Erosional response of South China to arc rifting and monsoonal strengthening recorded in the South China Sea

Peter Dominic Clift, J. I. Lee, J. Blusztajn, M. K. Clark

Research output: Contribution to journalArticle

139 Citations (Scopus)

Abstract

Ocean Drilling Program sampling of the distal passive margin of South China at Sites 1147 and 1148 has yielded clay-rich hemipelagic sediments dating to 32 Ma (Oligocene), just prior to the onset of seafloor spreading in the South China Sea. The location of the drill sites offshore the Pearl River suggests that this river, or its predecessor, may have been the source of the sediment in the basin, which accounts for only similar to1.8% of the total Neogene sediment in the Asian marginal seas. A mean erosion depth of similar to1 km over the current Pearl River drainage basin is sufficient to account for the sediment volume on the margin. Two-dimensional backstripping of across-margin seismic profiles shows that sedimentation rates peaked during the middle Miocene (11-16 Ma) and the Pleistocene (since 1.8 Ma). Nd isotopic analysis of clays yielded epsilon(Nd) values of -7.7 to -11.0, consistent with the South China Block being the major source of sediment. More positive epsilon(Nd) values during and shortly after rifting compared to later sedimentation reflect preferential erosion at that time of more juvenile continental arc rocks exposed along the margin. As the drainage basin developed and erosion shifted from within the rift to the continental interior epsilon(Nd) values became more negative. A rapid change in the clay mineralogy from smectite-dominated to illite-dominated at similar to15.5 Ma, synchronous with middle Miocene rapid sedimentation, mostly reflects a change to a wetter, more erosive climate. Evidence that the elevation of the Tibetan Plateau and erosion in the western Himalaya both peaked close to this time supports the suggestion that the Asian monsoon became much more intense at that time, much earlier than the 8.5 Ma age commonly accepted. (C) 2002 Elsevier Science B.V. All rights reserved.

Original languageEnglish
Pages (from-to)207-226
Number of pages19
JournalMarine Geology
Volume184
Issue number3-4
DOIs
Publication statusPublished - 2002

Keywords

  • South China Sea
  • provenance
  • Nd isotopes
  • clay
  • erosion
  • monsoon
  • INDIA-ASIA COLLISION
  • TIBETAN PLATEAU
  • NORTH PACIFIC
  • ISOTOPIC VARIATIONS
  • RIVER SYSTEMS
  • HONG-KONG
  • MYR AGO
  • SM-ND
  • HISTORY
  • CONSTRAINTS

Cite this

Erosional response of South China to arc rifting and monsoonal strengthening recorded in the South China Sea. / Clift, Peter Dominic; Lee, J. I.; Blusztajn, J.; Clark, M. K.

In: Marine Geology, Vol. 184, No. 3-4, 2002, p. 207-226.

Research output: Contribution to journalArticle

Clift, Peter Dominic ; Lee, J. I. ; Blusztajn, J. ; Clark, M. K. / Erosional response of South China to arc rifting and monsoonal strengthening recorded in the South China Sea. In: Marine Geology. 2002 ; Vol. 184, No. 3-4. pp. 207-226.
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abstract = "Ocean Drilling Program sampling of the distal passive margin of South China at Sites 1147 and 1148 has yielded clay-rich hemipelagic sediments dating to 32 Ma (Oligocene), just prior to the onset of seafloor spreading in the South China Sea. The location of the drill sites offshore the Pearl River suggests that this river, or its predecessor, may have been the source of the sediment in the basin, which accounts for only similar to1.8{\%} of the total Neogene sediment in the Asian marginal seas. A mean erosion depth of similar to1 km over the current Pearl River drainage basin is sufficient to account for the sediment volume on the margin. Two-dimensional backstripping of across-margin seismic profiles shows that sedimentation rates peaked during the middle Miocene (11-16 Ma) and the Pleistocene (since 1.8 Ma). Nd isotopic analysis of clays yielded epsilon(Nd) values of -7.7 to -11.0, consistent with the South China Block being the major source of sediment. More positive epsilon(Nd) values during and shortly after rifting compared to later sedimentation reflect preferential erosion at that time of more juvenile continental arc rocks exposed along the margin. As the drainage basin developed and erosion shifted from within the rift to the continental interior epsilon(Nd) values became more negative. A rapid change in the clay mineralogy from smectite-dominated to illite-dominated at similar to15.5 Ma, synchronous with middle Miocene rapid sedimentation, mostly reflects a change to a wetter, more erosive climate. Evidence that the elevation of the Tibetan Plateau and erosion in the western Himalaya both peaked close to this time supports the suggestion that the Asian monsoon became much more intense at that time, much earlier than the 8.5 Ma age commonly accepted. (C) 2002 Elsevier Science B.V. All rights reserved.",
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T1 - Erosional response of South China to arc rifting and monsoonal strengthening recorded in the South China Sea

AU - Clift, Peter Dominic

AU - Lee, J. I.

