Evolution of a rift basin dominated by subaerial deposits: The Guaritas Rift, Early Cambrian, Southern Brazil

Almeida, Renato Paes de; Janikian, Liliane; Fragoso-Cesar, Antônio Romalino Santos; Marconato, André

doi:10.1016/j.sedgeo.2009.01.010

Cited by 57 publications

(51 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…No entendimento dos autores mencionados, a Formação Missão Velha representaria a fase pré--rifte na evolução tectono-sedimentar das bacias da Depressão Afro-Brasileira. Mais recentemente, Fambrini et al (2010a) propuseram divisão em sequências tectono-deposicionais em base aos trabalhos de Prosser (1993) e de Almeida et al (2009), adiante discutidas.…”

Section: Introductionunclassified

Estratigrafia, arquitetura deposicional e faciologia da formação Missão Velha (Neojurássico-Eocretáceo) na área-tipo, bacia do Araripe, nordeste do Brasil: exemplo de sedimentação de estágio de início de rifte a clímax de rifte

Fambrini

Lemos

Tesser

et al. 2011

Geol. USP, Sér. cient.

View full text Add to dashboard Cite

Section: Introductionunclassified

Estratigrafia, arquitetura deposicional e faciologia da formação Missão Velha (Neojurássico-Eocretáceo) na área-tipo, bacia do Araripe, nordeste do Brasil: exemplo de sedimentação de estágio de início de rifte a clímax de rifte

Fambrini

Lemos

Tesser

et al. 2011

Geol. USP, Sér. cient.

View full text Add to dashboard Cite

“…These sedimentary units are part of to the Camaquã Basin, sedimentary basin related to the stages of stabilization of Gondwana (Almeida 1969). The basin was filled by siliciclastic and volcaniclastic rocks of Neoproterozoic to Eopaleozoic age which were deposited in rift systems developed subsequently to the Brasiliano orogenic event (Fragoso-Cesar et al 2000a, 2000band 2001, Almeida 2005, Almeida et al, 2009, 2010. Its occurrences are controlled by NNE faults, and the basin is divided into three sub-basins by two regional highs (Fig.…”

Section: Geological Contextmentioning

confidence: 99%

Paleostress Analysis in Brittle Structures of the Camaquã Copper Mines

Santos

Almeida

Fragoso-Cesar

2012

Rev. bras. geociênc.

View full text Add to dashboard Cite

Fault planes with striae and kinematic indicators from the Camaquã Copper Mines, Caçapava do Sul (Brazil), were analyzed through graphical methods and structural geology software in order to determine the stressfield orientation for the numerous tectonic events that affected the region, and in this way determine the paleostress fields. 94 faults with slickenside striae and kinematic indicators were acquired and interpreted in the field, and with the Tensor software. The relative chronology of the events was obtained through cross-cutting relationships of multiple overprinting fault striae, and stratigraphical analysis according to previous published papers. Field data was integrated through geographical information systems (GIS) for correlation with data obtained through remote sensing and imagery processing. We identified four distinct paleostress fields: ENE to NE extension (Cretaceous); NNE to N-S compression (Triassic); NW extension (Paleozoic); and WNW compression (Cambrian). A specific study was applied to the mineralized brittle structures, leading to the proposition of a model for the emplacement of the ore bodies of the Camaquã Copper Mines. This model is characterized by the opening and filling of fractures that were parallel to the maximum horizontal stress-field, resembling T-fracture structures, during the main deformational transcurrent event that affected the Camaquã Basin ~ 530 Ma.Keywords: structural geology; paleostress analysis; Camaquã Basin; Minas do Camaquã; mineralization control; Copper. Resumo Análise de Paleotensões em Estruturas Rúpteis das Minas de Cobre do Camaquã.Planos de falhas com estrias e indicadores de movimento encontrados nas Minas do Camaquã, Município de Caçapava do Sul (RS, Brasil), foram analisados por meio de métodos gráficos e softwares de geologia estrutural para a determinação das orientações dos campos de esforços envolvidos nos diversos eventos tectônicos que afetaram a região, obtendo-se, assim, os paleocampos de tensões. Foram adquiridos 94 dados de falhas com estrias e indicadores cinemáticos que foram interpretados em campo e pelo software Tensor. A cronologia relativa dos eventos foi determinada por relações de cortes entre estrias em planos de falha e análise estratigráfica, embasada em trabalhos regionais disponíveis na literatura. Os dados de campo foram integrados por meio de sistemas de informação geográfica para correlação com dados obtidos via sensoriamento remoto e processamento de imagens. Foram identificados quatro paleocampos de tensão distintos: distensão ENE a NE (Cretáceo); compressão NNE a N-S (Triássico); distensão NW (Paleozoico); compressão WNW (Cambriano). Um estudo específico envolvendo exclusivamente as estruturas rúpteis mineralizadas levou à proposição de um modelo de mineralização para as Minas do Camaquã. Esse modelo compreende um sistema de abertura e preenchimento de fraturas paralelas ao esforço horizontal máximo, semelhante a fraturas tipo-T, durante o evento de deformação transcorrente principal que afetou a Bacia do Camaq...

