The Potwar sub-basin is an important hydrocarbon producing zone of the Upper Indus basin and has ... more 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 bo...
The unique Middle Miocene reef belt formed within the Paratethyan realm constitutes at present th... more The unique Middle Miocene reef belt formed within the Paratethyan realm constitutes at present the Medobory Hills in western Ukraine and northernmost Moldova. Not only is the size of this structure (almost 300 km long) quite unusual, but also the development of peculiar facies and their spatial distribution. Two distinct reef generations appear in Medobory (Late Badenian and Early Sarmatian), both separated by a sharp erosional boundary. Two Upper Badenian calcareous lithofacies dominate – organodetrital and biohermal (with coralline-algae as main framework builders accompanied by a rich invertebrate assemblage). The Lower Sarmatian strata, although megascopically very similar to Upper Badenian ones, differ drastically when studied closely. The main reef components here are serpulids and microbialites, usually with ubiquitous, but taxonomically highly impoverished fauna. Differences in lithofacies and biotic communities between both reef systems unveil open-marine environment during...
<p>Middle Miocene crystals of sabre gypsum and subcrystal of giant gypsum i... more <p>Middle Miocene crystals of sabre gypsum and subcrystal of giant gypsum intergrowth cropping out in southern Poland near Busko have been analysed for their Sr isotope composition. The new isotopic data revealed fluctuations in <sup>87</sup>Sr/<sup>86</sup>Sr values within the primary gypsum crystals providing new insight into paleohydrological conditions during the Badenian salinity crisis in the Polish part of the Carpathian Foredeep Basin. The isotopic composition of a glassy gypsum subcrystal decreased progressively with the subcrystal growth, ranging from 0.70892 to 0.70884 near the crystal apex. The <sup>87</sup>Sr/<sup>86</sup>Sr ratios of the sabre gypsum crystals are in the range of 0.70887–0.70934 and there are significant fluctuations within each gypsum layer tested. Similar intra-layer fluctuation patterns observed in various sections provide a strong argument for the synchronous origin of the investigated portions of the sulphate successions.  </p><p>The studied primary gypsum has a more radiogenic composition than the Badenian seawater. Its isotope signatures reflect spatial and temporal changes in the supply of continental derived radiogenic Sr to the Carpathian Foredeep Basin. Contrary to previous studies, the Palaeozoic clastic rocks of the Holy Cross Mountains are suggested as potential sources of radiogenic strontium. The new Sr isotope data support a salina model for the evaporitic basin of the Carpathian Foredeep.</p><p>This study was supported by the Polish National Science Centre, grant No. 2017/27/B/ST10/00493.</p>
The aim of this study was to reconstruct the location mechanism of a Triassic sandstone wedge wit... more The aim of this study was to reconstruct the location mechanism of a Triassic sandstone wedge within folded Palaeozoic rocks. A vertically oriented Buntsandstein succession (Lower Triassic) from Jozefka Quarry (Holy Cross Mountains, central Poland), steeply wedged within folded Devonian carbonates, is recognised as an effect of normal faulting within a releasing stepover. The sandstone succession, corresponding to the Zagnansk Formation in the local lithostratigraphic scheme, is represented by two complexes, interpreted as deposits of a sand-dominated alluvial plain (older complex), and coarse-grained sands and gravels of a braided river system (younger complex). The sandstone complex was primarily formed as the lowermost part of the several kilometres thick Mesozoic cover of the Holy Cross Mountains Fold Belt (HCFB), later eroded as a result of the Late Cretaceous/Paleogene uplift of the area. Tectonic analysis of the present-day position of the deformed sandstone succession shows ...
Ewa SZARAWARSKA1, Mads HUUSE1, Andrew HURST1, Wytze de BOER2 and Peter RAWLINSON2 1 University of... more Ewa SZARAWARSKA1, Mads HUUSE1, Andrew HURST1, Wytze de BOER2 and Peter RAWLINSON2 1 University of Aberdeen, Department of Geology and Petroleum Geology, King’s College, Aberdeen, AB24 3UE, Scotland, UK 2 Marathon Oil, Marathon House, Rubislaw Hill, Anderson Drive, Aberdeen eas characterized by E-W to WNW-ESE structural trends show declinations rotated clockwise. Declinations show a correlation with the structural trend for both HT and LT components, but in the case of the LT component the magnitude of the declinations deviation is smaller. Results from the sandstones confirm the presented outcomes and additionally prove the heterochronic age of the deformations that differ between the marginal and the internal zone of the fold–and–thrust belt. The presented declination data support only local oroclinal bending which give rise to the strike deviations in the thrustbelt. In the Ardennes clockwise rotations of the thrust occurred only within narrow transpressive zones, active during th...
Badane utwory miocenskie, wapienie organodetrytyczne i podrzednie organogeniczne, odslaniające si... more Badane utwory miocenskie, wapienie organodetrytyczne i podrzednie organogeniczne, odslaniające sie w rejonie Szydlowa i Smerdyny tworzą dwa litosomy, o wyraźnym linijnym wydluzeniu. Charakteryzuje je dwudzielnośc budowy; nizszy zespol cechuje sie wielkoskalowym warstwowaniem skośnym a gorny, lezący niezgodnie, to roznego typu wapienie warstwowane skośnie i rynnowo. Potwierdzono związek formowania tych litosomow z synsedymentacyjną tektoniką oraz wskazano na mozliwośc zmian poziomu morza w basenie. REMARKS ON MIOCENE SEDIMENTATION IN THE AREA BETWEEN SZYDŁOW AND SMERDYNA, SOUTHEASTERN MARGIN OF THE HOLY CROSS MTS (CENTRAL POLAND) Summary Two rock bodies about 30 km long, composed of organodetritic and partly organogenic limestones, occur between Szydlow and Smerdyna in the southeastern margin of the Holy Cross Mts. The giant-scale cross-bedded calcarenites have been recognized in the lower part of this sequence. Its discordantly lying upper part encompass cross- and trough-bedded cal...
Appendix 1. (A) Point counting data and (B) textural features of the studied samples from the Na ... more Appendix 1. (A) Point counting data and (B) textural features of the studied samples from the Na Duong Basin. On a gray background data from the Na Duong Fm., on white – from the Rinh Chua Fm. Appendix 2. Geochemical characteristics of the studied samples from the Na Duong and Cao Bang basins. For samples from the Na Duong Basin, on a gray background data from the Na Duong Fm., on white – from the Rinh Chua Fm. (A) Geochemical data of samples from the Na Duong Basin. (B) Correlation coefficients of major and trace elements of samples from the Na Duong Basin. (C) Correlation coefficients of major and trace elements of samples from the Cao Bang Basin. (D) Chondrite-normalized REE concentrations and the calculated cerium and europium anomalies of samples from the Na Duong and Cao Bang basins. (E) Ratios of selected trace elements and other parameters related to geochemical composition of source rocks of samples from the Na Duong and Cao Bang basins. (F) Chemical index of alteration (Nesbitt and Young, 1982) with correction after McLennan (1993).
During the Miocene-Pleistocene, generally sub-tropical to tropical warm and humid paleoclimate pr... more During the Miocene-Pleistocene, generally sub-tropical to tropical warm and humid paleoclimate prevailed in Southeast Asia with a gradual cooling trend. The Truc Thon clay (TTC) mine presents interesting outcrops for sedimentological and provenance analysis. The present study uses results of geological investigation in 16 outcrops and wells at the clay mine Truc Thon. The TTC has lens-shaped geometry, filled with two clay bodies, including grey-white clay and multicolor clay. Bulk mineralogy indicates the predominance of quartz and a relatively high amount of pyrophyllite. Clay mineralogy shows the presence of main kaolinite, followed by illite and mixed-layer illite-smectite. These may interpret a warm, humid paleoclimatic condition in the source areas. Illite may be inherited from basement rocks. The bulk rock geochemistry supports intense chemical weathering with the Chemical Index of Alteration (CIA) in the TTC ranged ca. 80.6-98 (average = 90.4). In combination with the geochem...
