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Hubert Wierzbowski - One of the best experts on this subject based on the ideXlab platform.
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integrated stratigraphy and palaeoenvironmental interpretation of the upper Kimmeridgian to lower berriasian pelagic sequences of the velykyi kamianets section pieniny klippen belt ukraine
Palaeogeography Palaeoclimatology Palaeoecology, 2019Co-Authors: Jacek Grabowski, Daniela Reháková, V G Bakhmutov, Simon Kdýr, Michal Krobicki, Petr Pruner, Petr Schnabl, K Stoykova, Hubert WierzbowskiAbstract:Abstract A continuous sedimentary and stratigraphic record of Late Kimmeridgian – Early Berriasian age is presented from the pelagic succession from the eastern part of the Pieniny Klippen Belt (Velykyi Kamianets section, Ukraine). The studied section, 26-m-thick, was calibrated using biostratigraphy (calpionellids, calcareous dinocysts, calcareous nannofossils), magnetostratigraphy, stable isotope stratigraphy (δ13C and δ18O) and gamma ray spectrometry. Magnetic polarity zones from M23r to M18n were identified. The magnetostratigraphic calibration of calcareous dinocysts zonation around the Kimmeridgian/Tithonian boundary has been performed for the first time. The Carpistomiosphaera borzai/Committosphaera pulla calcareous dinocyst zonal boundary is situated at the bottom of magnetozone M22n, slightly lower than first occurrence of calcareous nannofossil Conusphaera mexicana minor and higher than the standard Kimmeridgian/Tithonian boundary (M22Ar/M22An; Hybonoticeras beckeri/Hybonoticeras hybonotum Ammonite Zone boundary). The position of the Tithonian/Berriasian boundary in the magnetosubzone M19n2n (Crassicollaria/Calpionella Calpionellid zonal boundary) has been confirmed. A decrease of terrigenous input and an increase of carbonate productivity correlate with increasing sedimentation rates from 0.7 to 1.1 m/Myr in the Upper Kimmeridgian (M23r to M22r) to 5–7 m/Myr in the uppermost Tithonian and Lower Berriasian (M19n to M18n). Transition between the Saccocoma and calpionellid microfacies occurs in a narrow time interval, mostly within polarity subchron M20n1r. This event is traceable in similar stratigraphic position in several Western Tethyan sections and correlates perfectly with Nannofossil Calcification Event of the early Late Tithonian.
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clumped isotope record of salinity variations in the subboreal province at the middle late jurassic transition
Global and Planetary Change, 2018Co-Authors: Hubert Wierzbowski, M A Rogov, David Bajnai, Ulrike Wacker, Jens Fiebig, Ekaterina TesakovaAbstract:Abstract Results of clumped isotope, oxygen isotope and elemental (Mg/Ca, Sr/Ca) analyses of exceptionally well-preserved belemnite rostra and ammonite shells from the uppermost Callovian–Upper Kimmeridgian (Lamberti–Mutabilis zones) of the Russian Platform are presented. Despite a significant decrease in belemnite δ18O values across the Upper Oxfordian–Lower Kimmeridgian, the clumped isotope data show a constant seawater temperature (ca. 16 °C) in the studied interval. The decrease in belemnite δ18O values and lower δ18O values measured from ammonite shells are interpreted as a result of the salinity decline of the Middle Russian Sea of ca. 12‰, and salinity stratification of the water column, respectively. The postulated secular palaeoenvironmental changes are linked to the inflow of subtropical, saline waters from the Tethys Ocean during a sea-level highstand at the Middle–Late Jurassic transition, and progressive isolation and freshening of the Middle Russian Sea during the Late Oxfordian–Kimmeridgian. The obtained clumped isotope data demonstrate relative stability of the Late Jurassic climate and a paramount effect of local palaeoceanographic conditions on carbonate δ18O record of shallow epeiric seas belonging to the Subboreal Province. Variations in Mg/Ca and Sr/Ca ratios of cylindroteuthid belemnite rostra, which are regarded by some authors as temperature proxies, are, in turn, interpreted to be primarily dependent on global changes in seawater chemistry. The paleoenvironmental variations deduced from clumped and oxygen isotope records of the Russian Platform correspond well with changes in local cephalopod and microfossil faunas, which show increasing provincialism during the Late Oxfordian and the Early Kimmeridgian. Based on the review of literature data it is suggested that the observed salinity decrease and restriction of Subboreal basins during the Late Jurassic played a major role in the formation of periodic bottom water anoxia and sedimentation of organic rich facies.
