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

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.