New insights of the tectonic and sedimentary evolution of the Rio Grande Rise, South Atlantic Ocean

Praxedes, Adriane Gomes Pinheiro; Castro, David Lopes de; Torres, Luiz C. B.; Gambôa, Luiz Antônio Pierantoni; Hackspacher, Peter Christian

doi:10.1016/j.marpetgeo.2019.07.035

Cited by 22 publications

(16 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The history of the Cruzeiro do Sul rift that cleaves both RGR Massif and Libra Massif of the southern ERGR is unclear. Although it has been explained as a later (Eocene) feature that formed from poorly understood regional mid‐plate tectonics (Mohriak et al., 2010; Ussami et al., 2012), a recent re‐examination of a multichannel seismic reflection profile across the RGR Massif summit interprets rift formation as beginning during the Late Cretaceous (Pinheiro Praxedes et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

Late Cretaceous Ridge Reorganization, Microplate Formation, and the Evolution of the Rio Grande Rise – Walvis Ridge Hot Spot Twins, South Atlantic Ocean

Sager

Thoram

Engfer

et al. 2021

Geochem Geophys Geosyst

View full text Add to dashboard Cite

The Rio Grande Rise (RGR) and the Walvis Ridge (WR) make an odd pair. Both are large igneous provinces (LIPs) apparently erupted at the same hot spot during the opening of the South Atlantic Ocean (Morgan, 1971, 1981, 1983). The conjugate LIPs formed because the hot spot erupted at the Mid-Atlantic Ridge (MAR) during the Late Cretaceous, emplacing volcanic edifices on both the South American and African plates (Kumar, 1979; O'Connor & Duncan, 1990). Despite the similar circumstances, the two features have Abstract Rio Grande Rise (RGR) and Walvis Ridge (WR) are South Atlantic large igneous provinces (LIPs), formed on the South American and African plates, respectively, mainly by volcanism from a hot spot erupting at the Mid-Atlantic Ridge (MAR) during the Late Cretaceous. Both display morphologic complexities that imply their tectonic evolution is incompletely understood. We studied bathymetry, gravity, and vertical gravity gradient maps derived from satellite altimetry to trace faults providing indications of seafloor spreading directions and changes. We also examined magnetic anomalies for time constraint and reflection seismic data for structural information. Abyssal hill fabric and magnetic anomaly data indicate that the area between RGR and WR was anomalous between anomalies C34 (83.6 Ma) and C30 (66.4 Ma) owing to reorganization of a right-lateral transform on the MAR. This event began ∼92 Ma as the transform shifted south to form multiple, short-offset right-lateral transforms, with the reorganization extending through anomaly C34 and ending before anomaly C30. Anomalous spacing of magnetic anomalies and discordant fault fabric indicate that a microplate formed with a core of Cretaceous Quiet Zone seafloor. As the MAR jumped eastward, this microplate was captured by the South American plate and now resides mostly in a basin between the main RGR plateau and a related ridge to the east (East Rio Grande Rise). The microplate is ringed by igneous massifs, implying a link with volcanism. The results presented here indicate that these two LIPs had a complex Late Cretaceous history that belies simple hot spot models. Plain Language Summary Rio Grande Rise (RGR) and Walvis Ridge (WR) are large volcanic mountains formed on the South American and African plates, respectively, as the South Atlantic Ocean opened during Cretaceous and Cenozoic time. They are considered to be similar to the classic Hawaiian-Emperor hot spot seamount chain and to represent motion of the two plates over a single mantle hot spot, once located at the Mid-Atlantic Ridge (MAR). Complex morphologies of these two igneous provinces imply that this simple model is an oversimplification. We examine geophysical evidence for Late Cretaceous time, mainly between magnetic anomalies C34 (83.6 Ma) to C30 (66.4 Ma). During this period the MAR reorganized, causing complex tectonics between RGR and WR. A long-offset, transform fault broke into a number of lesser offset transforms with several ridge jumps, beginning at ∼92 Ma and ending before anomaly C30. ...

show abstract

Section: Introductionmentioning

confidence: 99%

Late Cretaceous Ridge Reorganization, Microplate Formation, and the Evolution of the Rio Grande Rise – Walvis Ridge Hot Spot Twins, South Atlantic Ocean