Sedimentological, mineralogical, stable carbon and oxygen isotope determinations and biomarker an... more Sedimentological, mineralogical, stable carbon and oxygen isotope determinations and biomarker analyses were performed on siderite concretions occurring in terrestrial silts to understand their formation and to characterize the sedimentary and diagenetic conditions favouring their growth. High δ13C values (6·4‰ on average) indicate that siderite precipitated in an anoxic environment where bacterial methanogenesis operated. The development of anoxic conditions during shallow burial was induced by a change in sedimentary environment from flood plain to swamp, related to a rise of the ground-water table. Large amounts of decaying plant debris led to efficient oxygen consumption within the pore-water in the peat. Oxygen depletion, in combination with a decrease in sedimentation rate, promoted anoxic diagenetic conditions under the swamp and favoured abundant siderite precipitation. This shows how a change in sedimentary conditions can have a profound impact on the early-diagenetic environment and carbonate authigenesis. The concretions contain numerous rhizoliths; they are cemented with calcium-rhodochrosite, a feature which has not been reported before. The rhodochrosite cement has negative δ13C values (−16·5‰ on average) and precipitated in suboxic conditions due to microbial degradation of roots coupled to manganese reduction. The exceptional preservation of the epidermis/exodermis and xylem vessels of former root tissues indicates that the rhodochrosite formed shortly after the death of a root in water-logged sediments. Rhodochrosite precipitated during the initial stages of concretionary growth in suboxic microenvironments within roots, while siderite cementation occurred simultaneously around them in anoxic conditions. These suboxic microenvironments developed because oxygen was transported from the overlying oxygenated soil into sediments saturated with anoxic water via roots acting as permeable conduits. This model explains how separate generations of carbonate cements having different mineralogy and isotopic compositions, which would conventionally be regarded as cements precipitated sequentially in different diagenetic zones during gradual burial, can form simultaneously in shallow burial settings where strong redox gradients exist around vertically oriented permeable root structures.
The Potwar sub-basin is an important hydrocarbon producing zone of the Upper Indus basin and has ... more 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 bo...
The unique Middle Miocene reef belt formed within the Paratethyan realm constitutes at present th... more The unique Middle Miocene reef belt formed within the Paratethyan realm constitutes at present the Medobory Hills in western Ukraine and northernmost Moldova. Not only is the size of this structure (almost 300 km long) quite unusual, but also the development of peculiar facies and their spatial distribution. Two distinct reef generations appear in Medobory (Late Badenian and Early Sarmatian), both separated by a sharp erosional boundary. Two Upper Badenian calcareous lithofacies dominate – organodetrital and biohermal (with coralline-algae as main framework builders accompanied by a rich invertebrate assemblage). The Lower Sarmatian strata, although megascopically very similar to Upper Badenian ones, differ drastically when studied closely. The main reef components here are serpulids and microbialites, usually with ubiquitous, but taxonomically highly impoverished fauna. Differences in lithofacies and biotic communities between both reef systems unveil open-marine environment during...
<p>Middle Miocene crystals of sabre gypsum and subcrystal of giant gypsum i... more <p>Middle Miocene crystals of sabre gypsum and subcrystal of giant gypsum intergrowth cropping out in southern Poland near Busko have been analysed for their Sr isotope composition. The new isotopic data revealed fluctuations in <sup>87</sup>Sr/<sup>86</sup>Sr values within the primary gypsum crystals providing new insight into paleohydrological conditions during the Badenian salinity crisis in the Polish part of the Carpathian Foredeep Basin. The isotopic composition of a glassy gypsum subcrystal decreased progressively with the subcrystal growth, ranging from 0.70892 to 0.70884 near the crystal apex. The <sup>87</sup>Sr/<sup>86</sup>Sr ratios of the sabre gypsum crystals are in the range of 0.70887–0.70934 and there are significant fluctuations within each gypsum layer tested. Similar intra-layer fluctuation patterns observed in various sections provide a strong argument for the synchronous origin of the investigated portions of the sulphate successions.  </p><p>The studied primary gypsum has a more radiogenic composition than the Badenian seawater. Its isotope signatures reflect spatial and temporal changes in the supply of continental derived radiogenic Sr to the Carpathian Foredeep Basin. Contrary to previous studies, the Palaeozoic clastic rocks of the Holy Cross Mountains are suggested as potential sources of radiogenic strontium. The new Sr isotope data support a salina model for the evaporitic basin of the Carpathian Foredeep.</p><p>This study was supported by the Polish National Science Centre, grant No. 2017/27/B/ST10/00493.</p>
The aim of this study was to reconstruct the location mechanism of a Triassic sandstone wedge wit... more The aim of this study was to reconstruct the location mechanism of a Triassic sandstone wedge within folded Palaeozoic rocks. A vertically oriented Buntsandstein succession (Lower Triassic) from Jozefka Quarry (Holy Cross Mountains, central Poland), steeply wedged within folded Devonian carbonates, is recognised as an effect of normal faulting within a releasing stepover. The sandstone succession, corresponding to the Zagnansk Formation in the local lithostratigraphic scheme, is represented by two complexes, interpreted as deposits of a sand-dominated alluvial plain (older complex), and coarse-grained sands and gravels of a braided river system (younger complex). The sandstone complex was primarily formed as the lowermost part of the several kilometres thick Mesozoic cover of the Holy Cross Mountains Fold Belt (HCFB), later eroded as a result of the Late Cretaceous/Paleogene uplift of the area. Tectonic analysis of the present-day position of the deformed sandstone succession shows ...
Ewa SZARAWARSKA1, Mads HUUSE1, Andrew HURST1, Wytze de BOER2 and Peter RAWLINSON2 1 University of... more Ewa SZARAWARSKA1, Mads HUUSE1, Andrew HURST1, Wytze de BOER2 and Peter RAWLINSON2 1 University of Aberdeen, Department of Geology and Petroleum Geology, King’s College, Aberdeen, AB24 3UE, Scotland, UK 2 Marathon Oil, Marathon House, Rubislaw Hill, Anderson Drive, Aberdeen eas characterized by E-W to WNW-ESE structural trends show declinations rotated clockwise. Declinations show a correlation with the structural trend for both HT and LT components, but in the case of the LT component the magnitude of the declinations deviation is smaller. Results from the sandstones confirm the presented outcomes and additionally prove the heterochronic age of the deformations that differ between the marginal and the internal zone of the fold–and–thrust belt. The presented declination data support only local oroclinal bending which give rise to the strike deviations in the thrustbelt. In the Ardennes clockwise rotations of the thrust occurred only within narrow transpressive zones, active during th...
Badane utwory miocenskie, wapienie organodetrytyczne i podrzednie organogeniczne, odslaniające si... more Badane utwory miocenskie, wapienie organodetrytyczne i podrzednie organogeniczne, odslaniające sie w rejonie Szydlowa i Smerdyny tworzą dwa litosomy, o wyraźnym linijnym wydluzeniu. Charakteryzuje je dwudzielnośc budowy; nizszy zespol cechuje sie wielkoskalowym warstwowaniem skośnym a gorny, lezący niezgodnie, to roznego typu wapienie warstwowane skośnie i rynnowo. Potwierdzono związek formowania tych litosomow z synsedymentacyjną tektoniką oraz wskazano na mozliwośc zmian poziomu morza w basenie. REMARKS ON MIOCENE SEDIMENTATION IN THE AREA BETWEEN SZYDŁOW AND SMERDYNA, SOUTHEASTERN MARGIN OF THE HOLY CROSS MTS (CENTRAL POLAND) Summary Two rock bodies about 30 km long, composed of organodetritic and partly organogenic limestones, occur between Szydlow and Smerdyna in the southeastern margin of the Holy Cross Mts. The giant-scale cross-bedded calcarenites have been recognized in the lower part of this sequence. Its discordantly lying upper part encompass cross- and trough-bedded cal...
