Seismostratigraphy and Cenozoic evolution of a sector of the Nágera and Perito Moreno terraces, Patagonian Continental Margin

The continental passive margins, as the Argentine Continental Passive Volcanic Margin (MCAPV) (Franke et al., 2007; Schnabel et al., 2008; Becker et al., 2012), preserve in their sedimentary record eustatic changes and variations in the dynamics of the ocean currents, from global changes, as opening...

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Detalles Bibliográficos
Publicado: 2017
Materias:
Continental slope
Contouritic currents
Patagonian Continental Margin
Seismostratigraphy
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_16697316_v24_n1_p45_Isola
http://hdl.handle.net/20.500.12110/paper_16697316_v24_n1_p45_Isola
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_16697316_v24_n1_p45_Isola
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spelling paper:paper_16697316_v24_n1_p45_Isola2023-06-08T16:26:22Z Seismostratigraphy and Cenozoic evolution of a sector of the Nágera and Perito Moreno terraces, Patagonian Continental Margin Continental slope Contouritic currents Patagonian Continental Margin Seismostratigraphy The continental passive margins, as the Argentine Continental Passive Volcanic Margin (MCAPV) (Franke et al., 2007; Schnabel et al., 2008; Becker et al., 2012), preserve in their sedimentary record eustatic changes and variations in the dynamics of the ocean currents, from global changes, as opening and closure of ocean gateways, to local variations, as changes in depth in the boundary of different water masses. The Patagonian Continental Margin (MCP) is the portion of the MCAPV located south to the Colorado Fracture Zone (Fig. 1 a, b). The major features shaping the surface of the continental slope in the MCP are four contouritic terraces (Fig. 1b), from west to east: Nágera Terrace (TN), Perito Moreno Terrace (TPM), Piedra Buena Terrace and Valentín Feilberg Terrace. The genesis and evolution of the four terraces is linked to the activity of antartic sourced bottom currents. Previous works have described the seismostratigraphy and the oceanographic controls in the structural building of the two easternmost terraces, (e.i., Piedra Buena and Valentín Feilberg terraces). On the contrast, very little is known on the evolution of the Nágera and Perito Moreno terraces. This work aims to describe the Cenozoic stratigraphy of the TN (∼600 a 1000 m) and TPM (∼1000 a 1500 m), in relation to the major climatic and oceanographic changes occurred in the South Atlantic Ocean during this time. The study is based on the interpretation of two monochannel seismic lines acquired in 2014 on board of the Canadian vessel Coriolis II, and one multichannel seismic line provided from Secretaría de Energía de la Nación Argentina. Through the interpretation of the seismic lines (Figs. 2-4), following the seismostratigraphic method (Mitchum et al., 1977), four mayor unconformities were recognized (Table 1). These unconformities are interpreted as sequence boundaries. After correlate this unconformities with: Previous works in the MCA (data published of Tayra well by Continanzia et al., 2011; and cores published by Ewing & Lonardi, 1971) and main oceanographic-climatic changes, five seismic units (U0, U1, U2, U3 and U4; see table 1) were defined for this part of the margin. Finally, by the interpretation of these units, four stages of evolution for the TN and TPM could be defined (Fig. 5): 1) Paleocene - Eoceno, is characterized by thermal subsidence, as well as hemipelagic and gravitational sedimentation with negligible activity of deep ocean currents. 2) Eocene - Oligocene to mid Miocene, is characterized by the presence of a shallow marine environment with clinoforms in the outer shelf to middle slope, and it is interpreted as a deltaic progradation in a shallow sea environment. 3) Middle Miocene to Pliocene, is characterized by the first evidence of current activity in the area. It finishes with a strong erosive surface, and formation of the Nágera and Perito Moreno terraces. 4) Pliocene to Holocene is characterized by high ocean currents activity in the upper and middle slope, strong interaction between ocean currents and the seafloor, and development of contouritic deposits. © 2017 Asociación Argentina de Sedimentología. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_16697316_v24_n1_p45_Isola http://hdl.handle.net/20.500.12110/paper_16697316_v24_n1_p45_Isola
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Continental slope
Contouritic currents
Patagonian Continental Margin