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Clumped isotope record of salinity variations in the Subboreal Province at the Middle–Late Jurassic transition
Global and Planetary Change, 2018Co-Authors: Hubert Wierzbowski, Mikhail A. Rogov, David Bajnai, Ulrike Wacker, Jens Fiebig, Ekaterina TesakovaAbstract:Abstract Results of clumped isotope, oxygen isotope and elemental (Mg/Ca, Sr/Ca) analyses of exceptionally well-preserved belemnite rostra and ammonite shells from the uppermost Callovian–Upper Kimmeridgian (Lamberti–Mutabilis zones) of the Russian Platform are presented. Despite a significant decrease in belemnite δ18O values across the Upper Oxfordian–Lower Kimmeridgian, the clumped isotope data show a constant seawater temperature (ca. 16 °C) in the studied interval. The decrease in belemnite δ18O values and lower δ18O values measured from ammonite shells are interpreted as a result of the salinity decline of the Middle Russian Sea of ca. 12‰, and salinity stratification of the water column, respectively. The postulated secular palaeoenvironmental changes are linked to the inflow of subtropical, saline waters from the Tethys Ocean during a sea-level highstand at the Middle–Late Jurassic transition, and progressive isolation and freshening of the Middle Russian Sea during the Late Oxfordian–Kimmeridgian. The obtained clumped isotope data demonstrate relative stability of the Late Jurassic climate and a paramount effect of local palaeoceanographic conditions on carbonate δ18O record of shallow epeiric seas belonging to the Subboreal Province. Variations in Mg/Ca and Sr/Ca ratios of cylindroteuthid belemnite rostra, which are regarded by some authors as temperature proxies, are, in turn, interpreted to be primarily dependent on global changes in seawater chemistry. The paleoenvironmental variations deduced from clumped and oxygen isotope records of the Russian Platform correspond well with changes in local cephalopod and microfossil faunas, which show increasing provincialism during the Late Oxfordian and the Early Kimmeridgian. Based on the review of literature data it is suggested that the observed salinity decrease and restriction of Subboreal basins during the Late Jurassic played a major role in the formation of periodic bottom water anoxia and sedimentation of organic rich facies.
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A potential stratotype for the Oxfordian/Kimmeridgian boundary: Staffin Bay, Isle of Skye, UK
2015Co-Authors: Andrzej Wierzbowski, Bronis£aw A.matyja, Angela L. Coe, Mark W. Hounslow, James G. Ogg, Kevin N. Page, Hubert Wierzbowski, John K. WrightAbstract:Key-words: ammonite succession, Oxfordian/Kimmeridgian boundary, microfossils, isotope stratigraphy, magnetostratigraphy. ABSTRACT: A coastal exposure of the Staffin Shale Formation at Flodigarry, Staffin Bay, Isle of Skye, Scotland, UK fulfils the criteria for definition as the Global Stratotype Section and Point (GSSP) for the base of the Kimmeridgian Stage (Upper Jurassic). This marine shale succession was deposited during a long-term transgression, and is part of a complete, relatively well-expanded stratigraphic succession. A rich fauna of ammonites above and below the Oxfordian/Kimmeridgian boundary allows recognition of the Evoluta Subzone (Pseudocordata Zone) and Rosenkrantzi Subzone (Rosenkrantzi Zone) of the Subboreal and Boreal uppermost Oxfordian, and the Densicostata Subzone (Baylei Zone) and the Bauhini Zone of the Subboreal and Boreal lowermost Kimmeridgian). A suitable level for the boundary is thus marked by the replacement of the Subboreal Ringsteadia (M)/Microbiplices (m) by Pictonia (M)/Prorasenia (m), and by the first appearance of Boreal Amoeboceras (Plasmatites). Detailed study of the microfossil
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middle upper jurassic upper callovian lower Kimmeridgian stable isotope and elemental records of the russian platform indices of oceanographic and climatic changes
Global and Planetary Change, 2013Co-Authors: Hubert Wierzbowski, Bronis£aw A.matyja, M A Rogov, D N Kiselev, Alexei P IppolitovAbstract:Abstract New isotope (δ18O, δ13C) and elemental (Mg/Ca, Sr/Ca) data of well-preserved belemnite rostra, ammonite and gastropod shells from the Middle Oxfordian–Lower Kimmerdgian (Densiplicatum–Kitchini zones) of the Russian Platform are presented. This record is supplemented with published data from the Upper Callovian–Lower Kimmeridgian interval (Athleta–Kitchini zones). Significant differences in average temperatures calculated from δ18O values of particular fossil groups (5–15 °C) show the thermal gradient and the presence of cold bottom waters in the Middle Russian Sea during the Late Callovian–Middle Oxfordian. An Upper Oxfordian–lowermost Kimmeridgian decrease in δ18O values and an increase in Sr/Ca ratios of cylindroteuthid belemnite rostra likely reflect a warming of the bottom waters of ca. 3.5 °C. The gradual Late Oxfordian–earliest Kimmeridgian warming is followed by an abrupt temperature rise of 3–6 °C that occurred at the transition of the Early Kimmeridgian Bauhini and Kitchini chrons. The occurrences of cold bottom waters and of (Sub)Mediterranean ammonites and belemnites in the Middle Russian Sea at the Middle–Late Jurassic transition are regarded as a result of the opening of seaways during a sea level highstand. The bottom waters are considered to have been formed in the cool Boreal Sea. The subsequent retreats of the cold bottom waters and of the (Sub)Mediterranean cephalopods from the Middle Russian Sea in the Late Oxfordian are explained by the restriction of water circulation during a sea-level fall. The Early Kimmeridgian rise of bottom temperatures of the sea is linked to a global climate warming. The data presented do not support a major cooling of the Arctic and a consequent glaciation in this region at the Middle–Late Jurassic transition. Since occurrences of cold water masses are diachronous in different European basins, the observed variations in sea water temperatures are interpreted as a result of changes in marine currents and water circulation. δ13C values of belemnite rostra from the Russian Platform are scattered but show the long-term Upper Callovian–Middle Oxfordian positive excursion consistent with the previously published isotope records of the Boreal Realm and terrestrial organic matter.
