A new upper Middle Ordovician–Lower Silurian drillcore standard succession from Borenshult in Östergötland, southern Sweden: 1. Stratigraphical review with regional comparisons (original) (raw)
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Palaeogeography, Palaeoclimatology, Palaeoecology, 2016
A pioneer δ 13 Corg study through the upper Sandbian and Katian (Upper Ordovician) succession in the Röstånga 1 drill in the classical geological outcrop area at Röstånga in southernmost Sweden produced a wealth of new carbon isotope data which are useful for local and regional correlations. Among the Upper Ordovician positive δ 13 C excursions, the Guttenberg (GICE,) Waynesville (Saunja), Whitewater (Moe), Paroveja, and Hirnantian (HICE) isotopic carbon excursions are recognized but the Kope (Rakvere) δ 13 C excursion is missing, suggesting a stratigraphic gap. All these isotopic excursions are tied closely to biostratigraphy, especially graptolite biostratigraphy, and in the case of the Waynesville (Saunja) and Whitewater (Moe) excursions, for the first time anywhere in the world. The Röstånga GICE δ 13 Corg curve from the upper Sularp Shale shows a striking similarity to that of the Katian GSSP in Oklahoma, suggesting the potential of transAtlantic correlation. Based on a projection from the Katian GSSP, the previously poorly constrained position of the base of the Katian in southern Sweden appears to be in the uppermost Sularp Shale in strata of the upper Diplograptus foliaceus Zone. Previous interpretations of the relations between K-bentonite successions in southern Scandinavia are somewhat revised and the Kinnekulle K-bentonite is recognized for the first time in Scania. Based on new radiometric dates, this very prominent and widespread ash bed appears to be slightly older than the Deicke and Millbrig K-bentonites in eastern North America.
Estonian Journal of Earth Sciences, 2014
Based on δ 13 C data from two drillcores recovered from the Siljan district, we present a first continuous carbon isotope record of the upper Tremadocian-lower Katian limestone succession of central Sweden. New names for some isotopic carbon excursions from the Cambrian-Ordovician boundary through the basal Darriwilian are introduced. The Mora 001 core from the western part of the Siljan impact structure ranges through the Lower-Middle Ordovician, whereas the Solberga 1 core from its eastern part ranges through the Middle-lower Upper Ordovician. Upper Tremadocian and Floian units are extremely condensed and include extensive stratigraphic gaps. Multiple hardgrounds, sometimes with minor karstic overprint, imply recurrent periods of erosion and/or non-deposition. Like in other parts of Sweden, the Dapingian and Darriwilian succession is characterized by a relatively complete sedimentary record and low sedimentation rates.
Estonian Journal of Earth Sciences, 2014
Based on δ 13 C data from two drillcores recovered from the Siljan district, we present a first continuous carbon isotope record of the upper Tremadocian-lower Katian limestone succession of central Sweden. New names for some isotopic carbon excursions from the Cambrian-Ordovician boundary through the basal Darriwilian are introduced. The Mora 001 core from the western part of the Siljan impact structure ranges through the Lower-Middle Ordovician, whereas the Solberga 1 core from its eastern part ranges through the Middle-lower Upper Ordovician. Upper Tremadocian and Floian units are extremely condensed and include extensive stratigraphic gaps. Multiple hardgrounds, sometimes with minor karstic overprint, imply recurrent periods of erosion and/or non-deposition. Like in other parts of Sweden, the Dapingian and Darriwilian succession is characterized by a relatively complete sedimentary record and low sedimentation rates.
Integrated Upper Ordovician–lower Silurian biostratigraphy of the Grötlingbo-1 core section, Sweden
GFF, 2015
The biostratigraphical data obtained from the Grötlingbo-1 core section (southern Gotland, Sweden) enable recognition of most of the regional stages known from the Sandbian (Upper Ordovician) to lower Sheinwoodian (Wenlock, Silurian) interval in the East Baltic. The strata corresponding to the Upper Ordovician Keila-Nabala stages have markedly reduced thicknesses in the Grötlingbo-1 core section. Gaps of considerable duration were recognised in some parts of the section: lithological evidence suggest that only lower part of the Pirgu Stage (corresponds to all or part of the Jonstorp Fm.) is represented in the section; in the Llandovery, strata corresponding to the Aspelundia? fluegeli and Distomodus staurognathoides conodont biozones, and to the Pterospathodus eopennatus Conodont Zone (equivalent to the Conochitina alargada and Eisenackitina dolioliformis chitinozoan zones) are missing. Graptolites from the core indicate that the sedimentary record above the Aeronian to middle Telychian gap recommences in the lower part of the Oktavites spiralis Graptolite Zone. Co-occurrences of conodonts, graptolites and chitinozoans agree with earlier data suggesting correlation between the lower boundaries of the Cyrtograptus lapworthi GZ and Pt. am. amorphognathoides CZ, and between the lower and middle parts of the Ireviken Event and the upper Cyrt. murchisoni GZ. appearance of Fungochitina spinifera in sample JN-12 (421.87-421.93 m) and the occurrence of Armoricochitina reticulifera (Fig. 5: D, E) higher in the section, in the interval 420.45-421.65 m (samples JN-9 to JN-11), correlates this interval with the Fung. spinifera CtZ. The uppermost sample in this set, JN-8 (420.15-420.20 m), comes from a limestone with red spots and did not yield chitinozoans. Above sample JN-8, an interval almost 18 m thick, consisting mainly of red-coloured rocks, was not sampled. The samples above the unsampled strata (samples C-62, C-66, JN-1 to JN-7 from interval 397.60-402.55 m) were either barren or yielded long-ranging, stratigraphically undiagnostic taxa. Silurian 50 species of chitinozoans have been identified in the studied Silurian part of the Grötlingbo-1 core section (Figs 3, 6). The lowermost Silurian sample (C-62: 397.50-397.60 m) was barren. The next two samples (C-63 and C-64 from the interval 396.35-396.92 m) yielded only the long-ranging taxa Cyathochitina campanulaeformis (Fig. 6: A) and Ancyrochitina ancyrea which are known to occur also in the Upper Ordovician. The next samples (C-1 and C-65) from the interval 395.43-395.85 m contained Anc. cf. laevaensis and Plectochitina nodifera, indicating the basal Silurian Anc. laevaensis CtZ for this interval (Nestor 1994, 2012).
2014
Based on δC data from two drillcores recovered from the Siljan district, we present a first continuous carbon isotope record of the upper Tremadocianlower Katian limestone succession of central Sweden. New names for some isotopic carbon excursions from the CambrianOrdovician boundary through the basal Darriwilian are introduced. The Mora 001 core from the western part of the Siljan impact structure ranges through the LowerMiddle Ordovician, whereas the Solberga 1 core from its eastern part ranges through the Middlelower Upper Ordovician. Upper Tremadocian and Floian units are extremely condensed and include extensive stratigraphic gaps. Multiple hardgrounds, sometimes with minor karstic overprint, imply recurrent periods of erosion and/or non-deposition. Like in other parts of Sweden, the Dapingian and Darriwilian succession is characterized by a relatively complete sedimentary record and low sedimentation rates.
Carbon isotope stratigraphy in the latest Ordovician of Estonia
Chemical Geology, 2001
On the basis of bulk carbonate carbon isotope data from six drill cores and the type section of the Porkuni Stage of Estonia, d 13 C curves were compiled, which altogether cover nearly the whole succession of the latest Ordovician Ž .