Seismostratigraphy
spellingShingle Continental slope
Contouritic currents
Patagonian Continental Margin
Seismostratigraphy
Seismostratigraphy and Cenozoic evolution of a sector of the Nágera and Perito Moreno terraces, Patagonian Continental Margin
topic_facet Continental slope
Contouritic currents
Patagonian Continental Margin
Seismostratigraphy
description The continental passive margins, as the Argentine Continental Passive Volcanic Margin (MCAPV) (Franke et al., 2007; Schnabel et al., 2008; Becker et al., 2012), preserve in their sedimentary record eustatic changes and variations in the dynamics of the ocean currents, from global changes, as opening and closure of ocean gateways, to local variations, as changes in depth in the boundary of different water masses. The Patagonian Continental Margin (MCP) is the portion of the MCAPV located south to the Colorado Fracture Zone (Fig. 1 a, b). The major features shaping the surface of the continental slope in the MCP are four contouritic terraces (Fig. 1b), from west to east: Nágera Terrace (TN), Perito Moreno Terrace (TPM), Piedra Buena Terrace and Valentín Feilberg Terrace. The genesis and evolution of the four terraces is linked to the activity of antartic sourced bottom currents. Previous works have described the seismostratigraphy and the oceanographic controls in the structural building of the two easternmost terraces, (e.i., Piedra Buena and Valentín Feilberg terraces). On the contrast, very little is known on the evolution of the Nágera and Perito Moreno terraces. This work aims to describe the Cenozoic stratigraphy of the TN (∼600 a 1000 m) and TPM (∼1000 a 1500 m), in relation to the major climatic and oceanographic changes occurred in the South Atlantic Ocean during this time. The study is based on the interpretation of two monochannel seismic lines acquired in 2014 on board of the Canadian vessel Coriolis II, and one multichannel seismic line provided from Secretaría de Energía de la Nación Argentina. Through the interpretation of the seismic lines (Figs. 2-4), following the seismostratigraphic method (Mitchum et al., 1977), four mayor unconformities were recognized (Table 1). These unconformities are interpreted as sequence boundaries. After correlate this unconformities with: Previous works in the MCA (data published of Tayra well by Continanzia et al., 2011; and cores published by Ewing & Lonardi, 1971) and main oceanographic-climatic changes, five seismic units (U0, U1, U2, U3 and U4; see table 1) were defined for this part of the margin. Finally, by the interpretation of these units, four stages of evolution for the TN and TPM could be defined (Fig. 5): 1) Paleocene - Eoceno, is characterized by thermal subsidence, as well as hemipelagic and gravitational sedimentation with negligible activity of deep ocean currents. 2) Eocene - Oligocene to mid Miocene, is characterized by the presence of a shallow marine environment with clinoforms in the outer shelf to middle slope, and it is interpreted as a deltaic progradation in a shallow sea environment. 3) Middle Miocene to Pliocene, is characterized by the first evidence of current activity in the area. It finishes with a strong erosive surface, and formation of the Nágera and Perito Moreno terraces. 4) Pliocene to Holocene is characterized by high ocean currents activity in the upper and middle slope, strong interaction between ocean currents and the seafloor, and development of contouritic deposits. © 2017 Asociación Argentina de Sedimentología.
title Seismostratigraphy and Cenozoic evolution of a sector of the Nágera and Perito Moreno terraces, Patagonian Continental Margin
title_short Seismostratigraphy and Cenozoic evolution of a sector of the Nágera and Perito Moreno terraces, Patagonian Continental Margin
title_full Seismostratigraphy and Cenozoic evolution of a sector of the Nágera and Perito Moreno terraces, Patagonian Continental Margin
title_fullStr Seismostratigraphy and Cenozoic evolution of a sector of the Nágera and Perito Moreno terraces, Patagonian Continental Margin
title_full_unstemmed Seismostratigraphy and Cenozoic evolution of a sector of the Nágera and Perito Moreno terraces, Patagonian Continental Margin
title_sort seismostratigraphy and cenozoic evolution of a sector of the nágera and perito moreno terraces, patagonian continental margin
publishDate 2017
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_16697316_v24_n1_p45_Isola
http://hdl.handle.net/20.500.12110/paper_16697316_v24_n1_p45_Isola
_version_ 1768546369300070400

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