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Frank Scholze - One of the best experts on this subject based on the ideXlab platform.
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A multistratigraphic approach to pinpoint the Permian-Triassic boundary in continental deposits: The Zechstein-Lower Buntsandstein transition in Germany
Global and Planetary Change, 2017Co-Authors: Frank Scholze, Jörg W. Schneider, Xu Wang, Uwe Kirscher, Johannes Kraft, Annette E. Götz, Michael M. Joachimski, Valerian BachtadseAbstract:Abstract The Central European Basin is very suitable for high-resolution multistratigraphy of Late Permian to Early Triassic continental deposits. Here the well exposed continuous transition of the lithostratigraphic Zechstein and Buntsandstein Groups of Central Germany was studied for isotope-chemostratigraphy (δ13Corg, δ13Ccarb, δ18Ocarb), major and trace element geochemistry, magnetostratigraphy, palynology, and conchostracan biostratigraphy. The analysed material was obtained from both classical key sections (abandoned Nelben clay pit, Caaschwitz quarries, Thale railway cut, abandoned Heinebach clay pit) and a recent drill core section (Caaschwitz 6/2012) spanning the Permian-Triassic boundary. The Zechstein–Buntsandstein transition of Central Germany consists of a complex sedimentary facies comprising sabkha, playa lake, aeolian, and fluvial deposits of predominantly red-coloured siliciclastics and intercalations of lacustrine oolitic limestones. The new data on δ13Corg range from − 28.7 to − 21.7 ‰ showing multiple excursions. Most prominent negative shifts correlate with intercalations of oolites and grey-coloured clayey siltstones, while higher δ13Corg values correspond to an onset of palaeosol overprint. The δ13Ccarb values range from − 9.7 to − 1.3 ‰ with largest variations recorded in dolomitic nodules from the Zechstein Group. In contrast to sedimentary facies shifts across the Zechstein-Buntsandstein boundary, major element values used as a proxy (CIA, CIA*, CIA-K) for weathering conditions indicate climatic stability. Trace element data used for a geochemical characterization of the Late Permian to Early Triassic transition in Central Germany indicate a decrease in Rb contents at the Zechstein-Buntsandstein boundary. New palynological data obtained from the Caaschwitz quarry section reveal occurrences of Late Permian palynomorphs in the Lower Fulda Formation, while Early Triassic elements were recorded in the upper part of the Upper Fulda Formation. The present study confirms an onset of a normal-polarized magnetozone in the Upper Fulda Formation of the Caaschwitz quarry section supporting an interregional correlation of this crucial stratigraphic interval with the normal magnetic polarity of the basal Early Triassic known from marine sections in other regions. Based on a synthesis of the multistratigraphic data, the Permian-Triassic boundary is proposed to be placed in the lower part of the Upper Fulda Formation, which is biostratigraphically confirmed by the first occurrence date of the Early Triassic Euestheria gutta-Palaeolimnadiopsis vilujensis conchostracan fauna. Rare records of conchostracans reported from the siliciclastic deposits of the lower to middle Zechstein Group may point to its potential for further biostratigraphic subdivision of the Late Permian continental deposits.
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conchostracans in continental deposits of the Zechstein buntsandstein transition in central germany taxonomy and biostratigraphic implications for the position of the permian triassic boundary within the Zechstein group
Palaeogeography Palaeoclimatology Palaeoecology, 2016Co-Authors: Frank Scholze, Jörg W. Schneider, Ralf WerneburgAbstract:Abstract The end-Permian mass extinction marks the largest biotic crisis in the geologic record. The stratigraphic position of this boundary in continental deposits is still under discussion. In the present study, conchostracans from the Zechstein–Buntsandstein (Late Permian to Early Triassic) transition in central Germany have been taxonomically reinvestigated in order to better understand their utility for fine-scale biostratigraphy in continental Permian–Triassic boundary sections. The studied material was obtained from both collections and recent sampling activities in classical key sections and new outcrops of the Zechstein and Buntsandstein Groups. The sedimentary environments of the conchostracan occurrences are interpreted as lacustrine to fluvial facies depending on the paleogeographic position within the basin of the respective sections. The conchostracan fauna in the Zechstein–Buntsandstein transition consists of Euestheria gutta, Palaeolimnadiopsis vilujensis, Cornia germari, Estheriella marginostriata, Estheriella costata, Estheriella nodosocostata, Magniestheria mangaliensis, and Euestheria nordvikensis. Based on comparison with the Early Triassic conchostracan record in the Moscow syncline, the Palaeolimnadiopsis vilujensis–Euestheria gutta association in the upper part of the Fulda Formation indicates both its Early Triassic age and a position of the continental Permian–Triassic boundary within the Zechstein Group.
