Unraveling the origin of the Parnaiba Basin: Testing the rift to sag hypothesis using a multi-proxy provenance analysis

Autor(es)

Cerri, Rodrigo I. ^[1] ; Warren, Lucas V. ^{[1, 2]} ; Varejao, Filipe G. ^[3] ; Marconato, Andre ^[4] ; Luvizotto, George L. ^{[1, 2]} ; Assine, Mario L. ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista Unesp, Inst Geociencias & Ciencias Exatas, Ave 24-A, Vista 178, BR-13506900 Rio Claro, SP - Brazil

^[2] Marconato, Andre, Univ Fed Ouro Preto, Dept Geol, Escola Minas, Campus Morro Cruzeiro, BR-35400000 Ouro Preto, MG, Brazil.Cerri, Rodrigo I., Univ Estadual Paulista Unesp, Inst Geociencias & Ciencias Exatas, Ave 24-A, Vista 178, BR-13506900 Rio Claro, SP - Brazil

^[3] Univ Fed Parana, Inst LAMIR, Ctr Politecn, BR-81531980 Curitiba, PR - Brazil

^[4] Univ Fed Ouro Preto, Dept Geol, Escola Minas, Campus Morro Cruzeiro, BR-35400000 Ouro Preto, MG - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of South American Earth Sciences; v. 101, AUG 2020.
• Citações Web of Science: 0

Resumo

Syneclises are long-lived sedimentary basins characterized by complex subsidence and erosion histories. The premise that these geotectonic units evolve from initial rifting processes following thermal (or flexural) subsidence is widespread in the geologic sciences and, to this day, remains a controversial issue. Seeking to test this hypothesis, we proceeded a novel mull-proxy provenance study aiming to identify differences (and/or similarities) in the sedimentary signal and source areas of the Jaibaras (rift) and Parnaiba (sag) basins. We conducted a detailed analysis of trace elements geochemistry of detrital rutile grains, macroscopic gravel composition and paleocurrents from the sedimentary deposits of the Aprazivel Formation (Ediacaran - Cambrian, top of Jaibaras Basin) and the Ipu Formation (Ordovician, basal unit of Parnaiba Basin). Our data reveal that important changes in source areas occurred between the end of the rifting and the beginning of the sag phase, reinforcing the hypothesis that the evolution of the Jaibaras and Parnaiba basins were not genetically related. Our results demonstrate that conglomerates of the rift sequence are predominantly composed of volcanic, sedimentary, and metamorphic angular to sub-angular clasts, pointing to diverse, nearby source areas. Contrastingly, conglomerates of the initial sag sequence have greater sedimentary maturity, with dominant rounded vein quartz clasts and other minor source contributions, which suggest distant source areas, showing a consistent paleocurrent direction towards NW. Indeed, the detrital rutile trace elements geochemistry demonstrates that the source areas of these two units were distinct, revealing an important decrease in the input of granulite facies and metamafic grains in the sag basin comparing with the rift succession. In conclusion, as well as paleomagnetic and geochronological studies, the provenance methods using a mull-proxy approach proved to be an effective and powerful technique for distinguishing modifications in the sedimentary signal between rift-to-sag sequences. (AU)

• Processo FAPESP: 14/00519-9 - Centralidades do lazer noturno na cidade de São Carlos-SP e as relações de interface
• Beneficiário: Tiago Ferreira Lopes Machado
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 17/19550-1 - Gênese da tectonossequência Jaibaras (Ediacarano - Ordoviciano) e sua herança na sedimentação da sequência Serra Grande (Ordoviciano - Siluriano), borda nordeste da Bacia do Parnaiba
• Beneficiário: Rodrigo Irineu Cerri
• Modalidade de apoio: Bolsas no Brasil - Doutorado