Appendix 1. (A) Point counting data and (B) textural features of the studied samples from the Na ... more Appendix 1. (A) Point counting data and (B) textural features of the studied samples from the Na Duong Basin. On a gray background data from the Na Duong Fm., on white – from the Rinh Chua Fm. Appendix 2. Geochemical characteristics of the studied samples from the Na Duong and Cao Bang basins. For samples from the Na Duong Basin, on a gray background data from the Na Duong Fm., on white – from the Rinh Chua Fm. (A) Geochemical data of samples from the Na Duong Basin. (B) Correlation coefficients of major and trace elements of samples from the Na Duong Basin. (C) Correlation coefficients of major and trace elements of samples from the Cao Bang Basin. (D) Chondrite-normalized REE concentrations and the calculated cerium and europium anomalies of samples from the Na Duong and Cao Bang basins. (E) Ratios of selected trace elements and other parameters related to geochemical composition of source rocks of samples from the Na Duong and Cao Bang basins. (F) Chemical index of alteration (Nesbitt and Young, 1982) with correction after McLennan (1993).
During the Miocene-Pleistocene, generally sub-tropical to tropical warm and humid paleoclimate pr... more During the Miocene-Pleistocene, generally sub-tropical to tropical warm and humid paleoclimate prevailed in Southeast Asia with a gradual cooling trend. The Truc Thon clay (TTC) mine presents interesting outcrops for sedimentological and provenance analysis. The present study uses results of geological investigation in 16 outcrops and wells at the clay mine Truc Thon. The TTC has lens-shaped geometry, filled with two clay bodies, including grey-white clay and multicolor clay. Bulk mineralogy indicates the predominance of quartz and a relatively high amount of pyrophyllite. Clay mineralogy shows the presence of main kaolinite, followed by illite and mixed-layer illite-smectite. These may interpret a warm, humid paleoclimatic condition in the source areas. Illite may be inherited from basement rocks. The bulk rock geochemistry supports intense chemical weathering with the Chemical Index of Alteration (CIA) in the TTC ranged ca. 80.6-98 (average = 90.4). In combination with the geochem...
Sedimentological, mineralogical, stable carbon and oxygen isotope determinations and biomarker an... more Sedimentological, mineralogical, stable carbon and oxygen isotope determinations and biomarker analyses were performed on siderite concretions occurring in terrestrial silts to understand their formation and to characterize the sedimentary and diagenetic conditions favouring their growth. High δ13C values (6·4‰ on average) indicate that siderite precipitated in an anoxic environment where bacterial methanogenesis operated. The development of anoxic conditions during shallow burial was induced by a change in sedimentary environment from flood plain to swamp, related to a rise of the ground-water table. Large amounts of decaying plant debris led to efficient oxygen consumption within the pore-water in the peat. Oxygen depletion, in combination with a decrease in sedimentation rate, promoted anoxic diagenetic conditions under the swamp and favoured abundant siderite precipitation. This shows how a change in sedimentary conditions can have a profound impact on the early-diagenetic environment and carbonate authigenesis. The concretions contain numerous rhizoliths; they are cemented with calcium-rhodochrosite, a feature which has not been reported before. The rhodochrosite cement has negative δ13C values (−16·5‰ on average) and precipitated in suboxic conditions due to microbial degradation of roots coupled to manganese reduction. The exceptional preservation of the epidermis/exodermis and xylem vessels of former root tissues indicates that the rhodochrosite formed shortly after the death of a root in water-logged sediments. Rhodochrosite precipitated during the initial stages of concretionary growth in suboxic microenvironments within roots, while siderite cementation occurred simultaneously around them in anoxic conditions. These suboxic microenvironments developed because oxygen was transported from the overlying oxygenated soil into sediments saturated with anoxic water via roots acting as permeable conduits. This model explains how separate generations of carbonate cements having different mineralogy and isotopic compositions, which would conventionally be regarded as cements precipitated sequentially in different diagenetic zones during gradual burial, can form simultaneously in shallow burial settings where strong redox gradients exist around vertically oriented permeable root structures.
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