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- Ahlberg, Per, et al.
(author)
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Lotagnostus? : mystacinus, a rare agnostid from the Upper Cambrian of Sweden
- 2000
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In: Acta Palaeontologica Polonica. - 0567-7920. ; 45:1, s. 91-96
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Journal article (peer-reviewed)abstract
- Agnostids afford the best means of correlating Cambrian strata, and they are widely used for intercontinental correlations. They are most common in open-marine deposits and reached a maximum diversity during the Middle and early Late Cambrian. About twenty species of agnostids are known from the Upper Cambrian of Scandinavia. Lotagnostus? mystacinus Tjernvik, 1953 is a rare agnostid from the Upper Cambrian Agnostus pisiformis Zone of south-central Sweden. It is redescribed following examination of the holotype and an additional pygidium. The outline and morphology of especially the pygidial posteroaxis, which is distinctly trilobate by a pair of deep notular furrows, suggest that the species is best classified as a species of Lotagnostus. If correctly assigned to Lotagnostus, it would be the oldest known species of that genus.
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- Axheimer, Niklas, et al.
(author)
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A core drilling through Cambrian strata at Almbacken, Scania, S. Sweden: trilobites and stratigraphical assessment
- 2003
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In: GFF. - 2000-0863. ; 125, s. 139-156
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Journal article (peer-reviewed)abstract
- A core drilling at Almbacken in the village Sodra Sandby, Scania, southern Sweden, penetrated a c. 30 in thick succession of upper lower Cambrian and middle Cambrian strata. Only the uppermost part of the lower Cambrian (Gislov Formation) was recovered, comprising c. 1.50 m of unfossiliferous siltstones and a thin limestone bed at the base of the core. The core contains the most complete middle Cambrian succession so far documented in Scania. It contains a stratigraphical sequence from the Lejopyge laevigata Zone (upper Paradoxides forchhammeri Superzone) to the Holmia kjerulfi-group Zone (upper lower Cambrian). There is no faunal evidence for the presence of the Acadoparadoxides oelandicus Superzone. The middle Cambrian is 28.30 m thick and consists of dark grey to black mudstones and shales (Alum Shale) with stinkstones and limestone beds. Three major limestone beds were identified: the "Fragment Limestone" (0.35 m), the Exsulans Limestone (0.40 m), and the Andrarum Limestone (1.55 m). The middle Cambrian is richly fossiliferous, except in the lower six metres, and agnostoid trilobites generally dominate the faunas. Polymeroid trilobites and indeterminate lingulate brachiopods are abundant at some levels. The succession of trilobite species was used to erect a biostratigraphical subdivision into seven biozones. The preservation is generally good and 32 trilobites were identified to species level. The excellent preservation in the limestones allowed a description of growth stages in pygidia of Ptychagnostus punctuosus (Angelin, 1851).
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- Bergstrom, SM, et al.
(author)
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The Almelund Shale, a replacement name for the Upper Didymograptus Shale and the Lower Dicellograptus Shale in the lithostratigraphical classification of the Ordovician succession in Scania, Southern Sweden
- 2002
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In: Bulletin of the Geological Society of Denmark. - 0011-6297. ; 49, s. 41-47
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Journal article (peer-reviewed)abstract
- The formation name Almelund Shale is proposed for a lithostratigraphically defined unit to replace the outdated chronostratigraphical designations Upper Didymograptus Shale and Dicellograptus Shale in the Middle and lowermost Upper Ordovician succession in Scania. The Almelund Shale is a lithologically uniform unit of dark-grey to black shales with rare carbonate interbeds between the Komstad Limestone and the Sularp Shale. Apart from a diverse graptolite fauna it yields a few shelly fossils (mostly lingulate brachiopods) and biostratigraphically diagnostic conodonts and chitinozoans. In the type sections of the Almelund Shale along the Sularp Brook in the F (a) over circle gels (a) over circle ng area; W-central Scania, the top of the unit is taken to be the base of the F (a) over circle gels (a) over circle ng Phosphorite, and its basal contact is at the top of the underlying Komstad Limestone. Its total thickness in the F (a) over circle gels (a) over circle ng drill-core is 28.32 m. The unit is widely distributed in the subsurface in a SE-NW belt across Scania.
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