Miaolingian trilobiitide biostratigraafia ja susiniku kemostratigraafia Tingskulleni puuraugus Rootsis Olandi saarel

The Cambrian succession of the Tingskullen drill core from northern Öland comprises Cambrian Series 2 and Miaolingian (Wuliuan Stage) siliciclastic strata. The major portion of the succession is represented by the Miaolingian Borgholm Formation, which, in ascending order, is subdivided into the Mossberga, Bárstad and Äleklinta members. The Äleklinta Member is barren of body fossils, whereas the Mossberga and Bárstad members are moderately to highly fossiliferous and biostratigraphically reasonably well constrained. Trilobites and agnostoids from the Bárstad Member are indicative of the Acadoparadoxides pinus Zone. The Mossberga Member has not yielded any zonal guide fossils but is tentatively assigned to the Eccaparadoxides insularis Zone. A [[delta] sup.13][C.sub.org] curve throughout the Borgholm Formation shows a general positive trend up-section without any distinctive excursion, suggesting that the Wuliuan Acadoparadoxides (Baltoparadoxides) oelandicus Superzone (the 'Oelandicus beds') of Öland is younger than the negative Redlichiid-Olenellid Extinction Carbon isotope Excursion (ROECE), which is known from near the top of Stage 4 and close to the traditional 'Lower-Middle Cambrian boundary' in several parts of the world. Kambriumi läbilõige Tingskulleni puuraugus Ölandi saarel sisaldab 2. ladestiku ja Miaolingi (Wuliu lade) ränipurd-kivimeid. Läbilõike põhiosa moodustab Miaolingi Borgholmi kihistu, mis on jagatud Mossberga, Bårstadi ja Äleklinta kihistikuks. Äleklinta kihistik ei sisalda fossiile, kuid Mossberga ja Bårstadi kihistikud on fossiilirikkad ning biostratigraafiliselt küllalt hästi esindatud. Bårstadi kihistiku trilobiidid ja agnostiidid määravad selle kuulumise Acadoparadoxides pinus'e biotsooni. Mossberga kihistik ei sisalda indeksfossiile, kuid on tinglikult arvatud Eccaparadoxides insularis'e biotsooni kuuluvaks. Borgholmi kihistu [[delta] sup.13][C.sub.org] profiili iseloomustab üldine positiivne trend ja selgete isotoopsündmuste puudumine. See näitab, et Wuliu lademesse kuuluva Acadoparadoxides (Baltoparadoxides) oelandicus'e ülembiotsoon (Oelandicuse kihid) Ölandil on noorem kui redlihhiidide-olenelliidide väljasuremine ja negatiivne süsiniku isotoophälve (ROECE). Viimane on teada Kambriumi 4. lademe ülaosast ja asub lähedal traditsioonilisele Alam- ning Kesk-Kambriumi piirile maailma eri piirkondades. Key words: biostratigraphy, carbon isotope stratigraphy, Miaolingian Series, Wuliuan Stage, Cambrian, Öland, Sweden.