Sinistral transpressional and extensional tectonics in Dronning Maud Land, East Antarctica, including the Sør Rondane Mountains

Tsuyoshi Toyoshima, Yasuhito Osanai, Sotaro Baba, Tomokazu Hokada, Nobuhiko Nakano, Tatsuro Adachi, Makoto Otsubo, Masahiro Ishikawa, Yoshifumi Nogi

研究成果: ジャーナルへの寄稿記事

8 引用 (Scopus)

抄録

In this paper we clarify the history of deformation in the Sør Rondane Mountains (SRMs), eastern Dronning Maud Land (DML), East Antarctica, and construct a form-line contour map of the metamorphic and plutonic rocks in order to comprehend their structural features and provide constraints on the collisional tectonics of East and West Gondwana. We divide the deformational history in the SRMs into 13 stages (D1-D13). The tectonic regime varied frequently from extension (D3-D4) to layer-normal compression and layer-parallel extension (D5), to compression (D6), extension (D7), sinistral transtension and sinistral strike-slip (D8), compression (D9-D11), and finally extension related to dextral shearing (D12-D13). D7 and D8 indicate major extensional tectonic activity in the southern part of the East African and Antarctic Orogen (EAAO) before the Pan-African compressional event, and after the c. 600. Ma peak of metamorphism. The Pan-African compressional event resulted in the formation of upright folds with horizontal axes that curve along the coastline in central to eastern DML during the D9 deformation that took place between 600 and 560. Ma. The coastline-parallel fold axes and subvertical axial-planes correspond to the X-axes and the XY-planes, respectively, of strain ellipsoids that were progressively rotated counterclockwise toward the central parts of a sinistral shear zone. Therefore, the curved fold axes and axial-planes suggest the EAAO acted as a zone of sinistral transpression during the collision of parts of East and West Gondwana. Around 560-550. Ma, during D12, parallel dyke swarms of granitic pegmatite were intruded along normal faults under a regime of NNE-SSW horizontal extensional stress. The extensional paleo-stress and its related structures suggest dextral rather than sinistral shearing took place along the north-trending EAAO during this late Pan-African event. There is the possibility of a reversal of trans-orogen asymmetry from sinistral to dextral in the southern part of the EAAO. The dyke swarms are considered to have been the heralds of the voluminous 530-500. Ma A-type granite intrusions in DML. At the same time, the Lützow-Holm Complex was under a non-extensional tectonic regime, and may have been situated in a different orogen from the EAAO.

元の言語英語
ページ(範囲)30-46
ページ数17
ジャーナルPrecambrian Research
234
DOI
出版物ステータス出版済み - 9 1 2013

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extensional tectonics
Tectonics
mountain
dike swarm
compression
fold
Shearing
Gondwana
tectonics
transtension
transpression
contour map
coast
plutonic rock
pegmatite
history
metamorphic rock
normal fault
shear zone
asymmetry

All Science Journal Classification (ASJC) codes

  • Geology
  • Geochemistry and Petrology

これを引用

Sinistral transpressional and extensional tectonics in Dronning Maud Land, East Antarctica, including the Sør Rondane Mountains. / Toyoshima, Tsuyoshi; Osanai, Yasuhito; Baba, Sotaro; Hokada, Tomokazu; Nakano, Nobuhiko; Adachi, Tatsuro; Otsubo, Makoto; Ishikawa, Masahiro; Nogi, Yoshifumi.

:: Precambrian Research, 巻 234, 01.09.2013, p. 30-46.

研究成果: ジャーナルへの寄稿記事

Toyoshima, Tsuyoshi ; Osanai, Yasuhito ; Baba, Sotaro ; Hokada, Tomokazu ; Nakano, Nobuhiko ; Adachi, Tatsuro ; Otsubo, Makoto ; Ishikawa, Masahiro ; Nogi, Yoshifumi. / Sinistral transpressional and extensional tectonics in Dronning Maud Land, East Antarctica, including the Sør Rondane Mountains. :: Precambrian Research. 2013 ; 巻 234. pp. 30-46.
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abstract = "In this paper we clarify the history of deformation in the S{\o}r Rondane Mountains (SRMs), eastern Dronning Maud Land (DML), East Antarctica, and construct a form-line contour map of the metamorphic and plutonic rocks in order to comprehend their structural features and provide constraints on the collisional tectonics of East and West Gondwana. We divide the deformational history in the SRMs into 13 stages (D1-D13). The tectonic regime varied frequently from extension (D3-D4) to layer-normal compression and layer-parallel extension (D5), to compression (D6), extension (D7), sinistral transtension and sinistral strike-slip (D8), compression (D9-D11), and finally extension related to dextral shearing (D12-D13). D7 and D8 indicate major extensional tectonic activity in the southern part of the East African and Antarctic Orogen (EAAO) before the Pan-African compressional event, and after the c. 600. Ma peak of metamorphism. The Pan-African compressional event resulted in the formation of upright folds with horizontal axes that curve along the coastline in central to eastern DML during the D9 deformation that took place between 600 and 560. Ma. The coastline-parallel fold axes and subvertical axial-planes correspond to the X-axes and the XY-planes, respectively, of strain ellipsoids that were progressively rotated counterclockwise toward the central parts of a sinistral shear zone. Therefore, the curved fold axes and axial-planes suggest the EAAO acted as a zone of sinistral transpression during the collision of parts of East and West Gondwana. Around 560-550. Ma, during D12, parallel dyke swarms of granitic pegmatite were intruded along normal faults under a regime of NNE-SSW horizontal extensional stress. The extensional paleo-stress and its related structures suggest dextral rather than sinistral shearing took place along the north-trending EAAO during this late Pan-African event. There is the possibility of a reversal of trans-orogen asymmetry from sinistral to dextral in the southern part of the EAAO. The dyke swarms are considered to have been the heralds of the voluminous 530-500. Ma A-type granite intrusions in DML. At the same time, the L{\"u}tzow-Holm Complex was under a non-extensional tectonic regime, and may have been situated in a different orogen from the EAAO.",
author = "Tsuyoshi Toyoshima and Yasuhito Osanai and Sotaro Baba and Tomokazu Hokada and Nobuhiko Nakano and Tatsuro Adachi and Makoto Otsubo and Masahiro Ishikawa and Yoshifumi Nogi",
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T1 - Sinistral transpressional and extensional tectonics in Dronning Maud Land, East Antarctica, including the Sør Rondane Mountains