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Conchostracans in continental deposits of the Zechstein–Buntsandstein transition in central Germany: Taxonomy and biostratigraphic implications for the position of the Permian–Triassic boundary within the Zechstein Group
Palaeogeography Palaeoclimatology Palaeoecology, 2016Co-Authors: Frank Scholze, Jörg W. Schneider, Ralf WerneburgAbstract:Abstract The end-Permian mass extinction marks the largest biotic crisis in the geologic record. The stratigraphic position of this boundary in continental deposits is still under discussion. In the present study, conchostracans from the Zechstein–Buntsandstein (Late Permian to Early Triassic) transition in central Germany have been taxonomically reinvestigated in order to better understand their utility for fine-scale biostratigraphy in continental Permian–Triassic boundary sections. The studied material was obtained from both collections and recent sampling activities in classical key sections and new outcrops of the Zechstein and Buntsandstein Groups. The sedimentary environments of the conchostracan occurrences are interpreted as lacustrine to fluvial facies depending on the paleogeographic position within the basin of the respective sections. The conchostracan fauna in the Zechstein–Buntsandstein transition consists of Euestheria gutta, Palaeolimnadiopsis vilujensis, Cornia germari, Estheriella marginostriata, Estheriella costata, Estheriella nodosocostata, Magniestheria mangaliensis, and Euestheria nordvikensis. Based on comparison with the Early Triassic conchostracan record in the Moscow syncline, the Palaeolimnadiopsis vilujensis–Euestheria gutta association in the upper part of the Fulda Formation indicates both its Early Triassic age and a position of the continental Permian–Triassic boundary within the Zechstein Group.
Lars Stemmerik - One of the best experts on this subject based on the ideXlab platform.
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Upper Permian carbonates at the northern edge of the Zechstein basin, Utsira High, Norwegian North Sea
Marine and Petroleum Geology, 2018Co-Authors: Tone Sorento, Lars Stemmerik, Snorre OlaussenAbstract:Abstract The first detailed description of Zechstein carbonates and their diagenesis along the northern margin of the northern Zechstein basin is based on core material from four wells on Utsira High in the Norwegian sector of the North Sea. It provides a generic link to the better known southern Zechstein basin, and northwards to the Late Permian East Greenland basin. The Zechstein succession consists of shale-carbonate cycles, and anhydrite only occurs in the uppermost preserved cycle, believed to correlate to Zechstein 4. The eleven carbonate facies reflect deposition in shallow shelf and arid shoreline environments, and resemble Zechstein-2 and -3 carbonate facies from the southern Zechstein basin. The carbonates are pervasively dolomitized by an early texture-preserving dolomite characterized by δ18O values between −6‰ and +2.4‰ similar to dolomites in the southern Zechstein basin, and δ13C values between −0.7‰ and +5‰ which is significantly lower than time-equivalent dolomites from the southern Zechstein basin. Later, subaerial exposure and fresh water infiltration during the late Permian or early Triassic caused replacement of the upper part of the dolomite by crystalline, fabric destructive calcite (dedolomite). The dedolomitized zone is up to 23 m thick and calcite crystals are characterized by moderately negative δ18O values in the range −8‰ to −5.5‰, characteristic for meteoric water. The Utsira High carbonates thus share a depositional history with the classical Zechstein carbonates whereas their diagenesis seems to have more in common with the time equivalent succession in East Greenland. Early leaching and dolomitization enhanced porosity whereas subsequent late Permian – early Triassic subaerial exposure and widespread dedolomitization had profound negative impact on reservoir properties of the Zechstein carbonates.