John K. Wright - One of the best experts on this subject based on the ideXlab platform.
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A potential stratotype for the Oxfordian/Kimmeridgian boundary: Staffin Bay, Isle of Skye, UK
2015Co-Authors: Andrzej Wierzbowski, Bronis£aw A.matyja, Angela L. Coe, Mark W. Hounslow, James G. Ogg, Kevin N. Page, Hubert Wierzbowski, John K. WrightAbstract:Key-words: ammonite succession, Oxfordian/Kimmeridgian boundary, microfossils, isotope stratigraphy, magnetostratigraphy. ABSTRACT: A coastal exposure of the Staffin Shale Formation at Flodigarry, Staffin Bay, Isle of Skye, Scotland, UK fulfils the criteria for definition as the Global Stratotype Section and Point (GSSP) for the base of the Kimmeridgian Stage (Upper Jurassic). This marine shale succession was deposited during a long-term transgression, and is part of a complete, relatively well-expanded stratigraphic succession. A rich fauna of ammonites above and below the Oxfordian/Kimmeridgian boundary allows recognition of the Evoluta Subzone (Pseudocordata Zone) and Rosenkrantzi Subzone (Rosenkrantzi Zone) of the Subboreal and Boreal uppermost Oxfordian, and the Densicostata Subzone (Baylei Zone) and the Bauhini Zone of the Subboreal and Boreal lowermost Kimmeridgian). A suitable level for the boundary is thus marked by the replacement of the Subboreal Ringsteadia (M)/Microbiplices (m) by Pictonia (M)/Prorasenia (m), and by the first appearance of Boreal Amoeboceras (Plasmatites). Detailed study of the microfossil
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the aulacostephanidae ammonoidea of the oxfordian Kimmeridgian boundary beds upper jurassic of southern england
Palaeontology, 2010Co-Authors: John K. WrightAbstract:Abstract: Four areas in southern England centred on Swindon and Westbury (Wiltshire), Bourton (north Dorset) and the Dorset coast near Weymouth (south Dorset) have yielded well-preserved late Oxfordian and early Kimmeridgian (Upper Jurassic) ammonites in abundance. These ammonites belong principally to the aulacostephanid genera Ringsteadia and Pictonia, and their microconch equivalents Microbiplices and Prorasenia. Systematic descriptions of these genera are included herein. Within the zonal and subzonal sequence of the English Oxfordian/Kimmeridgian Stage boundary beds, the established subdivision of the Late Oxfordian Pseudocordata Zone into Pseudoyo, Pseudocordata and Evoluta Subzones is confirmed. In the Early Kimmeridgian Baylei Zone, however, the evidence is that the sequence throughout much of southern England is incomplete compared with more complete sequences such as that at Staffin in the Isle of Skye, with the presence of only one faunal biohorizon, the densicostata horizon.
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Magnetostratigraphic correlation of the Oxfordian-Kimmeridgian boundary
Earth and Planetary Science Letters, 2009Co-Authors: Piotr A. Przybylski, Andrzej Wierzbowski, John K. Wright, Angela L. Coe, Mark W. Hounslow, James G. Ogg, François Atrops, Erik SettlesAbstract:A magnetic polarity pattern for Boreal and Sub-Boreal ammonite zones of the Upper Oxfordian to Lower Kimmeridgian was established and confirmed in four British sections, including the proposed Global Boundary Stratotype Section and Point (GSSP) on the Isle of Skye (Scotland) to define the base of the international Kimmeridgian Stage. A coeval pattern for Sub-Mediterranean ammonite zones was compiled from seven sections in Poland, one German section and multi-section composites from France and Spain. The mean paleopole for the European Craton (excluding Spain) at the Oxfordian–Kimmeridgian boundary is 74.2°N, 181.3°E (Α95 = 3.8°). The common magnetic polarity scale enables inter-correlation of ammonite subzones among these three faunal provinces and to the marine magnetic-anomaly M-Sequence. The proposed GSSP at the base of the Pictonia baylei Zone is near the base of an extended interval dominated by reversed polarity, which is interpreted to be Chron M26r. This GSSP level projects to the lower to middle part of the Epipeltoceras bimammatum Subzone, which is the middle subzone of this E. bimammatum Zone in the Sub-Mediterranean standard zonation. In contrast, the traditional placement of the Oxfordian–Kimmeridgian boundary in that Sub-Mediterranean standard zonation (base of Sutneria platynota Zone) is at the base of Chron M25r, or nearly 1 million years younger.
