Early Holocene mud-ridge formation in the Yangtze offshore, China: A tidal-controlled estuarine pattern and sea-level implications

Zhongyuan Chen, Yoshiki Saito, Kazuaki Hori, Yiwen Zhao, Akihisa Kitamura

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)

Abstract

The purpose of the present study is to examine the topographic evolution and sedimentary characteristics of a mud-ridge system in the Yangtze offshore region. As revealed by seismic profiling, 2-3-km-wide, 5-8-km-long, up-to-15-m-thick mud ridges, situated 5-10 km apart, extend here in a southeasterly direction, approximately parallel to the direction of the ebb and flood flow of the modern tide. Directly resting upon the latest Pleistocene terrestrial sediments, some mud ridges are exposed on the present seafloor, while others are buried by landward-thickening Holocene deltaic sediments. An 11-m-long vibrocore recovered from one mud ridge reveals homogenous and mottled silty clay and clayey silt, rich in foraminifera, suggesting an estuarine environment of deposition. Chronostratigraphic correlation in association with acoustic facies indicate that the mud ridge was formed primarily during ∼ 10-7 ka, corresponding to a period of global decelerating rise in sea level. This mud ridge is underlain by thick, late Pleistocene fluvial to coastal fine to medium sands with an unconformity surface on top, and it is overlain by modern deltaic sediments with an erosional surface in between. We propose that the mud ridges were deposited under tidal-controlled estuarine conditions during the early Holocene deceleration of the rise in sea level. The Holocene transgression in the study area was nearly coeval with the mud ridge deposition, and the deltaic sedimentation occurred after the mud ridges formed. The ridges were subsequently reworked, largely by strong tidal currents.

Original languageEnglish
Pages (from-to)245-257
Number of pages13
JournalMarine Geology
Volume198
Issue number3-4
DOIs
Publication statusPublished - 2003 Jul 15
Externally publishedYes

Keywords

  • Early Holocene
  • Estuarine sedimentation
  • Mud ridges
  • Sea-level rise
  • Yangtze offshore

ASJC Scopus subject areas

  • Oceanography
  • Geology
  • Geochemistry and Petrology

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