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faunal migration into the late permian Zechstein basin evidence from bryozoan palaeobiogeography
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Anne Mehlin Sørensen, Lars Stemmerik, Eckart HåkanssonAbstract:Abstract Late Permian bryozoans from the Wegener Halvo, Ravnefjeld and Schuchert Formations in East Greenland have been investigated. 14 genera are recognised. Integration of the new bryozoan data from the Upper Permian of East Greenland with data on the distribution of Permian bryozoans along the northern margin of Pangea is used to test hypotheses concerning Late Palaeozoic evolution of the North Atlantic region. During the Permian, the Atlantic rift system formed a seaway between Norway and Greenland from the boreal Barents Shelf to the warm and arid Zechstein Basin. This seaway is considered to be the only marine connection to the Zechstein Basin and therefore the only possible migration route for bryozoans to enter the basin. The distribution of Permian bryozoans is largely in keeping with such a connection from the cool Barents Shelf past the East Greenland Basin to the warm Zechstein Basin and also corroborates the change in temperature through this connection.
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Faunal migration into the Late Permian Zechstein Basin – Evidence from bryozoan palaeobiogeography
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Anne Mehlin Sørensen, Eckart Håkansson, Lars StemmerikAbstract:Abstract Late Permian bryozoans from the Wegener Halvo, Ravnefjeld and Schuchert Formations in East Greenland have been investigated. 14 genera are recognised. Integration of the new bryozoan data from the Upper Permian of East Greenland with data on the distribution of Permian bryozoans along the northern margin of Pangea is used to test hypotheses concerning Late Palaeozoic evolution of the North Atlantic region. During the Permian, the Atlantic rift system formed a seaway between Norway and Greenland from the boreal Barents Shelf to the warm and arid Zechstein Basin. This seaway is considered to be the only marine connection to the Zechstein Basin and therefore the only possible migration route for bryozoans to enter the basin. The distribution of Permian bryozoans is largely in keeping with such a connection from the cool Barents Shelf past the East Greenland Basin to the warm Zechstein Basin and also corroborates the change in temperature through this connection.
Thilo Bechstädt - One of the best experts on this subject based on the ideXlab platform.
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sequence stratigraphy of a carbonate evaporite succession Zechstein 1 hessian basin germany
Sedimentology, 2006Co-Authors: Frank Becker, Thilo BechstädtAbstract:The evaporitic Hessian Zechstein Basin is a sub-basin of the Southern Zechstein Basin, situated at its southern margin. Twelve facies groups were identified in the Zechstein Limestone and Lower Werra Anhydrite in order to better understand the sequence-stratigraphic evolution of this sub-basin, which contains economically important potassium salts. Four different paleogeographic depositional areas were recognized based on the regional distribution of facies. Siliciclastic-carbonate, carbonate, carbonate-evaporite and evaporite shallowing-upward successions are developed. These allow the establishment of parasequences and sequences, as well as correlation throughout the Hessian Basin and into the Southern Zechstein Basin. Two depositional sequences are distinguished, Zechstein sequence 1 and Zechstein sequence 2. The former comprises the succession from the Variscan basement up to the lowermost part of the Werra Anhydrite, including the Kupferschiefer as part of the transgressive systems tract. The highstand systems tract is defined by the Zechstein Limestone, in which two parasequences are developed. In large parts of the Hessian Basin, Zechstein sequence 1 is capped by a karstic, subaerial exposure surface, interpreted as recording a type-1 sequence boundary that formed during a distinct brine level fall. Low-lying central areas (Central Hessian Sub-basin, Werra Sub-basin), however, were not exposed and show a correlative conformity. Topography was minimal at the end of sequence 1. Widely developed perilittoral, sabkha and salina shallowing-upward successions indicate a renewed rise of brine level (interpreted as a transgressive systems tract), because of inflow of preconcentrated brines from the Southern Zechstein Basin to the north. This marks the initiation of Zechstein sequence 2, which comprises most of the Lower Werra Anhydrite. In the Central Hessian Sub-basin, situated proximal to the brine inflow and on the ridges within the Hessian Basin, physico-chemical conditions were well suited for sulphate precipitation to form a thick cyclic succession. It consists of four parasequences that completely filled the increased accommodation space. In contrast, only minor sulphate accumulation occurred in the Werra Sub-basin, situated further southwards and distal to the inflow. As a result of substantially different sulphate precipitation rates during increased accommodation, water depth in the region became more variable. The Werra Sub-basin, characterized by very low sedimentation rates, became increasingly deeper through time, trapping dense halite brines and precipitating rock salt deposits (Werra Halite). This ‘self-organization’ model for an evaporitic basin, in which depositional relief evolves with sedimentation and relief is filled by evaporite thereafter, contradicts earlier interpretations, that call upon the existence of a tectonic depression in the Werra area, which controlled sedimentation from the beginning of the Zechstein.