show abstract

“…The basin is bounded by high-angle faults that uplifted Paleo and Neoproterozoic metamorphic rocks of the Dom Feliciano Belt and the Rio Vacacaí island arc terrane (Fragoso-Cesar 1991), being interpreted as a continental rift on the basis of its tectono-stratigraphic evolution (Almeida et al 2009). The Guaritas Group was deposited during the Early Cambrian, as indicated by the soft-sediment deformation features that occur at the contact with shallow sills of the 535 Ma Rodeio Velho Intrusive Suite (Almeida 2005).…”

Section: Geological Settingmentioning

confidence: 99%

“…Ribeiro and Lichtenberg 1978, Almeida 2005, Almeida et al 2009) and ephemeral river deposits (e.g. Paim 1994, 1995, Paim et al 2002, Almeida 2005, Almeida et al 2009), some facies of which have been alternatively interpreted as lacustrine deposits (Paim 1994).…”

Section: Geological Settingmentioning

confidence: 99%

Alluvial-eolian interaction in a Cambrian rift margin: the Pedra das Torrinhas and Pedra Pintada formations (Guaritas Group, RS)

Marconato

Almeida

Santos

et al. 2009

An. Acad. Bras. Ciênc.

Self Cite

View full text Add to dashboard Cite

This work presents a study of selected outcrops from the Pedra das Torrinhas Formation of the Guaritas Group (Cambrian, Camaquã Basin), near the basin bordering Encantadas Fault Zone. The studied succession includes alluvial fan deposits that pass laterally into eolian deposits. Sedimentary facies and architectural element analysis were performed, followed by sedimentary petrography and microscopic porosity analysis, aiming to characterize the porosity of the deposits and its spatial distribution. The main objective was to contribute to a better understanding of the porosity spatial distribution in depositional systems characterized by the interaction between alluvial and eolian processes, with special reference to deposits formed prior to the development of terrestrial plants. Porosity values are related to depositional processes, with higher porosities associated to eolian dune deposits (mean of 8.4%), and lower porosity related to interdunes (mean of 3.4%) and alluvial fans (mean of 4.3%). Architectural elements analysis revealed the spatial relationships of these deposits, a response to the interplay of the eolian and alluvial processes. The integration of porosity data reveals that the interaction of alluvial and eolian processes results in heterogeneous distribution of porosity at the facies association scale. Eolian reworking of alluvial facies increases porosity whereas sheet-flood and other alluvial processes in the interdune areas reduce porosity.

show abstract

Evolution of a rift basin dominated by subaerial deposits: The Guaritas Rift, Early Cambrian, Southern Brazil

Cited by 57 publications

References 25 publications

Estratigrafia, arquitetura deposicional e faciologia da formação Missão Velha (Neojurássico-Eocretáceo) na área-tipo, bacia do Araripe, nordeste do Brasil: exemplo de sedimentação de estágio de início de rifte a clímax de rifte

Estratigrafia, arquitetura deposicional e faciologia da formação Missão Velha (Neojurássico-Eocretáceo) na área-tipo, bacia do Araripe, nordeste do Brasil: exemplo de sedimentação de estágio de início de rifte a clímax de rifte

Paleostress Analysis in Brittle Structures of the Camaquã Copper Mines

Alluvial-eolian interaction in a Cambrian rift margin: the Pedra das Torrinhas and Pedra Pintada formations (Guaritas Group, RS)

Contact Info

Product

Resources

About