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a potential stratotype for the oxfordian Kimmeridgian boundary staffin bay isle of skye uk
Volumina Jurassica, 2006Co-Authors: Andrzej Wierzbowski, Bronis£aw A.matyja, Angela L. Coe, Mark W. Hounslow, James G. Ogg, Hubert Wierzbowski, Kevin Page, John K. WrightAbstract:A coastal exposure of the Staffin Shale Formation at Flodigarry, Staffin Bay, Isle of Skye, Scotland, UK fulfils the criteria for definition as the Global Stratotype Section and Point (GSSP) for the base of the Kimmeridgian Stage (Upper Jurassic). This marine shale succession was deposited during a long-term transgression, and is part of a complete, relatively well-expanded stratigraphic succession. A rich fauna of ammonites above and below the Oxfordian/Kimmeridgian boundary allows recognition of the Evoluta Subzone (Pseudocordata Zone) and Rosenkrantzi Subzone (Rosenkrantzi Zone) of the Subboreal and Boreal uppermost Oxfordian, and the Densicostata Subzone (Baylei Zone) and the Bauhini Zone of the Subboreal and Boreal lowermost Kimmeridgian). A suitable level for the boundary is thus marked by the replacement of the Subboreal Ringsteadia(M)/Microbiplices(m) by Pictonia (M)/Prorasenia(m), and by the first appearance of Boreal Amoeboceras (Plasmatites). Detailed study of the microfossils reveals an excellent dinoflagellate succession. A variety of stratigraphically important dinoflagellates are found, the assemblages being intermediate in character between Boreal and Subboreal ones. The magnetostratigraphic data, though rather troublesome to extract, shows a polarity pattern which can be confidently correlated to other UK boundary sections. The upper boundary of a normal magnetozone falls at, or very near, the proposed Oxfordian/Kimmeridgian boundary. The 87Sr/86Sr ratio at the boundary, based on an analysis of belemnites, lies between 0,70689 and 0,70697, averaging 0.70693. Matching worldwide trends, no distinct change in the ratio is seen across the boundary. A lack of variations in the carbon isotope composition of belemnites across the Oxfordian/Kimmeridgian boundary does not indicate perturbation in the global carbon cycle. However, high δ 13C values and their scatter suggest the influence of local fractionation affecting isotope composition of dissolved inorganic carbon (DIC) in the partly isolated Boreal sea. A fall in the belemnite δ 18O values in the Upper Oxfordian and Lower Kimmeridgian compared to the Mid Oxfordian suggests a slight rise in seawater temperature.
Andrzej Wierzbowski - One of the best experts on this subject based on the ideXlab platform.
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towards a consistent oxfordian Kimmeridgian global boundary current state of knowledge
Volumina Jurassica, 2016Co-Authors: Andrzej Wierzbowski, Federico Olóriz, Bronis£aw A.matyja, Mark W. Hounslow, M A Rogov, Kevin Page, François Atrops, Jacek Grabowski, Horacio Parent, Gunter SchweigertAbstract:New data are presented in relation to the worldwide definition of the Oxfordian/Kimmeridgian boundary, i.e. the base of the Kimmeridgian Stage. This data, mostly acquired in the past decade, supports the 2006 proposal to make the uniform boundary of the stages in the Flodigarry section at Staffin Bay on the Isle of Skye, northern Scotland. This boundary is based on the Subboreal-Boreal ammonite successions, and it is distinguished by the Pictonia flodigarriensis horizon at the base of the Subboreal Baylei Zone, and which corresponds precisely to the base of the Boreal Bauhini Zone. The boundary lies in the 0.16 m interval (1.24–1.08 m) below bed 36 in sections F6 at Flodigarry and it is thus proposed as the GSSP for the Oxfordian/Kimmeridgian boundary. This boundary is recognized also by other stratigraphical data – palaeontological, geochemical and palaeomagnetic (including its well documented position close to the boundary between magnetozones F3n, and F3r which is placed in the 0.20 m interval – 1.28 m to 1.48 m below bed 36 – the latter corresponding to marine magnetic anomaly M26r).The boundary is clearly recognizable also in other sections of the Subboreal and Boreal areas discussed in the study, including southern England, Pomerania and the Peri-Baltic Syneclise, Russian Platform, Northern Central Siberia, Franz-Josef Land, Barents Sea and Norwegian Sea. It can be recognized also in the Submediterranean-Mediterranean areas of Europe and Asia where it correlates with the boundary between the Hypselum and the Bimmamatum ammonite zones. The changes in ammonite faunas at the boundary of these ammonite zones – mostly of ammonites of the families Aspidoceratidae and Oppeliidae – also enables the recognition of the boundary in the Tethyan and Indo-Pacific areas – such as the central part of the Americas (Cuba, Mexico), southern America, and southern parts of Asia. The climatic and environmental changes near to the Oxfordian/Kimmeridgian boundary discussed in the study relate mostly to the European areas. They show that very unstable environments at the end of the Oxfordian were subsequently replaced by more stable conditions representing a generally warming trend during the earliest Kimmeridgian. The definition of the boundary between the Oxfordian and Kimmeridgian as given in this study results in its wide correlation potential and means that it can be recognized in the different marine successions of the World.