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Sequence stratigraphy of a carbonate‐evaporite succession (Zechstein 1, Hessian Basin, Germany)
Sedimentology, 2006Co-Authors: Frank Becker, Thilo BechstädtAbstract:The evaporitic Hessian Zechstein Basin is a sub-basin of the Southern Zechstein Basin, situated at its southern margin. Twelve facies groups were identified in the Zechstein Limestone and Lower Werra Anhydrite in order to better understand the sequence-stratigraphic evolution of this sub-basin, which contains economically important potassium salts. Four different paleogeographic depositional areas were recognized based on the regional distribution of facies. Siliciclastic-carbonate, carbonate, carbonate-evaporite and evaporite shallowing-upward successions are developed. These allow the establishment of parasequences and sequences, as well as correlation throughout the Hessian Basin and into the Southern Zechstein Basin. Two depositional sequences are distinguished, Zechstein sequence 1 and Zechstein sequence 2. The former comprises the succession from the Variscan basement up to the lowermost part of the Werra Anhydrite, including the Kupferschiefer as part of the transgressive systems tract. The highstand systems tract is defined by the Zechstein Limestone, in which two parasequences are developed. In large parts of the Hessian Basin, Zechstein sequence 1 is capped by a karstic, subaerial exposure surface, interpreted as recording a type-1 sequence boundary that formed during a distinct brine level fall. Low-lying central areas (Central Hessian Sub-basin, Werra Sub-basin), however, were not exposed and show a correlative conformity. Topography was minimal at the end of sequence 1. Widely developed perilittoral, sabkha and salina shallowing-upward successions indicate a renewed rise of brine level (interpreted as a transgressive systems tract), because of inflow of preconcentrated brines from the Southern Zechstein Basin to the north. This marks the initiation of Zechstein sequence 2, which comprises most of the Lower Werra Anhydrite. In the Central Hessian Sub-basin, situated proximal to the brine inflow and on the ridges within the Hessian Basin, physico-chemical conditions were well suited for sulphate precipitation to form a thick cyclic succession. It consists of four parasequences that completely filled the increased accommodation space. In contrast, only minor sulphate accumulation occurred in the Werra Sub-basin, situated further southwards and distal to the inflow. As a result of substantially different sulphate precipitation rates during increased accommodation, water depth in the region became more variable. The Werra Sub-basin, characterized by very low sedimentation rates, became increasingly deeper through time, trapping dense halite brines and precipitating rock salt deposits (Werra Halite). This ‘self-organization’ model for an evaporitic basin, in which depositional relief evolves with sedimentation and relief is filled by evaporite thereafter, contradicts earlier interpretations, that call upon the existence of a tectonic depression in the Werra area, which controlled sedimentation from the beginning of the Zechstein.
Jörg W. Schneider - One of the best experts on this subject based on the ideXlab platform.
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A multistratigraphic approach to pinpoint the Permian-Triassic boundary in continental deposits: The Zechstein-Lower Buntsandstein transition in Germany
Global and Planetary Change, 2017Co-Authors: Frank Scholze, Jörg W. Schneider, Xu Wang, Uwe Kirscher, Johannes Kraft, Annette E. Götz, Michael M. Joachimski, Valerian BachtadseAbstract:Abstract The Central European Basin is very suitable for high-resolution multistratigraphy of Late Permian to Early Triassic continental deposits. Here the well exposed continuous transition of the lithostratigraphic Zechstein and Buntsandstein Groups of Central Germany was studied for isotope-chemostratigraphy (δ13Corg, δ13Ccarb, δ18Ocarb), major and trace element geochemistry, magnetostratigraphy, palynology, and conchostracan biostratigraphy. The analysed material was obtained from both classical key sections (abandoned Nelben clay pit, Caaschwitz quarries, Thale railway cut, abandoned Heinebach clay pit) and a recent drill core section (Caaschwitz 6/2012) spanning the Permian-Triassic boundary. The Zechstein–Buntsandstein transition of Central Germany consists of a complex sedimentary facies comprising sabkha, playa lake, aeolian, and fluvial deposits of predominantly red-coloured siliciclastics and intercalations of lacustrine oolitic limestones. The new data on δ13Corg range from − 28.7 to − 21.7 ‰ showing multiple excursions. Most prominent negative shifts correlate with intercalations of oolites and grey-coloured clayey siltstones, while higher δ13Corg values correspond to an onset of palaeosol overprint. The δ13Ccarb values range from − 9.7 to − 1.3 ‰ with largest variations recorded in dolomitic nodules from the Zechstein Group. In contrast to sedimentary facies shifts across the Zechstein-Buntsandstein boundary, major element values used as a proxy (CIA, CIA*, CIA-K) for weathering conditions indicate climatic stability. Trace element data used for a geochemical characterization of the Late Permian to Early Triassic transition in Central Germany indicate a decrease in Rb contents at the Zechstein-Buntsandstein boundary. New palynological data obtained from the Caaschwitz quarry section reveal occurrences of Late Permian palynomorphs in the Lower Fulda Formation, while Early Triassic elements were recorded in the upper part of the Upper Fulda Formation. The present study confirms an onset of a normal-polarized magnetozone in the Upper Fulda Formation of the Caaschwitz quarry section supporting an interregional correlation of this crucial stratigraphic interval with the normal magnetic polarity of the basal Early Triassic known from marine sections in other regions. Based on a synthesis of the multistratigraphic data, the Permian-Triassic boundary is proposed to be placed in the lower part of the Upper Fulda Formation, which is biostratigraphically confirmed by the first occurrence date of the Early Triassic Euestheria gutta-Palaeolimnadiopsis vilujensis conchostracan fauna. Rare records of conchostracans reported from the siliciclastic deposits of the lower to middle Zechstein Group may point to its potential for further biostratigraphic subdivision of the Late Permian continental deposits.
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conchostracans in continental deposits of the Zechstein buntsandstein transition in central germany taxonomy and biostratigraphic implications for the position of the permian triassic boundary within the Zechstein group
Palaeogeography Palaeoclimatology Palaeoecology, 2016Co-Authors: Frank Scholze, Jörg W. Schneider, Ralf WerneburgAbstract:Abstract The end-Permian mass extinction marks the largest biotic crisis in the geologic record. The stratigraphic position of this boundary in continental deposits is still under discussion. In the present study, conchostracans from the Zechstein–Buntsandstein (Late Permian to Early Triassic) transition in central Germany have been taxonomically reinvestigated in order to better understand their utility for fine-scale biostratigraphy in continental Permian–Triassic boundary sections. The studied material was obtained from both collections and recent sampling activities in classical key sections and new outcrops of the Zechstein and Buntsandstein Groups. The sedimentary environments of the conchostracan occurrences are interpreted as lacustrine to fluvial facies depending on the paleogeographic position within the basin of the respective sections. The conchostracan fauna in the Zechstein–Buntsandstein transition consists of Euestheria gutta, Palaeolimnadiopsis vilujensis, Cornia germari, Estheriella marginostriata, Estheriella costata, Estheriella nodosocostata, Magniestheria mangaliensis, and Euestheria nordvikensis. Based on comparison with the Early Triassic conchostracan record in the Moscow syncline, the Palaeolimnadiopsis vilujensis–Euestheria gutta association in the upper part of the Fulda Formation indicates both its Early Triassic age and a position of the continental Permian–Triassic boundary within the Zechstein Group.