AU - Blusztajn, J.

AU - Clark, M. K.

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N2 - Ocean Drilling Program sampling of the distal passive margin of South China at Sites 1147 and 1148 has yielded clay-rich hemipelagic sediments dating to 32 Ma (Oligocene), just prior to the onset of seafloor spreading in the South China Sea. The location of the drill sites offshore the Pearl River suggests that this river, or its predecessor, may have been the source of the sediment in the basin, which accounts for only similar to1.8% of the total Neogene sediment in the Asian marginal seas. A mean erosion depth of similar to1 km over the current Pearl River drainage basin is sufficient to account for the sediment volume on the margin. Two-dimensional backstripping of across-margin seismic profiles shows that sedimentation rates peaked during the middle Miocene (11-16 Ma) and the Pleistocene (since 1.8 Ma). Nd isotopic analysis of clays yielded epsilon(Nd) values of -7.7 to -11.0, consistent with the South China Block being the major source of sediment. More positive epsilon(Nd) values during and shortly after rifting compared to later sedimentation reflect preferential erosion at that time of more juvenile continental arc rocks exposed along the margin. As the drainage basin developed and erosion shifted from within the rift to the continental interior epsilon(Nd) values became more negative. A rapid change in the clay mineralogy from smectite-dominated to illite-dominated at similar to15.5 Ma, synchronous with middle Miocene rapid sedimentation, mostly reflects a change to a wetter, more erosive climate. Evidence that the elevation of the Tibetan Plateau and erosion in the western Himalaya both peaked close to this time supports the suggestion that the Asian monsoon became much more intense at that time, much earlier than the 8.5 Ma age commonly accepted. (C) 2002 Elsevier Science B.V. All rights reserved.

AB - Ocean Drilling Program sampling of the distal passive margin of South China at Sites 1147 and 1148 has yielded clay-rich hemipelagic sediments dating to 32 Ma (Oligocene), just prior to the onset of seafloor spreading in the South China Sea. The location of the drill sites offshore the Pearl River suggests that this river, or its predecessor, may have been the source of the sediment in the basin, which accounts for only similar to1.8% of the total Neogene sediment in the Asian marginal seas. A mean erosion depth of similar to1 km over the current Pearl River drainage basin is sufficient to account for the sediment volume on the margin. Two-dimensional backstripping of across-margin seismic profiles shows that sedimentation rates peaked during the middle Miocene (11-16 Ma) and the Pleistocene (since 1.8 Ma). Nd isotopic analysis of clays yielded epsilon(Nd) values of -7.7 to -11.0, consistent with the South China Block being the major source of sediment. More positive epsilon(Nd) values during and shortly after rifting compared to later sedimentation reflect preferential erosion at that time of more juvenile continental arc rocks exposed along the margin. As the drainage basin developed and erosion shifted from within the rift to the continental interior epsilon(Nd) values became more negative. A rapid change in the clay mineralogy from smectite-dominated to illite-dominated at similar to15.5 Ma, synchronous with middle Miocene rapid sedimentation, mostly reflects a change to a wetter, more erosive climate. Evidence that the elevation of the Tibetan Plateau and erosion in the western Himalaya both peaked close to this time supports the suggestion that the Asian monsoon became much more intense at that time, much earlier than the 8.5 Ma age commonly accepted. (C) 2002 Elsevier Science B.V. All rights reserved.

KW - South China Sea

KW - provenance

KW - Nd isotopes

KW - clay

KW - erosion

KW - monsoon

KW - INDIA-ASIA COLLISION

KW - TIBETAN PLATEAU

KW - NORTH PACIFIC

KW - ISOTOPIC VARIATIONS

KW - RIVER SYSTEMS

KW - HONG-KONG

KW - MYR AGO

KW - SM-ND

KW - HISTORY

KW - CONSTRAINTS

U2 - 10.1016/S0025-3227(01)00301-2

DO - 10.1016/S0025-3227(01)00301-2

M3 - Article

VL - 184

SP - 207

EP - 226

JO - Marine Geology

JF - Marine Geology

SN - 0025-3227

IS - 3-4

ER -