Biostratigraphic significance of the latest Cambrian-earliest Ordovician agnostoid trilobites from Northwestern Argentina
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| Format: | Artículo científico |
| Language: | en |
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Universitat de Barcelona
2003
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| author | M. F. Tortello |
| author_facet | M. F. Tortello |
| contents | Biostratigraphic significance of the latest Cambrian-earliest Ordovician agnostoid trilobites from Northwestern Argentina M. F. Tortello Ciencias de la Tierra Trilobita Agnostida Latest Cambrian Biostratigraphy earliest Ordovician The biostratigraphic significance of the latest Cambrian-earliest Ordovician trilobite agnostoids from northwesternArgentina is summarized. A characterization of the faunas recognized below and above the Cambrian-Ordovicianboundary is presented on the bases of information from sierra de Cajas (Jujuy Province, Eastern Cordillera;Lampazar and Cardonal Formations), río Volcancito (La Rioja Province, Famatina range; VolcancitoFormation) and other localities assigned to the Parabolina frequens argentina Biozone. In addition, the stratigraphicmeaning of each agnostoid species from the P. frequens argentina Zone is updated. The uppermost Cambrianis characterized by a distinctive agnostoid assemblage composed of Lotagnostus (Lotagnostus) sp., Lotagnostus(Semagnostus) zuninoi (HARRINGTON and LEANZA), Micragnostus vilonii HARRINGTON and LEANZA, M.calviformis HARRINGTON and LEANZA, Strictagnostus? micropeltis (HARRINGTON and LEANZA), Pseudorhaptagnostus(Machairagnostus) tmetus HARRINGTON and LEANZA, Pseudorhaptagnostus (Machairagnostus) cf. tmetusHARRINGTON and LEANZA, Pseudorhaptagnostus (Machairagnostus) sp., Gymnagnostus bolivianus (HOEK), Gymnagnostusperinflatus HARRINGTON and LEANZA, and Leiagnostus turgidulus HARRINGTON and LEANZA. This faunais commonly recorded together with the polymeroid Beltella ulrichi (KAYSER), Onychopyge HARRINGTON, Plicatolinascalpta HARRINGTON and LEANZA, Parabolina frequens argentina (KAYSER), Parabolinella coelatifronsHARRINGTON and LEANZA, and Angelina hyeronimi (KAYSER). Based on this agnostoid-polymeroid fauna, aPseudorhaptagnostus (Machairagnostus) - Gymnagnostus Assemblage Subzone (lower part of the P. frequensargentina Zone) is formally proposed. Agnostoid diversity drastically declines through the Cambrian-Ordovicianboundary, probably as a consequence of a regional regressive-transgressive event. In the lowest Tremadoc theagnostoid records are mainly restricted to Trilobagnostus chiushuensis (KOBAYASHI) and some forms describedunder open nomenclature (Anglagnostus? sp., Micragnostus sp.). The upper part of the P. frequens argentinaZone is better defined by polymeroid trilobites. Jujuyaspis keideli KOBAYASHI is its most characteristic species. 2003 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50510106 en http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.1 Vol.1 |
| format | Artículo científico |
| id | redalyc_50510106 |
| institution | Redalyc |
| language | en |
| publishDate | 2003 |
| publisher | Universitat de Barcelona |
| spellingShingle | Biostratigraphic significance of the latest Cambrian-earliest Ordovician agnostoid trilobites from Northwestern Argentina M. F. Tortello Ciencias de la Tierra Trilobita Agnostida Latest Cambrian Biostratigraphy earliest Ordovician Biostratigraphic significance of the latest Cambrian-earliest Ordovician agnostoid trilobites from Northwestern Argentina M. F. Tortello Ciencias de la Tierra Trilobita Agnostida Latest Cambrian Biostratigraphy earliest Ordovician The biostratigraphic significance of the latest Cambrian-earliest Ordovician trilobite agnostoids from northwesternArgentina is summarized. A characterization of the faunas recognized below and above the Cambrian-Ordovicianboundary is presented on the bases of information from sierra de Cajas (Jujuy Province, Eastern Cordillera;Lampazar and Cardonal Formations), río Volcancito (La Rioja Province, Famatina range; VolcancitoFormation) and other localities assigned to the Parabolina frequens argentina Biozone. In addition, the stratigraphicmeaning of each agnostoid species from the P. frequens argentina Zone is updated. The uppermost Cambrianis characterized by a distinctive agnostoid assemblage composed of Lotagnostus (Lotagnostus) sp., Lotagnostus(Semagnostus) zuninoi (HARRINGTON and LEANZA), Micragnostus vilonii HARRINGTON and LEANZA, M.calviformis HARRINGTON and LEANZA, Strictagnostus? micropeltis (HARRINGTON and LEANZA), Pseudorhaptagnostus(Machairagnostus) tmetus HARRINGTON and LEANZA, Pseudorhaptagnostus (Machairagnostus) cf. tmetusHARRINGTON and LEANZA, Pseudorhaptagnostus (Machairagnostus) sp., Gymnagnostus bolivianus (HOEK), Gymnagnostusperinflatus HARRINGTON and LEANZA, and Leiagnostus turgidulus HARRINGTON and LEANZA. This faunais commonly recorded together with the polymeroid Beltella ulrichi (KAYSER), Onychopyge HARRINGTON, Plicatolinascalpta HARRINGTON and LEANZA, Parabolina frequens argentina (KAYSER), Parabolinella coelatifronsHARRINGTON and LEANZA, and Angelina hyeronimi (KAYSER). Based on this agnostoid-polymeroid fauna, aPseudorhaptagnostus (Machairagnostus) - Gymnagnostus Assemblage Subzone (lower part of the P. frequensargentina Zone) is formally proposed. Agnostoid diversity drastically declines through the Cambrian-Ordovicianboundary, probably as a consequence of a regional regressive-transgressive event. In the lowest Tremadoc theagnostoid records are mainly restricted to Trilobagnostus chiushuensis (KOBAYASHI) and some forms describedunder open nomenclature (Anglagnostus? sp., Micragnostus sp.). The upper part of the P. frequens argentinaZone is better defined by polymeroid trilobites. Jujuyaspis keideli KOBAYASHI is its most characteristic species. 2003 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50510106 en http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.1 Vol.1 |
| title | Biostratigraphic significance of the latest Cambrian-earliest Ordovician agnostoid trilobites from Northwestern Argentina |
| topic | Ciencias de la Tierra Trilobita Agnostida Latest Cambrian Biostratigraphy earliest Ordovician |
| url | https://www.redalyc.org/articulo.oa?id=50510106 |