Conodonts and brachiopods from the Volkhov Stage (Lower Ordovician) microbial mud mound at Putilovo Quarry, north-western Russia

Tolmacheva, T. Yu.; Fedorov, Petr V.; Egerquist, Eva

doi:10.37570/bgsd-2003-50-05

Cited by 19 publications

(8 citation statements)

References 5 publications

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“…In the 'normal' succession at this locality there is a well-developed 'Steklo' hardground upon which follows an approximately 1•2 m-thick carbonate sequence containing conodonts of the B. navis Zone. An interesting and unusual feature in the Putilovo Quarry is the presence of a microbial mud mound, which is about 300 m wide and up to 3•5 m thick in its centre (Fedorov 1999(Fedorov , 2003. Detailed conodont biostratigraphic investigations of this structure (Tolmacheva et al 2003) & Fedorov 2001).…”

Section: St Petersburg Region Northwestern Russiamentioning

confidence: 99%

“…For the present study, the investigations along Lava River (Tolmacheva & Fedorov 2001) and at the Putilovo Quarry (Tolmacheva et al 2003) are of special interest. In the former section (Fig.…”

Section: St Petersburg Region Northwestern Russiamentioning

confidence: 99%

“…Floian and Dapingian strata are locally well exposed in the classical Ordovician outcrop area in the St Petersburg region of northwestern Russia (Ma ¨nnil & Meidla 1994;Dronov et al 1995Dronov et al , 1996. Recent conodont investigations (Tolmacheva & Fedorov 2001;Tolmacheva 2001;Tolmacheva et al , 2003 have produced important new information regarding the identity of many of Pander's (1856) and Sergeeva's (1963Sergeeva's ( , 1974 taxa, as well as on the conodont faunal succession.…”

Section: St Petersburg Region Northwestern Russiamentioning

confidence: 99%

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The base of the global Dapingian Stage (Ordovician) in Baltoscandia: conodonts, graptolites and unconformities

Bergström¹,

Löfgren²

2008

Earth and Environmental Science Transactions of the Royal Socie

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In the recently completed and formally ratified new series and stage classification of the Ordovician System, the base of the Middle Ordovician Series coincides with the base of the global Dapingian Stage. In the Global Stratotype Section and Point (GSSP) of this stage, which is located at Huanghuachang in southern China, the base of the Dapingian Stage is defined as the level of first appearance of the conodont Baltoniodus triangularis. The fact that this species, along with some other taxa present at the Dapingian GSSP, occurs in many sections in Baltoscandia makes it possible to recognise with considerable precision the level of this global stage boundary in Sweden, Estonia, northwestern Russia, and Denmark. In several, but not all, regions, especially in the East Baltic, the global stage boundary coincides with the base of the regional Volkhov Stage and can be tied to the base of the Megistaspis polyphemus Trilobite Zone. The regionally somewhat different relationships between the position of the global stage boundary and a very widespread hardground complex are probably due to the occurrence of local and/or regional unconformities in the upper Floian–lower Dapingian interval. Although biostratigraphically important graptolites are present in the study interval in some Baltoscandic sections, the precise graptolite correlation of the base of the Dapingian Stage remains somewhat unclear, although it appears to be near, or at, the base of the Isograptus victoriae victoriae Zone (Ca 2).

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Section: St Petersburg Region Northwestern Russiamentioning

confidence: 99%

Section: St Petersburg Region Northwestern Russiamentioning

confidence: 99%

Section: St Petersburg Region Northwestern Russiamentioning

confidence: 99%

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The base of the global Dapingian Stage (Ordovician) in Baltoscandia: conodonts, graptolites and unconformities

Bergström¹,

Löfgren²

2008

Earth and Environmental Science Transactions of the Royal Socie

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“…From Estonia -Ma ¨ekalda in N Estonia (Viira et al 2001), and the Tamsalu drill-core in north-central Estonia (Sjo ¨strand 2003;Lo ¨fgren 2004;Viira et al 2006). From Russia -from the St Petersburg region: the Lava and Putilovo sections (Tolmacheva & Fedorov 2001).…”

Section: Localities and Materialsmentioning

confidence: 99%

Morphology, evolution and stratigraphic distribution in the Middle Ordovician conodont genus Microzarkodina

