Deep-water circulation at low latitudes in the western North Pacific

Assimilation of Radiocarbon and Chlorofluorocarbon Data to Constrain Deep and Bottom Water Transports in the World Ocean

“…8b) is consistent with previous work (Fukasawa et al 2004;Hogg 2001;Kawabe et al 2003;Mantyla and Reid 1995;van Aken et al 2004;Warren and Johnson 2002), and the deep water flow directions in the central and eastern Pacific as well as in the Indian Ocean (Fig. 8a) agree with the spreading directions of deep water 3 He plumes originating from hydrothermal vents (Lupton 1998;Srinivasan et al 2004).…”

Helium isotopes of seawater in the Philippine Sea and the western North Pacific

“…Then, it may flow eastward out of the Philippine Sea through the gap between the Izu and the Ogasawara ridges or through that between the Ogasawara and the Mariana ridges. Although these flows inferred from the δ 3 He distribution are roughly similar to those that have been estimated from physical water properties such as temperature, salinity, and dissolved oxygen concentration (e.g., Fujio et al, 1992;Reid, 1997;Kawabe et al, 2003), the δ 3 He distribution could reveal that deep-water circulation seems to be different at each depth (2000, 2500, 3000 m) that have not been published before. Whereas deep current at 3000 m depth seems to flow northward along the Izu-Ogasawara Ridge, it does not occur at 2000-2500 m depth.…”

“…Isopycnal maps constructed by Reid (1997) suggest that deep seawater from the South Pacific enters the Philippine Sea along its western boundary. Kawabe et al (2003) reported that a deep western boundary current at 2000-3000 m depth may flow from the Melanesian Basin, change direction and flow around the upper Solomon Rise to the southwestern, and proceed into the East Caroline Basin, as suggested by hydrographic data observed with a conductivity-temperature-depth profiler equipped with IOR, Izu-Ogasawara Ridge; MR, Mariana Ridge; YR, Yap Ridge; SR, Solomon Rise; CS, Caroline Seamounts; SB, Shikoku Basin; PB, Philippine Basin; WMB, West Mariana Basin; EMB, East Mariana Basin; WCB, West Caroline Basin; ECB, East Caroline Basin; MB, Melanesian Basin; NPB, Northwest Pacific Basin. (b) Sampling sites of seawaters in the western North Pacific and the western Philippine Sea .…”

Late Cenozoic history of deep water circulation in the western North Pacific: Evidence from Nd isotopes of ferromanganese crusts

“…A modern nearby seawater profile, TPS 24 271-1, also reveals that typical southern component water signal ( Nd values of 4.5 to 5.0) occurs only at water depths below ~4000 m [14]. As mentioned above, modern UCDW which ventilates the western North pacific at about 3000-3500 m follows the route east of the Solomon Rise (Figure 1), but a large fraction of it does not directly flow into the east Mariana basin [2,5]. Instead, the major route turns westward near Papua New Guinea arc and then flows into the Philippine Sea.…”

“…According to the water properties studies [1][2][3][4][5], the modern oxygen-rich Lower Circumpolar Deep Water (LCDW >3500 m) bifurcates at the equatorial central Pacific basin. The western branch of it flows northwest toward Mariana arc below water depth of ~4000 m and the eastern branch flows across the Wake Passage and then into the central North Pacific.…”