Late Devonian – Early Carboniferous conodonts of deepwater deposits

Laboratory of stratigraphy

Author Plotitsyn

A.N.Scientific supervisor D.Sc.(Geol.& Min.) Beznosova T.M.

Institute of GeologyKomi Science Center

Ural Division of the Russian Academy of Sciences

Keywords

Conodonts – конодонты

Deepwater deposits – глубоководные отложения

Agnatha - бесчелюстные

Annelids - кольчатые черви

Nematode worms - круглые черви

Clams - двустворчатые моллюски

Arthropoda - членистоногие

Coelenterates - кишечнополостные

Seaweed - морские водоросли

Logbook - полевой дневник

Conodonts – who are they?

Reconstructions of the conodont animal

Conodontassemblage

Different conodont elements

(A) Dorsal view of the reconstructed, closed apparatus of Novispathodus.(B) Orientation of the apparatus within the conodont’s head

Each organism had a set of morphologically distinct conodont elements

Christian Heinrich Pander (1794–1865), first researcher of conodonts.

First described by Christian H. Pander in 1859 from clays near St. Petersburg, Russia. He originally thought that they were a variety of small fish teeth. Afterwards there were a lot of different hypotheses concerning conodonts. For example: - agnatha;- annelids;- nematode worms;- clams; - arthropoda; - coelenterate; - seaweed; and etc. By the early 70s only two hypotheses were considered to be the most probable which substantiate the propinquity between conodonts and polychaeta worms and chordates.

Relevance

Upper Devonian and Lower Carboniferous conodonts are widespread at the Urals and in the matter of biota abundance and stratigraphic completeness play a great role for fauna evolution, patterns cognition, biostratigraphy issues clarification, regional and international zonal scales correlation and also for bounds delimitation between Devon and Carbon. At the research area deep facies deposits are poorly characterized by faunal remains. Conodonts are one of the main groups of fauna which is suitable for biostratigraphy and correlation of Upper Devonian and Lower Carboniferous sediments. Their geographical spread and fast evolution give us an opportunity to compare researched deep-water sections with standard and basic different facies sections on a regional, interregional and even intercontinental level. Conodont sequence creation for this very facial type of sediments within North Urals region is necessary to determine the level of regional boundary between Devon and Carbon.

The main objective of the research is to investigate conodonts of the Devonian (Famennian) and Carboniferous (Tournaisian) deposits. For the objective achievement the following tasks should be solved:

• Consider systematic composition of the conodont fauna and conduct biofacial analysis.

• Discover zonal conodont sequence in deepwater sediments and reveal the location of the bound between Devon and Carbon.

• Identify the boundaries of regional events and a scope of a Hangenberg global geological event (HGGE) in Subpolar and Polar Urals sections.

Fieldwork Page from logbook

Carbonate deposits

Scanning electron microscope

Binocular microscope

Franke chambers

Tectonic map of basin of the river Kozhim

Geological scheme of the middle reaches of the river Syvyu

Conodonts of Syvyu River section

1. Polygnathus - 12 species and subspecies (Pic. 3, 4, 5, 6, 17, 18, 22, 23, 24, 25, 27)

2. Palmatolepis - 6 species and subspecies (Pic. 1, 8, 9, 10)

3. Pseudopolygnathus - 4 species (Pic. 13, 21)

4. Bispathodus - 3 species and subspecies (Pic. 14, 20)

5. Branmehla - 2 species (Pic. 12 и 15)

6. Siphonodella - 2 species (Pic. 19 и 26)

7. Mehlina -1 species (Pic. 11)8. Hindeodus - 1 species 9. Pseudognathodus - 1

species10. Bizignathus - 1 species

(Pic. 7)11. Rhodalepis - 1 species (Pic.

16)

Boundary of the Devonian and Carboniferous systems and stratigraphic equivalents of Hangenberg shale

Thank you forattention!