or the eogenetic stage), in an epicontinental, shallow, warm, stagnant marine reservoir with increased seawater salinity and the participation of meteoric waters. Some of the magnesium in the seawater came from the release of magnesium from the skeletons of dead organisms. The dolomite phases were formed during the compaction of the sediment. The dolomite mineralisation is probably the result of metasomatic processes. Huntite formed with the participation of waters from the vadose zone (aeration).
• According to the theory of the rocks origin the formation and diagenesis of the Gogolin limestones (Lower Muschelkalk) probably occurred in the deep-sea zone, the marine phreatic zone, and the shallow-sea bottom and shallow-subsurface areas (the eogenetic stage of diagenesis). In some areas, this process occurred with the participation of meteoric waters under conditions of initial marine transgression. The limestones of the Diplopore Dolomite formations (Middle Muschelkalk) probably formed and underwent diagenesis under conditions of marine regression. The dolomites of the Tarnowice Unit (Middle Muschelkalk), meanwhile, may have formed as a result of metasomatic processes, similarly to ore-bearing dolomites. The Boruszowice layers are a typical example of a formation resulting from a drying sea.