Sager

Thoram

Engfer

et al. 2021

Geochem Geophys Geosyst

View full text Add to dashboard Cite

show abstract

“…Essas estruturas montiformas foram também observadas dentro do pacote sedimentar na ERG, conforme mostrado na Figura 9. Essas estruturas possivelmente estão associadas a chaminé de gás ou atividade hidrotermal (Praxedes et al, 2019), ou ainda ao vulcanismo do Eoceno (Gambôa e Rabinowitz, 1984). Os mounds ocorrem nas proximidades de expressivos montes submarinos.…”

Section: Resultsunclassified

“…Outro aspecto importante na ERG é um evento tectônico e vulcânico no Eoceno, que seria o responsável pelo soerguimento de partes da elevação acima do nível do mar. Esse evento teria formado ilhas vulcânicas que foram posteriormente erodidas (Gambôa e Rabinowitz, 1984;Mohriak et al, 2010;Praxedes et al, 2019). Essas antigas ilhas vulcânicas estão atualmente a cerca de 700 m abaixo do nível do mar, configurando os pontos mais altos da ERG, cujos entornos chegam a 4.000 m de profundidade.…”

Section: Elevação Do Rio Grandeunclassified

“…Esse extenso vale falhado tem direção NW-SE, cerca de 1.000 km de comprimento, 10-20 km de largura e profundidade de mais de 1 km. Blocos falhados e rotacionados formam um estilo de falhamento em dominó na porção central do rifte, que é preenchido parcialmente por sequências sedimentares cenozoicas (Praxedes et al, 2019).…”

Section: Elevação Do Rio Grandeunclassified

“…Os dados sísmicos multicanais 2D de domínio público utilizados neste trabalho são oriundos de dois projetos distintos: As seções sísmicas da UTIG sobre a ERG foram reprocessadas e interpretadas por Praxedes et al (2019) e as linhas LEPLAC 500-0041, 500-0042 e 500-0511 (Figura 2), na margem continental adjacente, são apresentadas neste estudo e correlacionadas com as sequências sismoestratigráficas da ERG.…”

Section: Materiais E Métodosunclassified

See 2 more Smart Citations

Correlação tectono-deposicional entre a margem continental brasileira e a Elevação do Rio Grande

Praxedes

Castro

2020

Geol. USP. Sér. Cient.

Self Cite

View full text Add to dashboard Cite

A margem continental brasileira foi formada pelo processo de abertura do Atlântico Sul, com a ruptura do Gondwana Oeste, e a separação entre a América do Sul e África, no Cretáceo Inferior. Por sua vez, a Elevação do Rio Grande (ERG) teria sido originada por pontos quentes ao longo da porção oceânica da placa sul-americana em movimento. Alternativamente, a ERG seria parte de crosta continental, que teria sido submersa após se desprender do continente, ou ainda seria a combinação de uma província vulcânica com um microcontinente. Nós propomos fazer uma correlação tectono-deposicional entre a ERG e a margem continental brasileira adjacente, dentro do contexto de evolução do Atlântico Sul. A partir da interpretação de seções sísmicas e dados de furos estratigráficos, foi possível identificar semelhanças entre as fácies sísmicas nos pacotes vulcanossedimentares na ERG e a margem continental brasileira mais distal, além de correlação em termos do desenvolvimento cronoestratigráfico das duas regiões. Essas semelhanças no pacote sedimentar incluem o evento vulcânico no Eoceno e a tectônica distensional no Paleógeno e no Neógeno para evidenciar evolução tectono-deposicional comum tanto na ERG quanto na margem continental adjacente.

show abstract

Brazilian Continental Margin morphology

Alberoni¹,

Jeck²

2022

Meso-Cenozoic Brazilian Offshore Magmatism

View full text Add to dashboard Cite

New insights of the tectonic and sedimentary evolution of the Rio Grande Rise, South Atlantic Ocean

Cited by 22 publications

References 25 publications

Late Cretaceous Ridge Reorganization, Microplate Formation, and the Evolution of the Rio Grande Rise – Walvis Ridge Hot Spot Twins, South Atlantic Ocean

Late Cretaceous Ridge Reorganization, Microplate Formation, and the Evolution of the Rio Grande Rise – Walvis Ridge Hot Spot Twins, South Atlantic Ocean

Correlação tectono-deposicional entre a margem continental brasileira e a Elevação do Rio Grande

Brazilian Continental Margin morphology

Contact Info

Product

Resources

About