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Conchostracans in continental deposits of the Zechstein–Buntsandstein transition in central Germany: Taxonomy and biostratigraphic implications for the position of the Permian–Triassic boundary within the Zechstein Group
Palaeogeography Palaeoclimatology Palaeoecology, 2016Co-Authors: Frank Scholze, Jörg W. Schneider, Ralf WerneburgAbstract:Abstract The end-Permian mass extinction marks the largest biotic crisis in the geologic record. The stratigraphic position of this boundary in continental deposits is still under discussion. In the present study, conchostracans from the Zechstein–Buntsandstein (Late Permian to Early Triassic) transition in central Germany have been taxonomically reinvestigated in order to better understand their utility for fine-scale biostratigraphy in continental Permian–Triassic boundary sections. The studied material was obtained from both collections and recent sampling activities in classical key sections and new outcrops of the Zechstein and Buntsandstein Groups. The sedimentary environments of the conchostracan occurrences are interpreted as lacustrine to fluvial facies depending on the paleogeographic position within the basin of the respective sections. The conchostracan fauna in the Zechstein–Buntsandstein transition consists of Euestheria gutta, Palaeolimnadiopsis vilujensis, Cornia germari, Estheriella marginostriata, Estheriella costata, Estheriella nodosocostata, Magniestheria mangaliensis, and Euestheria nordvikensis. Based on comparison with the Early Triassic conchostracan record in the Moscow syncline, the Palaeolimnadiopsis vilujensis–Euestheria gutta association in the upper part of the Fulda Formation indicates both its Early Triassic age and a position of the continental Permian–Triassic boundary within the Zechstein Group.
Tadeusz Marek Peryt - One of the best experts on this subject based on the ideXlab platform.
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Sedimentary and environmental history of the Late Permian Bonikowo Reef (Zechstein Limestone, Wuchiapingian), western Poland
Journal of Palaeogeography, 2017Co-Authors: Paweł Raczyński, Tadeusz Marek Peryt, Wacław StrobelAbstract:Abstract The Bonikowo Reef occurs in the central part of the Zechstein Limestone Basin in western Poland and was growing on the topmost edges of tilted blocks and/or on the top of uplifted horsts of the Brandenburg–Wolsztyn–Pogorzela High. Its size is ca . 1.6 km 2 . The Bonikowo Reef shows the thickest reef section (90.5 m) recorded in the High. The Zechstein Limestone unit is represented mostly by limestones, often thoroughly recrystallized, although the macrotextures and biota of the boundstone are identifiable in most cases. The drillcore section is a mixture of boundstones (microbial and bryozoan), wackestones, packstones and grainstones, which often co-occur. The δ 13 C and δ 18 O values for both calcite (avg. 3.8 ± 0.8‰ and −3.4 ± 1.7‰, respectively) and dolomite (avg. 3.5 ± 0.7‰ and −5.2 ± 1.3‰, respectively) are transitional between the values previously reported for condensed sequences of the basinal facies and larger reef complexes. The biofacies of the Bonikowo Reef are very similar to those recognized in other reefs of the Brandenburg–Wolsztyn–Pogorzela High, which owe their origin to the destruction of bryozoan boundstones. The biota composition is typical and characteristic of other Zechstein Limestone reefs. However, the Bonikowo Reef demonstrates the importance of microbialites, laminar and nodose encrustations, in the growth and cohesion of the Zechstein Limestone reefs. Such encrustations abound within the Zechstein Limestone although, in many cases, the real nature of the encrustations is difficult to ascertain. These laminated encrustations show great similarity to Archaeolithoporella that is one of the most important Permian reef-building organisms. The encrustations considered to represent Archaeolithoporella were also previously recorded in the Zechstein Limestone of western Poland and in its stratigraphic equivalent, the Middle Magnesian Limestone of Northeast England. The lower part of the sequence shows great biofacies variability that reflects common environmental changes. The major part of the section is represented by slope deposits grading upward into the reef, which reflects the prograding nature of reef margin. The progradation rate for the Bonikowo Reef is estimated at 400 m/My.
