Seismic reflection evidence for a Dangerous Grounds miniplate: No extrusion origin for the South China Sea

Peter Clift, Gwang H. Lee, Nguyan Anh Duc, Udo Barckhausen, Hoang Van Long, Sun Zhen

Research output: Contribution to journalArticle

132 Citations (Scopus)

Abstract

The collision of India and Asia has caused large strike-slip faults to form in east Asia, resulting in the "extrusion'' of crustal blocks toward the southeast since the Eocene as a result of the indentation of rigid India into Asia. It has been suggested that the South China Sea opened as a result of relative motion between a rigid Indochina (Sundaland) block and China. Alternative models propose that rifting and seafloor spreading were driven by trench forces to the south. We test these competing models by analysis of seismic reflection profiles across the boundary between Sundaland and the southern rifted margin, known as the Dangerous Grounds. We show that the southern boundary of the Dangerous Grounds is a subduction zone that jammed in the middle Miocene. To the west the Dangerous Grounds are bounded by a strike-slip zone, also active until similar to 16 Ma, that becomes diffuse south of the now inactive South China Sea seafloor spreading center. We place the western edge of the Dangerous Grounds just to the east of the Natuna Arch (Lupar Line). The West Baram Line is confirmed as originating as a major strike-slip fault within the Dangerous Grounds and is continuous with the Red River Fault Zone. Because the Dangerous Grounds were independent of Sundaland until similar to 6 Ma, its motion cannot have been constrained by motion of this block, making extrusion impossible as a mechanism to rift the South China Sea. SE motion by both the Dangerous Grounds and Sundaland suggests subduction forces were the primary trigger for plate motions. Our reconstruction places a similar to 280 km upper limit on the motion on the Red River Fault and a similar to 1400 km width to the paleo-South China Sea.

Original languageEnglish
Number of pages16
JournalTectonics
Volume27
Issue number3
Early online date4 Jun 2008
DOIs
Publication statusPublished - Jun 2008

Keywords

  • river shear zone
  • miocene collisional belt
  • Indo-China
  • tectonic evolution
  • strike-slip
  • Continental-margin
  • uplift mechanism
  • North Borneo
  • fault system
  • rift basins
  • South China Sea
  • extrusion
  • transform tectonics
  • subduction

Cite this

Seismic reflection evidence for a Dangerous Grounds miniplate : No extrusion origin for the South China Sea. / Clift, Peter; Lee, Gwang H.; Duc, Nguyan Anh; Barckhausen, Udo; Van Long, Hoang; Zhen, Sun.

In: Tectonics, Vol. 27, No. 3, 06.2008.

Research output: Contribution to journalArticle

Clift, Peter ; Lee, Gwang H. ; Duc, Nguyan Anh ; Barckhausen, Udo ; Van Long, Hoang ; Zhen, Sun. / Seismic reflection evidence for a Dangerous Grounds miniplate : No extrusion origin for the South China Sea. In: Tectonics. 2008 ; Vol. 27, No. 3.
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abstract = "The collision of India and Asia has caused large strike-slip faults to form in east Asia, resulting in the {"}extrusion'' of crustal blocks toward the southeast since the Eocene as a result of the indentation of rigid India into Asia. It has been suggested that the South China Sea opened as a result of relative motion between a rigid Indochina (Sundaland) block and China. Alternative models propose that rifting and seafloor spreading were driven by trench forces to the south. We test these competing models by analysis of seismic reflection profiles across the boundary between Sundaland and the southern rifted margin, known as the Dangerous Grounds. We show that the southern boundary of the Dangerous Grounds is a subduction zone that jammed in the middle Miocene. To the west the Dangerous Grounds are bounded by a strike-slip zone, also active until similar to 16 Ma, that becomes diffuse south of the now inactive South China Sea seafloor spreading center. We place the western edge of the Dangerous Grounds just to the east of the Natuna Arch (Lupar Line). The West Baram Line is confirmed as originating as a major strike-slip fault within the Dangerous Grounds and is continuous with the Red River Fault Zone. Because the Dangerous Grounds were independent of Sundaland until similar to 6 Ma, its motion cannot have been constrained by motion of this block, making extrusion impossible as a mechanism to rift the South China Sea. SE motion by both the Dangerous Grounds and Sundaland suggests subduction forces were the primary trigger for plate motions. Our reconstruction places a similar to 280 km upper limit on the motion on the Red River Fault and a similar to 1400 km width to the paleo-South China Sea.",
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T1 - Seismic reflection evidence for a Dangerous Grounds miniplate

T2 - No extrusion origin for the South China Sea

AU - Clift, Peter

AU - Lee, Gwang H.

