The regional stratotype section and point for the base of the Hirnantian Stage (the uppermost Ordovician) at Mirny Creek, Omulev Mountains, Northeast Russia
A complete Hirnantian sequence comprising the Normalograptus extraordinarius and N. persculptus biozones is well developed at the Mirny Creek section in the Omulev Mountains. The underlying beds are assigned to the Appendispinograptus supernus Biozone, and in the overlying strata the lower boundar...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Estonian Academy Publishers
2008-03-01
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| Series: | Estonian Journal of Earth Sciences |
| Subjects: | |
| Online Access: | http://eap.ee/public/Estonian_Journal_of_Earth_Sciences/2008/issue_1/earth-2008-1-1.pdf |
| _version_ | 1818422519987699712 |
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| author | Koren, Tatyana N. Sobolevskaya, Rimma F. |
| author_facet | Koren, Tatyana N. Sobolevskaya, Rimma F. |
| author_sort | Koren, Tatyana N. |
| collection | DOAJ |
| description | A complete Hirnantian sequence comprising the Normalograptus extraordinarius and N. persculptus biozones is well developed at the Mirny Creek section in the Omulev Mountains. The underlying beds are assigned to the Appendispinograptus supernus Biozone, and in the overlying strata the lower boundary of the Silurian is precisely defined at the base of the Akidograptus ascensus Biozone. Due to the completeness of the sedimentary and palaeontological record, the Mirny Creek section can be considered as a reference section for the Hirnantian Stage. The succession, about 100 m thick, is composed of calcareous siltstones and marls with pebble-shaped limestones, deposited at a high sedimentation rate in shallow shelf settings. The regional stratotype section and point (RSSP) for the lower boundary of the Hirnantian is established at the base of member 68, where Normalograptus extraordinarius first appears. This level can be precisely correlated with that at the GSSP section in Yichang and with the sections in Kazakhstan and North America. The position of the Ordovician-Silurian boundary is redefined and placed at the FAD of A. ascensus at the base of member 74. |
| first_indexed | 2024-12-14T13:27:33Z |
| format | Article |
| id | doaj.art-1c6853125f414bc2b983a13dc2e67101 |
| institution | Directory Open Access Journal |
| issn | 1736-4728 |
| language | English |
| last_indexed | 2024-12-14T13:27:33Z |
| publishDate | 2008-03-01 |
| publisher | Estonian Academy Publishers |
| record_format | Article |
| series | Estonian Journal of Earth Sciences |
| spelling | doaj.art-1c6853125f414bc2b983a13dc2e671012022-12-21T22:59:47ZengEstonian Academy PublishersEstonian Journal of Earth Sciences1736-47282008-03-01571110The regional stratotype section and point for the base of the Hirnantian Stage (the uppermost Ordovician) at Mirny Creek, Omulev Mountains, Northeast RussiaKoren, Tatyana N.Sobolevskaya, Rimma F.A complete Hirnantian sequence comprising the Normalograptus extraordinarius and N. persculptus biozones is well developed at the Mirny Creek section in the Omulev Mountains. The underlying beds are assigned to the Appendispinograptus supernus Biozone, and in the overlying strata the lower boundary of the Silurian is precisely defined at the base of the Akidograptus ascensus Biozone. Due to the completeness of the sedimentary and palaeontological record, the Mirny Creek section can be considered as a reference section for the Hirnantian Stage. The succession, about 100 m thick, is composed of calcareous siltstones and marls with pebble-shaped limestones, deposited at a high sedimentation rate in shallow shelf settings. The regional stratotype section and point (RSSP) for the lower boundary of the Hirnantian is established at the base of member 68, where Normalograptus extraordinarius first appears. This level can be precisely correlated with that at the GSSP section in Yichang and with the sections in Kazakhstan and North America. The position of the Ordovician-Silurian boundary is redefined and placed at the FAD of A. ascensus at the base of member 74.http://eap.ee/public/Estonian_Journal_of_Earth_Sciences/2008/issue_1/earth-2008-1-1.pdfHirnantianregional stratotypegraptolitesbrachiopodsNE Russia |
| spellingShingle | Koren, Tatyana N. Sobolevskaya, Rimma F. The regional stratotype section and point for the base of the Hirnantian Stage (the uppermost Ordovician) at Mirny Creek, Omulev Mountains, Northeast Russia Estonian Journal of Earth Sciences Hirnantian regional stratotype graptolites brachiopods NE Russia |
| title | The regional stratotype section and point for the base of the Hirnantian Stage (the uppermost Ordovician) at Mirny Creek, Omulev Mountains, Northeast Russia |
| title_full | The regional stratotype section and point for the base of the Hirnantian Stage (the uppermost Ordovician) at Mirny Creek, Omulev Mountains, Northeast Russia |
| title_fullStr | The regional stratotype section and point for the base of the Hirnantian Stage (the uppermost Ordovician) at Mirny Creek, Omulev Mountains, Northeast Russia |
| title_full_unstemmed | The regional stratotype section and point for the base of the Hirnantian Stage (the uppermost Ordovician) at Mirny Creek, Omulev Mountains, Northeast Russia |
| title_short | The regional stratotype section and point for the base of the Hirnantian Stage (the uppermost Ordovician) at Mirny Creek, Omulev Mountains, Northeast Russia |
| title_sort | regional stratotype section and point for the base of the hirnantian stage the uppermost ordovician at mirny creek omulev mountains northeast russia |
| topic | Hirnantian regional stratotype graptolites brachiopods NE Russia |
| url | http://eap.ee/public/Estonian_Journal_of_Earth_Sciences/2008/issue_1/earth-2008-1-1.pdf |
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