Late OrdovicianHolorhynchussuccession in the Siljan district, Sweden: facies, faunas and a latest Katian event (original) (raw)
Related papers
2010
The correlation of the uppermost Boda Core Member of the Boda Limestone is reassessed and the beds assigned to the upper Katian. This is based on the identification of the brachiopod species Brevilamnulella kjerulfi (Kiaer) and Amphiplecia tardicostata Wright & Jaanusson from the highest beds in the unit. The former species is overwhelmingly abundant in the uppermost beds of the Boda Core Member in Osmundsberget quarry, forming an almost monospecific coquina. Also occurring in the coquina, is Clorilamnulella osmundsbergensis gen. et sp. nov., which ranges into the overlying Hirnantian Glisstjärn Formation. The new genus is here regarded as a transitional form between Brevilamnulella and Clorinda. The oldest occurrence of this latter genus is here revised and not found in rocks older than the Aeronian. Instead, previous Rhuddanian occurrences of 'Clorinda' are transferred to Clorilamnulella based on a dorsal cardinalia that differs from both that of Brevilamnulella, as well as that of Clorinda. Moreover, gigantic shells of a new species of Brevilamnulella, B. umbosulcata sp. nov, are described from the nearby Solberga quarry where the species occurs in great abundance in a local fossil pocket, that also is correlated with the upper Katian. These new virgianid and clorindoid occurrences, together with previously described occurrences of Holorhynchus and Costilamnulella, demonstrate that during the late Katian, the Boda Limestone was a virgianid hotspot crucial in the evolution of the earliest pentameroid family, the Virgianidae, as well as a possible early cradle for the evolution of the hitherto exclusively Silurian superfamily, the Clorindoidea.
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.
Discinacean brachiopods from the Ordovician Kullsberg and Boda limestones of Dalarna, Sweden
Geologiska Foereningens I Stockholm Foerhandlingar, 1987
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2007
Abstract. Integrated palaeontological and sedimentological study of the Upper Ordovician Vormsi Stage in the Lelle drill core section, Central Estonia, revealed an association of shelly fauna containing the endemic saukrodictyid brachiopod Hulterstadia cor (Wiman), which is otherwise known only from erratic boulders close to Hulterstad in the southeastern area of the Island of Öland, Sweden. In the Lelle core this fauna occurs in the uppermost Fungochitina spinifera chitinozoan Biozone of mid-Vormsi age.
Lethaia, 2008
Bulk samples of brachiopods from the middle and upper parts of the Arnestad Formation and the entire Frognerkilen Formation in the Oslo Region demonstrate major vertical changes in the Sandbian to Katian amphicratonic fauna of this part of the Baltic Province. The main influx of new taxa occurred in the upper part of the Arnestad Formation (uppermost Sandbian), and in the succeeding Frognerkilen Formation (basal Katian). Faunal change is initially reflected in an increase in diversity and not as a replacement of the previously incumbent genera, which remain throughout the studied sequence. The majority of the new genera migrated from the East Baltic Region or through this region from Avalonia, while the marginal Laurentian taxa first occupied the Scandinavian part of Baltica. Six taxa migrated from Laurentia, three from Avalonia, two from Gondwana and one apparently originated on the South China palaeoplate. The faunal shifts and immigration of brachiopods appear to have been in response to an initial transgression together with the movement of Baltica into more warm temperate latitudes, but the diverse faunas developed both against a background of subsequent regression and in response to an offshore shift of biofacies. The new amphicratonic fauna was thus generated by faunal shifts from elsewhere in the Baltic Province to the marginal environments of the Oslo Region together with more exotic elements from neighbouring continents and microcontinents. ᮀ Arnestad Formation, brachiopods, Frognerkilen Formation, immigration, Late Ordovician, Oslo Region.
Middle Ordovician phosphatic inarticulate brachiopods from Vastergotland and Dalarna, Sweden
1989
Fossils and Strata is an international series of monographs and memoirs in palaeontology and stratigraphy, published in coopera tion between the Scandinavian countries. It is issued in Numbers with individual pagination, listed cumulatively on the back of each cover. 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 or preferences. Fos sils and Strata, however, is an outlet for more comprehensive system atic 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 availabili ty. Articles can normally only be accepted if they are heavily subsidized by the national Research Council in their country of origin or by other fu nds. All income is reinvested in fo rthcoming numbers of the series. Manuscripts should conform with the instructions on p. 30fthis cover. Normally the text should be submitted as word-processor LETHAlA
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.
GFF, 2008
Stegerhynchus eoborealis sp. nov. from the Dalmanitina Beds (Hirnantian, uppermost Ordovician), Borenshult, Östergötland, Sweden, is described in this study as the earliest known species of Stegerhynchus, within the family Rhynchotrematidae. This implies that Stegerhynchus originated during the latest Ordovician mass extinction event, and radiated in the Silurian Period to become one of most common rhynchonellide brachiopod genera in shallow tropical seas. In the early evolutionary stage of the genus, Stegerhynchus eoborealis already exhibited a notable reduction in the size of septalium compared to the closely related genus Rhynchotrema. Compared to its Silurian counterparts (e.g. Stegerhynchus borealis and S. peneborealis), Stegerhynchus eoborealis has some variable characters within single populations, particularly in the number of costae in the sulcus and on the fold, implying a morphological plasticity during the early evolutionary stage of the genus. During the Hirnantian mass extinction events, five rhynchonellide families were represented by small taxonomic groups, but only the Rhynchotrematidae and Trigonirhynchiidae diversified into many highly successful clades of rhynchonellides during the Silurian and Devonian. However, the Ancistrorhynchidae, Orthorhynchulidae, and Sphenotretidae largely disappeared by the end of the Ordovician, with a few species (such as Plectothyrella sp.) surviving into the earliest Silurian but shortly becoming extinct.