Organic walled microfossils in wet peperites from the early Cretaceous Parana-Etendeka volcanism of Brazil

Author(s):Show less -

Del Mouro, Lucas ; Becker-Kerber, Bruno ; Janasi, Valdecir A. ; de Araujo Carvalho, Marcelo ; Waichel, Breno L. ; Lima, Evandro F. ; Rossetti, Lucas M. M. ; Cruz, Vinicius ; Silva, Mateus Souza ; Famelli, Natalia ; Ortega-Hernandez, Javier

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 13, n. 1, p. 10-pg., 2023-09-16.

Abstract

Large igneous provinces (LIPs) are major magmatic events that have a significant impact on the global environment and the biosphere, for example as triggers of mass extinctions. LIPs provide an excellent sedimentological and geochemical record of short but intense periods of geological activity in the past, but their contribution towards understanding ancient life is much more restricted due to the destructive nature of their igneous origin. Here, we provide the first paleontological evidence for organic walled microfossils extracted from wet peperites from the Early Cretaceous Paran & aacute;-Etendeka intertrappean deposits of the Paran & aacute; basin in Brazil. Wet peperites are a volcaniclastic rock formed by the interaction of lava and subaqueous sediments.The Paran & aacute;-Etendeka was formed during the Valanginian (ca. 132 Ma) as a continental flood basalt in present day South America and Namibia, and released enormous amounts of carbon dioxide, sulfur dioxide, methane and hydrogen fluoride into the atmosphere. The organic walled microfossils recovered from the Paran & aacute;-Etendeka peperites include pollen grains, spores, acritarchs, and other remains of unidentifiable organic matter. In addition to the peperites, organic walled microfossils were also found in heterolithic sandstones and interpillow sandstones. Our findings represent the first insight into the biodiversity of the Paran & aacute; Basin during the Early Cretaceous during a period of intense magmatism, and the microfossil assemblages corroborate a regional paleoclimatic transition from arid to more humid conditions that were likely induced by the volcanic activity. We corroborate the potential of wet peperite rocks as a valuable source of paleobiological data and emphasize the importance of sampling volcaniclastic units that have been traditionally considered with lower fossiliferous potential due to their igneous origin. (AU)

• FAPESP's process: 19/22084-8 - The Paraná Magmatic Province: petrogenesis, chronology and environmental impact of Cretaceous tholeiitic, alkaline and silicic magmatism in the Brazilian Platform
• Grantee: Valdecir de Assis Janasi
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 21/01886-9 - Palynology analyses of sedimentary and volcanoclastic rocks associated to Serra Geral Group
• Grantee: Lucas Del Mouro
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 21/14704-6 - Microfossils from volcaniclastic rocks of Serra Geral Group: establishing a background knowledge using Harvard paleontological collections and field sampling
• Grantee: Lucas Del Mouro
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor