Persistent sea surface temperature and declined sea surface salinity in the northwestern tropical Pacific over the past 7500years

Li Lo, Yung Hsiang Lai, Kuo Yen Wei, Yu Shih Lin, Horng Sheng Mii, Chuan Chou Shen

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

To understand Holocene climate evolutions in low-latitude region of the western Pacific, paired δ18O and Mg/Ca records of planktonic foraminifer Globigerinoides ruber (250-300μm, sensu stricto, s.s.) from a marine core ORI715-21 (121.5°E, 22.7°N, water depth 760m) underneath the Kuroshio Current (KC) off eastern Taiwan were analyzed. Over the past 7500years, the geochemical proxy-inferred sea surface temperature (SST) hovered around 27-28°C and seawater δ18O (δ18OW) slowly decreased 0.2-0.4‰ for two KC sites at 22.7° and 25.3°N. Comparison with a published high-SST and high-salinity equatorial tropical Pacific record, MD98-2181 located at the Mindanao Current (MC) at 6.3°N, reveals an anomalous time interval at 3.5-1.5kyr ago (before 1950 AD). SST gradient between the MC site and two KC site decrease from 1.5-2.0°C to only 0-1°C, and δ18OW from 0.1-0.3‰ to 0‰ for this 2-kyr time window. The high SST and low gradient could result from a northward shift of the North Equatorial Current, which implies a weakened KC. The long-term descending δ18OW and increasing precipitation in the entire low-latitude western Pacific and the gradually decreasing East Asian summer monsoonal rainfall during middle-to-late Holocene is likely caused by different land and ocean responses to solar insolation and/or enhanced moisture transportation from the Atlantic to Pacific associated with the southward movement of ITCZ.

Original languageEnglish
Pages (from-to)234-239
Number of pages6
JournalJournal of Asian Earth Sciences
Volume66
DOIs
Publication statusPublished - 2013 Apr 8

Keywords

  • Holocene
  • Kuroshio Current
  • Mindanao Current
  • North Equatorial Current
  • Northwestern Pacific
  • Sea surface temperature
  • Seawater δO

ASJC Scopus subject areas

  • Geology
  • Earth-Surface Processes

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