Dry climate near the Western Pacific Warm Pool: Pleistocene caliches of the Nansha Islands, South China Sea

Shou Yeh Gong, Horng Sheng Mii, Kuo Yen Wei, Chorng Sherng Horng, Chen Feng You, Fu Wen Huang, Wen Rong Chi, Tzen Fu Yui, Pei Keng Torng, Shieu Tsann Huang, Shih Wei Wang, Jong Chang Wu, Kenn Ming Yang

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The Nansha (Spratly) Islands are located in the middle of the South China Sea (at about 10°N) near the northwestern margin of the Western Pacific Warm Pool (WPWP). A borehole was drilled at an atoll at Nansha, and cores were taken. The upper 165.4 m of the borehole consists entirely of limestone of reef facies and lagoon facies, which had been influenced by extensive meteoric diagenesis. Petrographic and geochemical studies have identified at least four subaerial exposure surfaces (SES) in the Pleistocene carbonate sequence. These SES are thought to have resulted from global sea-level changes and characterized by caliche formation. When developed in limestone, caliches typically form in areas where annual precipitation ranges from 500 mm up to about 1200 mm, compared with 1800-2200 mm of annual rainfall of the present-day Nansha Islands. The Nansha caliche therefore indicates the existence of several dry climate episodes during Pleistocene sea-level lowstands. Lower rainfall and higher evaporation during such dry conditions may explain the higher sea-surface salinities reported elsewhere in the South China Sea. The Nansha caliche may also indicate reduced extent of the WPWP and southerly shift of the Intertropical Convergence Zone during major sea-level lowstands.

Original languageEnglish
Pages (from-to)205-213
Number of pages9
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume226
Issue number3-4
DOIs
Publication statusPublished - 2005 Oct 14

Keywords

  • Caliche
  • Nansha Islands
  • Palaeoclimate
  • Sea-level changes
  • South China Sea

ASJC Scopus subject areas

  • Oceanography
  • Ecology, Evolution, Behavior and Systematics
  • Earth-Surface Processes
  • Palaeontology

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    Gong, S. Y., Mii, H. S., Wei, K. Y., Horng, C. S., You, C. F., Huang, F. W., Chi, W. R., Yui, T. F., Torng, P. K., Huang, S. T., Wang, S. W., Wu, J. C., & Yang, K. M. (2005). Dry climate near the Western Pacific Warm Pool: Pleistocene caliches of the Nansha Islands, South China Sea. Palaeogeography, Palaeoclimatology, Palaeoecology, 226(3-4), 205-213. https://doi.org/10.1016/j.palaeo.2005.05.012