Brachiopods and Trilobites of the Early Ordovician Serpentine Otta Conglomerate, South Central Norway (original) (raw)
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Brachiopod associations from the Middle Ordovician of the Oslo Region, Norway
Palaeontology, 2010
ABSTRACT The marine upper Darriwilian (Middle Ordovician) Elnes Formation of southern Norway contains very rich and diverse invertebrate faunas. Stratigraphically detailed recent collections of these well-preserved faunas have permitted a more thorough description of the various faunal groups and their preferences in the late Middle Ordovician of the Oslo Region, southern Norway, than ever before. The brachiopod faunas are described in the present article, which include a new genus and a new species respectively Wandaasella modheimrensis and Cyclomyonia vikersundi. The brachiopod fauna is largely dominated by linguliformeans although some sections of the formation are dominated by the plectambonitoids Alwynella ildjernensis Spjeldnæs or Cathrynia aequistriata (Hadding) or by orthid brachiopods. Statistical analysis of the brachiopod fauna reveals that the general depositional trend of the Elnes Formation is that of a regressive event from the lower part of the Sjøstrand Member to the Håkavik Member. Three main brachiopod associations are recognised: a deep-water, lingulid dominated association associated with quiet and dysoxic bottom conditions, a sowerbyellid dominated association (e.g. Cathrynia and Alwynella) found in muddy to marly deposits formed around maximal storm wave base and an orthid-dominated association representing an environment characterised by a fairly coarse or hard bottom substrate formed well above storm wave base but below fair weather wave base.
2006
The aim of the present study is to improve knowledge of the brachiopod fauna in the lower part of the Arnestad Formation (Caradoc) in the OsloAsker district and to document faunal changes prior to the Scoto-Appalachian brachiopod migration into the Oslo Region. This migration appears to have taken place during deposition of the upper Haljala and Keila stages (Lower Caradoc). Like the faunas in other parts of Baltica, the brachiopod fauna in the lower part of the Arnestad Formation, occupied an environment influenced by moderate current or wave regimes. It has a lower diversity than the more cosmopolitan brachiopod fauna in the upper part of the formation. The fauna in the lower part of the Arnestad Formation is, however, more diverse than the equivalent Swedish faunas in the Scanian Confacies Belt (“Outer facies belt”). The closest affinity, at the generic level, is with the faunas from the Livonian Tongue of the Central Baltoscandian Confacies Belt (“Middle facies belt”). The Onnie...
Orthacean and strophomenid brachiopods from the Lower Silurian of the central Oslo Region
Lethaia, 1995
Fossils and Strata is an international series of monographs and memoirs in palaeontology and stratigraphy, published in cooperation between the Scandinavian countries.1t is issued in Numbers with individual pagination. Fossils and Strata forms part of the same structured publishing programme as the journals Lethaia and Boreas. These two journals are fully international and accept papers within their respective sectors of science without national limitations orpreferences. Fossils and Strata, however, is an outlet for more comprehensive systematic and regional monographs emanating primarily from the five countries of Norden. Contributions from other countries may also be included if this series is deemed appropriate with regard to distribution and availability. Articles can normally only be accepted if they are heavily subsidized by the national Research Council in their country of origin or by other funds. All in come is reinvested in forthcoming numbers of the series. Although articles in German and French may be accepted, the use of English is strongly preferred. An English abstract should always be provided, and non-English articles should have English versions of the figure captions. Abstracts or summaries in one or more additional languages may be added. Many regional or systematic descriptions and revisions contain a nucleus of resuIts which are of immediate and general interest in international palaeontology and stratigraphy. It is expected that authors of such papers will to some extent duplicate their publication in the form of an article for a journal, in the first place Lethaia or Boreas.
1984
The Nakholmen Formation, at its type locality on the island of Nakholmen, Bunnefjord, consists of 13-14 m of dark shales with a few horizons of limestone nodules. The low-diversity but locally abundant fauna includes the brachiopods Hisingerella nana, Onniella cf. bancrofti and Sericoidea gamma, the trilobites Broeggerolithus discors and Lonchodomas aff. rostratus and the graptolites Amplexograptus rugosus, Climacograptus antiquus lineatus and Corynoides incurvus. The shelly and graptolite faunas suggest correlations with the Woolstonian-Actonian stages of the Caradoc and the lower part of the Dicranograp tus clingani Zone respectively. The assemblage represents a deepwater, euxinic, biofacies offshore from the well-developed shelly associations in coeval strata in Asker, Ringerike and Hadeland. The brachio pod fauna is markedly dissimilar from those coeval associations elsewhere in the region, but the trilobite faunas have many elements in common.