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Controls on basal Zechstein (Wuchiapingian) evaporite deposition in SW Poland
geological Quarterly, 2014Co-Authors: Kazimierz Dyjaczyński, Tadeusz Marek PerytAbstract:The development of basal Zechstein (Wuchiapingian) strata inSW Polandindicates the existence of a diversified relief inherited after the flooding of the pre-existing depression by the transgressing Zechstein sea. The deeper parts of the basin were the place of development of thin basinal Zechstein Limestone showing sedimentary condensation manifested by bored and encrusted grains and thick evaporites (mostly halite), and in shallow parts Zechstein Limestone reefs followed by thinner evaporite sequences (dominated by anhydrite) occur. The analysis of 3D seismic sections showed that instead of three conventionally recognized evaporite units of stratigraphic potential in the PZ1 cycle, five units occur (from the base to the top: Lower Anhydrite, Lower Oldest Halite, Middle Anhydrite, Upper Oldest Halite, Upper Anhydrite). In a particular place their number may vary from two (Lower Anhydrite at the base of the PZ1 cycle and Upper Anhydrite at the top of the PZ1 cycle) to five. There are two complexes of Lower Anhydrite occurring throughout the platform and basinal zones showing deepening-upward (transgressive) trend. The halite sedimentation in the deepest parts of salt basins began shortly after the deposition of the upper Lower Anhydrite complex while in the sulphate platform areas the sulphate deposition lasted still for a long time. The Lower Oldest Halite deposits occur in the depressions. Between the halite basins, anhydrite platforms occur, and the thickness of anhydrite platform deposits is smaller than it is observed in salt basins. The Upper Oldest Halite in turn is recorded above the anhydrite platform. The two halite units represent different phases of development of halite basins. The Lower Oldest Halite basins are related to the pre-Zechstein depressions, although in some cases their syndepositional subsidence was controlled by reactivation, during the deposition of basal Zechstein strata, of former faults. In turn, the Upper Oldest Halite basins used the accommodation space created due to anhydritization of the Lower Anhydrite deposits composed originally of selenitic gypsum. The 3D seismics evidences that the PZ1 evaporites inSW Polandhave been deposited in far more complex and dynamic system than it was assumed before.
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Carbon and oxygen isotopic composition and foraminifers of condensed basal Zechstein (Upper Permian) strata in western Poland: environmental and stratigraphic implications
Geological Journal, 2014Co-Authors: Tadeusz Marek Peryt, Stanisław Hałas, Danuta PerytAbstract:The basinal facies of the Lopingian Zechstein Limestone in SW Poland consists of thin (often less than 1 m thick) limestones and/or dolomites, often containing the Kupferschiefer (few tens of centimetres thick) at their base, and local thick (up to 90 m) reefal carbonates. The δ13C curve of these basal Zechstein deposits strongly suggests that even when the Kupferschiefer is lacking, the thin (condensed) sequences record the entire interval of the Zechstein prior to the onset of evaporite deposition, in contrast to the thick reef sequences which lack the characteristic δ13C curve for the lowermost part of the Zechstein. The calcite samples show considerable ranges of δ18O values. If the maximum δ18O values are considered to be the closest to the pristine original ones and if δ18Owater value = 0 is assumed, then the calculated range of palaeotemperatures for the Kupferschiefer and Zechstein Limestone calcite ranges from 19 to 34 °C. The faunal restriction, common dwarf foraminifers and the predominance of lagenids in the foraminiferal assemblage indicate continual dysaerobic conditions and possibly elevated salinity of seawater during deposition of thin basinal Zechstein Limestone deposits. The mixing of shallow and deeper waters in the stratified Zechstein Basin caused by upwelling could result in prolific carbonate precipitation in reefs located at the slope of the marginal carbonate platform of the Zechstein Limestone and in isolated reefs related to palaeohighs within the basin; however, there is no isotopic record of eventual upwelling. Copyright © 2014 John Wiley & Sons, Ltd.