Löfgren¹,

Tolmacheva²

2008

Earth and Environmental Science Transactions of the Royal Socie

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Microzarkodina is a genus of mainly Middle Ordovician conodonts that has its centre of distribution in Baltoscandia, and much less commonly occurs in southern China, Australia, Argentina and Laurentia. In Baltica a series of species, Microzarkodina russica n. sp., M. flabellum, M. parva, M. bella, M. hagetiana and M. ozarkodella, established themselves successfully. The succession of species ranges from just below the base of the Middle Ordovician (M. russica) to the upper part of the Middle Ordovician (M. ozarkodella). The species are frequently used for biostratigraphical purposes. The largely contemporaneous species Microzarkodina bella and M. hagetiana probably both evolved from M. parva and mostly occurred in separate areas. Microzarkodina ozarkodella probably evolved from M. hagetiana. This present investigation is based on a total of 94,208 elements, collected from 20 sections and one drill-core site in Sweden, one drill-core site and one outcrop in Estonia and two sections in the St Petersburg area in Russia. The Microzarkodina apparatus probably consisted of 15 or 17 elements: four P, two or four M and nine S elements. The S elements include different Sa, Sb 1 , Sb 2 , and Sc element types. KEY WORDS: Baltoscandia, biostratigraphy, Conodonta, Microzarkodina russica n. sp., taxonomy Microzarkodina Lindströ m, 1971, is a chiefly Middle Ordovician conodont genus with its major area of distribution in Baltoscandia. The first appearance of Microzarkodina occurs in the late Floian, the Second Stage of the Ordovician, and in the upper range of its distribution rare, stunted specimens of M. ozarkodella have even been retrieved from the late Middle Ordovician Eoplacognathus robustus Subzone of the Pygodus serra Zone in Poland (Dzik 1994). The main stratigraphic distribution of Microzarkodina is more restricted, ranging from the uppermost Oepikodus evae Zone (or the Baltoniodus triangularis Zone at the base of the Middle Ordovician in many areas) and throughout the M. ozarkodella Subzone of the Eoplacognathus pseudoplanus Zone.The six species of Microzarkodina treated in this study are morphologically very similar, they occur successively in the sections that have been investigated and elsewhere (Fig. 1) and several of them seem to be largely restricted in distribution to Baltica. In the absence of other, closely related taxa the most probable assumption is that these six species form a lineage with M. russica n. sp. as the oldest ancestor. Microzarkodina flabellum and, later M. parva, follow and seem to be more widely distributed geographically than M. russica n. sp. Microzarkodina parva is probably directly ancestral to both M. hagetiana and M. bella, which partly overlap stratigraphically. Morphological and distributional similarities makes it most probable that M. ozarkodella evolved from M. hagetiana.Microzarkodina migrated into the Baltoscandian basin at approximately the same time as some other conodont taxa, such as Trapezognathus and Baltoniodus.

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“…Conodont microfossils have been known for more than 160 years with the first description of these phosphatic elements published being that of Pander (1856), who based his study on material from the St. Petersburg region, Russia. Since then, several studies have dealt with Ordovician conodonts from this area (e.g., Sergeeva 1962Sergeeva , 1963Sergeeva , 1974Bergström 1988;Tolmacheva et al , 2003aTolmacheva et al , 2003b. The present study follows this research tradition and is based on conodonts from the Lynna River section of Russia (Fig.…”

Section: Introductionmentioning

confidence: 99%

Middle Ordovician Drepanoistodus (Vertebrata, Conodonta) from Baltica, with description of three new species

Rasmussen

Eriksson

Lindskog

2021

EJT

594

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Drepanoistodus basiovalis (Sergeeva, 1963) is a common conodont species in Middle Ordovician strata of Baltica. For many years it has been widely accepted that the species encompasses a wide range of morphological plasticity. Hence, several different morphotypes that significantly deviate from the holotype have nonetheless been included in the broad species concept. In this study, we performed a detailed taxonomical study on 112 predominantly well-preserved specimens (geniculate elements) from the St. Petersburg region of Russia; 37 of these were selected for morphometric analyses together with 21 well-illustrated specimens from the published literature. The results demonstrate that, among the morphotypes that share some characteristics with D. basiovalis sensu lato, at least five species can be readily distinguished. Hence, three new species – Drepanoistodus iommii sp. nov., D. svendi sp. nov. and D. viirae sp. nov. – are here added to the previously known D. basiovalis and D. contractus (Lindström, 1955). In addition, some specimens were left under open nomenclature and assigned to Drepanoistodus aff. basiovalis and D. cf. suberectus (Branson & Mehl, 1933). In order to objectively compare the Drepanoistodus taxa and test the validity of the new species, we performed a Principal Component Analysis combined with non-parametric (PERMANOVA) tests based on 21 morphological characters.

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Conodonts and brachiopods from the Volkhov Stage (Lower Ordovician) microbial mud mound at Putilovo Quarry, north-western Russia

Cited by 19 publications

References 5 publications

The base of the global Dapingian Stage (Ordovician) in Baltoscandia: conodonts, graptolites and unconformities

The base of the global Dapingian Stage (Ordovician) in Baltoscandia: conodonts, graptolites and unconformities

Morphology, evolution and stratigraphic distribution in the Middle Ordovician conodont genus Microzarkodina

Middle Ordovician Drepanoistodus (Vertebrata, Conodonta) from Baltica, with description of three new species

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