Biostratigraphical and palaeobiogeographical implications of Lower Silurian Radiolaria from black cherts of the Armorican Massif (France)
A moderately well-preserved radiolarian assemblage was recovered from organic-rich black chert in a Llandovery (Lower Silurian) sequence that crops out in southern Brittany (Chalonnes-sur-Loire section, Armorican Massif, France). The assemblage is composed of two families (Rotasphaeridae and Haplota...
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ftcopernicus:oai:publications.copernicus.org:jm65690 2023-05-15T15:07:33+02:00 Biostratigraphical and palaeobiogeographical implications of Lower Silurian Radiolaria from black cherts of the Armorican Massif (France) Tetard, Martin Danelian, Taniel Noble, Paula 2018-09-27 application/pdf https://doi.org/10.1144/jmpaleo2014-013 https://jm.copernicus.org/articles/33/165/2014/ eng eng doi:10.1144/jmpaleo2014-013 https://jm.copernicus.org/articles/33/165/2014/ eISSN: 2041-4978 Text 2018 ftcopernicus https://doi.org/10.1144/jmpaleo2014-013 2020-07-20T16:24:58Z A moderately well-preserved radiolarian assemblage was recovered from organic-rich black chert in a Llandovery (Lower Silurian) sequence that crops out in southern Brittany (Chalonnes-sur-Loire section, Armorican Massif, France). The assemblage is composed of two families (Rotasphaeridae and Haplotaeniatidae), four genera (? Diparvapila, Secuicollacta, Orbiculopylorum, Haplotaeniatum ) and 13 species. Some were identified from whole specimens preserved in silica and extracted following dilute hydrofluoric acid processing, while others were recognized in thin-section preparations, as they are beautifully preserved as ‘carbonized’ microfossils. The age range suggested by conodonts and chitinozoans yielded after HF processing from one of the 27 studied samples is in good agreement with the previously published age based on graptolites. The recovered radiolarians are discussed, documented and compared with known Rhuddanian, Aeronian and lower Telychian assemblages in the literature. The stratigraphic ranges are extended for the species Secuicollacta bipola, S. hexactinia, S. parvitesta, Orbiculopylorum granti and O. splendens based on our new data. A significant number of radiolarians found in our samples occur in Llandovery sections from Alaska, Nevada, Arctic Canada and Sweden. These similarities are used to discuss the palaeodistribution of Lower Silurian Radiolaria and our observations support the hypothesis of a wide geographical distribution for these Palaeozoic species. Text Arctic Alaska Copernicus Publications: E-Journals Arctic Canada Journal of Micropalaeontology 33 2 165 178 |
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Copernicus Publications: E-Journals |
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language |
English |
description |
A moderately well-preserved radiolarian assemblage was recovered from organic-rich black chert in a Llandovery (Lower Silurian) sequence that crops out in southern Brittany (Chalonnes-sur-Loire section, Armorican Massif, France). The assemblage is composed of two families (Rotasphaeridae and Haplotaeniatidae), four genera (? Diparvapila, Secuicollacta, Orbiculopylorum, Haplotaeniatum ) and 13 species. Some were identified from whole specimens preserved in silica and extracted following dilute hydrofluoric acid processing, while others were recognized in thin-section preparations, as they are beautifully preserved as ‘carbonized’ microfossils. The age range suggested by conodonts and chitinozoans yielded after HF processing from one of the 27 studied samples is in good agreement with the previously published age based on graptolites. The recovered radiolarians are discussed, documented and compared with known Rhuddanian, Aeronian and lower Telychian assemblages in the literature. The stratigraphic ranges are extended for the species Secuicollacta bipola, S. hexactinia, S. parvitesta, Orbiculopylorum granti and O. splendens based on our new data. A significant number of radiolarians found in our samples occur in Llandovery sections from Alaska, Nevada, Arctic Canada and Sweden. These similarities are used to discuss the palaeodistribution of Lower Silurian Radiolaria and our observations support the hypothesis of a wide geographical distribution for these Palaeozoic species. |
format |
Text |
author |
Tetard, Martin Danelian, Taniel Noble, Paula |
spellingShingle |
Tetard, Martin Danelian, Taniel Noble, Paula Biostratigraphical and palaeobiogeographical implications of Lower Silurian Radiolaria from black cherts of the Armorican Massif (France) |
author_facet |
Tetard, Martin Danelian, Taniel Noble, Paula |
author_sort |
Tetard, Martin |
title |
Biostratigraphical and palaeobiogeographical implications of Lower Silurian Radiolaria from black cherts of the Armorican Massif (France) |
title_short |
Biostratigraphical and palaeobiogeographical implications of Lower Silurian Radiolaria from black cherts of the Armorican Massif (France) |
title_full |
Biostratigraphical and palaeobiogeographical implications of Lower Silurian Radiolaria from black cherts of the Armorican Massif (France) |
title_fullStr |
Biostratigraphical and palaeobiogeographical implications of Lower Silurian Radiolaria from black cherts of the Armorican Massif (France) |
title_full_unstemmed |
Biostratigraphical and palaeobiogeographical implications of Lower Silurian Radiolaria from black cherts of the Armorican Massif (France) |
title_sort |
biostratigraphical and palaeobiogeographical implications of lower silurian radiolaria from black cherts of the armorican massif (france) |
publishDate |
2018 |
url |
https://doi.org/10.1144/jmpaleo2014-013 https://jm.copernicus.org/articles/33/165/2014/ |
geographic |
Arctic Canada |
geographic_facet |
Arctic Canada |
genre |
Arctic Alaska |
genre_facet |
Arctic Alaska |
op_source |
eISSN: 2041-4978 |
op_relation |
doi:10.1144/jmpaleo2014-013 https://jm.copernicus.org/articles/33/165/2014/ |
op_doi |
https://doi.org/10.1144/jmpaleo2014-013 |
container_title |
Journal of Micropalaeontology |
container_volume |
33 |
container_issue |
2 |
container_start_page |
165 |
op_container_end_page |
178 |
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1766339033988857856 |