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A potential stratotype for the Oxfordian/Kimmeridgian boundary: Staffin Bay, Isle of Skye, UK
2015Co-Authors: Andrzej Wierzbowski, Bronis£aw A.matyja, Angela L. Coe, Mark W. Hounslow, James G. Ogg, Kevin N. Page, Hubert Wierzbowski, John K. WrightAbstract:Key-words: ammonite succession, Oxfordian/Kimmeridgian boundary, microfossils, isotope stratigraphy, magnetostratigraphy. ABSTRACT: A coastal exposure of the Staffin Shale Formation at Flodigarry, Staffin Bay, Isle of Skye, Scotland, UK fulfils the criteria for definition as the Global Stratotype Section and Point (GSSP) for the base of the Kimmeridgian Stage (Upper Jurassic). This marine shale succession was deposited during a long-term transgression, and is part of a complete, relatively well-expanded stratigraphic succession. A rich fauna of ammonites above and below the Oxfordian/Kimmeridgian boundary allows recognition of the Evoluta Subzone (Pseudocordata Zone) and Rosenkrantzi Subzone (Rosenkrantzi Zone) of the Subboreal and Boreal uppermost Oxfordian, and the Densicostata Subzone (Baylei Zone) and the Bauhini Zone of the Subboreal and Boreal lowermost Kimmeridgian). A suitable level for the boundary is thus marked by the replacement of the Subboreal Ringsteadia (M)/Microbiplices (m) by Pictonia (M)/Prorasenia (m), and by the first appearance of Boreal Amoeboceras (Plasmatites). Detailed study of the microfossil
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Biostratigraphy and ammonites of the Middle Oxfordian to lowermost Upper Kimmeridgian in northern Central Siberia
Russian Geology and Geophysics, 2013Co-Authors: Andrzej Wierzbowski, Mikhail A. RogovAbstract:Abstract The Middle Oxfordian to lowermost Upper Kimmeridgian ammonite faunas from northern Central Siberia (Nordvik, Chernokhrebetnaya, and Levaya Boyarka sections) are discussed, giving the basis for distinguishing the ammonite zones based on cardioceratid ammonites of the genus Amoeboceras (Boreal zonation), and, within the Kimmeridgian Stage, faunas–for distinguishing zones based on the aulacostephanid ammonites (Subboreal zonation). The succession of Boreal ammonites is essentially the same as in other areas of the Arctic and NW Europe, but the Subboreal ammonites differ somewhat from those known from NW Europe and Greenland. The Siberian aulacostephanid zones—the Involuta Zone and the Evoluta Zone—are correlated with the Baylei Zone (without its lowermost portion), and the Cymodoce Zone/lowermost part of the Mutabilis Zone (the Askepta Subzone) from NW Europe. The uniform character of the Boreal ammonite faunas in the Arctic makes possible a discussion on their phylogeny during the Late Oxfordian and Kimmeridgian: the succession of particular groups of Amoeboceras species referred to successive subgenera is revealed by the occurrence of well differentiated assemblages of typical normal-sized macro and microconchs, intermittently marked by the occurrence of assemblages of paedomorphic “small-sized microconchs” appearing at some levels preceeding marked evolutionary modifications. Some comments on the paleontology of separate groups of ammonites are also given. These include a discussion on the occurrence of Middle Oxfordian ammonites of the genus Cardioceras in the Nordvik section in relation to the critical review of the paper of Rogov and Wierzbowski (2009) by Nikitenko et al. (2011). The discussion shows that the oldest deposits in the section belong to the Middle Oxfordian, which results in the necessity for some changes in the foraminiferal zonal scheme of Nikitenko et al. (2011). The ammonites of the Pictonia involuta group are distinguished as the new subgenus Mesezhnikovia Wierzbowski and Rogov.
