| Texto completo | |
| Autor(es): |
Ribeiro, Victor Rodrigues
;
Ghilardi, Renato Pirani
Número total de Autores: 2
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Journal of South American Earth Sciences; v. 167, p. 12-pg., 2025-09-16. |
| Resumo | |
During the Devonian many sea-level fluctuations, anoxia, and biotic crises impacted marine faunas on a global and local scale. In southwestern Gondwana, these events can be identified by geochemical signatures, changes in the ichnofabric, and in the fossil assemblage. This study investigates the morphometric responses of brachiopods (Orbiculoidea; O. baini, O. bodenbenderi, and O. excentrica) to transgressive-regressive cycles and anoxic events (Basal Zl & iacute;chov, Chote & ccaron;, Daleje and Ka & ccaron;& aacute;k) through the Devonian of Paran & aacute; Basin. The Pragian-Emsian transgression, good paleoenvironmental conditions allowed brachiopods to reach a wide range of sizes, with large specimens (e.g.: dorsal valves of O. baini: 32.7 x 28.0 mm to 10.7 x 10.7 mm). Associated with the Basal Emsian Zl & iacute;chov Event, no significant size changes were detected during this transgressive event. However, the subsequent Chote & ccaron; Event (Emsian-Eifelian) triggered an irregular pattern of growth lines, suggesting changes in the oxygenation and geochemistry of the basin waters. The peak of environmental stress occurred during the Eifelian-Givetian transgression (Ka & ccaron;& aacute;k Event), leading to widespread anoxia and the "Lilliput Effect". O. baini dorsal valves shrank by similar to 90 % (15.7 x 15.1 mm to 5.2 x 5.9 mm), while O. excentrica exhibited similar dwarfing. Regional variations in growth patterns between northern and southern basins suggest localized paleoenvironmental stress and tropical water influx from the Parna & iacute;ba Basin. These findings highlight the differential impact of Devonian crises on brachiopods from the Paran & aacute; Basin, such as stable growth during transgressions, subtle ecophenotypic changes (pattern of growth lines) under moderate stress, and extreme size reduction during anoxia. (AU) | |
| Processo FAPESP: | 24/16899-7 - Incursões marinhas e trocas faunísticas no interior da América do Sul durante o Devoniano e os impactos paleobiogeográficos na Bacia do Paraná |
| Beneficiário: | Renato Pirani Ghilardi |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 25/07209-0 - Aplicação da morfometria linear e esclerocronologia nos braquiópodes da Bacia do Paraná para identificação das crises bióticas do Devoniano Inferior-Médio. |
| Beneficiário: | Victor Rodrigues Ribeiro |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |
| Processo FAPESP: | 20/12409-4 - Paleobiogeografia e rotas migratórias de paleoinvertebrados devonianos das Bacias Intracratônicas Brasileiras do Paraná, Parecis, Parnaíba e Alto Tapajós |
| Beneficiário: | Renato Pirani Ghilardi |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |