O lineamento Piúma, sul do estado do Espírito Santo: expressão estrutural e significado tectônico

The Piúma lineament, located in the Southern Espírito Santo State, Brazil, is one of the most prominent linear morphostructural features of the northern Mantiqueira Province. The lineament stands out in satellite images and topographic maps, extending for about 70 km in a N50°W direction, between the towns of Iconha and Conceição do Castelo (Espírito Santo). In order to investigate the nature and role played by the Piúma lineament in the tectonic evolution of the Mantiqueira Province and adjacent Campos Basin, we carried out a detailed structural analysis based on fieldwork, as well as geophysical data processing and interpretation. The results we obtained indicate that the Piúma lineament is a brittle shear zone characterized by N50W-trending and SW-dipping shear fractures, faults and joints. These structures record two distinct and incompatible motions, thereby recording the operation of two tectonic regimes: NNE-SSW extension and E-W transtension. Comparing our results with the literature on the Southeastern Brazilian Continental Margin, we conclude that the Piúma lineament more likely developed after the Ediacaran Brasiliano orogenic event in response to an NNE-SSW extension, experiencing later a reactivation as normal dextral to dextral transtensional zone, probably in connection with the South Atlantic rifting in the Lower Cretaceous.The Piúma lineament, located in the Southern Espírito Santo State, Brazil, is one of the most prominent linear morphostructural features of the northern Mantiqueira Province. The lineament stands out in satellite images and topographic maps, extending for about 70 km in a N50°W direction, between the towns of Iconha and Conceição do Castelo (Espírito Santo). In order to investigate the nature and role played by the Piúma lineament in the tectonic evolution of the Mantiqueira Province and adjacent Campos Basin, we carried out a detailed structural analysis based on fieldwork, as well as geophysical data processing and interpretation. The results we obtained indicate that the Piúma lineament is a brittle shear zone characterized by N50W-trending and SW-dipping shear fractures, faults and joints. These structures record two distinct and incompatible motions, thereby recording the operation of two tectonic regimes: NNE-SSW extension and E-W transtension. Comparing our results with the literature on the Southeastern Brazilian Continental Margin, we conclude that the Piúma lineament more likely developed after the Ediacaran Brasiliano orogenic event in response to an NNE-SSW extension, experiencing later a reactivation as normal dextral to dextral transtensional zone, probably in connection with the South Atlantic rifting in the Lower Cretaceous.The Piuma lineament, located in the Southern Espirito Santo State, Brazil, is one of the most prominent linear morphostructural features of the northern Mantiqueira Province. The lineament stands out in satellite images and topographic maps, extending for464531546sem informaçãosem informaçãoO lineamento Piúma, situado na porção sul do estado do Espírito Santo, está entre as feições morfo-estruturais mais proeminentes da província Mantiqueira Setentrional. Constitui uma feição linear regional, bem marcada em imagens de sensoriamento remoto e mapas topográficos, com aproximadamente 70 km de comprimento e direção N50°W, entre as cidades de Iconha e Conceição do Castelo (Espírito Santo). Para investigar sua natureza e o papel que desempenha na evolução tectônica da Província Mantiqueira e da bacia de Campos, adjacente, foi feita uma analise estrutural detalhada, levada a efeito através de trabalhos de campo, processamento e interpretação de dados geofísicos. Os resultados obtidos indicam que o lineamento Piúma se traduz numa zona de cisalhamento rúptil, caracterizada pela presença de falhas e juntas com direção preferencial N50W e mergulho para SW. Essas estruturas registram a ação de dois movimentos distintos e incompatíveis, que marcam a ação de dois regimes tectônicos: distensão NNE-SSW e transtração E-W. Comparando-se os resultados com a literatura disponível para a margem continental sudeste brasileira, conclui-se que o lineamento Piúma, provavelmente, se desenvolveu em algum momento após o evento orogenético ediacarano Brasiliano, em resposta a uma distensão NNE--SSW, posteriormente sendo reativado como uma zona normal dextral a transtracional dextral, possivelmente relacionada à abertura do rifte do Atlântico Sul, no Cretáceo InferiorO lineamento Piúma, situado na porção sul do estado do Espírito Santo, está entre as feições morfo-estruturais mais proeminentes da província Mantiqueira Setentrional. Constitui uma feição linear regional, bem marcada em imagens de sensoriamento remoto

The Piúma lineament, southern Espirito Santo: structural expression and tectonic significance

ABSTRACT: The Piúma lineament, located in the Southern Espírito Santo State, Brazil, is one of the most prominent linear morphostructural features of the northern Mantiqueira Province. The lineament stands out in satellite images and topographic maps, extending for about 70 km in a N50°W direction, between the towns of Iconha and Conceição do Castelo (Espírito Santo). In order to investigate the nature and role played by the Piúma lineament in the tectonic evolution of the Mantiqueira Province and adjacent Campos Basin, we carried out a detailed structural analysis based on fieldwork, as well as geophysical data processing and interpretation. The results we obtained indicate that the Piúma lineament is a brittle shear zone characterized by N50W-trending and SW-dipping shear fractures, faults and joints. These structures record two distinct and incompatible motions, thereby recording the operation of two tectonic regimes: NNE-SSW extension and E-W transtension. Comparing our results with the literature on the Southeastern Brazilian Continental Margin, we conclude that the Piúma lineament more likely developed after the Ediacaran Brasiliano orogenic event in response to an NNE-SSW extension, experiencing later a reactivation as normal dextral to dextral transtensional zone, probably in connection with the South Atlantic rifting in the Lower Cretaceous