The Kuroshio, one of the most important western boundary currents of world, controls modern hydrology conditions of the East China Sea (ECS) and carries warm and saline water to high latitudes. Previous researches mentioned that the Kuroshio might change its flow path and volume in the ECS by East Asia monsoon (EAM), Equatorial climate conditions, or global sea level change during glacials. However, shifting or not of the Kuroshio out of the Okinawa Trough during Last Glacial Maximum (LGM) is still in debate. In this study, records derived from multi-proxies, include of Mg/Ca-based paleotemperatures and stable isotopes and foraminiferal census data, of core GH08-2004 was conducted for comparing with records derived from core MD012404 to understand the possible changes of the Kuroshio in the ESC since 26 ka. Our comparing results reveal that the surface hydrological environments have no obvious difference between eastern and western sides of the Ryukyu Arc and imply that the Kuroshio might not shifted outside of the OT during LGM. Otherwise, our reconstructed temperatures, oxygen isotopes and foraminiferal assemblages infer that the flowing volume of the Kuroshio was gradually increased since 19 ka associated with rising sea level. Thus we believe that emerged terrain caused by shallow sea level may be an important factor controlling the flowing path of the Kuroshio. In this study, differences of paleotemperatures and oxygen isotopes between G. ruber and N. dutertrei, surface and subsurface dweller, were decreased at the Holocene, whereas the delta values of carbon isotopes were larger meanwhile. This descrapncy implies that the East Asian winter and summer monsoons were enhanced synchronously.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0216112-080737 |
| Date | 16 February 2012 |
| Creators | Liu, Chin-Hsing |
| Contributors | Min-Te Chen, Yuan-Pin Chang, Chuan-Chou Shen |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0216112-080737 |
| Rights | unrestricted, Copyright information available at source archive |
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