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on the oxfordian Kimmeridgian boundary and its gssp current state of knowledge
Volumina Jurassica, 2010Co-Authors: Andrzej WierzbowskiAbstract:An ample report presenting the current progress in recognition of the Global stratotype section and Point (GssP) for the base of the Kimmeridgian stage has been presented in the last issue of isJs Newsletter (Wierzbowski, 2008). It should be remembered that the Flodigarry section at Staffin Bay in Skye, northern Scotland, has been accepted both by the Kimmeridgian Working Group, and the international subcommission on Jurassic stratigraphy as the primary standard for the Kimmeridgian stage with its base located at the base of the subboreal baylei ammonite zone. The only problem (and the most complicated one) which is still unresolved is which of the two ammonite horizons based on successive members of the genus Pictonia marks the base of the baylei zone: the flodigarriensis horizon or, lying directly above, the densicostata horizon (Fig. 1; see also Matyja et al., 2006; Wierzbowski et al., 2006 where the horizons and the section in question are described in detail). New biostratigraphical data from other sections (cores from barents sea and Norwegian sea, the Nordvik section of northern siberia, the Unzha river section of the kostroma District of russian Platform) revealed a larger correlation potential for the base of the flodigarriensis horizon than the base of the densicostata horizon, and thus its larger significance in recognition of the base of the Kimmeridgian Stage in the Subboreal and Boreal areas of Arctic, as well as northern europe and northern Asia (Wierzbowski, smelror, 1993; Wierzbowski et al., 2002; rogov, Wierzbowski, 2009; Glowniak et al., 2010). This preference results from good correlation between the base of the flodigarriensis horizon treated as the base of the subboreal baylei zone, and the base of the boreal bauhini zone – marked by appearance of ammonites of Amoeboceras (Plasmatites) group such as A. (P.) praebauhini (salfeld) and A. (P.) lineatum (Quenstedt) (see Wierzbowski, 2008) which show a wide palaeogeographical distribution and are very useful in stratigraphical correlations. The recent study of the subboreal aulacostephanids from southern england – i.e. their “home area” (Wright, 2010) – evidences the incompleteness of the succession at the boundary of the oxfordian and Kimmeridgian in these sections, but indicates the presence of the flodigarriensis horizon in some basinal sections of the area, such as the Wessex basin. Thus, the previously supposed local occurrence of an index ammonite – the Pictonia flodigarriensis of the flodigarriensis horizon in northern scotland only – used as argument against wider recognition of the base of the flodigarriensis horizon as a uniform boundary of the oxfordian/ Kimmeridgian boundary, is not substantiated. The problem still not resolved is the correlation potential of the flodigarriensis horizon versus that of the densicostata horizon in recognition of the uniform oxfordian/Kimmeridgian boundary in the submediterranean/Mediterranean and other (e.g. Pacific) successions of the World. Nevertheless, general opinions related to wider recognition of the oxfordian/Kimmeridgian boundary outside the subboreal/boreal successions can be given. The results of studies of subboreal and boreal ammonites occurring in the submediterranean succession in europe (especially in Poland and
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Magnetostratigraphic correlation of the Oxfordian-Kimmeridgian boundary
Earth and Planetary Science Letters, 2009Co-Authors: Piotr A. Przybylski, Andrzej Wierzbowski, John K. Wright, Angela L. Coe, Mark W. Hounslow, James G. Ogg, François Atrops, Erik SettlesAbstract:A magnetic polarity pattern for Boreal and Sub-Boreal ammonite zones of the Upper Oxfordian to Lower Kimmeridgian was established and confirmed in four British sections, including the proposed Global Boundary Stratotype Section and Point (GSSP) on the Isle of Skye (Scotland) to define the base of the international Kimmeridgian Stage. A coeval pattern for Sub-Mediterranean ammonite zones was compiled from seven sections in Poland, one German section and multi-section composites from France and Spain. The mean paleopole for the European Craton (excluding Spain) at the Oxfordian–Kimmeridgian boundary is 74.2°N, 181.3°E (Α95 = 3.8°). The common magnetic polarity scale enables inter-correlation of ammonite subzones among these three faunal provinces and to the marine magnetic-anomaly M-Sequence. The proposed GSSP at the base of the Pictonia baylei Zone is near the base of an extended interval dominated by reversed polarity, which is interpreted to be Chron M26r. This GSSP level projects to the lower to middle part of the Epipeltoceras bimammatum Subzone, which is the middle subzone of this E. bimammatum Zone in the Sub-Mediterranean standard zonation. In contrast, the traditional placement of the Oxfordian–Kimmeridgian boundary in that Sub-Mediterranean standard zonation (base of Sutneria platynota Zone) is at the base of Chron M25r, or nearly 1 million years younger.
Felix Schlagintweit - One of the best experts on this subject based on the ideXlab platform.