AU - Duc, Nguyan Anh

AU - Barckhausen, Udo

AU - Van Long, Hoang

AU - Zhen, Sun

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N2 - The collision of India and Asia has caused large strike-slip faults to form in east Asia, resulting in the "extrusion'' of crustal blocks toward the southeast since the Eocene as a result of the indentation of rigid India into Asia. It has been suggested that the South China Sea opened as a result of relative motion between a rigid Indochina (Sundaland) block and China. Alternative models propose that rifting and seafloor spreading were driven by trench forces to the south. We test these competing models by analysis of seismic reflection profiles across the boundary between Sundaland and the southern rifted margin, known as the Dangerous Grounds. We show that the southern boundary of the Dangerous Grounds is a subduction zone that jammed in the middle Miocene. To the west the Dangerous Grounds are bounded by a strike-slip zone, also active until similar to 16 Ma, that becomes diffuse south of the now inactive South China Sea seafloor spreading center. We place the western edge of the Dangerous Grounds just to the east of the Natuna Arch (Lupar Line). The West Baram Line is confirmed as originating as a major strike-slip fault within the Dangerous Grounds and is continuous with the Red River Fault Zone. Because the Dangerous Grounds were independent of Sundaland until similar to 6 Ma, its motion cannot have been constrained by motion of this block, making extrusion impossible as a mechanism to rift the South China Sea. SE motion by both the Dangerous Grounds and Sundaland suggests subduction forces were the primary trigger for plate motions. Our reconstruction places a similar to 280 km upper limit on the motion on the Red River Fault and a similar to 1400 km width to the paleo-South China Sea.

AB - The collision of India and Asia has caused large strike-slip faults to form in east Asia, resulting in the "extrusion'' of crustal blocks toward the southeast since the Eocene as a result of the indentation of rigid India into Asia. It has been suggested that the South China Sea opened as a result of relative motion between a rigid Indochina (Sundaland) block and China. Alternative models propose that rifting and seafloor spreading were driven by trench forces to the south. We test these competing models by analysis of seismic reflection profiles across the boundary between Sundaland and the southern rifted margin, known as the Dangerous Grounds. We show that the southern boundary of the Dangerous Grounds is a subduction zone that jammed in the middle Miocene. To the west the Dangerous Grounds are bounded by a strike-slip zone, also active until similar to 16 Ma, that becomes diffuse south of the now inactive South China Sea seafloor spreading center. We place the western edge of the Dangerous Grounds just to the east of the Natuna Arch (Lupar Line). The West Baram Line is confirmed as originating as a major strike-slip fault within the Dangerous Grounds and is continuous with the Red River Fault Zone. Because the Dangerous Grounds were independent of Sundaland until similar to 6 Ma, its motion cannot have been constrained by motion of this block, making extrusion impossible as a mechanism to rift the South China Sea. SE motion by both the Dangerous Grounds and Sundaland suggests subduction forces were the primary trigger for plate motions. Our reconstruction places a similar to 280 km upper limit on the motion on the Red River Fault and a similar to 1400 km width to the paleo-South China Sea.

KW - river shear zone

KW - miocene collisional belt

KW - Indo-China

KW - tectonic evolution

KW - strike-slip

KW - Continental-margin

KW - uplift mechanism

KW - North Borneo

KW - fault system

KW - rift basins

KW - South China Sea

KW - extrusion

KW - transform tectonics

KW - subduction

U2 - 10.1029/2007TC002216

DO - 10.1029/2007TC002216

M3 - Article

VL - 27

JO - Tectonics

JF - Tectonics

SN - 0278-7407

IS - 3

ER -