AU - Toyoshima, Tsuyoshi

AU - Osanai, Yasuhito

AU - Baba, Sotaro

AU - Hokada, Tomokazu

AU - Nakano, Nobuhiko

AU - Adachi, Tatsuro

AU - Otsubo, Makoto

AU - Ishikawa, Masahiro

AU - Nogi, Yoshifumi

PY - 2013/9/1

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N2 - In this paper we clarify the history of deformation in the Sør Rondane Mountains (SRMs), eastern Dronning Maud Land (DML), East Antarctica, and construct a form-line contour map of the metamorphic and plutonic rocks in order to comprehend their structural features and provide constraints on the collisional tectonics of East and West Gondwana. We divide the deformational history in the SRMs into 13 stages (D1-D13). The tectonic regime varied frequently from extension (D3-D4) to layer-normal compression and layer-parallel extension (D5), to compression (D6), extension (D7), sinistral transtension and sinistral strike-slip (D8), compression (D9-D11), and finally extension related to dextral shearing (D12-D13). D7 and D8 indicate major extensional tectonic activity in the southern part of the East African and Antarctic Orogen (EAAO) before the Pan-African compressional event, and after the c. 600. Ma peak of metamorphism. The Pan-African compressional event resulted in the formation of upright folds with horizontal axes that curve along the coastline in central to eastern DML during the D9 deformation that took place between 600 and 560. Ma. The coastline-parallel fold axes and subvertical axial-planes correspond to the X-axes and the XY-planes, respectively, of strain ellipsoids that were progressively rotated counterclockwise toward the central parts of a sinistral shear zone. Therefore, the curved fold axes and axial-planes suggest the EAAO acted as a zone of sinistral transpression during the collision of parts of East and West Gondwana. Around 560-550. Ma, during D12, parallel dyke swarms of granitic pegmatite were intruded along normal faults under a regime of NNE-SSW horizontal extensional stress. The extensional paleo-stress and its related structures suggest dextral rather than sinistral shearing took place along the north-trending EAAO during this late Pan-African event. There is the possibility of a reversal of trans-orogen asymmetry from sinistral to dextral in the southern part of the EAAO. The dyke swarms are considered to have been the heralds of the voluminous 530-500. Ma A-type granite intrusions in DML. At the same time, the Lützow-Holm Complex was under a non-extensional tectonic regime, and may have been situated in a different orogen from the EAAO.

AB - In this paper we clarify the history of deformation in the Sør Rondane Mountains (SRMs), eastern Dronning Maud Land (DML), East Antarctica, and construct a form-line contour map of the metamorphic and plutonic rocks in order to comprehend their structural features and provide constraints on the collisional tectonics of East and West Gondwana. We divide the deformational history in the SRMs into 13 stages (D1-D13). The tectonic regime varied frequently from extension (D3-D4) to layer-normal compression and layer-parallel extension (D5), to compression (D6), extension (D7), sinistral transtension and sinistral strike-slip (D8), compression (D9-D11), and finally extension related to dextral shearing (D12-D13). D7 and D8 indicate major extensional tectonic activity in the southern part of the East African and Antarctic Orogen (EAAO) before the Pan-African compressional event, and after the c. 600. Ma peak of metamorphism. The Pan-African compressional event resulted in the formation of upright folds with horizontal axes that curve along the coastline in central to eastern DML during the D9 deformation that took place between 600 and 560. Ma. The coastline-parallel fold axes and subvertical axial-planes correspond to the X-axes and the XY-planes, respectively, of strain ellipsoids that were progressively rotated counterclockwise toward the central parts of a sinistral shear zone. Therefore, the curved fold axes and axial-planes suggest the EAAO acted as a zone of sinistral transpression during the collision of parts of East and West Gondwana. Around 560-550. Ma, during D12, parallel dyke swarms of granitic pegmatite were intruded along normal faults under a regime of NNE-SSW horizontal extensional stress. The extensional paleo-stress and its related structures suggest dextral rather than sinistral shearing took place along the north-trending EAAO during this late Pan-African event. There is the possibility of a reversal of trans-orogen asymmetry from sinistral to dextral in the southern part of the EAAO. The dyke swarms are considered to have been the heralds of the voluminous 530-500. Ma A-type granite intrusions in DML. At the same time, the Lützow-Holm Complex was under a non-extensional tectonic regime, and may have been situated in a different orogen from the EAAO.

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