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some microfossils dasycladales benthic foraminifera sponges from the upper jurassic mozduran formation ne iran kopet dagh and their biostratigraphic and palaeobiogeographic importance
Rivista Italiana Di Paleontologia E Stratigrafia, 2019Co-Authors: Felix Schlagintweit, Zohreh Kadivar, Koorosh RashidiAbstract:The Mozduran Formation represents mainly carbonatic shallow-water deposits from the Kopet-Dagh basin of northeast Iran. Longtime considered to be of exclusively Late Jurassic (Oxfordian-Kimmeridgian) age, its ranging into the Early Cretaceous has been demonstrated in recent times. The micropalaeontological inventory and biostratigraphic data however, are still poorly constrained. In the present contribution, some taxa of Dasycladales [Campbelliella striata (Carozzi), Montenegrella florifera Bernier, Petrascula bugesiaca Bernier, Petrascula cf. bursiformis (Ettalon), Triploporella sp.], benthic foraminifera [Neokilianina rahonensis (Foury & Vincent), Spiraloconulus suprajurassicus Schlagintweit], and sponges (Paronadella? sp., Neuropora lusitanica G. Termier & H. Termier, Thalamopora sp.) are reported. Some taxa are reported for the first time from this formation, some even for the first time from Iran. The identified assemblage is assigned to the Tithonian, although a late Kimmeridgian age for the lowermost part of the section studied is possible. A palaeobiogeographic restriction to the former Neotethysian margin might be possible for the two Petrascula species.
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SOME MICROFOSSILS (DASYCLADALES, BENTHIC FORAMINIFERA, SPONGES) FROM THE UPPER JURASSIC MOZDURAN FORMATION (NE IRAN, KOPET-DAGH) AND THEIR BIOSTRATIGRAPHIC AND PALAEOBIOGEOGRAPHIC IMPORTANCE
Università degli Studi di Milano, 2019Co-Authors: Felix Schlagintweit, Zohreh Kadivar, Koorosh RashidiAbstract:The Mozduran Formation represents mainly carbonatic shallow-water deposits from the Kopet-Dagh basin of northeast Iran. Longtime considered to be of exclusively Late Jurassic (Oxfordian-Kimmeridgian) age, its ranging into the Early Cretaceous has been demonstrated in recent times. The micropalaeontological inventory and biostratigraphic data however, are still poorly constrained. In the present contribution, some taxa of Dasycladales [Campbelliella striata (Carozzi), Montenegrella florifera Bernier, Petrascula bugesiaca Bernier, Petrascula cf. bursiformis (Éttalon), Triploporella sp.], benthic foraminifera [Neokilianina rahonensis (Foury & Vincent), Spiraloconulus suprajurassicus Schlagintweit], and sponges (Paronadella? sp., Neuropora lusitanica G. Termier & H. Termier, Thalamopora sp.) are reported. Some taxa are reported for the first time from this formation, some even for the first time from Iran. The identified assemblage is assigned to the Tithonian, although a late Kimmeridgian age for the lowermost part of the section studied is possible. A palaeobiogeographic restriction to the former Neotethysian margin might be possible for the two Petrascula species
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berriasian drowning of the plassen carbonate platform at the type locality and its bearing on the early eoalpine orogenic dynamics in the northern calcareous alps austria
International Journal of Earth Sciences, 2006Co-Authors: Hansjurgen Gawlick, Felix SchlagintweitAbstract:The Plassen carbonate platform (Kimmeridgian to Early Berriasian) developed above the Callovian to Tithonian carbonate clastic radiolaritic flysch basins of the Northern Calcareous Alps during a tectonically active period in a convergent regime. Remnants of the drowning sequence of the Plassen Formation have been discovered at Mount Plassen in the Austrian Salzkammergut. It is represented by calpionellid-radiolaria wacke- to packstones that, due to the occurrence of Calpionellopsis oblonga (Cadisch), are of Late Berriasian age (oblonga Subzone). Thus, the Plassen Formation at its type-locality shows the most complete profile presently known, documenting the carbonate platform evolution from the initial shallowing upward evolution in the Kimmeridgian until the final Berriasian drowning. The shift from neritic to pelagic sedimentation took place during Berriasian times. A siliciclastic-influenced drowning sequence sealed the highly differentiated Plassen carbonate platform. The former interpretation of a Late Jurassic carbonate platform formed under conditions of tectonic quiescence cannot be confirmed. The onset, evolution and drowning of the Plassen carbonate platform took place at an active continental margin. The tectonic evolution of the Northern Calcareous Alps during the Kimmeridgian to Berriasian time span and the reasons for the final drowning of the Plassen carbonate platform are to be seen in connection with further tectonic shortening after the closure of the Tethys Ocean.