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Possibility of sequence stratigraphic subdivision of the Zechstein in the Polish Basin
Geological Quarterly, 2013Co-Authors: Ryszard Wagner, Tadeusz Marek PerytAbstract:Applying the Exxon method for sequence distinction, four depositional sequences can be distinguished in the Polish Zechstein, out of which the first commenced during the deposition of the upper portion of the Rotliegend and the fourth continued up to the lower portion of the Buntsandstein. In our opinion the Exxon approach is not a significant step in understanding the principles controlling the Zechstein basin evolution during the deposition of carbonate and evaporite-dominated, lower and middle parts of the Zechstein. The fourth depositional sequence commences with evaporite deposits of LST, but afterwards a general change of sedimentary regime occurred and the uppermost part of the Zechstein is dominated by terrigenous-evaporite litho-facies. Because it is not possible to distinguish typical depositional sequences in the Zechstein terrigenous-evaporite lithofacies, it was decided to distinguish climatic sequences. Despite of fundamental differences between the origin of climatic and eustatic sequences, they have an important common feature; their boundaries are isochronous.
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Foraminiferal colonization related to the Zechstein (Lopingian) transgression in the western part of the Wolsztyn Palaeo-Ridge area, Western Poland
Geological Quarterly, 2012Co-Authors: Danuta Peryt, Tadeusz Marek Peryt, Paweł Raczyński, Krzysztof ChłódekAbstract:The basal Zechstein succession in SW Poland is dominated by breccias and/or conglomerates or extraclast-bearing bioclastic limestones, which were deposited during rapid flooding of the pre-existing intracontinental basin in the early Lopingian (Late Permian). Of these, the boulder-cobble breccias and conglomerates are interpreted as deposited in a rocky shore-zone where density flows and upwelling prevailed. The breccias gradually pass up into bryozoan (or other bioclastics) grainstones. The matrix-supported breccias were deposited as large extraclasts and blocks of Carboniferous rock were rolled down or detached from a cliff and were then either embedded into a carbonate sand or formed a framework supplying voids that could be colonized by tubular encrusting foraminifers. These foraminifers abound in all basal Zechstein facies (except in the debris-flow deposits) and are attributed to Palaeonubecularia . The associated faunas include other foraminifers (uniserial and hemigordiopsids), bryozoans, brachiopods, bivalves, gastropods, and microbial deposits. The prolific growth of tubular encrusting foraminifers has resulted from nutrient supply from the basin by upwelling. Botryoidal aragonite cements (also interpreted as due to upwelling) also characterize the basal Zechstein strata, although they were previously reported only from the upper Zechstein Limestone. The d13C values of the basal Zechstein deposits show small variation and oscillated around 4.0‰, suggesting that these deposits are younger than the Kupferschiefer. The basal Zechstein strata in SW Poland consisting of breccias and/or conglomerates or bioclastic limestones (often containing extraclasts of Carboniferous rocks) originated following the rapid flood of the pre-existing intracontinental basin; this general transgression was followed by subsequent increases of sea level. Boulder-cobble breccias and conglomerates occurring at the base of the Zechstein are interpreted as a rocky-shore deposit; d epositional processes of the basal Zechstein deposits were dominated by density flows. The breccias are gradually passing into bioclastic (mostly bryozoan) grainstones, and m atrix-supported breccias originated when usually large extraclasts and blocks of Carboniferous rocks were rolled down or detached from cliff and were either embedded into the carbonate sandy material or formed a framework supplying voids that could be colonized by tubular encrusting foraminifers. These foraminifers abound in all basal Zechstein facies and are included into Palaeonubecularia . They are accompanied by other foraminifers (uniserial, Agathammina , spiral) as well as bryozoans, brachiopods, bivalves, gastropods and microbial formations. The prolific growth of tubular encrusting foraminifers has resulted from supply of the nutrients from the basin by the upwelling. The botryoidal aragonite cements (interpreted as due to upwelling as well) occur in the basal Zechstein strata; previously they were reported only from the upper part of the Zechstein Limestone. The δ 13 C values of basal Zechstein deposits show small variation and oscillated around 4.0‰; they strongly suggest that these deposits are younger than the Kupferschiefer.