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pinnatiporidium untersbergensis n sp a new siphonous green alga of the family protohalimedaceae dragastan littler littler 2002 from the upper jurassic of the northern calcareous alps austria
2004Co-Authors: Felix Schlagintweit, Ovidiu DragastanAbstract:The Alpine Plassen Formation (Kimmeridgian - Berriasian) yields a particularly diversified association of siphonous green algae and Rivularia-type Cyanophceans (former "Porostromata"). Most abundantly they occur within both, back-reef/open lagoon rud- to packstones and internal infralittoral wackestones. Thus, their occurrence/missing within certain localities can be explained by their different facies evolution. With a total of more than 30 species, the Plassen Formation of the Northern Calcareous Alps shows strong affinities to the East Carpathians, exhibiting the type-localties of many of these taxa. A new species is introduced as Pinnatiporidium untersbergensis n. sp. from the Upper Kimmeridgian of Mount Untersberg near Salzburg, Austria being distinctly smaller than the type-species P. cylindricus DRAGASTAN 1990 and P. alpidicum (DRAGASTAN, 1999) nov. comb.
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the context of lowstand events in the Kimmeridgian late jurassic sequence stratigraphic evolution of the wessex weald basin southern england
Sedimentary Geology, 2002Co-Authors: S.p Taylor, Bruce W. SellwoodAbstract:Abstract A depositional sequence stratigraphic framework for the Kimmeridgian Stage of the Wessex–Weald Basin, southern England, is applied in the investigation of the sedimentary and erosional response to proposed lowstand events. This framework recognises 13 sequence boundaries (Km1-Km13) and is based on the integrated assessment of geophysical, sedimentological, palaeontological and geochemical data. Changes in the nature and continuity of Kimmeridgian unconformity surfaces record the effect of the reorganisation of the onshore basins in response to eustasy and tectonic movements. During the Earliest Kimmeridgian, the basin geometry was such that falls in relative sea level generated widespread unconformities. Associated lowstand events are recorded in marginal areas by a number of sand units, derived from a variety of local sources. A tectonically enhanced deepening event during the late Early Kimmeridgian (Eudoxus Zone) led to unconformities being confined in their distribution, to the basin margins. As sea level fell during the Latest Kimmeridgian, a progressive reduction in the depositional area led to an amplification of the effects of lowstand processes at the basin margins where unconformity surfaces are amalgamated. On the most positive areas these surfaces are overprinted by a major interregional hiatus, the ‘Late Cimmerian Unconformity’. The timing and effects of Kimmeridgian lowstand events were intimately linked to the tectonic evolution of the Wessex–Weald Basin. Thus at times when rates and amounts of eustatic change are small (i.e. during ‘greenhouse times’) the tectonic signature of a basin will be the primary signal recorded in sedimentary successions.
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a sequence stratigraphy of the Kimmeridgian and bolonian stages late jurassic wessex weald basin southern england
Journal of the Geological Society, 2001Co-Authors: S.p Taylor, Bruce W. Sellwood, Ramues W Gallois, Martin H ChambersAbstract:A sequence stratigraphic framework for the late Jurassic Kimmeridgian and Bolonian stages of the Wessex–Weald Basin, southern England is proposed, based on the integration of sedimentological, geophysical and geochemical data. The NERC-funded Rapid Global Geological Events (RGGE) boreholes of Swanworth Quarry 1 and 2, and Metherhills 1, are used as reference sections. Eleven complete depositional sequences and their component systems tracts are recognized within the Kimmeridge Clay Formation, bounded by 12 sequence boundaries (Km1–12). Seventy-four boreholes have been used in this study. During the Kimmeridgian, a major transgression, associated with tectonic movements, led to a marked change in basin geometry. Major deepening of the sea during the late Kimmeridgian (Eudoxus Zone) led to a change from unconformities of basinwide extent to those confined to the basin margins. The progressive deepening of the basin towards a highstand in the mid-Bolonian (Wheatleyensis to Pectinatus zones) was associated with a broad-scale change in sedimentary, faunal and geochemical characters. The ‘layer-cake’ basin architecture and thickening of the Kimmeridge Clay Formation towards the basin centre suggests a dominantly aggradational system. The partially enclosed nature of the Kimmeridgian and Bolonian seas generated basin dynamics more analogous to those of modern day meromictic lakes. Consequently, sequence stratigraphic approaches derived from continental shelf-margins are inappropriate in epicontinental basins of this type.
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a palaeoclimate model for the Kimmeridgian
Palaeogeography Palaeoclimatology Palaeoecology, 1992Co-Authors: Paul J Valdes, Bruce W. SellwoodAbstract:Abstract Most attempts at using numerical General Circulation Model (GCM) to simulate Mesozoic climates have studied the Late Cretaceous and have focused on the enigmaof apparently equable global climates. However, this climate regime lasted throughout the Mesozoic and it is of interest to examine other periods. We present the results of an integration for the late Jurassic using a relatively detailed and high-resolution model. There is generally good agreement between the model climate and the existing geological data. In particular, the simulation predicts no permanent ice cover near either pole, arid conditions over the southwestern USA, seasonally arid climate over southern Europe, and winter storminess over Europe and Australia. However, the surface temperatures over Siberia and Southeastern Gondwanaland drop below zero for a significant part of the winter.
